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authorSebastian Huber <sebastian.huber@embedded-brains.de>2020-02-26 15:58:27 +0100
committerSebastian Huber <sebastian.huber@embedded-brains.de>2020-03-02 08:11:42 +0100
commit43b7eeb5b0ad7bf701195366130ac68eeea15001 (patch)
tree529c7f3f8fb19b639cdbe797c6aa84c5036230fa
parentc-user: Canonicalize two glossary acronyms (diff)
downloadrtems-docs-43b7eeb5b0ad7bf701195366130ac68eeea15001.tar.bz2
c-user: Use four spaces per indent level
Four spaces per indent level is used in most files. Update #3853.
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@@ -4,777 +4,777 @@ Glossary
********
.. glossary::
- :sorted:
+ :sorted:
- active
- A term used to describe an object which has been created by an
- application.
+ active
+ A term used to describe an object which has been created by an
+ application.
- aperiodic task
- A task which must execute only at irregular intervals and has only a soft
- deadline.
+ aperiodic task
+ A task which must execute only at irregular intervals and has only a soft
+ deadline.
- API
- An acronym for Application Programming Interface.
+ API
+ An acronym for Application Programming Interface.
- application
- In this document, software which makes use of RTEMS.
+ application
+ In this document, software which makes use of RTEMS.
- ASR
- An acronym for :term:`Asynchronous Signal Routine`.
+ ASR
+ An acronym for :term:`Asynchronous Signal Routine`.
- asynchronous
- Not related in order or timing to other occurrences in the system.
+ asynchronous
+ Not related in order or timing to other occurrences in the system.
- Asynchronous Signal Routine
- Similar to a hardware interrupt except that it is associated with a task
- and is run in the context of a task. The directives provided by the
- signal manager are used to service signals.
+ Asynchronous Signal Routine
+ Similar to a hardware interrupt except that it is associated with a task
+ and is run in the context of a task. The directives provided by the
+ signal manager are used to service signals.
- atomic operations
- Atomic operations are defined in terms of :term:`C11`.
+ atomic operations
+ Atomic operations are defined in terms of :term:`C11`.
- awakened
- A term used to describe a task that has been unblocked and may be
- scheduled to the CPU.
+ awakened
+ A term used to describe a task that has been unblocked and may be
+ scheduled to the CPU.
- big endian
- A data representation scheme in which the bytes composing a numeric value
- are arranged such that the most significant byte is at the lowest
- address.
+ big endian
+ A data representation scheme in which the bytes composing a numeric value
+ are arranged such that the most significant byte is at the lowest
+ address.
- bit-mapped
- A data encoding scheme in which each bit in a variable is used to
- represent something different. This makes for compact data
- representation.
+ bit-mapped
+ A data encoding scheme in which each bit in a variable is used to
+ represent something different. This makes for compact data
+ representation.
- block
- A physically contiguous area of memory.
+ block
+ A physically contiguous area of memory.
- blocked task
- The task state entered by a task which has been previously started and
- cannot continue execution until the reason for waiting has been
- satisfied. Blocked tasks are not an element of the set of ready tasks of
- a scheduler instance.
+ blocked task
+ The task state entered by a task which has been previously started and
+ cannot continue execution until the reason for waiting has been
+ satisfied. Blocked tasks are not an element of the set of ready tasks of
+ a scheduler instance.
- broadcast
- To simultaneously send a message to a logical set of destinations.
+ broadcast
+ To simultaneously send a message to a logical set of destinations.
- Board Support Package
- A collection of device initialization and control routines specific to a
- particular type of board or collection of boards.
+ Board Support Package
+ A collection of device initialization and control routines specific to a
+ particular type of board or collection of boards.
- buffer
- A fixed length block of memory allocated from a partition.
+ buffer
+ A fixed length block of memory allocated from a partition.
- BSP
- An acronym for :term:`Board Support Package`.
+ BSP
+ An acronym for :term:`Board Support Package`.
- C11
- The standard ISO/IEC 9899:2011.
+ C11
+ The standard ISO/IEC 9899:2011.
- C++11
- The standard ISO/IEC 14882:2011.
+ C++11
+ The standard ISO/IEC 14882:2011.
- calling convention
- The processor and compiler dependent rules which define the mechanism
- used to invoke subroutines in a high-level language. These rules define
- the passing of arguments, the call and return mechanism, and the register
- set which must be preserved.
+ calling convention
+ The processor and compiler dependent rules which define the mechanism
+ used to invoke subroutines in a high-level language. These rules define
+ the passing of arguments, the call and return mechanism, and the register
+ set which must be preserved.
- Central Processing Unit
- This term is equivalent to the terms processor and microprocessor.
+ Central Processing Unit
+ This term is equivalent to the terms processor and microprocessor.
- chain
- A data structure which allows for efficient dynamic addition and removal
- of elements. It differs from an array in that it is not limited to a
- predefined size.
+ chain
+ A data structure which allows for efficient dynamic addition and removal
+ of elements. It differs from an array in that it is not limited to a
+ predefined size.
- cluster
- We have clustered scheduling in case the set of processors of a system is
- partitioned into non-empty pairwise disjoint subsets. These subsets are
- called clusters. Clusters with a cardinality of one are partitions.
- Each cluster is owned by exactly one scheduler instance.
+ cluster
+ We have clustered scheduling in case the set of processors of a system is
+ partitioned into non-empty pairwise disjoint subsets. These subsets are
+ called clusters. Clusters with a cardinality of one are partitions.
