spec: Move application configuration items

173 files changed, 4459 insertions, 0 deletions

diff --git a/spec/if/acfg/appl-disable-filesystem.yml b/spec/if/acfg/appl-disable-filesystem.yml
new file mode 100644
index 00000000..f9ec07f3
--- /dev/null
+++ b/spec/if/acfg/appl-disable-filesystem.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then a base filesystem and the
+  configured filesystems are initialized during system initialization.
+description: |
+  In case this configuration option is defined, then **no** base filesystem is
+  initialized during system initialization and **no** filesystems are
+  configured.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
+notes: |
+  Filesystems shall be initialized to support file descriptor based device
+  drivers and basic input/output functions such as :c:func:`printf`.
+  Filesystems can be disabled to reduce the memory footprint of an application.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-does-not-need-clock-driver.yml b/spec/if/acfg/appl-does-not-need-clock-driver.yml
new file mode 100644
index 00000000..67a89324
--- /dev/null
+++ b/spec/if/acfg/appl-does-not-need-clock-driver.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then a Clock Driver may be
+  initialized during system initialization.
+description: |
+  In case this configuration option is defined, then **no** Clock Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER
+notes: |
+  This configuration parameter is intended to prevent the common user error
+  of using the Hello World example as the baseline for an application and
+  leaving out a clock tick source.
+
+  The application shall define exactly one of the following configuration options
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`,
+
+  * `CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`,
+
+  otherwise a compile time error in the configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-extra-drivers.yml b/spec/if/acfg/appl-extra-drivers.yml
new file mode 100644
index 00000000..e2d053f7
--- /dev/null
+++ b/spec/if/acfg/appl-extra-drivers.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of initializers for
+    structures of type :c:type:`rtems_driver_address_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is the empty list.
+description: |
+  The value of this configuration option is used to initialize the Device
+  Driver Table.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_EXTRA_DRIVERS
+notes: |
+  The value of this configuration option is placed after the entries of other
+  device driver configuration options.
+
+  See :ref:`CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS` for an alternative
+  placement of application device driver initializers.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-ata-driver.yml b/spec/if/acfg/appl-needs-ata-driver.yml
new file mode 100644
index 00000000..a7a3344c
--- /dev/null
+++ b/spec/if/acfg/appl-needs-ata-driver.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the ATA Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_ATA_DRIVER
+notes: |
+  Most BSPs do not include support for an ATA Driver.
+
+  If this option is defined and the BSP does not have this device driver, then
+  the user will get a link time error for an undefined symbol.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-clock-driver.yml b/spec/if/acfg/appl-needs-clock-driver.yml
new file mode 100644
index 00000000..c3993bcf
--- /dev/null
+++ b/spec/if/acfg/appl-needs-clock-driver.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Clock Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+notes: |
+  The Clock Driver is responsible for providing a regular interrupt
+  which invokes a clock tick directive.
+
+  The application shall define exactly one of the following configuration options
+
+  * `CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`,
+
+  * :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`,
+
+  otherwise a compile time error in the configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-console-driver.yml b/spec/if/acfg/appl-needs-console-driver.yml
new file mode 100644
index 00000000..6c0e8f06
--- /dev/null
+++ b/spec/if/acfg/appl-needs-console-driver.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Console Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+notes: |
+  The Console Driver is responsible for providing the :file:`/dev/console`
+  device file.  This device is used to initialize the standard input, output,
+  and error file descriptors.
+
+  BSPs should be constructed in a manner that allows :c:func:`printk` to work
+  properly without the need for the Console Driver to be configured.
+
+  The
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`,
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER`
+
+  configuration options are mutually exclusive.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-framebuffer-driver.yml b/spec/if/acfg/appl-needs-framebuffer-driver.yml
new file mode 100644
index 00000000..654b5a2d
--- /dev/null
+++ b/spec/if/acfg/appl-needs-framebuffer-driver.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Frame Buffer Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_FRAME_BUFFER_DRIVER
+notes: |
+  Most BSPs do not include support for a Frame Buffer Driver. This is
+  because many boards do not include the required hardware.
+
+  If this option is defined and the BSP does not have this device driver, then
+  the user will get a link time error for an undefined symbol.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-ide-driver.yml b/spec/if/acfg/appl-needs-ide-driver.yml
new file mode 100644
index 00000000..17969fea
--- /dev/null
+++ b/spec/if/acfg/appl-needs-ide-driver.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the IDE Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_IDE_DRIVER
+notes: |
+  Most BSPs do not include support for an IDE Driver.
+
+  If this option is defined and the BSP does not have this device driver, then
+  the user will get a link time error for an undefined symbol.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-libblock.yml b/spec/if/acfg/appl-needs-libblock.yml
new file mode 100644
index 00000000..dfbaa333
--- /dev/null
+++ b/spec/if/acfg/appl-needs-libblock.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Block Device Cache is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_APPLICATION_NEEDS_LIBBLOCK
+notes: |
+  Each option of the Block Device Cache (bdbuf) configuration can be explicitly
+  set by the user with the configuration options below.  The Block Device Cache
+  is used for example by the RFS and DOSFS filesystems.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-null-driver.yml b/spec/if/acfg/appl-needs-null-driver.yml
new file mode 100644
index 00000000..b7f5722d
--- /dev/null
+++ b/spec/if/acfg/appl-needs-null-driver.yml
@@ -0,0 +1,19 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the :file:`/dev/null`
+  Driver is initialized during system initialization.
+enabled-by: true
+index-entries:
+- /dev/null
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_NULL_DRIVER
+notes: |
+  This device driver is supported by all BSPs.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-rtc-driver.yml b/spec/if/acfg/appl-needs-rtc-driver.yml
new file mode 100644
index 00000000..bb0bfd3e
--- /dev/null
+++ b/spec/if/acfg/appl-needs-rtc-driver.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Real-Time Clock Driver
+  is initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_RTC_DRIVER
+notes: |
+  Most BSPs do not include support for a real-time clock (RTC). This is because
+  many boards do not include the required hardware.
+
+  If this is defined and the BSP does not have this device driver, then the
+  user will get a link time error for an undefined symbol.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-simple-console-driver.yml b/spec/if/acfg/appl-needs-simple-console-driver.yml
new file mode 100644
index 00000000..37af5591
--- /dev/null
+++ b/spec/if/acfg/appl-needs-simple-console-driver.yml
@@ -0,0 +1,37 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Simple Console Driver
+  is initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER
+notes: |
+  This device driver is responsible for providing the :file:`/dev/console`
+  device file.  This device is used to initialize the standard input, output,
+  and error file descriptors.
+
+  This device driver reads via :c:func:`getchark`.
+
+  This device driver writes via :c:func:`rtems_putc`.
+
+  The Termios framework is not used.  There is no support to change device
+  settings, e.g. baud, stop bits, parity, etc.
+
+  The
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`,
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER`
+
+  configuration options are mutually exclusive.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-simple-task-console-driver.yml b/spec/if/acfg/appl-needs-simple-task-console-driver.yml
new file mode 100644
index 00000000..15ad5efa
--- /dev/null
+++ b/spec/if/acfg/appl-needs-simple-task-console-driver.yml
@@ -0,0 +1,46 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Simple Task Console
+  Driver is initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER
+notes: |
+  This device driver is responsible for providing the :file:`/dev/console`
+  device file.  This device is used to initialize the standard input, output,
+  and error file descriptors.
+
+  This device driver reads via :c:func:`getchark`.
+
+  This device driver writes into a write buffer.  The count of characters
+  written into the write buffer is returned.  It might be less than the
+  requested count, in case the write buffer is full.  The write is
+  non-blocking and may be called from interrupt context.  A dedicated task
+  reads from the write buffer and outputs the characters via
+  :c:func:`rtems_putc`.  This task runs with the least important priority.
+  The write buffer size is 2047 characters and it is not configurable.
+
+  Use ``fsync(STDOUT_FILENO)`` or ``fdatasync(STDOUT_FILENO)`` to drain the
+  write buffer.
+
+  The Termios framework is not used.  There is no support to change device
+  settings, e.g.  baud, stop bits, parity, etc.
+
+  The
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER`,
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER`, and
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_SIMPLE_TASK_CONSOLE_DRIVER`
+
+  configuration options are mutually exclusive.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-stub-driver.yml b/spec/if/acfg/appl-needs-stub-driver.yml
new file mode 100644
index 00000000..36654cfe
--- /dev/null
+++ b/spec/if/acfg/appl-needs-stub-driver.yml
@@ -0,0 +1,19 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Stub Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER
+notes: |
+  This device driver simply provides entry points that return successful and
+  is primarily a test fixture. It is supported by all BSPs.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-timer-driver.yml b/spec/if/acfg/appl-needs-timer-driver.yml
new file mode 100644
index 00000000..93ae9923
--- /dev/null
+++ b/spec/if/acfg/appl-needs-timer-driver.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Benchmark Timer Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER
+notes: |
+  The Benchmark Timer Driver is intended for the benchmark tests of the RTEMS
+  Testsuite.  Applications should not use this driver.
+
+  The application shall define exactly one of the following configuration options
+
+  * :ref:`CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER`,
+
+  * :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`, or
+
+  * `CONFIGURE_APPLICATION_NEEDS_TIMER_DRIVER`,
+
+  otherwise a compile time error will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-watchdog-driver.yml b/spec/if/acfg/appl-needs-watchdog-driver.yml
new file mode 100644
index 00000000..63053c98
--- /dev/null
+++ b/spec/if/acfg/appl-needs-watchdog-driver.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the Watchdog Driver is
+  initialized during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_WATCHDOG_DRIVER
+notes: |
+  Most BSPs do not include support for a watchdog device driver. This is
+  because many boards do not include the required hardware.
+
+  If this is defined and the BSP does not have this device driver, then the
+  user will get a link time error for an undefined symbol.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-needs-zero-driver.yml b/spec/if/acfg/appl-needs-zero-driver.yml
new file mode 100644
index 00000000..d69f3489
--- /dev/null
+++ b/spec/if/acfg/appl-needs-zero-driver.yml
@@ -0,0 +1,19 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the :file:`/dev/zero`
+  Driver is initialized during system initialization.
+enabled-by: true
+index-entries:
+- /dev/zero
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER
+notes: |
+  This device driver is supported by all BSPs.
+text: ''
+type: interface
diff --git a/spec/if/acfg/appl-prerequisite-drivers.yml b/spec/if/acfg/appl-prerequisite-drivers.yml
new file mode 100644
index 00000000..ace0d734
--- /dev/null
+++ b/spec/if/acfg/appl-prerequisite-drivers.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of initializers for
+    structures of type :c:type:`rtems_driver_address_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is the empty list.
+description: |
+  The value of this configuration option is used to initialize the Device
+  Driver Table.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+name: CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS
+notes: |
+  The value of this configuration option is placed after the entries defined by
+  :ref:`CONFIGURE_BSP_PREREQUISITE_DRIVERS` and before all other device driver
+  configuration options.
+
+  See :ref:`CONFIGURE_APPLICATION_EXTRA_DRIVERS` for an alternative placement
+  of application device driver initializers.
+text: ''
+type: interface
diff --git a/spec/if/acfg/ata-driver-task-priority.yml b/spec/if/acfg/ata-driver-task-priority.yml
new file mode 100644
index 00000000..30cfb6fd
--- /dev/null
+++ b/spec/if/acfg/ata-driver-task-priority.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: 140
+description: |
+  The value of this configuration option defines the ATA task priority.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+- role: constraint
+  uid: constraint-prioclassic
+name: CONFIGURE_ATA_DRIVER_TASK_PRIORITY
+notes: |
+  This configuration option is only evaluated if the configuration option
+  :ref:`CONFIGURE_APPLICATION_NEEDS_ATA_DRIVER` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-buffer-max-size.yml b/spec/if/acfg/bdbuf-buffer-max-size.yml
new file mode 100644
index 00000000..08ca7ff7
--- /dev/null
+++ b/spec/if/acfg/bdbuf-buffer-max-size.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+  texts:
+  - It shall be an integral multiple of :ref:`CONFIGURE_BDBUF_BUFFER_MIN_SIZE`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 4096
+description: |
+  The value of this configuration option defines the maximum size of a buffer
+  in bytes.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_BDBUF_BUFFER_MAX_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-buffer-min-size.yml b/spec/if/acfg/bdbuf-buffer-min-size.yml
new file mode 100644
index 00000000..2839b596
--- /dev/null
+++ b/spec/if/acfg/bdbuf-buffer-min-size.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 512
+description: |
+  The value of this configuration option defines the minimum size of a buffer
+  in bytes.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_BDBUF_BUFFER_MIN_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-cache-memory-size.yml b/spec/if/acfg/bdbuf-cache-memory-size.yml
new file mode 100644
index 00000000..4e02351c
--- /dev/null
+++ b/spec/if/acfg/bdbuf-cache-memory-size.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 32768
+description: |
+  The value of this configuration option defines the size of the cache memory
+  in bytes.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_BDBUF_CACHE_MEMORY_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-max-read-ahead-blocks.yml b/spec/if/acfg/bdbuf-max-read-ahead-blocks.yml
new file mode 100644
index 00000000..9d9134d0
--- /dev/null
+++ b/spec/if/acfg/bdbuf-max-read-ahead-blocks.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum blocks per
+  read-ahead request.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS
+notes: |
+  A value of 0 disables the read-ahead task (default).  The read-ahead task
+  will issue speculative read transfers if a sequential access pattern is
+  detected.  This can improve the performance on some systems.
