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+System Initialization
+After the RTEMS initialization is performed, the application’s
+initialization will be performed. Part of initialization is a call to
+rtems_filesystem_initialize(). This routine will mount the ‘In Memory File
+System’ as the base filesystem. Mounting the base filesystem consists
+of the following:
+- Initialization of mount table chain control structure
+- Allocation of a ``jnode`` structure that will server as the root node
+ of the ‘In Memory Filesystem’
+- Initialization of the allocated ``jnode`` with the appropriate OPS,
+ directory handlers and pathconf limits and options.
+- Allocation of a memory region for filesystem specific global
+ management variables
+- Creation of first mount table entry for the base filesystem
+- Initialization of the first mount table chain entry to indicate that
+ the mount point is NULL and the mounted filesystem is the base file
+ system
+After the base filesystem has been mounted, the following operations are
+performed under its directory structure:
+- Creation of the /dev directory
+- Registration of devices under /dev directory
+Base Filesystem
+RTEMS initially mounts a RAM based file system known as the base file system.
+The root directory of this file system tree serves as the logical root of the
+directory hierarchy (Figure 3). Under the root directory a ‘/dev’ directory
+is created under which all I/O device directories and files are registered as
+part of the file system hierarchy.
+.. code:: c
+ Figure of the tree structure goes here.
+A RAM based file system draws its management resources from memory. File and
+directory nodes are simply allocated blocks of memory. Data associated with
+regular files is stored in collections of memory blocks. When the system is
+turned off or restarted all memory-based components of the file system are
+The base file system serves as a starting point for the mounting of file
+systems that are resident on semi-permanent storage media. Examples of such
+media include non- volatile memory, flash memory and IDE hard disk drives
+(Figure 3). File systems of other types will be mounted onto mount points
+within the base file system or other file systems that are subordinate to the
+base file system. The framework set up under the base file system will allow
+for these new file system types and the unique data and functionality that is
+required to manage the future file systems.
+Base Filesystem Mounting
+At present, the first file system to be mounted is the ‘In Memory File
+System’. It is mounted using a standard MOUNT() command in which the mount
+point is NULL. This flags the mount as the first file system to be
+registered under the operating system and appropriate initialization of file
+system management information is performed (See figures 4 and 5). If a
+different file system type is desired as the base file system, alterations
+must be made to base_fs.c. This routine handles the mount of the base file
+.. code:: c
+ Figure of the mount table chain goes here.
+Once the root of the base file system has been established and it has been
+recorded as the mount point of the base file system, devices are integrated
+into the base file system. For every device that is configured into the
+system (See ioman.c) a device registration process is performed. Device
+registration produces a unique dev_t handle that consists of a major and
+minor device number. In addition, the configuration information for each
+device contains a text string that represents the fully qualified pathname to
+that device’s place in the base file system’s hierarchy. A file system node
+is created for the device along the specified registration path.
+.. code:: c
+ Figure of the Mount Table Processing goes here.
+Note: Other file systems can be mounted but they are mounted onto points
+(directory mount points) in the base file system.
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+.. COMMENT: All rights reserved.