+ Each cluster is owned by exactly one scheduler instance.
- coalesce
- The process of merging adjacent holes into a single larger hole.
- Sometimes this process is referred to as garbage collection.
+ coalesce
+ The process of merging adjacent holes into a single larger hole.
+ Sometimes this process is referred to as garbage collection.
- Configuration Table
- A table which contains information used to tailor RTEMS for a particular
- application.
+ Configuration Table
+ A table which contains information used to tailor RTEMS for a particular
+ application.
- context
- All of the processor registers and operating system data structures
- associated with a task.
+ context
+ All of the processor registers and operating system data structures
+ associated with a task.
- context switch
- Alternate term for task switch. Taking control of the processor from one
- task and transferring it to another task.
+ context switch
+ Alternate term for task switch. Taking control of the processor from one
+ task and transferring it to another task.
- control block
- A data structure used by the executive to define and control an object.
+ control block
+ A data structure used by the executive to define and control an object.
- core
- When used in this manual, this term refers to the internal executive
- utility functions. In the interest of application portability, the core
- of the executive should not be used directly by applications.
+ core
+ When used in this manual, this term refers to the internal executive
+ utility functions. In the interest of application portability, the core
+ of the executive should not be used directly by applications.
- CPU
- An acronym for :term:`Central Processing Unit`.
+ CPU
+ An acronym for :term:`Central Processing Unit`.
- critical section
- A section of code which must be executed indivisibly.
+ critical section
+ A section of code which must be executed indivisibly.
- CRT
- An acronym for Cathode Ray Tube. Normally used in reference to the
- man-machine interface.
-
- deadline
- A fixed time limit by which a task must have completed a set of actions.
- Beyond this point, the results are of reduced value and may even be
- considered useless or harmful.
-
- device
- A peripheral used by the application that requires special operation
- software. See also device driver.
-
- device driver
- Control software for special peripheral devices used by the application.
-
- directives
- RTEMS' provided routines that provide support mechanisms for real-time
- applications.
-
- dispatch
- The act of loading a task's context onto the CPU and transferring control
- of the CPU to that task.
-
- dormant
- The state entered by a task after it is created and before it has been
- started.
-
- Device Driver Table
- A table which contains the entry points for each of the configured device
- drivers.
-
- dual-ported
- A term used to describe memory which can be accessed at two different
- addresses.
-
- embedded
- An application that is delivered as a hidden part of a larger system.
- For example, the software in a fuel-injection control system is an
- embedded application found in many late-model automobiles.
+ CRT
+ An acronym for Cathode Ray Tube. Normally used in reference to the
+ man-machine interface.
+
+ deadline
+ A fixed time limit by which a task must have completed a set of actions.
+ Beyond this point, the results are of reduced value and may even be
+ considered useless or harmful.
+
+ device
+ A peripheral used by the application that requires special operation
+ software. See also device driver.
+
+ device driver
+ Control software for special peripheral devices used by the application.
+
+ directives
+ RTEMS' provided routines that provide support mechanisms for real-time
+ applications.
+
+ dispatch
+ The act of loading a task's context onto the CPU and transferring control
+ of the CPU to that task.
+
+ dormant
+ The state entered by a task after it is created and before it has been
+ started.
+
+ Device Driver Table
+ A table which contains the entry points for each of the configured device
+ drivers.
+
+ dual-ported
+ A term used to describe memory which can be accessed at two different
+ addresses.
+
+ embedded
+ An application that is delivered as a hidden part of a larger system.
+ For example, the software in a fuel-injection control system is an
+ embedded application found in many late-model automobiles.
- envelope
- A buffer provided by the MPCI layer to RTEMS which is used to pass
- messages between nodes in a multiprocessor system. It typically contains
- routing information needed by the MPCI. The contents of an envelope are
- referred to as a packet.
-
- entry point
- The address at which a function or task begins to execute. In C, the
- entry point of a function is the function's name.
-
- events
- A method for task communication and synchronization. The directives
- provided by the event manager are used to service events.
+ envelope
+ A buffer provided by the MPCI layer to RTEMS which is used to pass
+ messages between nodes in a multiprocessor system. It typically contains
+ routing information needed by the MPCI. The contents of an envelope are
+ referred to as a packet.
+
+ entry point
+ The address at which a function or task begins to execute. In C, the
+ entry point of a function is the function's name.
+
+ events
+ A method for task communication and synchronization. The directives
+ provided by the event manager are used to service events.
- exception
- A synonym for interrupt.
+ exception
+ A synonym for interrupt.
- executing task
- The task state entered by a task after it has been given control of the
- processor. In SMP configurations, a task may be registered as executing
- on more than one processor for short time frames during task migration.
- Blocked tasks can be executing until they issue a thread dispatch.
+ executing task
+ The task state entered by a task after it has been given control of the
+ processor. In SMP configurations, a task may be registered as executing
+ on more than one processor for short time frames during task migration.
+ Blocked tasks can be executing until they issue a thread dispatch.
- executive
- In this document, this term is used to referred to RTEMS. Commonly, an
- executive is a small real-time operating system used in embedded systems.
+ executive
+ In this document, this term is used to referred to RTEMS. Commonly, an
+ executive is a small real-time operating system used in embedded systems.
- exported
- An object known by all nodes in a multiprocessor system. An object
- created with the GLOBAL attribute will be exported.