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-max-write-blocks.yml b/spec/if/acfg/bdbuf-max-write-blocks.yml
new file mode 100644
index 00000000..2fe9018c
--- /dev/null
+++ b/spec/if/acfg/bdbuf-max-write-blocks.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 16
+description: |
+  The value of this configuration option defines the maximum blocks per write
+  request.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_BDBUF_MAX_WRITE_BLOCKS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-read-ahead-task-priority.yml b/spec/if/acfg/bdbuf-read-ahead-task-priority.yml
new file mode 100644
index 00000000..34ed8993
--- /dev/null
+++ b/spec/if/acfg/bdbuf-read-ahead-task-priority.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 15
+description: |
+  The value of this configuration option defines the read-ahead task priority.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+- role: constraint
+  uid: constraint-prioclassic
+name: CONFIGURE_BDBUF_READ_AHEAD_TASK_PRIORITY
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-swapout-block-hold.yml b/spec/if/acfg/bdbuf-swapout-block-hold.yml
new file mode 100644
index 00000000..b4a54042
--- /dev/null
+++ b/spec/if/acfg/bdbuf-swapout-block-hold.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 1000
+description: |
+  The value of this configuration option defines the swapout task maximum block
+  hold time in milliseconds.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_SWAPOUT_BLOCK_HOLD
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-swapout-swap-period.yml b/spec/if/acfg/bdbuf-swapout-swap-period.yml
new file mode 100644
index 00000000..ee4c8dd5
--- /dev/null
+++ b/spec/if/acfg/bdbuf-swapout-swap-period.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 250
+description: |
+  The value of this configuration option defines the swapout task swap period
+  in milliseconds.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_SWAPOUT_SWAP_PERIOD
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-swapout-task-priority.yml b/spec/if/acfg/bdbuf-swapout-task-priority.yml
new file mode 100644
index 00000000..82a5dd09
--- /dev/null
+++ b/spec/if/acfg/bdbuf-swapout-task-priority.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 15
+description: |
+  The value of this configuration option defines the swapout task priority.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+- role: constraint
+  uid: constraint-prioclassic
+name: CONFIGURE_SWAPOUT_TASK_PRIORITY
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-swapout-worker-taskp-riority.yml b/spec/if/acfg/bdbuf-swapout-worker-taskp-riority.yml
new file mode 100644
index 00000000..fa942af0
--- /dev/null
+++ b/spec/if/acfg/bdbuf-swapout-worker-taskp-riority.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 15
+description: |
+  The value of this configuration option defines the swapout worker task
+  priority.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+- role: constraint
+  uid: constraint-prioclassic
+name: CONFIGURE_SWAPOUT_WORKER_TASK_PRIORITY
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-swapout-worker-tasks.yml b/spec/if/acfg/bdbuf-swapout-worker-tasks.yml
new file mode 100644
index 00000000..6e0d7e1e
--- /dev/null
+++ b/spec/if/acfg/bdbuf-swapout-worker-tasks.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the swapout worker task count.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+name: CONFIGURE_SWAPOUT_WORKER_TASKS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bdbuf-task-stack-size.yml b/spec/if/acfg/bdbuf-task-stack-size.yml
new file mode 100644
index 00000000..f17f1f27
--- /dev/null
+++ b/spec/if/acfg/bdbuf-task-stack-size.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``RTEMS_MINIMUM_STACK_SIZE``'
+description: |
+  The value of this configuration option defines the task stack size of the
+  Block Device Cache tasks in bytes.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bdbuf
+- role: constraint
+  uid: constraint-stackspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_BDBUF_TASK_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bsp-idle-task-body.yml b/spec/if/acfg/bsp-idle-task-body.yml
new file mode 100644
index 00000000..3fa18bec
--- /dev/null
+++ b/spec/if/acfg/bsp-idle-task-body.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void *( *idle_body )( uintptr_t )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is BSP-specific.
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then the value of this configuration option defines the default value of
+  :ref:`CONFIGURE_IDLE_TASK_BODY`.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+name: BSP_IDLE_TASK_BODY
+notes: |
+  As it has knowledge of the specific CPU model, system controller logic, and
+  peripheral buses, a BSP-specific IDLE task may be capable of turning
+  components off to save power during extended periods of no task activity.
+text: ''
+type: interface
diff --git a/spec/if/acfg/bsp-idle-task-stack-size.yml b/spec/if/acfg/bsp-idle-task-stack-size.yml
new file mode 100644
index 00000000..5a982222
--- /dev/null
+++ b/spec/if/acfg/bsp-idle-task-stack-size.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is BSP-specific.
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then the value of this configuration option defines the default value of
+  :ref:`CONFIGURE_IDLE_TASK_SIZE`.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+- role: constraint
+  uid: constraint-idlestackarea
+- role: constraint
+  uid: constraint-bspappmin
+name: BSP_IDLE_TASK_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bsp-initial-extension.yml b/spec/if/acfg/bsp-initial-extension.yml
new file mode 100644
index 00000000..a24078b8
--- /dev/null
+++ b/spec/if/acfg/bsp-initial-extension.yml
@@ -0,0 +1,32 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of initializers for
+    structures of type :c:type:`rtems_extensions_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is BSP-specific.
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then the value of this configuration option is used to initialize the table
+  of initial user extensions.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+name: BSP_INITIAL_EXTENSION
+notes: |
+  The value of this configuration option is placed after the entries of all
+  other initial user extensions.
+text: ''
+type: interface
diff --git a/spec/if/acfg/bsp-interrupt-stack-size.yml b/spec/if/acfg/bsp-interrupt-stack-size.yml
new file mode 100644
index 00000000..c28fb731
--- /dev/null
+++ b/spec/if/acfg/bsp-interrupt-stack-size.yml
@@ -0,0 +1,32 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is BSP-specific.
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then the value of this configuration option defines the default value of
+  :ref:`CONFIGURE_INTERRUPT_STACK_SIZE`.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+- role: constraint
+  uid: constraint-isrstackalign
+- role: constraint
+  uid: constraint-isrstackarea
+- role: constraint
+  uid: constraint-bspappmin
+name: BSP_INTERRUPT_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/bsp-prerequisite-drivers.yml b/spec/if/acfg/bsp-prerequisite-drivers.yml
new file mode 100644
index 00000000..4f1e5ef6
--- /dev/null
+++ b/spec/if/acfg/bsp-prerequisite-drivers.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of initializers for
+    structures of type :c:type:`rtems_extensions_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is BSP-specific.
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then the value of this configuration option is used to initialize the table
+  of initial user extensions.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+name: CONFIGURE_BSP_PREREQUISITE_DRIVERS
+notes: |
+  The value of this configuration option is placed before the entries of all
+  other initial user extensions (including
+  :ref:`CONFIGURE_APPLICATION_PREREQUISITE_DRIVERS`).
+text: ''
+type: interface
diff --git a/spec/if/acfg/cbs-max-servers.yml b/spec/if/acfg/cbs-max-servers.yml
new file mode 100644
index 00000000..63c30a81
--- /dev/null
+++ b/spec/if/acfg/cbs-max-servers.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: :ref:`CONFIGURE_MAXIMUM_TASKS`
+description: |
+  The value of this configuration option defines the maximum number Constant
+  Bandwidth Servers that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_CBS_MAXIMUM_SERVERS
+notes: |
+  This configuration option is only evaluated if the configuration option
+  :ref:`CONFIGURE_SCHEDULER_CBS` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/constraint-bspappmin.yml b/spec/if/acfg/constraint-bspappmin.yml
new file mode 100644
index 00000000..0cebb9b6
--- /dev/null
+++ b/spec/if/acfg/constraint-bspappmin.yml
@@ -0,0 +1,11 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be greater than or equal to a
+  BSP-specific and application-specific minimum value.
+type: constraint
diff --git a/spec/if/acfg/constraint-idlestackarea.yml b/spec/if/acfg/constraint-idlestackarea.yml
new file mode 100644
index 00000000..aaf1f8b3
--- /dev/null
+++ b/spec/if/acfg/constraint-idlestackarea.yml
@@ -0,0 +1,12 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be small enough so that the IDLE
+  task stack area calculation carried out by ``<rtems/confdefs.h>`` does not
+  overflow an integer of type ``size_t``.
+type: constraint
diff --git a/spec/if/acfg/constraint-isrstackalign.yml b/spec/if/acfg/constraint-isrstackalign.yml
new file mode 100644
index 00000000..14189aa7
--- /dev/null
+++ b/spec/if/acfg/constraint-isrstackalign.yml
@@ -0,0 +1,11 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be aligned according to
+  ``CPU_INTERRUPT_STACK_ALIGNMENT``.
+type: constraint
diff --git a/spec/if/acfg/constraint-isrstackarea.yml b/spec/if/acfg/constraint-isrstackarea.yml
new file mode 100644
index 00000000..e096f008
--- /dev/null
+++ b/spec/if/acfg/constraint-isrstackarea.yml
@@ -0,0 +1,12 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be small enough so that the
+  interrupt stack area calculation carried out by ``<rtems/confdefs.h>`` does
+  not overflow an integer of type ``size_t``.
+type: constraint
diff --git a/spec/if/acfg/constraint-memsz.yml b/spec/if/acfg/constraint-memsz.yml
new file mode 100644
index 00000000..b3a2204e
--- /dev/null
+++ b/spec/if/acfg/constraint-memsz.yml
@@ -0,0 +1,12 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be less than or equal to a
+  BSP-specific and application-specific value which depends on the size of the
+  memory available to the application.
+type: constraint
diff --git a/spec/if/acfg/constraint-posix.yml b/spec/if/acfg/constraint-posix.yml
new file mode 100644
index 00000000..fa76c0a3
--- /dev/null
+++ b/spec/if/acfg/constraint-posix.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be zero if the POSIX API is not
+  enabled (e.g. RTEMS was built without the ``--enable-posix`` build
+  configuration option).  Otherwise a compile time error in the configuration
+  file will occur.
+type: constraint
diff --git a/spec/if/acfg/constraint-prioclassic.yml b/spec/if/acfg/constraint-prioclassic.yml
new file mode 100644
index 00000000..dead5852
--- /dev/null
+++ b/spec/if/acfg/constraint-prioclassic.yml
@@ -0,0 +1,11 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be a valid Classic API task
+  priority.  The set of valid task priorities is scheduler-specific.
+type: constraint
diff --git a/spec/if/acfg/constraint-stackspace.yml b/spec/if/acfg/constraint-stackspace.yml
new file mode 100644
index 00000000..4eec247d
--- /dev/null
+++ b/spec/if/acfg/constraint-stackspace.yml
@@ -0,0 +1,12 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be small enough so that the task
+  stack space calculation carried out by ``<rtems/confdefs.h>`` does not
+  overflow an integer of type ``uintptr_t``.
+type: constraint
diff --git a/spec/if/acfg/constraint-unlimited.yml b/spec/if/acfg/constraint-unlimited.yml
new file mode 100644
index 00000000..786fd53d
--- /dev/null
+++ b/spec/if/acfg/constraint-unlimited.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option may be defined through
+  :c:func:`rtems_resource_unlimited` the enable unlimited objects for this
+  object class, if the value passed to :c:func:`rtems_resource_unlimited`
+  satisfies all other constraints of this configuration option.
+type: constraint
diff --git a/spec/if/acfg/constraint-wkspace.yml b/spec/if/acfg/constraint-wkspace.yml
new file mode 100644
index 00000000..0c87371a
--- /dev/null
+++ b/spec/if/acfg/constraint-wkspace.yml
@@ -0,0 +1,12 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+enabled-by: true
+links: []
+rationale: null
+scope: user
+text: |
+  The value of this configuration option shall be small enough so that the
+  RTEMS Workspace size calculation carried out by ``<rtems/confdefs.h>`` does
+  not overflow an integer of type ``uintptr_t``.
+type: constraint
diff --git a/spec/if/acfg/dirty-memory.yml b/spec/if/acfg/dirty-memory.yml
new file mode 100644
index 00000000..59af9ec3
--- /dev/null
+++ b/spec/if/acfg/dirty-memory.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the memory areas used for
+  the RTEMS Workspace and the C Program Heap are dirtied with a ``0xCF`` byte
+  pattern during system initialization.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_DIRTY_MEMORY
+notes: |
+  Dirtying memory can add significantly to system initialization time.  It may
+  assist in finding code that incorrectly assumes the contents of free memory
+  areas is cleared to zero during system initialization.  In case
+  :ref:`CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY` is also defined, then the
+  memory is first dirtied and then zeroed.
+
+  See also :ref:`CONFIGURE_MALLOC_DIRTY`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/disable-bsp-settings.yml b/spec/if/acfg/disable-bsp-settings.yml
new file mode 100644
index 00000000..9ca726de
--- /dev/null
+++ b/spec/if/acfg/disable-bsp-settings.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the following BSP related
+  configuration options are undefined:
+
+  * :ref:`BSP_IDLE_TASK_BODY`
+
+  * :ref:`BSP_IDLE_TASK_STACK_SIZE`
+
+  * :ref:`BSP_INITIAL_EXTENSION`
+
+  * :ref:`BSP_INTERRUPT_STACK_SIZE`
+
+  * :ref:`CONFIGURE_BSP_PREREQUISITE_DRIVERS`
+
+  * :ref:`CONFIGURE_MALLOC_BSP_SUPPORTS_SBRK`
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+name: CONFIGURE_DISABLE_BSP_SETTINGS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/disable-newlib-reentrancy.yml b/spec/if/acfg/disable-newlib-reentrancy.yml
new file mode 100644
index 00000000..b3390e7c
--- /dev/null
+++ b/spec/if/acfg/disable-newlib-reentrancy.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the Newlib reentrancy
+  support per thread is disabled and a global reentrancy structure is used.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_DISABLE_NEWLIB_REENTRANCY
+notes: |
+  You can enable this option to reduce the size of the :term:`TCB`.  Use this
+  option with care, since it can lead to race conditions and undefined system
+  behaviour.  For example, :c:data:`errno` is no longer a thread-local variable
+  if this option is enabled.
+text: ''
+type: interface
diff --git a/spec/if/acfg/executive-ram-size.yml b/spec/if/acfg/executive-ram-size.yml
new file mode 100644
index 00000000..fb7b3038
--- /dev/null
+++ b/spec/if/acfg/executive-ram-size.yml
@@ -0,0 +1,28 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINTPTR_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: |
+  If this configuration option is undefined, then the RTEMS Workspace and task
+  stack space size is calculated by ``<rtems/confdefs.h>`` based on the values
+  configuration options.
+description: |
+  The value of this configuration option defines the RTEMS Workspace size in
+  bytes.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_EXECUTIVE_RAM_SIZE
+notes: |
+  This is an advanced configuration option.  Use it only if you know exactly
+  what you are doing.
+text: ''
+type: interface
diff --git a/spec/if/acfg/extra-task-stacks.yml b/spec/if/acfg/extra-task-stacks.yml
new file mode 100644
index 00000000..c9d16774
--- /dev/null
+++ b/spec/if/acfg/extra-task-stacks.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the number of bytes the
+  applications wishes to add to the task stack requirements calculated by
+  ``<rtems/confdefs.h>``.
+enabled-by: true
+index-entries:
+- memory for task tasks
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-stackspace
+name: CONFIGURE_EXTRA_TASK_STACKS
+notes: |
+  This parameter is very important.  If the application creates tasks with
+  stacks larger then the minimum, then that memory is **not** accounted for by
+  ``<rtems/confdefs.h>``.
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-all.yml b/spec/if/acfg/filesystem-all.yml
new file mode 100644
index 00000000..9e03e126
--- /dev/null
+++ b/spec/if/acfg/filesystem-all.yml
@@ -0,0 +1,31 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the following
+  configuration options will be defined as well
+
+  * :ref:`CONFIGURE_FILESYSTEM_DOSFS`,
+
+  * :ref:`CONFIGURE_FILESYSTEM_FTPFS`,
+
+  * :ref:`CONFIGURE_FILESYSTEM_IMFS`,
+
+  * :ref:`CONFIGURE_FILESYSTEM_JFFS2`,
+
+  * :ref:`CONFIGURE_FILESYSTEM_NFS`,
+
+  * :ref:`CONFIGURE_FILESYSTEM_RFS`, and
+
+  * :ref:`CONFIGURE_FILESYSTEM_TFTPFS`.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_ALL
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-dosfs.yml b/spec/if/acfg/filesystem-dosfs.yml
new file mode 100644
index 00000000..d67b49f6
--- /dev/null
+++ b/spec/if/acfg/filesystem-dosfs.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the DOS (FAT) filesystem
+  is registered, so that instances of this filesystem can be mounted by the
+  application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_DOSFS
+notes: |
+  This filesystem requires a Block Device Cache configuration, see
+  :ref:`CONFIGURE_APPLICATION_NEEDS_LIBBLOCK`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-ftpfs.yml b/spec/if/acfg/filesystem-ftpfs.yml
new file mode 100644
index 00000000..aca6c3f5
--- /dev/null
+++ b/spec/if/acfg/filesystem-ftpfs.yml
@@ -0,0 +1,18 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the FTP filesystem (FTP
+  client) is registered, so that instances of this filesystem
+  can be mounted by the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_FTPFS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-imfs.yml b/spec/if/acfg/filesystem-imfs.yml
new file mode 100644
index 00000000..dfeb3469
--- /dev/null
+++ b/spec/if/acfg/filesystem-imfs.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the In-Memory Filesystem
+  (IMFS) is registered, so that instances of this filesystem can be mounted by
+  the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_IMFS
+notes: |
+  Applications will rarely need this configuration option.  This configuration
+  option is intended for test programs.  You do not need to define this
+  configuration option for the base filesystem (also known as root filesystem).
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-jffs2.yml b/spec/if/acfg/filesystem-jffs2.yml
new file mode 100644
index 00000000..ca9c5b01
--- /dev/null
+++ b/spec/if/acfg/filesystem-jffs2.yml
@@ -0,0 +1,18 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the JFFS2 filesystem
+  is registered, so that instances of this filesystem can be mounted by the
+  application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_JFFS2
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-nfs.yml b/spec/if/acfg/filesystem-nfs.yml
new file mode 100644
index 00000000..a846229b
--- /dev/null
+++ b/spec/if/acfg/filesystem-nfs.yml
@@ -0,0 +1,18 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the Network Filesystem
+  (NFS) client is registered, so that instances of this filesystem can be
+  mounted by the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_NFS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-rfs.yml b/spec/if/acfg/filesystem-rfs.yml
new file mode 100644
index 00000000..f2d5ba58
--- /dev/null
+++ b/spec/if/acfg/filesystem-rfs.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the RTEMS Filesystem (RFS)
+  is registered, so that instances of this filesystem can be mounted by the
+  application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_RFS
+notes: |
+  This filesystem requires a Block Device Cache configuration, see
+  :ref:`CONFIGURE_APPLICATION_NEEDS_LIBBLOCK`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/filesystem-tftpfs.yml b/spec/if/acfg/filesystem-tftpfs.yml
new file mode 100644
index 00000000..9ab6d4d2
--- /dev/null
+++ b/spec/if/acfg/filesystem-tftpfs.yml
@@ -0,0 +1,18 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the TFTP filesystem (TFTP
+  client) is registered, so that instances of this filesystem can be mounted by
+  the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_FILESYSTEM_TFTPFS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-bdbuf.yml b/spec/if/acfg/group-bdbuf.yml
new file mode 100644
index 00000000..502e05e3
--- /dev/null
+++ b/spec/if/acfg/group-bdbuf.yml
@@ -0,0 +1,14 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the Block Device Cache
+  (bdbuf).
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Block Device Cache Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-bsp.yml b/spec/if/acfg/group-bsp.yml
new file mode 100644
index 00000000..623b2d04
--- /dev/null
+++ b/spec/if/acfg/group-bsp.yml
@@ -0,0 +1,16 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the BSP.  Some
+  configuration options may have a BSP-specific setting which is defined by
+  ``<bsp.h>``.  The BSP-specific settings can be disabled by the
+  :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` configuration option.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: BSP Related Configuration Options
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-classic.yml b/spec/if/acfg/group-classic.yml
new file mode 100644
index 00000000..cb718de0
--- /dev/null
+++ b/spec/if/acfg/group-classic.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the Classic API.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Classic API Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-classicinit.yml b/spec/if/acfg/group-classicinit.yml
new file mode 100644
index 00000000..dc46849f
--- /dev/null
+++ b/spec/if/acfg/group-classicinit.yml
@@ -0,0 +1,14 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the Classic API
+  initialization task.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Classic API Initialization Task Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-devdrv.yml b/spec/if/acfg/group-devdrv.yml
new file mode 100644
index 00000000..db54eb73
--- /dev/null
+++ b/spec/if/acfg/group-devdrv.yml
@@ -0,0 +1,14 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the device drivers.
+  Note that network device drivers are not covered by the following options.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Device Driver Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-eventrecord.yml b/spec/if/acfg/group-eventrecord.yml
new file mode 100644
index 00000000..29e4319d
--- /dev/null
+++ b/spec/if/acfg/group-eventrecord.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  This section describes configuration options related to the event recording.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Event Recording Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-filesystem.yml b/spec/if/acfg/group-filesystem.yml
new file mode 100644
index 00000000..977641fa
--- /dev/null
+++ b/spec/if/acfg/group-filesystem.yml
@@ -0,0 +1,53 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to filesytems.
+  By default, the In-Memory Filesystem (IMFS) is used as the base filesystem (also
+  known as root filesystem).  In order to save some memory for your application,
+  you can disable the filesystem support with the
+  :ref:`CONFIGURE_APPLICATION_DISABLE_FILESYSTEM` configuration option.
+  Alternatively, you can strip down the features of the base filesystem with the
+  :ref:`CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM` and
+  :ref:`CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM` configuration options.  These
+  three configuration options are mutually exclusive.  They are intended for an
+  advanced application configuration.
+
+  Features of the IMFS can be disabled and enabled with the following
+  configuration options:
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHMOD`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHOWN`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_LINK`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_MKNOD`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_MKNOD_FILE`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_MOUNT`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_READDIR`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_READLINK`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_RENAME`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_RMNOD`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_SYMLINK`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UNMOUNT`
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UTIME`
+
+  * :ref:`CONFIGURE_IMFS_ENABLE_MKFIFO`
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Filesystem Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-general.yml b/spec/if/acfg/group-general.yml
new file mode 100644
index 00000000..86b37237
--- /dev/null
+++ b/spec/if/acfg/group-general.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes general system configuration options.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: General System Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-idle.yml b/spec/if/acfg/group-idle.yml
new file mode 100644
index 00000000..4e9dc5f4
--- /dev/null
+++ b/spec/if/acfg/group-idle.yml
@@ -0,0 +1,13 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the idle tasks.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Idle Task Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-mpci.yml b/spec/if/acfg/group-mpci.yml
new file mode 100644
index 00000000..238b898a
--- /dev/null
+++ b/spec/if/acfg/group-mpci.yml
@@ -0,0 +1,18 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes multiprocessing related configuration options.  The
+  options are only used if RTEMS was built with the ``--enable-multiprocessing``
+  build configuration option.  Additionally, this class of configuration options
+  are only applicable if the configuration option :ref:`CONFIGURE_MP_APPLICATION`
+  is defined.  The multiprocessing (MPCI) support must not be confused with the
+  SMP support.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Multiprocessing Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-posix.yml b/spec/if/acfg/group-posix.yml
new file mode 100644
index 00000000..ff24c8de
--- /dev/null
+++ b/spec/if/acfg/group-posix.yml
@@ -0,0 +1,16 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the POSIX API.  Most
+  POSIX API objects are available by default since RTEMS 5.1.  The queued signals
+  and timers are only available if RTEMS was built with the ``--enable-posix``
+  build configuration option.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: POSIX API Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-posixinit.yml b/spec/if/acfg/group-posixinit.yml
new file mode 100644
index 00000000..ff093c07
--- /dev/null
+++ b/spec/if/acfg/group-posixinit.yml
@@ -0,0 +1,14 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the POSIX
+  initialization thread.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: POSIX Initialization Thread Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-schedgeneral.yml b/spec/if/acfg/group-schedgeneral.yml
new file mode 100644
index 00000000..93429ed0
--- /dev/null
+++ b/spec/if/acfg/group-schedgeneral.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to selecting a
+  scheduling algorithm for an application.  A scheduler configuration is optional
+  and only necessary in very specific circumstances.  A normal application
+  configuration does not need any of the configuration options described in this
+  section.
+
+  By default, the :ref:`Deterministic Priority Scheduler <SchedulerPriority>`
+  algorithm is used in uniprocessor configurations.  In case SMP is enabled and
+  the configured maximum processors
+  (:ref:`CONFIGURE_MAXIMUM_PROCESSORS <CONFIGURE_MAXIMUM_PROCESSORS>`) is greater
+  than one, then the :ref:`Earliest Deadline First (EDF) SMP Scheduler
+  <SchedulerSMPEDF>` is selected as the default scheduler algorithm.
+
+  For the :ref:`schedulers built into
+  RTEMS <SchedulingConcepts>`, the configuration is straightforward.  All that is
+  required is to define the configuration option which specifies which scheduler
+  you want for in your application.
+
+  The pluggable scheduler interface also enables the user to provide their own
+  scheduling algorithm.  If you choose to do this, you must define multiple
+  configuration option.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: General Scheduler Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/group-stackalloc.yml b/spec/if/acfg/group-stackalloc.yml
new file mode 100644
index 00000000..e847fbbf
--- /dev/null
+++ b/spec/if/acfg/group-stackalloc.yml
@@ -0,0 +1,17 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  This section describes configuration options related to the task stack
+  allocator.  RTEMS allows the application or BSP to define its own allocation
+  and deallocation methods for task stacks. This can be used to place task stacks
+  in special areas of memory or to utilize a Memory Management Unit so that stack
+  overflows are detected in hardware.
+enabled-by: true
+interface-type: appl-config-group
+links:
+- role: requirement-refinement
+  uid: ../../applconfig
+name: Task Stack Allocator Configuration
+text: ''
+type: interface
diff --git a/spec/if/acfg/idle-task-body.yml b/spec/if/acfg/idle-task-body.yml
new file mode 100644
index 00000000..a4221954
--- /dev/null
+++ b/spec/if/acfg/idle-task-body.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void *( *idle_body )( uintptr_t )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  If :ref:`BSP_IDLE_TASK_BODY` is defined, then this will be the default value,
+  otherwise the default value is ``_CPU_Thread_Idle_body``.