+ exported
+ An object known by all nodes in a multiprocessor system. An object
+ created with the GLOBAL attribute will be exported.
- external address
- The address used to access dual-ported memory by all the nodes in a
- system which do not own the memory.
+ external address
+ The address used to access dual-ported memory by all the nodes in a
+ system which do not own the memory.
- FIFO
- An acronym for :term:`First In First Out`.
-
- First In First Out
- A discipline for manipulating entries in a data structure.
+ FIFO
+ An acronym for :term:`First In First Out`.
+
+ First In First Out
+ A discipline for manipulating entries in a data structure.
- floating point coprocessor
- A component used in computer systems to enhance performance in
- mathematically intensive situations. It is typically viewed as a logical
- extension of the primary processor.
+ floating point coprocessor
+ A component used in computer systems to enhance performance in
+ mathematically intensive situations. It is typically viewed as a logical
+ extension of the primary processor.
- freed
- A resource that has been released by the application to RTEMS.
-
- global
- An object that has been created with the GLOBAL attribute and exported to
- all nodes in a multiprocessor system.
+ freed
+ A resource that has been released by the application to RTEMS.
+
+ global
+ An object that has been created with the GLOBAL attribute and exported to
+ all nodes in a multiprocessor system.
- handler
- The equivalent of a manager, except that it is internal to RTEMS and
- forms part of the core. A handler is a collection of routines which
- provide a related set of functions. For example, there is a handler used
- by RTEMS to manage all objects.
+ handler
+ The equivalent of a manager, except that it is internal to RTEMS and
+ forms part of the core. A handler is a collection of routines which
+ provide a related set of functions. For example, there is a handler used
+ by RTEMS to manage all objects.
- hard real-time system
- A real-time system in which a missed deadline causes the worked performed
- to have no value or to result in a catastrophic effect on the integrity
- of the system.
+ hard real-time system
+ A real-time system in which a missed deadline causes the worked performed
+ to have no value or to result in a catastrophic effect on the integrity
+ of the system.
- heap
- A data structure used to dynamically allocate and deallocate variable
- sized blocks of memory.
+ heap
+ A data structure used to dynamically allocate and deallocate variable
+ sized blocks of memory.
- heir task
- A task is an heir if it is registered as an heir in a processor of the
- system. A task can be the heir on at most one processor in the system.
- In case the executing and heir tasks differ on a processor and a thread
- dispatch is marked as necessary, then the next thread dispatch will make
- the heir task the executing task.
+ heir task
+ A task is an heir if it is registered as an heir in a processor of the
+ system. A task can be the heir on at most one processor in the system.
+ In case the executing and heir tasks differ on a processor and a thread
+ dispatch is marked as necessary, then the next thread dispatch will make
+ the heir task the executing task.
- heterogeneous
- A multiprocessor computer system composed of dissimilar processors.
+ heterogeneous
+ A multiprocessor computer system composed of dissimilar processors.
- homogeneous
- A multiprocessor computer system composed of a single type of processor.
+ homogeneous
+ A multiprocessor computer system composed of a single type of processor.
- ID
- An RTEMS assigned identification tag used to access an active object.
+ ID
+ An RTEMS assigned identification tag used to access an active object.
- IDLE task
- A special low priority task which assumes control of the CPU when no
- other task is able to execute.
+ IDLE task
+ A special low priority task which assumes control of the CPU when no
+ other task is able to execute.
- interface
- A specification of the methodology used to connect multiple independent
- subsystems.
+ interface
+ A specification of the methodology used to connect multiple independent
+ subsystems.
- internal address
- The address used to access dual-ported memory by the node which owns the
- memory.
+ internal address
+ The address used to access dual-ported memory by the node which owns the
+ memory.
- interrupt
- A hardware facility that causes the CPU to suspend execution, save its
- status, and transfer control to a specific location.
+ interrupt
+ A hardware facility that causes the CPU to suspend execution, save its
+ status, and transfer control to a specific location.
- interrupt level
- A mask used to by the CPU to determine which pending interrupts should be
- serviced. If a pending interrupt is below the current interrupt level,
- then the CPU does not recognize that interrupt.
+ interrupt level
+ A mask used to by the CPU to determine which pending interrupts should be
+ serviced. If a pending interrupt is below the current interrupt level,
+ then the CPU does not recognize that interrupt.
- Interrupt Service Routine
- An ISR is invoked by the CPU to process a pending interrupt.
+ Interrupt Service Routine
+ An ISR is invoked by the CPU to process a pending interrupt.
- I/O
- An acronym for Input/Output.
+ I/O
+ An acronym for Input/Output.
- ISR
- An acronym for :term:`Interrupt Service Routine`.
+ ISR
+ An acronym for :term:`Interrupt Service Routine`.
- kernel
- In this document, this term is used as a synonym for executive.
+ kernel
+ In this document, this term is used as a synonym for executive.
- list
- A data structure which allows for dynamic addition and removal of
- entries. It is not statically limited to a particular size.
+ list
+ A data structure which allows for dynamic addition and removal of
+ entries. It is not statically limited to a particular size.
- little endian
- A data representation scheme in which the bytes composing a numeric value
- are arranged such that the least significant byte is at the lowest
- address.
+ little endian
+ A data representation scheme in which the bytes composing a numeric value
+ are arranged such that the least significant byte is at the lowest
+ address.