+description: |
+  The value of this configuration option initializes the IDLE thread body.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-idle
+name: CONFIGURE_IDLE_TASK_BODY
+notes: |
+  IDLE threads shall not block.  A blocking IDLE thread results in undefined
+  system behaviour because the scheduler assume that at least one ready thread
+  exists.
+
+  IDLE threads can be used to initialize the application, see configuration
+  option :ref:`CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/idle-task-init-appl.yml b/spec/if/acfg/idle-task-init-appl.yml
new file mode 100644
index 00000000..378fb73e
--- /dev/null
+++ b/spec/if/acfg/idle-task-init-appl.yml
@@ -0,0 +1,43 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the user is assumed to
+  provide one or more initialization tasks.
+description: |
+  This configuration option is defined to indicate that the user has configured
+  **no** user initialization tasks or threads and that the user provided IDLE
+  task will perform application initialization and then transform itself into
+  an IDLE task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-idle
+name: CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION
+notes: |
+  If you use this option be careful, the user IDLE task **cannot** block at all
+  during the initialization sequence.  Further, once application
+  initialization is complete, it shall make itself preemptible and enter an idle
+  body loop.
+
+  The IDLE task shall run at the lowest priority of all tasks in the system.
+
+  If this configuration option is defined, then it is mandatory to configure a
+  user IDLE task with the :ref:`CONFIGURE_IDLE_TASK_BODY` configuration option,
+  otherwise a compile time error in the configuration file will occur.
+
+  The application shall define exactly one of the following configuration
+  options
+
+  * :ref:`CONFIGURE_RTEMS_INIT_TASKS_TABLE`,
+
+  * :ref:`CONFIGURE_POSIX_INIT_THREAD_TABLE`, or
+
+  * `CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION`
+
+  otherwise a compile time error in the configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/idle-task-stack-size.yml b/spec/if/acfg/idle-task-stack-size.yml
new file mode 100644
index 00000000..a4137f5d
--- /dev/null
+++ b/spec/if/acfg/idle-task-stack-size.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`
+description: |
+  The value of this configuration option defines the task stack size for an
+  IDLE task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-idle
+- role: constraint
+  uid: constraint-idlestackarea
+- role: constraint
+  uid: constraint-bspappmin
+name: CONFIGURE_IDLE_TASK_STACK_SIZE
+notes: |
+  In SMP configurations, there is one IDLE task per configured processor, see
+  :ref:`CONFIGURE_MAXIMUM_PROCESSORS`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-chmod.yml b/spec/if/acfg/imfs-disable-chmod.yml
new file mode 100644
index 00000000..88c80592
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-chmod.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  changing the mode of files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support changing the mode of files (no support for :c:func:`chmod`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_CHMOD
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-chown.yml b/spec/if/acfg/imfs-disable-chown.yml
new file mode 100644
index 00000000..ae33bcf6
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-chown.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  changing the ownership of files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support changing the ownership of files (no support for :c:func:`chown`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_CHOWN
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-link.yml b/spec/if/acfg/imfs-disable-link.yml
new file mode 100644
index 00000000..130958e6
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-link.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports hard
+  links.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support hard links (no support for :c:func:`link`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_LINK
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-mknod-device.yml b/spec/if/acfg/imfs-disable-mknod-device.yml
new file mode 100644
index 00000000..332c16ab
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-mknod-device.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default: |
+  If this configuration option is undefined, then the root IMFS supports making
+  device files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support making device files.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_MKNOD_DEVICE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-mknod-file.yml b/spec/if/acfg/imfs-disable-mknod-file.yml
new file mode 100644
index 00000000..952d7b77
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-mknod-file.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports making
+  regular files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support making regular files.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_MKNOD_FILE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-mknod.yml b/spec/if/acfg/imfs-disable-mknod.yml
new file mode 100644
index 00000000..1bd389f3
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-mknod.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports making
+  files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support making files (no support for :c:func:`mknod`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_MKNOD
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-mount.yml b/spec/if/acfg/imfs-disable-mount.yml
new file mode 100644
index 00000000..e434ff51
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-mount.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  mounting other filesystems.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support mounting other filesystems (no support for :c:func:`mount`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_MOUNT
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-readdir.yml b/spec/if/acfg/imfs-disable-readdir.yml
new file mode 100644
index 00000000..d3f8cc68
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-readdir.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  reading directories.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support reading directories (no support for :c:func:`readdir`).  It is still
+  possible to open files in a directory.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_READDIR
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-readlink.yml b/spec/if/acfg/imfs-disable-readlink.yml
new file mode 100644
index 00000000..5bfc00c4
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-readlink.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  reading symbolic links.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support reading symbolic links (no support for :c:func:`readlink`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_READLINK
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-rename.yml b/spec/if/acfg/imfs-disable-rename.yml
new file mode 100644
index 00000000..60a33fff
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-rename.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  renaming files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support renaming files (no support for :c:func:`rename`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_RENAME
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-rmnod.yml b/spec/if/acfg/imfs-disable-rmnod.yml
new file mode 100644
index 00000000..3686ab03
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-rmnod.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  removing files.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support removing files (no support for :c:func:`rmnod`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_RMNOD
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-symlink.yml b/spec/if/acfg/imfs-disable-symlink.yml
new file mode 100644
index 00000000..d4b507db
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-symlink.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  creating symbolic links.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support creating symbolic links (no support for :c:func:`symlink`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_SYMLINK
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-unmount.yml b/spec/if/acfg/imfs-disable-unmount.yml
new file mode 100644
index 00000000..20cf5e15
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-unmount.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  unmounting other filesystems.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support unmounting other filesystems (no support for :c:func:`unmount`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_UNMOUNT
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-disable-utime.yml b/spec/if/acfg/imfs-disable-utime.yml
new file mode 100644
index 00000000..49a13c28
--- /dev/null
+++ b/spec/if/acfg/imfs-disable-utime.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS supports
+  changing file times.
+description: |
+  In case this configuration option is defined, then the root IMFS does not
+  support changing file times (no support for :c:func:`utime`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_DISABLE_UTIME
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-enable-mkfifo.yml b/spec/if/acfg/imfs-enable-mkfifo.yml
new file mode 100644
index 00000000..22aed1da
--- /dev/null
+++ b/spec/if/acfg/imfs-enable-mkfifo.yml
@@ -0,0 +1,20 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the root IMFS does not
+  support making FIFOs (no support for :c:func:`mkfifo`).
+description: |
+  In case this configuration option is defined, then the root IMFS supports
+  making FIFOs.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_ENABLE_MKFIFO
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/imfs-memfile-bytes-per-block.yml b/spec/if/acfg/imfs-memfile-bytes-per-block.yml
new file mode 100644
index 00000000..7f7ed899
--- /dev/null
+++ b/spec/if/acfg/imfs-memfile-bytes-per-block.yml
@@ -0,0 +1,51 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  set:
+  - 16
+  - 32
+  - 64
+  - 128
+  - 256
+  - 512
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 128
+description: |
+  The value of this configuration option defines the block size for in-memory
+  files managed by the IMFS.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
+notes: |
+  The configured block size has two impacts. The first is the average amount of
+  unused memory in the last block of each file.  For example, when the block
+  size is 512, on average one-half of the last block of each file will remain
+  unused and the memory is wasted. In contrast, when the block size is 16, the
+  average unused memory per file is only 8 bytes. However, it requires more
+  allocations for the same size file and thus more overhead per block for the
+  dynamic memory management.
+
+  Second, the block size has an impact on the maximum size file that can be
+  stored in the IMFS. With smaller block size, the maximum file size is
+  correspondingly smaller. The following shows the maximum file size possible
+  based on the configured block size:
+
+  * when the block size is 16 bytes, the maximum file size is 1,328 bytes.
+
+  * when the block size is 32 bytes, the maximum file size is 18,656 bytes.
+
+  * when the block size is 64 bytes, the maximum file size is 279,488 bytes.
+
+  * when the block size is 128 bytes, the maximum file size is 4,329,344 bytes.
+
+  * when the block size is 256 bytes, the maximum file size is 68,173,568 bytes.
+
+  * when the block size is 512 bytes, the maximum file size is 1,082,195,456
+    bytes.
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-arguments.yml b/spec/if/acfg/init-task-arguments.yml
new file mode 100644
index 00000000..f20f3187
--- /dev/null
+++ b/spec/if/acfg/init-task-arguments.yml
@@ -0,0 +1,23 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a valid integer of type
+    ``rtems_task_argument``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines task argument of the Classic
+  API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_INIT_TASK_ARGUMENTS
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-attributes.yml b/spec/if/acfg/init-task-attributes.yml
new file mode 100644
index 00000000..5bfa6aa2
--- /dev/null
+++ b/spec/if/acfg/init-task-attributes.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a valid task attribute set.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``RTEMS_DEFAULT_ATTRIBUTES``'
+description: |
+  The value of this configuration option defines the task attributes of the
+  Classic API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_INIT_TASK_ATTRIBUTES
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-entrypoint.yml b/spec/if/acfg/init-task-entrypoint.yml
new file mode 100644
index 00000000..2b5813dc
--- /dev/null
+++ b/spec/if/acfg/init-task-entrypoint.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void ( *entry_point )( rtems_task_argument )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is ``Init``.
+description: |
+  The value of this configuration option initializes the entry point of the
+  Classic API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_INIT_TASK_ENTRY_POINT
+notes: |
+  The application shall provide the function referenced by this configuration
+  option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-initial-modes.yml b/spec/if/acfg/init-task-initial-modes.yml
new file mode 100644
index 00000000..3c1f99f3
--- /dev/null
+++ b/spec/if/acfg/init-task-initial-modes.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a valid task mode set.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  In SMP  configurations, the default value is ``RTEMS_DEFAULT_MODES``,
+  otherwise the default value is ``RTEMS_NO_PREEMPT``.
+description: |
+  The value of this configuration option defines the initial execution mode of
+  the Classic API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_INIT_TASK_INITIAL_MODES
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-name.yml b/spec/if/acfg/init-task-name.yml
new file mode 100644
index 00000000..9ce6f52e
--- /dev/null
+++ b/spec/if/acfg/init-task-name.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a valid integer of type
+    ``rtems_name``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is ``rtems_build_name( 'U', 'I', '1', ' ' )``.
+description: |
+  The value of this configuration option defines the name of the Classic API
+  initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_INIT_TASK_NAME
+notes: |
+  Use :c:func:`rtems_build_name` to define the task name.
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-priority.yml b/spec/if/acfg/init-task-priority.yml
new file mode 100644
index 00000000..f5da6b4f
--- /dev/null
+++ b/spec/if/acfg/init-task-priority.yml
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 1
+description: |
+  The value of this configuration option defines the initial priority of the
+  Classic API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+- role: constraint
+  uid: constraint-prioclassic
+name: CONFIGURE_INIT_TASK_PRIORITY
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/init-task-stack-size.yml b/spec/if/acfg/init-task-stack-size.yml
new file mode 100644
index 00000000..fb3daa0a
--- /dev/null
+++ b/spec/if/acfg/init-task-stack-size.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`
+description: |
+  The value of this configuration option defines the task stack size of the
+  Classic API initialization task.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+- role: constraint
+  uid: constraint-stackspace
+name: CONFIGURE_INIT_TASK_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/initial-extensions.yml b/spec/if/acfg/initial-extensions.yml
new file mode 100644
index 00000000..9d742c05
--- /dev/null
+++ b/spec/if/acfg/initial-extensions.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of initializers for
+    structures of type :c:type:`rtems_extensions_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is the empty list.
+description: |
+  The value of this configuration option is used to initialize the table of
+  initial user extensions.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_INITIAL_EXTENSIONS
+notes: |
+  The value of this configuration option is placed before the entries of
+  :ref:`BSP_INITIAL_EXTENSION` and after the entries of all other initial
+  user extensions.
+text: ''
+type: interface
diff --git a/spec/if/acfg/interrupt-stack-size.yml b/spec/if/acfg/interrupt-stack-size.yml
new file mode 100644
index 00000000..b2986237
--- /dev/null
+++ b/spec/if/acfg/interrupt-stack-size.yml
@@ -0,0 +1,43 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is :ref:`BSP_INTERRUPT_STACK_SIZE` in case it is defined,
+  otherwise the default value is ``CPU_STACK_MINIMUM_SIZE``.
+description: |
+  The value of this configuration option defines the size of an interrupt stack
+  in bytes.
+enabled-by: true
+index-entries:
+- interrupt stack size
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-isrstackalign
+- role: constraint
+  uid: constraint-isrstackarea
+- role: constraint
+  uid: constraint-bspappmin
+name: CONFIGURE_INTERRUPT_STACK_SIZE
+notes: |
+  There is one interrupt stack available for each configured processor
+  (:ref:`CONFIGURE_MAXIMUM_PROCESSORS`).  The interrupt stack areas are
+  statically allocated in a special linker section (``.rtemsstack.interrupt``).
+  The placement of this linker section is BSP-specific.
+
+  Some BSPs use the interrupt stack as the initialization stack which is used
+  to perform the sequential system initialization before the multithreading
+  is started.
+
+  The interrupt stacks are covered by the :ref:`stack checker
+  <CONFIGURE_STACK_CHECKER_ENABLED>`.  However, using a too small interrupt
+  stack size may still result in undefined behaviour.
+
+  In releases before RTEMS 5.1 the default value was
+  :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE` instead of ``CPU_STACK_MINIMUM_SIZE``.
+text: ''
+type: interface
diff --git a/spec/if/acfg/malloc-bsp-supports-sbrk.yml b/spec/if/acfg/malloc-bsp-supports-sbrk.yml
new file mode 100644
index 00000000..8ffd6a31
--- /dev/null
+++ b/spec/if/acfg/malloc-bsp-supports-sbrk.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  If
+
+  * this configuration option is defined by the BSP
+
+  * and :ref:`CONFIGURE_DISABLE_BSP_SETTINGS` is undefined,
+
+  then not all memory is made available to the C Program Heap immediately at
+  system initialization time.  When :c:func:`malloc()` or other standard memory
+  allocation functions are unable to allocate memory, they will call the BSP
+  supplied :c:func:`sbrk()` function to obtain more memory.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-bsp
+name: CONFIGURE_MALLOC_BSP_SUPPORTS_SBRK
+notes: |
+  This option should not be defined by the application. Only the BSP knows how
+  it allocates memory to the C Program Heap.
+text: ''
+type: interface
diff --git a/spec/if/acfg/malloc-dirty.yml b/spec/if/acfg/malloc-dirty.yml
new file mode 100644
index 00000000..8840eff6
--- /dev/null
+++ b/spec/if/acfg/malloc-dirty.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then each memory area returned
+  by C Program Heap allocator functions such as :c:func:`malloc` is dirtied
+  with a ``0xCF`` byte pattern before it is handed over to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_MALLOC_DIRTY
+notes: |
+  The dirtying performed by this option is carried out for each successful
+  memory allocation from the C Program Heap in contrast to
+  :ref:`CONFIGURE_DIRTY_MEMORY` which dirties the memory only once during the
+  system initialization.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-barriers.yml b/spec/if/acfg/max-barriers.yml
new file mode 100644
index 00000000..77bc28e2
--- /dev/null
+++ b/spec/if/acfg/max-barriers.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Barriers that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_BARRIERS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-drivers.yml b/spec/if/acfg/max-drivers.yml
new file mode 100644
index 00000000..fb2220ee
--- /dev/null
+++ b/spec/if/acfg/max-drivers.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  texts:
+  - |
+    It shall be greater than or equal than the number of statically configured
+    device drivers.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  This is computed by default, and is set to the number of device drivers
+  configured using the ``CONFIGURE_APPLICATIONS_NEEDS_XXX_DRIVER``
+  configuration options.
+description: |
+  The value of this configuration option defines the number of device drivers.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-devdrv
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_DRIVERS
+notes: |
+  If the application will dynamically install device drivers, then this
+  configuration parameter shall be larger than the number of statically
+  configured device drivers. Drivers configured using the
+  ``CONFIGURE_APPLICATIONS_NEEDS_XXX_DRIVER`` configuration options are
+  statically installed.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-file-descriptors.yml b/spec/if/acfg/max-file-descriptors.yml
new file mode 100644
index 00000000..dd6baed7
--- /dev/null
+++ b/spec/if/acfg/max-file-descriptors.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 3
+description: |
+  The value of this configuration option defines the maximum number of file
+  like objects that can be concurrently open.
+enabled-by: true
+index-entries:
+- maximum file descriptors
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_FILE_DESCRIPTORS
+notes: |
+  The default value of three file descriptors allows RTEMS to support standard
+  input, output, and error I/O streams on ``/dev/console``.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-message-queues.yml b/spec/if/acfg/max-message-queues.yml
new file mode 100644
index 00000000..e8963de9
--- /dev/null
+++ b/spec/if/acfg/max-message-queues.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Message Queues that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_MESSAGE_QUEUES
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.  You have to account for the memory used to
+  store the messages of each message queue, see
+  :ref:`CONFIGURE_MESSAGE_BUFFER_MEMORY`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-partitions.yml b/spec/if/acfg/max-partitions.yml
new file mode 100644
index 00000000..b6c088a6
--- /dev/null
+++ b/spec/if/acfg/max-partitions.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Partitions that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_PARTITIONS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-periods.yml b/spec/if/acfg/max-periods.yml
new file mode 100644
index 00000000..694ab3c0
--- /dev/null
+++ b/spec/if/acfg/max-periods.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Periods that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_PERIODS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-ports.yml b/spec/if/acfg/max-ports.yml
new file mode 100644
index 00000000..a1752318
--- /dev/null
+++ b/spec/if/acfg/max-ports.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Ports that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_PORTS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-key-value-pairs.yml b/spec/if/acfg/max-posix-key-value-pairs.yml
new file mode 100644
index 00000000..694fbee0
--- /dev/null
+++ b/spec/if/acfg/max-posix-key-value-pairs.yml
@@ -0,0 +1,34 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is
+  :ref:`CONFIGURE_MAXIMUM_POSIX_KEYS` *
+  :ref:`CONFIGURE_MAXIMUM_TASKS` +
+  :ref:`CONFIGURE_MAXIMUM_POSIX_THREADS`.
+description: |
+  The value of this configuration option defines the maximum number of key
+  value pairs used by POSIX API Keys that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_KEY_VALUE_PAIRS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  A key value pair is created by :c:func:`pthread_setspecific` if the value
+  is not :c:macro:`NULL`, otherwise it is deleted.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-keys.yml b/spec/if/acfg/max-posix-keys.yml
new file mode 100644
index 00000000..5239647c
--- /dev/null
+++ b/spec/if/acfg/max-posix-keys.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Keys that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_KEYS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-message-queues.yml b/spec/if/acfg/max-posix-message-queues.yml
new file mode 100644
index 00000000..097871f8
--- /dev/null
+++ b/spec/if/acfg/max-posix-message-queues.yml
@@ -0,0 +1,31 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Message Queues that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_MESSAGE_QUEUES
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.  You have to account for the memory used to
+  store the messages of each message queue, see
+  :ref:`CONFIGURE_MESSAGE_BUFFER_MEMORY`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-queued-signals.yml b/spec/if/acfg/max-posix-queued-signals.yml
new file mode 100644
index 00000000..541c8ffd
--- /dev/null
+++ b/spec/if/acfg/max-posix-queued-signals.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Queued Signals that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-posix
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_QUEUED_SIGNALS
+notes: |
+  Unlimited objects are not available for queued signals.
+
+  Queued signals are only available if RTEMS was built with the
+  ``--enable-posix`` build configuration option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-semaphores.yml b/spec/if/acfg/max-posix-semaphores.yml
new file mode 100644
index 00000000..5c313fee
--- /dev/null
+++ b/spec/if/acfg/max-posix-semaphores.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Named Semaphores that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_SEMAPHORES
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  Named semaphores are created with :c:func:`sem_open()`.  Semaphores
+  initialized with :c:func:`sem_init()` are not affected by this configuration
+  option since the storage space for these semaphores is user-provided.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-shms.yml b/spec/if/acfg/max-posix-shms.yml
new file mode 100644
index 00000000..d3f544a6
--- /dev/null
+++ b/spec/if/acfg/max-posix-shms.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Shared Memory objects that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_SHMS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-threads.yml b/spec/if/acfg/max-posix-threads.yml
new file mode 100644
index 00000000..0b314d5c
--- /dev/null
+++ b/spec/if/acfg/max-posix-threads.yml
@@ -0,0 +1,40 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Threads that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-stackspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_THREADS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  This calculations for the required memory in the RTEMS Workspace for
+  threads assume that each thread has a minimum stack size and has floating
+  point support enabled.  The configuration option
+  :ref:`CONFIGURE_EXTRA_TASK_STACKS` is used to specify thread stack
+  requirements **above** the minimum size required.  See :ref:`Reserve
+  Task/Thread Stack Memory Above Minimum` for more information about
+  ``CONFIGURE_EXTRA_TASK_STACKS``.
+
+  The maximum number of Classic API Tasks is specified by
+  :ref:`CONFIGURE_MAXIMUM_TASKS`.
+
+  All POSIX threads have floating point enabled.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-posix-timers.yml b/spec/if/acfg/max-posix-timers.yml
new file mode 100644
index 00000000..67b1056e
--- /dev/null
+++ b/spec/if/acfg/max-posix-timers.yml
@@ -0,0 +1,32 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of POSIX
+  API Timers that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-posix
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_POSIX_TIMERS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  Timers are only available if RTEMS was built with the
+  ``--enable-posix`` build configuration option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-priority.yml b/spec/if/acfg/max-priority.yml
new file mode 100644
index 00000000..9cd3f58a
--- /dev/null
+++ b/spec/if/acfg/max-priority.yml
@@ -0,0 +1,58 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  set:
+  - 3
+  - 7
+  - 31
+  - 63
+  - 127
+  - 255
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 255
+description: |
+  For the following schedulers
+
+  * :ref:`SchedulerPriority`, which is the default in uniprocessor
+    configurations and can be configured through the
+    :ref:`CONFIGURE_SCHEDULER_PRIORITY` configuration option,
+
+  * :ref:`SchedulerSMPPriority` which can be configured through the
+    :ref:`CONFIGURE_SCHEDULER_PRIORITY_SMP` configuration option, and
+
+  * :ref:`SchedulerSMPPriorityAffinity` which can be configured through the
+    :ref:`CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP` configuration option
+
+  this configuration option specifies the maximum numeric priority of any task
+  for these schedulers and one less that the number of priority levels for
+  these schedulers.  For all other schedulers provided by RTEMS, this
+  configuration option has no effect.
+enabled-by: true
+index-entries:
+- maximum priority
+- number of priority levels
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_MAXIMUM_PRIORITY
+notes: |
+  The numerically greatest priority is the logically lowest priority in the
+  system and will thus be used by the IDLE task.
+
+  Priority zero is reserved for internal use by RTEMS and is not available to
+  applications.
+
+  Reducing the number of priorities through this configuration option reduces
+  the amount of memory allocated by the schedulers listed above.  These
+  schedulers use a chain control structure per priority and this structure
+  consists of three pointers.  On a 32-bit architecture, the allocated memory
+  is 12 bytes * (``CONFIGURE_MAXIMUM_PRIORITY`` + 1), e.g. 3072 bytes for 256
+  priority levels (default), 48 bytes for 4 priority levels
+  (``CONFIGURE_MAXIMUM_PRIORITY == 3``).
+
+  The default value is 255, because RTEMS shall support 256 priority levels to
+  be compliant with various standards.  These priorities range from 0 to 255.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-processors.yml b/spec/if/acfg/max-processors.yml
new file mode 100644
index 00000000..9341c97c
--- /dev/null
+++ b/spec/if/acfg/max-processors.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``CPU_MAXIMUM_PROCESSORS``'
+  min: 1
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 1
+description: |
+  The value of this configuration option defines the maximum number of
+  processors an application intends to use.  The number of actually available
+  processors depends on the hardware and may be less.  It is recommended to use
+  the smallest value suitable for the application in order to save memory.
+  Each processor needs an IDLE task stack and interrupt stack for example.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_MAXIMUM_PROCESSORS
+notes: |
+  If there are more processors available than configured, the rest will be
+  ignored.
+
+  This configuration option is only evaluated in SMP configurations (e.g. RTEMS
+  was built with the ``--enable-smp`` build configuration option).  In all
+  other configurations it has no effect.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-regions.yml b/spec/if/acfg/max-regions.yml
new file mode 100644
index 00000000..fe06f81f
--- /dev/null
+++ b/spec/if/acfg/max-regions.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Regions that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_REGIONS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-semaphores.yml b/spec/if/acfg/max-semaphores.yml
new file mode 100644
index 00000000..76798f34
--- /dev/null
+++ b/spec/if/acfg/max-semaphores.yml
@@ -0,0 +1,31 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Semaphore that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_SEMAPHORES
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  In SMP configurations, the size of a Semaphore Control Block depends on the
+  scheduler count (see :ref:`ConfigurationSchedulerTable`).  The semaphores
+  using the :ref:`MrsP` need a ceiling priority per scheduler.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-tasks.yml b/spec/if/acfg/max-tasks.yml
new file mode 100644
index 00000000..45b00175
--- /dev/null
+++ b/spec/if/acfg/max-tasks.yml
@@ -0,0 +1,45 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Tasks that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-stackspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_TASKS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+
+  The calculations for the required memory in the RTEMS Workspace for tasks
+  assume that each task has a minimum stack size and has floating point
+  support enabled.  The configuration parameter
+  ``CONFIGURE_EXTRA_TASK_STACKS`` is used to specify task stack requirements
+  *ABOVE* the minimum size required.  See :ref:`Reserve Task/Thread Stack
+  Memory Above Minimum` for more information about
+  ``CONFIGURE_EXTRA_TASK_STACKS``.
+
+  The maximum number of POSIX threads is specified by
+  :ref:`CONFIGURE_MAXIMUM_POSIX_THREADS`.
+
+  A future enhancement to ``<rtems/confdefs.h>`` could be to eliminate the
+  assumption that all tasks have floating point enabled. This would require
+  the addition of a new configuration parameter to specify the number of
+  tasks which enable floating point support.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-thread-name-size.yml b/spec/if/acfg/max-thread-name-size.yml
new file mode 100644
index 00000000..e8f3c552
--- /dev/null
+++ b/spec/if/acfg/max-thread-name-size.yml
@@ -0,0 +1,31 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 16
+description: |
+  The value of this configuration option defines the maximum thread name size
+  including the terminating ``NUL`` character.