- local
- An object which was created with the LOCAL attribute and is accessible
- only on the node it was created and resides upon. In a single processor
- configuration, all objects are local.
+ local
+ An object which was created with the LOCAL attribute and is accessible
+ only on the node it was created and resides upon. In a single processor
+ configuration, all objects are local.
- local operation
- The manipulation of an object which resides on the same node as the
- calling task.
+ local operation
+ The manipulation of an object which resides on the same node as the
+ calling task.
- logical address
- An address used by an application. In a system without memory
- management, logical addresses will equal physical addresses.
+ logical address
+ An address used by an application. In a system without memory
+ management, logical addresses will equal physical addresses.
- loosely-coupled
- A multiprocessor configuration where shared memory is not used for
- communication.
+ loosely-coupled
+ A multiprocessor configuration where shared memory is not used for
+ communication.
- major number
- The index of a device driver in the Device Driver Table.
+ major number
+ The index of a device driver in the Device Driver Table.
- manager
- A group of related RTEMS' directives which provide access and control
- over resources.
+ manager
+ A group of related RTEMS' directives which provide access and control
+ over resources.
- MCS
- An acronym for Mellor-Crummey Scott.
+ MCS
+ An acronym for Mellor-Crummey Scott.
- memory pool
- Used interchangeably with heap.
+ memory pool
+ Used interchangeably with heap.
- message
- A sixteen byte entity used to communicate between tasks. Messages are
- sent to message queues and stored in message buffers.
+ message
+ A sixteen byte entity used to communicate between tasks. Messages are
+ sent to message queues and stored in message buffers.
- message buffer
- A block of memory used to store messages.
+ message buffer
+ A block of memory used to store messages.
- message queue
- An RTEMS object used to synchronize and communicate between tasks by
- transporting messages between sending and receiving tasks.
+ message queue
+ An RTEMS object used to synchronize and communicate between tasks by
+ transporting messages between sending and receiving tasks.
- Message Queue Control Block
- A data structure associated with each message queue used by RTEMS to
- manage that message queue.
+ Message Queue Control Block
+ A data structure associated with each message queue used by RTEMS to
+ manage that message queue.
- minor number
- A numeric value passed to a device driver, the exact usage of which is
- driver dependent.
+ minor number
+ A numeric value passed to a device driver, the exact usage of which is
+ driver dependent.
- mode
- An entry in a task's control block that is used to determine if the task
- allows preemption, timeslicing, processing of signals, and the interrupt
- disable level used by the task.
+ mode
+ An entry in a task's control block that is used to determine if the task
+ allows preemption, timeslicing, processing of signals, and the interrupt
+ disable level used by the task.
- MPCI
- An acronym for :term:`Multiprocessor Communications Interface Layer`.
+ MPCI
+ An acronym for :term:`Multiprocessor Communications Interface Layer`.
- multiprocessing
- The simultaneous execution of two or more processes by a multiple
- processor computer system.
+ multiprocessing
+ The simultaneous execution of two or more processes by a multiple
+ processor computer system.
- multiprocessor
- A computer with multiple CPUs available for executing applications.
+ multiprocessor
+ A computer with multiple CPUs available for executing applications.
- Multiprocessor Communications Interface Layer
- A set of user-provided routines which enable the nodes in a
- multiprocessor system to communicate with one another.
+ Multiprocessor Communications Interface Layer
+ A set of user-provided routines which enable the nodes in a
+ multiprocessor system to communicate with one another.
- Multiprocessor Configuration Table
- The data structure defining the characteristics of the multiprocessor
- target system with which RTEMS will communicate.
+ Multiprocessor Configuration Table
+ The data structure defining the characteristics of the multiprocessor
+ target system with which RTEMS will communicate.
- multitasking
- The alternation of execution amongst a group of processes on a single
- CPU. A scheduling algorithm is used to determine which process executes
- at which time.
+ multitasking
+ The alternation of execution amongst a group of processes on a single
+ CPU. A scheduling algorithm is used to determine which process executes
+ at which time.
- mutual exclusion
- A term used to describe the act of preventing other tasks from accessing
- a resource simultaneously.
+ mutual exclusion
+ A term used to describe the act of preventing other tasks from accessing
+ a resource simultaneously.
- nested
- A term used to describe an ASR that occurs during another ASR or an ISR
- that occurs during another ISR.
+ nested
+ A term used to describe an ASR that occurs during another ASR or an ISR
+ that occurs during another ISR.
- node
- A term used to reference a processor running RTEMS in a multiprocessor
- system.
+ node
+ A term used to reference a processor running RTEMS in a multiprocessor
+ system.
- non-existent
- The state occupied by an uncreated or deleted task.
-
- NUMA
- An acronym for Non-Uniform Memory Access.
+ non-existent
+ The state occupied by an uncreated or deleted task.
+
+ NUMA
+ An acronym for Non-Uniform Memory Access.
- numeric coprocessor
- A component used in computer systems to enhance performance in
- mathematically intensive situations. It is typically viewed as a logical
- extension of the primary processor.
+ numeric coprocessor
+ A component used in computer systems to enhance performance in
+ mathematically intensive situations. It is typically viewed as a logical
+ extension of the primary processor.
- object
- In this document, this term is used to refer collectively to tasks,
- timers, message queues, partitions, regions, semaphores, ports, and rate
- monotonic periods. All RTEMS objects have IDs and user-assigned names.