+enabled-by: true
+index-entries:
+- maximum thread name size
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_THREAD_NAME_SIZE
+notes: |
+  The default value was chosen for Linux compatibility, see
+  `PTHREAD_SETNAME_NP(3) <http://man7.org/linux/man-pages/man3/pthread_setname_np.3.html>`_.
+
+  The size of the thread control block is increased by the maximum thread name
+  size.
+
+  This configuration option is available since RTEMS 5.1.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-timers.yml b/spec/if/acfg/max-timers.yml
new file mode 100644
index 00000000..0ecfe00f
--- /dev/null
+++ b/spec/if/acfg/max-timers.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API Timers that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-unlimited
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_TIMERS
+notes: |
+  This object class can be configured in unlimited allocation mode, see
+  :ref:`ConfigUnlimitedObjects`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/max-user-extensions.yml b/spec/if/acfg/max-user-extensions.yml
new file mode 100644
index 00000000..c3b46807
--- /dev/null
+++ b/spec/if/acfg/max-user-extensions.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: 65535
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the maximum number of Classic
+  API User Extensions that can be concurrently active.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classic
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MAXIMUM_USER_EXTENSIONS
+notes: |
+  This object class cannot be configured in unlimited allocation mode.
+text: ''
+type: interface
diff --git a/spec/if/acfg/memory-overhead.yml b/spec/if/acfg/memory-overhead.yml
new file mode 100644
index 00000000..a7a07757
--- /dev/null
+++ b/spec/if/acfg/memory-overhead.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the number of kilobytes the
+  application wishes to add to the RTEMS Workspace size calculated by
+  ``<rtems/confdefs.h>``.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MEMORY_OVERHEAD
+notes: |
+  This configuration option should only be used when it is suspected that a bug
+  in ``<rtems/confdefs.h>`` has resulted in an underestimation.  Typically the
+  memory allocation will be too low when an application does not account for
+  all message queue buffers or task stacks, see
+  :ref:`CONFIGURE_MESSAGE_BUFFER_MEMORY`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/message-buffer-memory.yml b/spec/if/acfg/message-buffer-memory.yml
new file mode 100644
index 00000000..0f98d9d4
--- /dev/null
+++ b/spec/if/acfg/message-buffer-memory.yml
@@ -0,0 +1,72 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 0
+description: |
+  The value of this configuration option defines the number of bytes reserved
+  for message queue buffers in the RTEMS Workspace.
+enabled-by: true
+index-entries:
+- configure message queue buffer memory
+- CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE
+- memory for a single message queue's buffers
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-wkspace
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_MESSAGE_BUFFER_MEMORY
+notes: |
+  The configuration options :ref:`CONFIGURE_MAXIMUM_MESSAGE_QUEUES` and
+  :ref:`CONFIGURE_MAXIMUM_POSIX_MESSAGE_QUEUES` define only how many message
+  queues can be created by the application.  The memory for the message
+  buffers is configured by this option.  For each message queue you have to
+  reserve some memory for the message buffers.  The size dependes on the
+  maximum number of pending messages and the maximum size of the messages of
+  a message queue.  Use the ``CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()`` macro
+  to specify the message buffer memory for each message queue and sum them up
+  to define the value for ``CONFIGURE_MAXIMUM_MESSAGE_QUEUES``.
+
+  The interface for the ``CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()`` help
+  macro is as follows:
+
+  .. code-block:: c
+
+      CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( max_messages, max_msg_size )
+
+  Where ``max_messages`` is the maximum number of pending messages and
+  ``max_msg_size`` is the maximum size in bytes of the messages of the
+  corresponding message queue.  Both parameters shall be compile time
+  constants.  Not using this help macro (e.g. just using
+  ``max_messages * max_msg_size``) may result in an underestimate of the
+  RTEMS Workspace size.
+
+  The following example illustrates how the
+  `CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE()` help macro can be used to assist in
+  calculating the message buffer memory required.  In this example, there are
+  two message queues used in this application.  The first message queue has a
+  maximum of 24 pending messages with the message structure defined by the
+  type ``one_message_type``.  The other message queue has a maximum of 500
+  pending messages with the message structure defined by the type
+  ``other_message_type``.
+
+  .. code-block:: c
+
+      #define CONFIGURE_MESSAGE_BUFFER_MEMORY ( \
+          CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( \
+            24, \
+            sizeof( one_message_type ) \
+          ) \
+          + CONFIGURE_MESSAGE_BUFFERS_FOR_QUEUE( \
+            500, \
+            sizeof( other_message_type ) \
+          ) \
+        )
+text: ''
+type: interface
diff --git a/spec/if/acfg/microseconds-per-tick.yml b/spec/if/acfg/microseconds-per-tick.yml
new file mode 100644
index 00000000..ee1480f1
--- /dev/null
+++ b/spec/if/acfg/microseconds-per-tick.yml
@@ -0,0 +1,45 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - It shall be greater than or equal to a Clock Driver specific value.
+  - It shall be less than or equal to a Clock Driver specific value.
+  - The resulting clock ticks per second should be an integer.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 10000
+description: |
+  The value of this configuration option defines the length of time in
+  microseconds between clock ticks (clock tick quantum).
+
+  When the clock tick quantum value is too low, the system will spend so much
+  time processing clock ticks that it does not have processing time available
+  to perform application work. In this case, the system will become
+  unresponsive.
+
+  The lowest practical time quantum varies widely based upon the speed of the
+  target hardware and the architectural overhead associated with
+  interrupts. In general terms, you do not want to configure it lower than is
+  needed for the application.
+
+  The clock tick quantum should be selected such that it all blocking and
+  delay times in the application are evenly divisible by it. Otherwise,
+  rounding errors will be introduced which may negatively impact the
+  application.
+enabled-by: true
+index-entries:
+- clock tick quantum
+- tick quantum
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_MICROSECONDS_PER_TICK
+notes: |
+  This configuration option has no impact if the Clock Driver is not
+  configured, see :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`.
+
+  There may be Clock Driver specific limits on the resolution or maximum value
+  of a clock tick quantum.
+text: ''
+type: interface
diff --git a/spec/if/acfg/min-posix-thread-stack-size.yml b/spec/if/acfg/min-posix-thread-stack-size.yml
new file mode 100644
index 00000000..6a2e819f
--- /dev/null
+++ b/spec/if/acfg/min-posix-thread-stack-size.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is two times the value of
+  :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`.
+description: |
+  The value of this configuration option defines the minimum stack size in
+  bytes for every POSIX thread in the system.
+enabled-by: true
+index-entries:
+- minimum POSIX thread stack size
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posix
+- role: constraint
+  uid: constraint-bspappmin
+- role: constraint
+  uid: constraint-stackspace
+name: CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/min-task-stack-size.yml b/spec/if/acfg/min-task-stack-size.yml
new file mode 100644
index 00000000..b64b1ab4
--- /dev/null
+++ b/spec/if/acfg/min-task-stack-size.yml
@@ -0,0 +1,44 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints: {}
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``CPU_STACK_MINIMUM_SIZE``'
+description: |
+  The value of this configuration option defines the minimum stack size in
+  bytes for every user task or thread in the system.
+enabled-by: true
+index-entries:
+- minimum task stack size
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+- role: constraint
+  uid: constraint-bspappmin
+- role: constraint
+  uid: constraint-stackspace
+name: CONFIGURE_MINIMUM_TASK_STACK_SIZE
+notes: |
+  Adjusting this parameter should be done with caution.  Examining the actual
+  stack usage using the stack checker usage reporting facility is recommended
+  (see also :ref:`CONFIGURE_STACK_CHECKER_ENABLED`).
+
+  This parameter can be used to lower the minimum from that recommended. This
+  can be used in low memory systems to reduce memory consumption for
+  stacks. However, this shall be done with caution as it could increase the
+  possibility of a blown task stack.
+
+  This parameter can be used to increase the minimum from that
+  recommended. This can be used in higher memory systems to reduce the risk
+  of stack overflow without performing analysis on actual consumption.
+
+  By default, this configuration parameter defines also the minimum stack
+  size of POSIX threads.  This can be changed with the
+  :ref:`CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE`
+  configuration option.
+
+  In releases before RTEMS 5.1 the ``CONFIGURE_MINIMUM_TASK_STACK_SIZE`` was
+  used to define the default value of :ref:`CONFIGURE_INTERRUPT_STACK_SIZE`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-appl.yml b/spec/if/acfg/mp-appl.yml
new file mode 100644
index 00000000..2474a79b
--- /dev/null
+++ b/spec/if/acfg/mp-appl.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then the multiprocessing services
+  are not initialized.
+description: |
+  This configuration option is defined to indicate that the application intends
+  to be part of a multiprocessing configuration.  Additional configuration
+  options are assumed to be provided.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_APPLICATION
+notes: |
+  This configuration option shall be undefined if the multiprocessing support
+  is not enabled (e.g. RTEMS was built without the ``--enable-multiprocessing``
+  build configuration option).  Otherwise a compile time error in the
+  configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-extra-server-stack.yml b/spec/if/acfg/mp-extra-server-stack.yml
new file mode 100644
index 00000000..25f11bd8
--- /dev/null
+++ b/spec/if/acfg/mp-extra-server-stack.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+  texts:
+  - |
+    The value of this configuration option shall be small enough so that the
+    MPCI receive server stack area calculation carried out by
+    ``<rtems/confdefs.h>`` does not overflow an integer of type ``size_t``.
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: 0
+description: |
+  The value of this configuration option defines the number of bytes the
+  applications wishes to add to the MPCI task stack on top of
+  :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_EXTRA_MPCI_RECEIVE_SERVER_STACK
+notes: |
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-max-global-objects.yml b/spec/if/acfg/mp-max-global-objects.yml
new file mode 100644
index 00000000..f795d53a
--- /dev/null
+++ b/spec/if/acfg/mp-max-global-objects.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 32
+description: |
+  The value of this configuration option defines the maximum number of
+  concurrently active global objects in a multiprocessor system.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_MAXIMUM_GLOBAL_OBJECTS
+notes: |
+  This value corresponds to the total number of objects which can be created
+  with the ``RTEMS_GLOBAL`` attribute.
+
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-max-nodes.yml b/spec/if/acfg/mp-max-nodes.yml
new file mode 100644
index 00000000..5342ea01
--- /dev/null
+++ b/spec/if/acfg/mp-max-nodes.yml
@@ -0,0 +1,23 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 2
+description: |
+  The value of this configuration option defines the maximum number of nodes in
+  a multiprocessor system.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_MAXIMUM_NODES
+notes: |
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-max-proxies.yml b/spec/if/acfg/mp-max-proxies.yml
new file mode 100644
index 00000000..f20b5333
--- /dev/null
+++ b/spec/if/acfg/mp-max-proxies.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 32
+description: |
+  The value of this configuration option defines the maximum number of
+  concurrently active thread/task proxies on this node in a multiprocessor
+  system.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_MAXIMUM_PROXIES
+notes: |
+  Since a proxy is used to represent a remote task/thread which is blocking
+  on this node. This configuration parameter reflects the maximum number of
+  remote tasks/threads which can be blocked on objects on this node, see
+  :ref:`MPCIProxies`.
+
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-mpci-table-pointer.yml b/spec/if/acfg/mp-mpci-table-pointer.yml
new file mode 100644
index 00000000..8d0f00cb
--- /dev/null
+++ b/spec/if/acfg/mp-mpci-table-pointer.yml
@@ -0,0 +1,29 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a pointer to
+    :c:type:`rtems_mpci_table`.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``&MPCI_table``'
+description: |
+  The value of this configuration option initializes the MPCI Configuration
+  Table.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_MPCI_TABLE_POINTER
+notes: |
+  RTEMS provides a Shared Memory MPCI Device Driver which can be used on any
+  Multiprocessor System assuming the BSP provides the proper set of
+  supporting methods.
+
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/mp-node-number.yml b/spec/if/acfg/mp-node-number.yml
new file mode 100644
index 00000000..1a51de4a
--- /dev/null
+++ b/spec/if/acfg/mp-node-number.yml
@@ -0,0 +1,28 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``NODE_NUMBER``'
+description: |
+  The value of this configuration option defines the node number of this node
+  in a multiprocessor system.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-mpci
+name: CONFIGURE_MP_NODE_NUMBER
+notes: |
+  In the RTEMS Multiprocessing Test Suite, the node number is derived from
+  the Makefile variable ``NODE_NUMBER``. The same code is compiled with the
+  ``NODE_NUMBER`` set to different values. The test programs behave
+  differently based upon their node number.
+
+  This configuration option is only evaluated if
+  :ref:`CONFIGURE_MP_APPLICATION` is defined.