+ object
+ In this document, this term is used to refer collectively to tasks,
+ timers, message queues, partitions, regions, semaphores, ports, and rate
+ monotonic periods. All RTEMS objects have IDs and user-assigned names.
- object-oriented
- A term used to describe systems with common mechanisms for utilizing a
- variety of entities. Object-oriented systems shield the application from
- implementation details.
+ object-oriented
+ A term used to describe systems with common mechanisms for utilizing a
+ variety of entities. Object-oriented systems shield the application from
+ implementation details.
- operating system
- The software which controls all the computer's resources and provides the
- base upon which application programs can be written.
+ operating system
+ The software which controls all the computer's resources and provides the
+ base upon which application programs can be written.
- overhead
- The portion of the CPUs processing power consumed by the operating
- system.
+ overhead
+ The portion of the CPUs processing power consumed by the operating
+ system.
- packet
- A buffer which contains the messages passed between nodes in a
- multiprocessor system. A packet is the contents of an envelope.
+ packet
+ A buffer which contains the messages passed between nodes in a
+ multiprocessor system. A packet is the contents of an envelope.
- partition
- An RTEMS object which is used to allocate and deallocate fixed size
- blocks of memory from an dynamically specified area of memory.
+ partition
+ An RTEMS object which is used to allocate and deallocate fixed size
+ blocks of memory from an dynamically specified area of memory.
- partition
- Clusters with a cardinality of one are partitions.
+ partition
+ Clusters with a cardinality of one are partitions.
- Partition Control Block
- A data structure associated with each partition used by RTEMS to manage
- that partition.
+ Partition Control Block
+ A data structure associated with each partition used by RTEMS to manage
+ that partition.
- pending
- A term used to describe a task blocked waiting for an event, message,
- semaphore, or signal.
+ pending
+ A term used to describe a task blocked waiting for an event, message,
+ semaphore, or signal.
- periodic task
- A task which must execute at regular intervals and comply with a hard
- deadline.
+ periodic task
+ A task which must execute at regular intervals and comply with a hard
+ deadline.
- physical address
- The actual hardware address of a resource.
+ physical address
+ The actual hardware address of a resource.
- poll
- A mechanism used to determine if an event has occurred by periodically
- checking for a particular status. Typical events include arrival of
- data, completion of an action, and errors.
+ poll
+ A mechanism used to determine if an event has occurred by periodically
+ checking for a particular status. Typical events include arrival of
+ data, completion of an action, and errors.
- pool
- A collection from which resources are allocated.
+ pool
+ A collection from which resources are allocated.
- portability
- A term used to describe the ease with which software can be rehosted on
- another computer.
+ portability
+ A term used to describe the ease with which software can be rehosted on
+ another computer.
- posting
- The act of sending an event, message, semaphore, or signal to a task.
+ posting
+ The act of sending an event, message, semaphore, or signal to a task.
- preempt
- The act of forcing a task to relinquish the processor and dispatching to
- another task.
+ preempt
+ The act of forcing a task to relinquish the processor and dispatching to
+ another task.
- priority
- A mechanism used to represent the relative importance of an element in a
- set of items. RTEMS uses priority to determine which task should
- execute.
+ priority
+ A mechanism used to represent the relative importance of an element in a
+ set of items. RTEMS uses priority to determine which task should
+ execute.
- priority boosting
- A simple approach to extend the priority inheritance protocol for
- clustered scheduling is priority boosting. In case a mutex is owned by a
- task of another cluster, then the priority of the owner task is raised to
- an artificially high priority, the pseudo-interrupt priority.
+ priority boosting
+ A simple approach to extend the priority inheritance protocol for
+ clustered scheduling is priority boosting. In case a mutex is owned by a
+ task of another cluster, then the priority of the owner task is raised to
+ an artificially high priority, the pseudo-interrupt priority.
- priority inheritance
- An algorithm that calls for the lower priority task holding a resource to
- have its priority increased to that of the highest priority task blocked
- waiting for that resource. This avoids the problem of priority
- inversion.
+ priority inheritance
+ An algorithm that calls for the lower priority task holding a resource to
+ have its priority increased to that of the highest priority task blocked
+ waiting for that resource. This avoids the problem of priority
+ inversion.
- priority inversion
- A form of indefinite postponement which occurs when a high priority tasks
- requests access to shared resource currently allocated to low priority
- task. The high priority task must block until the low priority task
- releases the resource.
+ priority inversion
+ A form of indefinite postponement which occurs when a high priority tasks
+ requests access to shared resource currently allocated to low priority
+ task. The high priority task must block until the low priority task
+ releases the resource.
- processor utilization
- The percentage of processor time used by a task or a set of tasks.
+ processor utilization
+ The percentage of processor time used by a task or a set of tasks.
- proxy
- An RTEMS control structure used to represent, on a remote node, a task
- which must block as part of a remote operation.
-
- Proxy Control Block
- A data structure associated with each proxy used by RTEMS to manage that
- proxy.
-
- PTCB
- An acronym for :term:`Partition Control Block`.
-
- PXCB
- An acronym for :term:`Proxy Control Block`.
-
- quantum
- The application defined unit of time in which the processor is allocated.
-
- queue
- Alternate term for message queue.
-
- QCB
- An acronym for :term:`Message Queue Control Block`.
-
- ready task
- A task occupies this state when it is available to be given control of a
- processor. A ready task has no processor assigned. The scheduler
- decided that other tasks are currently more important. A task that is
- ready to execute and has a processor assigned is called scheduled.
+ proxy
+ An RTEMS control structure used to represent, on a remote node, a task
+ which must block as part of a remote operation.
+
+ Proxy Control Block
+ A data structure associated with each proxy used by RTEMS to manage that
+ proxy.
+
+ PTCB
+ An acronym for :term:`Partition Control Block`.
+
+ PXCB
+ An acronym for :term:`Proxy Control Block`.
+
+ quantum
+ The application defined unit of time in which the processor is allocated.
+
+ queue
+ Alternate term for message queue.
+
+ QCB
+ An acronym for :term:`Message Queue Control Block`.
+
+ ready task
+ A task occupies this state when it is available to be given control of a
+ processor. A ready task has no processor assigned. The scheduler
+ decided that other tasks are currently more important. A task that is
+ ready to execute and has a processor assigned is called scheduled.
- real-time
- A term used to describe systems which are characterized by requiring
- deterministic response times to external stimuli. The external stimuli
- require that the response occur at a precise time or the response is
- incorrect.
-
- reentrant
- A term used to describe routines which do not modify themselves or global
- variables.
-
- region
- An RTEMS object which is used to allocate and deallocate variable size
- blocks of memory from a dynamically specified area of memory.
-
- Region Control Block
- A data structure associated with each region used by RTEMS to manage that
- region.
-
- registers
- Registers are locations physically located within a component, typically
- used for device control or general purpose storage.
-
- remote
- Any object that does not reside on the local node.
-
- remote operation
- The manipulation of an object which does not reside on the same node as
- the calling task.
-
- return code
- Also known as error code or return value.
-
- resource
- A hardware or software entity to which access must be controlled.
-
- resume
- Removing a task from the suspend state. If the task's state is ready
- following a call to the ``rtems_task_resume`` directive, then the task is
- available for scheduling.
-
- return code
- A value returned by RTEMS directives to indicate the completion status of
- the directive.
-
- RNCB
- An acronym for :term:`Region Control Block`.
-
- round-robin
- A task scheduling discipline in which tasks of equal priority are
- executed in the order in which they are made ready.
-
- RS-232
- A standard for serial communications.
-
- running
- The state of a rate monotonic timer while it is being used to delineate a
- period. The timer exits this state by either expiring or being canceled.
-
- schedulable
- A set of tasks which can be guaranteed to meet their deadlines based upon
- a specific scheduling algorithm.
+ real-time
+ A term used to describe systems which are characterized by requiring
+ deterministic response times to external stimuli. The external stimuli
+ require that the response occur at a precise time or the response is
+ incorrect.
+
+ reentrant
+ A term used to describe routines which do not modify themselves or global
+ variables.
+
+ region
+ An RTEMS object which is used to allocate and deallocate variable size
+ blocks of memory from a dynamically specified area of memory.
+
+ Region Control Block
+ A data structure associated with each region used by RTEMS to manage that
+ region.
+
+ registers
+ Registers are locations physically located within a component, typically
+ used for device control or general purpose storage.
+
+ remote
+ Any object that does not reside on the local node.
+
+ remote operation
+ The manipulation of an object which does not reside on the same node as
+ the calling task.
+
+ return code
+ Also known as error code or return value.
+
+ resource
+ A hardware or software entity to which access must be controlled.
+
+ resume
+ Removing a task from the suspend state. If the task's state is ready
+ following a call to the ``rtems_task_resume`` directive, then the task is
+ available for scheduling.
+
+ return code
+ A value returned by RTEMS directives to indicate the completion status of
+ the directive.
+
+ RNCB
+ An acronym for :term:`Region Control Block`.
+
+ round-robin
+ A task scheduling discipline in which tasks of equal priority are
+ executed in the order in which they are made ready.
+
+ RS-232
+ A standard for serial communications.
+
+ running
+ The state of a rate monotonic timer while it is being used to delineate a
+ period. The timer exits this state by either expiring or being canceled.
+
+ schedulable
+ A set of tasks which can be guaranteed to meet their deadlines based upon
+ a specific scheduling algorithm.
- schedule
- The process of choosing which task should next enter the executing state.
-
- scheduled task
- A task is scheduled if it is allowed to execute and has a processor
- assigned. Such a task executes currently on a processor or is about to
- start execution. A task about to start execution it is an heir task on
- exactly one processor in the system.
-
- scheduler
- A scheduler or scheduling algorithm allocates processors to a subset of
- its set of ready tasks. So it manages access to the processor resource.
- Various algorithms exist to choose the tasks allowed to use a processor
- out of the set of ready tasks. One method is to assign each task a
- priority number and assign the tasks with the lowest priority number to
- one processor of the set of processors owned by a scheduler instance.
+ schedule
+ The process of choosing which task should next enter the executing state.
+
+ scheduled task
+ A task is scheduled if it is allowed to execute and has a processor
+ assigned. Such a task executes currently on a processor or is about to
+ start execution. A task about to start execution it is an heir task on
+ exactly one processor in the system.
+
+ scheduler
+ A scheduler or scheduling algorithm allocates processors to a subset of
+ its set of ready tasks. So it manages access to the processor resource.
+ Various algorithms exist to choose the tasks allowed to use a processor
+ out of the set of ready tasks. One method is to assign each task a
+ priority number and assign the tasks with the lowest priority number to
+ one processor of the set of processors owned by a scheduler instance.