+text: ''
+type: interface
diff --git a/spec/if/acfg/posix-init-thread-entry-point.yml b/spec/if/acfg/posix-init-thread-entry-point.yml
new file mode 100644
index 00000000..fca4e899
--- /dev/null
+++ b/spec/if/acfg/posix-init-thread-entry-point.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void *( *entry_point )( void * )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``POSIX_Init``'
+description: |
+  The value of this configuration option initializes the entry point of the
+  POSIX API initialization thread.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posixinit
+name: CONFIGURE_POSIX_INIT_THREAD_ENTRY_POINT
+notes: |
+  The application shall provide the function referenced by this configuration
+  option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/posix-init-thread-stack-size.yml b/spec/if/acfg/posix-init-thread-stack-size.yml
new file mode 100644
index 00000000..59a3ead4
--- /dev/null
+++ b/spec/if/acfg/posix-init-thread-stack-size.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  min: :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE`
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: :ref:`CONFIGURE_MINIMUM_POSIX_THREAD_STACK_SIZE`
+description: |
+  The value of this configuration option defines the thread stack size of the
+  POSIX API initialization thread.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posixinit
+- role: constraint
+  uid: constraint-stackspace
+name: CONFIGURE_POSIX_INIT_THREAD_STACK_SIZE
+notes: null
+text: ''
+type: interface
diff --git a/spec/if/acfg/posix-init-thread-table.yml b/spec/if/acfg/posix-init-thread-table.yml
new file mode 100644
index 00000000..6a7d9250
--- /dev/null
+++ b/spec/if/acfg/posix-init-thread-table.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then exactly one POSIX
+  initialization thread is configured.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-posixinit
+name: CONFIGURE_POSIX_INIT_THREAD_TABLE
+notes: |
+  The application shall define exactly one of the following configuration
+  options
+
+  * :ref:`CONFIGURE_RTEMS_INIT_TASKS_TABLE`,
+
+  * `CONFIGURE_POSIX_INIT_THREAD_TABLE`, or
+
+  * :ref:`CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION`
+
+  otherwise a compile time error in the configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/record-extensions-enabled.yml b/spec/if/acfg/record-extensions-enabled.yml
new file mode 100644
index 00000000..3486238b
--- /dev/null
+++ b/spec/if/acfg/record-extensions-enabled.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2019 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case
+
+  * this configuration option is defined
+
+  * and :ref:`CONFIGURE_RECORD_PER_PROCESSOR_ITEMS` is properly defined,
+
+  then the event record extensions are enabled.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-eventrecord
+name: CONFIGURE_RECORD_EXTENSIONS_ENABLED
+notes: |
+  The record extensions capture thread create, start, restart, delete, switch,
+  begin, exitted and terminate events.
+text: ''
+type: interface
diff --git a/spec/if/acfg/record-fatal-dump-base64-zlib.yml b/spec/if/acfg/record-fatal-dump-base64-zlib.yml
new file mode 100644
index 00000000..731a6a72
--- /dev/null
+++ b/spec/if/acfg/record-fatal-dump-base64-zlib.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case
+
+  * this configuration option is defined
+
+  * and :ref:`CONFIGURE_RECORD_PER_PROCESSOR_ITEMS` is properly defined,
+
+  then the event records are compressed by zlib and dumped in Base64 encoding
+  in a fatal error extension (see :ref:`Terminate`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-eventrecord
+name: CONFIGURE_RECORD_FATAL_DUMP_BASE64_ZLIB
+notes: |
+  The zlib compression needs about 512KiB of RAM.  This extension can be used
+  to produce crash dumps.
+text: ''
+type: interface
diff --git a/spec/if/acfg/record-fatal-dump-base64.yml b/spec/if/acfg/record-fatal-dump-base64.yml
new file mode 100644
index 00000000..14ab9517
--- /dev/null
+++ b/spec/if/acfg/record-fatal-dump-base64.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case
+
+  * this configuration option is defined
+
+  * and :ref:`CONFIGURE_RECORD_PER_PROCESSOR_ITEMS` is properly defined,
+
+  * and :ref:`CONFIGURE_RECORD_FATAL_DUMP_BASE64_ZLIB` is undefined,
+
+  then the event records are dumped in Base64 encoding in a fatal error
+  extension (see :ref:`Terminate`).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-eventrecord
+name: CONFIGURE_RECORD_FATAL_DUMP_BASE64
+notes: |
+  This extension can be used to produce crash dumps.
+text: ''
+type: interface
diff --git a/spec/if/acfg/record-per-processor-items.yml b/spec/if/acfg/record-per-processor-items.yml
new file mode 100644
index 00000000..335c4fca
--- /dev/null
+++ b/spec/if/acfg/record-per-processor-items.yml
@@ -0,0 +1,28 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``SIZE_MAX``'
+  min: 16
+  texts:
+  - It shall be a power of two.
+copyrights:
+- Copyright (C) 2019 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: 0
+description: |
+  The value of this configuration option defines the event record item count
+  per processor.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-eventrecord
+- role: constraint
+  uid: constraint-memsz
+name: CONFIGURE_RECORD_PER_PROCESSOR_ITEMS
+notes: |
+  The event record buffers are statically allocated for each configured
+  processor (:ref:`CONFIGURE_MAXIMUM_PROCESSORS`).  If the value of this
+  configuration option is zero, then nothing is allocated.
+text: ''
+type: interface
diff --git a/spec/if/acfg/rtems-init-tasks-table.yml b/spec/if/acfg/rtems-init-tasks-table.yml
new file mode 100644
index 00000000..24a35697
--- /dev/null
+++ b/spec/if/acfg/rtems-init-tasks-table.yml
@@ -0,0 +1,27 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then exactly one Classic API
+  initialization task is configured.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-classicinit
+name: CONFIGURE_RTEMS_INIT_TASKS_TABLE
+notes: |
+  The application shall define exactly one of the following configuration
+  options
+
+  * `CONFIGURE_RTEMS_INIT_TASKS_TABLE`,
+
+  * :ref:`CONFIGURE_POSIX_INIT_THREAD_TABLE`, or
+
+  * :ref:`CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION`
+
+  otherwise a compile time error in the configuration file will occur.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-assignments.yml b/spec/if/acfg/scheduler-assignments.yml
new file mode 100644
index 00000000..e678d6c3
--- /dev/null
+++ b/spec/if/acfg/scheduler-assignments.yml
@@ -0,0 +1,36 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a list of the following
+    macros:
+
+    * ``RTEMS_SCHEDULER_ASSIGN( processor_index, attributes )``
+
+    * :c:macro:`RTEMS_SCHEDULER_ASSIGN_NO_SCHEDULER`
+  - |
+    The value of this configuration option shall be a list of exactly
+    :ref:`CONFIGURE_MAXIMUM_PROCESSORS` elements.
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: |
+  The default value of this configuration option is computed so that the
+  default scheduler is assigned to each configured processor (up to 32).
+description: |
+  The value of this configuration option is used to initialize the initial
+  scheduler to processor assignments.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_ASSIGNMENTS
+notes: |
+  This configuration option is only evaluated in SMP configurations.
+
+  This is an advanced configuration option, see
+  :ref:`ConfigurationSchedulersClustered`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-cbs.yml b/spec/if/acfg/scheduler-cbs.yml
new file mode 100644
index 00000000..7431d659
--- /dev/null
+++ b/spec/if/acfg/scheduler-cbs.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Constant Bandwidth Server (CBS) Scheduler <SchedulerCBS>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_CBS
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for exactly one processor.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-edf-smp.yml b/spec/if/acfg/scheduler-edf-smp.yml
new file mode 100644
index 00000000..526b051c
--- /dev/null
+++ b/spec/if/acfg/scheduler-edf-smp.yml
@@ -0,0 +1,31 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Earliest Deadline First (EDF) SMP Scheduler <SchedulerSMPEDF>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_EDF_SMP
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  This scheduler algorithm is only available when RTEMS is built with SMP
+  support enabled.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for up to 32 processors.
+
+  This scheduler algorithm is the default in SMP configurations if
+  :ref:`CONFIGURE_MAXIMUM_PROCESSORS` is
+  greater than one.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-edf.yml b/spec/if/acfg/scheduler-edf.yml
new file mode 100644
index 00000000..36f89170
--- /dev/null
+++ b/spec/if/acfg/scheduler-edf.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Earliest Deadline First (EDF) Scheduler <SchedulerEDF>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_EDF
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for exactly one processor.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-name.yml b/spec/if/acfg/scheduler-name.yml
new file mode 100644
index 00000000..652fabe3
--- /dev/null
+++ b/spec/if/acfg/scheduler-name.yml
@@ -0,0 +1,46 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be a valid integer of type
+    ``rtems_name``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is
+
+  * ``"MEDF"`` for the :ref:`EDF SMP Scheduler <SchedulerSMPEDF>`,
+
+  * ``"MPA "`` for the :ref:`Arbitrary Processor Affinity Priority SMP Scheduler <SchedulerSMPPriorityAffinity>`,
+
+  * ``"MPD "`` for the :ref:`Deterministic Priority SMP Scheduler <SchedulerSMPPriority>`,
+
+  * ``"MPS "`` for the :ref:`Simple Priority SMP Scheduler <SchedulerSMPPrioritySimple>`,
+
+  * ``"UCBS"`` for the :ref:`Uniprocessor CBS Scheduler <SchedulerCBS>`,
+
+  * ``"UEDF"`` for the :ref:`Uniprocessor EDF Scheduler <SchedulerEDF>`,
+
+  * ``"UPD "`` for the :ref:`Uniprocessor Deterministic Priority Scheduler <SchedulerPriority>`, and
+
+  * ``"UPS "`` for the :ref:`Uniprocessor Simple Priority Scheduler <SchedulerPrioritySimple>`.
+description: |
+  The value of this configuration option defines the name of the default
+  scheduler.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_NAME
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  Schedulers can be identified via c:func:`rtems_scheduler_ident`.
+
+  Use :c:func:`rtems_build_name` to define the scheduler name.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-priority-affinity-smp.yml b/spec/if/acfg/scheduler-priority-affinity-smp.yml
new file mode 100644
index 00000000..5fce590c
--- /dev/null
+++ b/spec/if/acfg/scheduler-priority-affinity-smp.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Arbitrary Processor Affinity SMP Scheduler <SchedulerSMPPriorityAffinity>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_PRIORITY_AFFINITY_SMP
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  This scheduler algorithm is only available when RTEMS is built with SMP
+  support enabled.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for up to 32 processors.
+
+  The memory allocated for this scheduler depends on the
+  :ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-priority-smp.yml b/spec/if/acfg/scheduler-priority-smp.yml
new file mode 100644
index 00000000..f23010bf
--- /dev/null
+++ b/spec/if/acfg/scheduler-priority-smp.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Deterministic Priority SMP Scheduler <SchedulerSMPPriority>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_PRIORITY_SMP
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  This scheduler algorithm is only available when RTEMS is built with SMP
+  support enabled.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for up to 32 processors.
+
+  The memory allocated for this scheduler depends on the
+  :ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-priority.yml b/spec/if/acfg/scheduler-priority.yml
new file mode 100644
index 00000000..4f991320
--- /dev/null
+++ b/spec/if/acfg/scheduler-priority.yml
@@ -0,0 +1,32 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2010 Gedare Bloom
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Deterministic Priority Scheduler <SchedulerPriority>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_PRIORITY
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for exactly one processor.
+
+  This scheduler algorithm is the default when
+  :ref:`CONFIGURE_MAXIMUM_PROCESSORS` is
+  exactly one.
+
+  The memory allocated for this scheduler depends on the
+  :ref:`CONFIGURE_MAXIMUM_PRIORITY` configuration option.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-simple-smp.yml b/spec/if/acfg/scheduler-simple-smp.yml
new file mode 100644
index 00000000..d3e0ac65
--- /dev/null
+++ b/spec/if/acfg/scheduler-simple-smp.yml
@@ -0,0 +1,28 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Simple Priority SMP Scheduler <SchedulerSMPPrioritySimple>`
+  algorithm is made available to the application.
+  application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_SIMPLE_SMP
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  This scheduler algorithm is only available when RTEMS is built with SMP
+  support enabled.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for up to 32 processors.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-simple.yml b/spec/if/acfg/scheduler-simple.yml
new file mode 100644
index 00000000..61e69517
--- /dev/null
+++ b/spec/if/acfg/scheduler-simple.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then
+  :ref:`Simple Priority Scheduler <SchedulerPrioritySimple>`
+  algorithm is made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_SIMPLE
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  In case no explicit :ref:`clustered scheduler configuration
+  <ConfigurationSchedulersClustered>` is present, then it is used as the
+  scheduler for exactly one processor.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-strong-apa.yml b/spec/if/acfg/scheduler-strong-apa.yml
new file mode 100644
index 00000000..d4a98198
--- /dev/null
+++ b/spec/if/acfg/scheduler-strong-apa.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then Strong APA algorithm is
+  made available to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_STRONG_APA
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  This scheduler algorithm is only available when RTEMS is built with SMP
+  support enabled.
+
+  This scheduler algorithm is not correctly implemented.  Do not use it.
+text: ''
+type: interface
diff --git a/spec/if/acfg/scheduler-user.yml b/spec/if/acfg/scheduler-user.yml
new file mode 100644
index 00000000..b7967f1d
--- /dev/null
+++ b/spec/if/acfg/scheduler-user.yml
@@ -0,0 +1,42 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2010 Gedare Bloom
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the user shall provide a
+  scheduler algorithm to the application.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-schedgeneral
+name: CONFIGURE_SCHEDULER_USER
+notes: |
+  This scheduler configuration option is an advanced configuration option.
+  Think twice before you use it.
+
+  RTEMS allows the application to provide its own task/thread scheduling
+  algorithm. In order to do this, one shall define
+  ``CONFIGURE_SCHEDULER_USER`` to indicate the application provides its own
+  scheduling algorithm. If ``CONFIGURE_SCHEDULER_USER`` is defined then the
+  following additional macros shall be defined:
+
+  * ``CONFIGURE_SCHEDULER`` shall be defined to a static definition of
+    the scheduler data structures of the user scheduler.