- scheduler instance
- A scheduler instance is a scheduling algorithm with a corresponding
- context to store its internal state. Each processor in the system is
- owned by at most one scheduler instance. The processor to scheduler
- instance assignment is determined at application configuration time. See
- :ref:`Configuring a System`.
-
- segments
- Variable sized memory blocks allocated from a region.
-
- semaphore
- An RTEMS object which is used to synchronize tasks and provide mutually
- exclusive access to resources.
-
- Semaphore Control Block
- A data structure associated with each semaphore used by RTEMS to manage
- that semaphore.
-
- shared memory
- Memory which is accessible by multiple nodes in a multiprocessor system.
-
- signal
- An RTEMS provided mechanism to communicate asynchronously with a task.
- Upon reception of a signal, the ASR of the receiving task will be
- invoked.
-
- signal set
- A thirty-two bit entity which is used to represent a task's collection of
- pending signals and the signals sent to a task.
-
- SMCB
- An acronym for :term:`Semaphore Control Block`.
-
- SMP
- An acronym for Symmetric Multiprocessing.
-
- SMP locks
- The SMP locks ensure mutual exclusion on the lowest level and are a
- replacement for the sections of disabled interrupts. Interrupts are
- usually disabled while holding an SMP lock. They are implemented using
- atomic operations. Currently a ticket lock is used in RTEMS.
-
- SMP barriers
- The SMP barriers ensure that a defined set of independent threads of
- execution on a set of processors reaches a common synchronization point
- in time. They are implemented using atomic operations. Currently a
- sense barrier is used in RTEMS.
-
- soft real-time system
- A real-time system in which a missed deadline does not compromise the
- integrity of the system.
-
- sporadic task
- A task which executes at irregular intervals and must comply with a hard
- deadline. A minimum period of time between successive iterations of the
- task can be guaranteed.
-
- stack
- A data structure that is managed using a Last In First Out (LIFO)
- discipline. Each task has a stack associated with it which is used to
- store return information and local variables.
-
- status code
- Also known as error code or return value.
-
- suspend
- A term used to describe a task that is not competing for the CPU because it
- has had a ``rtems_task_suspend`` directive.
-
- synchronous
- Related in order or timing to other occurrences in the system.
-
- system call
- In this document, this is used as an alternate term for directive.
-
- target
- The system on which the application will ultimately execute.
-
- TAS
- An acronym for Test-And-Set.
-
- task
- A logically complete thread of execution. It consists normally of a set
- of registers and a stack. The scheduler assigns processors to a subset
- of the ready tasks. The terms task and thread are synonym in RTEMS. The
- term task is used throughout the Classic API, however, internally in the
- operating system implementation and the POSIX API the term thread is
- used.
-
- Task Control Block
- A data structure associated with each task used by RTEMS to manage that
- task.
-
- task migration
- Task migration happens in case a task stops execution on one processor
- and resumes execution on another processor.
-
- task processor affinity
- The set of processors on which a task is allowed to execute.
+ scheduler instance
+ A scheduler instance is a scheduling algorithm with a corresponding
+ context to store its internal state. Each processor in the system is
+ owned by at most one scheduler instance. The processor to scheduler
+ instance assignment is determined at application configuration time. See
+ :ref:`Configuring a System`.
+
+ segments
+ Variable sized memory blocks allocated from a region.
+
+ semaphore
+ An RTEMS object which is used to synchronize tasks and provide mutually
+ exclusive access to resources.
+
+ Semaphore Control Block
+ A data structure associated with each semaphore used by RTEMS to manage
+ that semaphore.
+
+ shared memory
+ Memory which is accessible by multiple nodes in a multiprocessor system.
+
+ signal
+ An RTEMS provided mechanism to communicate asynchronously with a task.
+ Upon reception of a signal, the ASR of the receiving task will be
+ invoked.
+
+ signal set
+ A thirty-two bit entity which is used to represent a task's collection of
+ pending signals and the signals sent to a task.
+
+ SMCB
+ An acronym for :term:`Semaphore Control Block`.
+
+ SMP
+ An acronym for Symmetric Multiprocessing.
+
+ SMP locks
+ The SMP locks ensure mutual exclusion on the lowest level and are a
+ replacement for the sections of disabled interrupts. Interrupts are
+ usually disabled while holding an SMP lock. They are implemented using
+ atomic operations. Currently a ticket lock is used in RTEMS.
+
+ SMP barriers
+ The SMP barriers ensure that a defined set of independent threads of
+ execution on a set of processors reaches a common synchronization point
+ in time. They are implemented using atomic operations. Currently a
+ sense barrier is used in RTEMS.
+
+ soft real-time system
+ A real-time system in which a missed deadline does not compromise the
+ integrity of the system.
+
+ sporadic task
+ A task which executes at irregular intervals and must comply with a hard
+ deadline. A minimum period of time between successive iterations of the
+ task can be guaranteed.
+
+ stack
+ A data structure that is managed using a Last In First Out (LIFO)
+ discipline. Each task has a stack associated with it which is used to
+ store return information and local variables.
+
+ status code
+ Also known as error code or return value.
+
+ suspend
+ A term used to describe a task that is not competing for the CPU because it
+ has had a ``rtems_task_suspend`` directive.
+
+ synchronous
+ Related in order or timing to other occurrences in the system.
+
+ system call
+ In this document, this is used as an alternate term for directive.
+
+ target
+ The system on which the application will ultimately execute.
+
+ TAS
+ An acronym for Test-And-Set.
+
+ task
+ A logically complete thread of execution. It consists normally of a set
+ of registers and a stack. The scheduler assigns processors to a subset
+ of the ready tasks. The terms task and thread are synonym in RTEMS. The
+ term task is used throughout the Classic API, however, internally in the
+ operating system implementation and the POSIX API the term thread is
+ used.
+
+ Task Control Block
+ A data structure associated with each task used by RTEMS to manage that
+ task.
+
+ task migration
+ Task migration happens in case a task stops execution on one processor
+ and resumes execution on another processor.
+
+ task processor affinity
+ The set of processors on which a task is allowed to execute.
- task switch
- Alternate terminology for context switch. Taking control of the
- processor from one task and given to another.
+ task switch
+ Alternate terminology for context switch. Taking control of the
+ processor from one task and given to another.
- TCB
- An acronym for :term:`Task Control Block`.
+ TCB
+ An acronym for :term:`Task Control Block`.
- thread
- This term has the same meaning as :term:`task`.
+ thread
+ This term has the same meaning as :term:`task`.
- thread dispatch
- The thread dispatch transfers control of the processor from the currently
- executing thread to the heir thread of the processor.
+ thread dispatch
+ The thread dispatch transfers control of the processor from the currently
+ executing thread to the heir thread of the processor.
- tick
- The basic unit of time used by RTEMS. It is a user-configurable number
- of microseconds. The current tick expires when a clock tick directive is
- invoked.
+ tick
+ The basic unit of time used by RTEMS. It is a user-configurable number
+ of microseconds. The current tick expires when a clock tick directive is
+ invoked.
- tightly-coupled
- A multiprocessor configuration system which communicates via shared
- memory.
+ tightly-coupled
+ A multiprocessor configuration system which communicates via shared
+ memory.
- timeout
- An argument provided to a number of directives which determines the
- maximum length of time an application task is willing to wait to acquire
- the resource if it is not immediately available.
+ timeout
+ An argument provided to a number of directives which determines the
+ maximum length of time an application task is willing to wait to acquire
+ the resource if it is not immediately available.
- timer
- An RTEMS object used to invoke subprograms at a later time.
+ timer
+ An RTEMS object used to invoke subprograms at a later time.
- Timer Control Block
- A data structure associated with each timer used by RTEMS to manage that
- timer.
+ Timer Control Block
+ A data structure associated with each timer used by RTEMS to manage that
+ timer.
- timeslicing
- A task scheduling discipline in which tasks of equal priority are
- executed for a specific period of time before being preempted by another
- task.
+ timeslicing
+ A task scheduling discipline in which tasks of equal priority are
+ executed for a specific period of time before being preempted by another
+ task.
- timeslice
- The application defined unit of time in which the processor is allocated.
+ timeslice
+ The application defined unit of time in which the processor is allocated.
- TLS
- An acronym for Thread-Local Storage :cite:`Drepper:2013:TLS`. TLS is
- available in :term:`C11` and :term:`C++11`. The support for TLS depends
- on the CPU port :cite:`RTEMS:CPU`.
+ TLS
+ An acronym for Thread-Local Storage :cite:`Drepper:2013:TLS`. TLS is
+ available in :term:`C11` and :term:`C++11`. The support for TLS depends
+ on the CPU port :cite:`RTEMS:CPU`.
- TMCB
- An acronym for :term:`Timer Control Block`.
+ TMCB
+ An acronym for :term:`Timer Control Block`.
- transient overload
- A temporary rise in system activity which may cause deadlines to be
- missed. Rate Monotonic Scheduling can be used to determine if all
- deadlines will be met under transient overload.
+ transient overload
+ A temporary rise in system activity which may cause deadlines to be
+ missed. Rate Monotonic Scheduling can be used to determine if all
+ deadlines will be met under transient overload.
- TTAS
- An acronym for Test and Test-And-Set.
+ TTAS
+ An acronym for Test and Test-And-Set.
- user extensions
- Software routines provided by the application to enhance the
- functionality of RTEMS.
+ user extensions
+ Software routines provided by the application to enhance the
+ functionality of RTEMS.
- User Extension Table
- A table which contains the entry points for each user extensions.
+ User Extension Table
+ A table which contains the entry points for each user extensions.
- User Initialization Tasks Table
- A table which contains the information needed to create and start each of
- the user initialization tasks.
+ User Initialization Tasks Table
+ A table which contains the information needed to create and start each of
+ the user initialization tasks.
- user-provided
- These terms are used to designate any software routines which must be
- written by the application designer.
+ user-provided
+ These terms are used to designate any software routines which must be
+ written by the application designer.
- user-supplied
- This term has the same meaning as :term:`user-provided`.
+ user-supplied
+ This term has the same meaning as :term:`user-provided`.
- vector
- Memory pointers used by the processor to fetch the address of routines
- which will handle various exceptions and interrupts.
+ vector
+ Memory pointers used by the processor to fetch the address of routines
+ which will handle various exceptions and interrupts.
- wait queue
- The list of tasks blocked pending the release of a particular resource.
- Message queues, regions, and semaphores have a wait queue associated with
- them.
+ wait queue
+ The list of tasks blocked pending the release of a particular resource.
+ Message queues, regions, and semaphores have a wait queue associated with
+ them.
- yield
- When a task voluntarily releases control of the processor.
+ yield
+ When a task voluntarily releases control of the processor.