+
+  * ``CONFIGURE_SCHEDULER_TABLE_ENTRIES`` shall be defined to a scheduler
+    table entry initializer for the user scheduler.
+
+  * ``CONFIGURE_SCHEDULER_USER_PER_THREAD`` shall be defined to the type of
+    the per-thread information of the user scheduler.
+
+  At this time, the mechanics and requirements for writing a new scheduler
+  are evolving and not fully documented.  It is recommended that you look at
+  the existing Deterministic Priority Scheduler in
+  ``cpukit/score/src/schedulerpriority*.c`` for guidance.  For guidance on
+  the configuration macros, please examine ``cpukit/sapi/include/confdefs.h``
+  for how these are defined for the Deterministic Priority Scheduler.
+text: ''
+type: interface
diff --git a/spec/if/acfg/stack-checker-enabled.yml b/spec/if/acfg/stack-checker-enabled.yml
new file mode 100644
index 00000000..ca0e55fc
--- /dev/null
+++ b/spec/if/acfg/stack-checker-enabled.yml
@@ -0,0 +1,22 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the stack checker is
+  enabled.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_STACK_CHECKER_ENABLED
+notes: |
+  The stack checker performs run-time stack bounds checking.  This increases
+  the time required to create tasks as well as adding overhead to each context
+  switch.
+
+  In 4.9 and older, this configuration option was named ``STACK_CHECKER_ON``.
+text: ''
+type: interface
diff --git a/spec/if/acfg/task-stack-allocator-init.yml b/spec/if/acfg/task-stack-allocator-init.yml
new file mode 100644
index 00000000..139ecf27
--- /dev/null
+++ b/spec/if/acfg/task-stack-allocator-init.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void ( *initialize )( size_t )`` or to ``NULL``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: '``NULL``'
+description: |
+  The value of this configuration option initializes the stack allocator
+  initialization handler.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-stackalloc
+name: CONFIGURE_TASK_STACK_ALLOCATOR_INIT
+notes: |
+  A correctly configured system shall configure the following to be consistent:
+
+  * `CONFIGURE_TASK_STACK_ALLOCATOR_INIT`
+
+  * :ref:`CONFIGURE_TASK_STACK_ALLOCATOR`
+
+  * :ref:`CONFIGURE_TASK_STACK_DEALLOCATOR`
+text: ''
+type: interface
diff --git a/spec/if/acfg/task-stack-allocator.yml b/spec/if/acfg/task-stack-allocator.yml
new file mode 100644
index 00000000..acedb118
--- /dev/null
+++ b/spec/if/acfg/task-stack-allocator.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void *( *allocate )( size_t )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is ``_Workspace_Allocate``, which indicates that task
+  stacks will be allocated from the RTEMS Workspace.
+description: |
+  The value of this configuration option initializes the stack allocator
+  allocate handler.
+enabled-by: true
+index-entries:
+- task stack allocator
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-stackalloc
+name: CONFIGURE_TASK_STACK_ALLOCATOR
+notes: |
+  A correctly configured system shall configure the following to be consistent:
+
+  * :ref:`CONFIGURE_TASK_STACK_ALLOCATOR_INIT`
+
+  * `CONFIGURE_TASK_STACK_ALLOCATOR`
+
+  * :ref:`CONFIGURE_TASK_STACK_DEALLOCATOR`
+text: ''
+type: interface
diff --git a/spec/if/acfg/task-stack-deallocator.yml b/spec/if/acfg/task-stack-deallocator.yml
new file mode 100644
index 00000000..50c21616
--- /dev/null
+++ b/spec/if/acfg/task-stack-deallocator.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a valid function
+    pointer of the type ``void ( *deallocate )( void * )``.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: |
+  The default value is ``_Workspace_Free``, which indicates that task stacks
+  will be allocated from the RTEMS Workspace.
+description: |
+  The value of this configuration option initializes the stack allocator
+  deallocate handler.
+enabled-by: true
+index-entries:
+- task stack deallocator
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-stackalloc
+name: CONFIGURE_TASK_STACK_DEALLOCATOR
+notes: |
+  A correctly configured system shall configure the following to be consistent:
+
+  * :ref:`CONFIGURE_TASK_STACK_ALLOCATOR_INIT`
+
+  * :ref:`CONFIGURE_TASK_STACK_ALLOCATOR`
+
+  * `CONFIGURE_TASK_STACK_DEALLOCATOR`
+text: ''
+type: interface
diff --git a/spec/if/acfg/task-stack-from-alloc.yml b/spec/if/acfg/task-stack-from-alloc.yml
new file mode 100644
index 00000000..b9dc7390
--- /dev/null
+++ b/spec/if/acfg/task-stack-from-alloc.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: initializer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall be defined to a macro which
+    accepts exactly one parameter and returns an unsigned integer.  The
+    parameter will be an allocation size and the macro shall return this size
+    plus the overhead of the allocator to manage an allocation request for this
+    size.
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+default-value: |
+  The default value is a macro which supports the system heap allocator.
+description: |
+  The value of this configuration option is used to calculate the task stack
+  space size.
+enabled-by: true
+index-entries:
+- task stack allocator
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-stackalloc
+name: CONFIGURE_TASK_STACK_FROM_ALLOCATOR
+notes: |
+  This configuration option may be used if a custom task stack allocator is
+  configured, see :ref:`CONFIGURE_TASK_STACK_ALLOCATOR`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/task-stack-no-workspace.yml b/spec/if/acfg/task-stack-no-workspace.yml
new file mode 100644
index 00000000..ab1c7693
--- /dev/null
+++ b/spec/if/acfg/task-stack-no-workspace.yml
@@ -0,0 +1,19 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
+description: |
+  In case this configuration option is defined, then the system is informed
+  that the task stack allocator does not use the RTEMS Workspace.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-stackalloc
+name: CONFIGURE_TASK_STACK_ALLOCATOR_AVOIDS_WORK_SPACE
+notes: |
+  This configuration option may be used if a custom task stack allocator is
+  configured, see :ref:`CONFIGURE_TASK_STACK_ALLOCATOR`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/ticks-per-time-slice.yml b/spec/if/acfg/ticks-per-time-slice.yml
new file mode 100644
index 00000000..24e5f0f8
--- /dev/null
+++ b/spec/if/acfg/ticks-per-time-slice.yml
@@ -0,0 +1,24 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  max: '``UINT32_MAX``'
+  min: 0
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 50
+description: |
+  The value of this configuration option defines the length of the timeslice
+  quantum in ticks for each task.
+enabled-by: true
+index-entries:
+- ticks per timeslice
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_TICKS_PER_TIMESLICE
+notes: |
+  This configuration option has no impact if the Clock Driver is not
+  configured, see :ref:`CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/unified-work-areas.yml b/spec/if/acfg/unified-work-areas.yml
new file mode 100644
index 00000000..1a99d8f1
--- /dev/null
+++ b/spec/if/acfg/unified-work-areas.yml
@@ -0,0 +1,33 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default: |
+  If this configuration option is undefined, then there will be separate memory
+  pools for the RTEMS Workspace and C Program Heap.
+description: |
+  In case this configuration option is defined, then the RTEMS Workspace and
+  the C Program Heap will be one pool of memory.
+enabled-by: true
+index-entries:
+- unified work areas
+- separate work areas
+- RTEMS Workspace
+- C Program Heap
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_UNIFIED_WORK_AREAS
+notes: |
+  Having separate pools does have some advantages in the event a task blows a
+  stack or writes outside its memory area. However, in low memory systems the
+  overhead of the two pools plus the potential for unused memory in either
+  pool is very undesirable.
+
+  In high memory environments, this is desirable when you want to use the
+  :ref:`ConfigUnlimitedObjects` option.  You will be able to create objects
+  until you run out of all available memory rather then just until you run out
+  of RTEMS Workspace.
+text: ''
+type: interface
diff --git a/spec/if/acfg/unlimited-allocation-size.yml b/spec/if/acfg/unlimited-allocation-size.yml
new file mode 100644
index 00000000..d77027c1
--- /dev/null
+++ b/spec/if/acfg/unlimited-allocation-size.yml
@@ -0,0 +1,30 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: integer
+constraints:
+  texts:
+  - |
+    The value of this configuration option shall meet the constraints of all
+    object classes to which it is applied.
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+default-value: 8
+description: |
+  If :ref:`CONFIGURE_UNLIMITED_OBJECTS` is defined, then the value of this
+  configuration option defines the default objects maximum of all object
+  classes supporting :ref:`ConfigUnlimitedObjects` to
+  ``rtems_resource_unlimited(CONFIGURE_UNLIMITED_ALLOCATION_SIZE)``.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_UNLIMITED_ALLOCATION_SIZE
+notes: |
+  By allowing users to declare all resources as being unlimited the user can
+  avoid identifying and limiting the resources used.
+
+  The object maximum of each class can be configured also individually using
+  the :c:func:`rtems_resource_unlimited` macro.
+text: ''
+type: interface
diff --git a/spec/if/acfg/unlimited-objects.yml b/spec/if/acfg/unlimited-objects.yml
new file mode 100644
index 00000000..74b0a1c5
--- /dev/null
+++ b/spec/if/acfg/unlimited-objects.yml
@@ -0,0 +1,25 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then unlimited objects are used
+  by default.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_UNLIMITED_OBJECTS
+notes: |
+  When using unlimited objects, it is common practice to also specify
+  :ref:`CONFIGURE_UNIFIED_WORK_AREAS` so the system operates with a single pool
+  of memory for both RTEMS Workspace and C Program Heap.
+
+  This option does not override an explicit configuration for a particular
+  object class by the user.
+
+  See also :ref:`CONFIGURE_UNLIMITED_ALLOCATION_SIZE`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/use-devfs-as-base-filesystem.yml b/spec/if/acfg/use-devfs-as-base-filesystem.yml
new file mode 100644
index 00000000..c6f25693
--- /dev/null
+++ b/spec/if/acfg/use-devfs-as-base-filesystem.yml
@@ -0,0 +1,50 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then an IMFS with a reduced
+  feature set will be the base filesystem (also known as root filesystem).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
+notes: |
+  In case this configuration option is defined, then the following
+  configuration options will be defined as well
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHMOD`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHOWN`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_LINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_MKNOD_FILE`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_MOUNT`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_READDIR`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_READLINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_RENAME`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_RMNOD`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_SYMLINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UTIME`, and
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UNMOUNT`.
+
+  In addition, a simplified path evaluation is enabled.  It allows only a look
+  up of absolute paths.
+
+  This configuration of the IMFS is basically a device-only filesystem.  It is
+  comparable in functionality to the pseudo-filesystem name space provided
+  before RTEMS release 4.5.0.
+text: ''
+type: interface
diff --git a/spec/if/acfg/use-miniimfs-as-base-filesystem.yml b/spec/if/acfg/use-miniimfs-as-base-filesystem.yml
new file mode 100644
index 00000000..1d14e1b3
--- /dev/null
+++ b/spec/if/acfg/use-miniimfs-as-base-filesystem.yml
@@ -0,0 +1,35 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then an IMFS with a reduced
+  feature set will be the base filesystem (also known as root filesystem).
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-filesystem
+name: CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
+notes: |
+  In case this configuration option is defined, then the following
+  configuration options will be defined as well
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHMOD`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_CHOWN`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_LINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_READLINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_RENAME`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_SYMLINK`,
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UTIME`, and
+
+  * :ref:`CONFIGURE_IMFS_DISABLE_UNMOUNT`.
+text: ''
+type: interface
diff --git a/spec/if/acfg/verbose-system-init.yml b/spec/if/acfg/verbose-system-init.yml
new file mode 100644
index 00000000..f39cf1dd
--- /dev/null
+++ b/spec/if/acfg/verbose-system-init.yml
@@ -0,0 +1,19 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the system initialization
+  is verbose.
+enabled-by: true
+index-entries: []
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_VERBOSE_SYSTEM_INITIALIZATION
+notes: |
+  You may use this feature to debug system initialization issues.  The
+  :c:func:`printk` function is used to print the information.
+text: ''
+type: interface
diff --git a/spec/if/acfg/zero-workspace-automatically.yml b/spec/if/acfg/zero-workspace-automatically.yml
new file mode 100644
index 00000000..64acbcb7
--- /dev/null
+++ b/spec/if/acfg/zero-workspace-automatically.yml
@@ -0,0 +1,26 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+appl-config-option-type: feature-enable
+copyrights:
+- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+description: |
+  In case this configuration option is defined, then the memory areas used for
+  the RTEMS Workspace and the C Program Heap are zeroed with a ``0x00`` byte
+  pattern during system initialization.
+enabled-by: true
+index-entries:
+- clear C Program Heap
+- clear RTEMS Workspace
+- zero C Program Heap
+- zero RTEMS Workspace
+interface-type: appl-config-option
+links:
+- role: appl-config-group-member
+  uid: group-general
+name: CONFIGURE_ZERO_WORKSPACE_AUTOMATICALLY
+notes: |
+  Zeroing memory can add significantly to the system initialization time. It is
+  not necessary for RTEMS but is often assumed by support libraries.  In case
+  :ref:`CONFIGURE_DIRTY_MEMORY` is also defined, then the memory is first
+  dirtied and then zeroed.
+text: ''
+type: interface