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diff --git a/doc/user/glossary.texi b/doc/user/glossary.texi deleted file mode 100644 index bf22cf6133..0000000000 --- a/doc/user/glossary.texi +++ /dev/null @@ -1,845 +0,0 @@ -@c -@c COPYRIGHT (c) 1989-2011. -@c On-Line Applications Research Corporation (OAR). -@c All rights reserved. - -@node Glossary, Command and Variable Index, Example Application, Top -@chapter Glossary - -@table @dfn -@item active -A term used to describe an object -which has been created by an application. - -@item aperiodic task -A task which must execute only at -irregular intervals and has only a soft deadline. - -@item application -In this document, software which makes -use of RTEMS. - -@item ASR -see Asynchronous Signal Routine. - -@item asynchronous -Not related in order or timing to -other occurrences in the system. - -@item 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. - -@item atomic operations -Atomic operations are defined in terms of @cite{ISO/IEC 9899:2011}. - -@item awakened -A term used to describe a task that has -been unblocked and may be scheduled to the CPU. - -@item 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. - -@item 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. - -@item block -A physically contiguous area of memory. - -@item 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. - -@item broadcast -To simultaneously send a message to a -logical set of destinations. - -@item BSP -see Board Support Package. - -@item Board Support Package -A collection of device -initialization and control routines specific to a particular -type of board or collection of boards. - -@item buffer -A fixed length block of memory allocated -from a partition. - -@item 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. - -@item Central Processing Unit -This term is equivalent to -the terms processor and microprocessor. - -@item 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. - -@item 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 -@dfn{clusters}. Clusters with a cardinality of one are partitions. Each -cluster is owned by exactly one scheduler instance. - -@item coalesce -The process of merging adjacent holes into -a single larger hole. Sometimes this process is referred to as -garbage collection. - -@item Configuration Table -A table which contains -information used to tailor RTEMS for a particular application. - -@item context -All of the processor registers and -operating system data structures associated with a task. - -@item context switch -Alternate term for task switch. -Taking control of the processor from one task and transferring -it to another task. - -@item control block -A data structure used by the -executive to define and control an object. - -@item 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. - -@item CPU -An acronym for Central Processing Unit. - -@item critical section -A section of code which must be -executed indivisibly. - -@item CRT -An acronym for Cathode Ray Tube. Normally used -in reference to the man-machine interface. - -@item 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. - -@item device -A peripheral used by the application that -requires special operation software. See also device driver. - -@item device driver -Control software for special -peripheral devices used by the application. - -@item directives -RTEMS' provided routines that provide -support mechanisms for real-time applications. - -@item dispatch -The act of loading a task's context onto -the CPU and transferring control of the CPU to that task. - -@item dormant -The state entered by a task after it is -created and before it has been started. - -@item Device Driver Table -A table which contains the -entry points for each of the configured device drivers. - -@item dual-ported -A term used to describe memory which -can be accessed at two different addresses. - -@item 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. - -@item 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. - -@item 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. - -@item events -A method for task communication and -synchronization. The directives provided by the event manager -are used to service events. - -@item exception -A synonym for interrupt. - -@item executing task -The task state entered by a task after it has been given control of the -processor. On 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. - -@item 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. - -@item exported -An object known by all nodes in a -multiprocessor system. An object created with the GLOBAL -attribute will be exported. - -@item external address -The address used to access -dual-ported memory by all the nodes in a system which do not own -the memory. - -@item FIFO -An acronym for First In First Out. - -@item First In First Out -A discipline for manipulating entries in a data structure. - -@item 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. - -@item freed -A resource that has been released by the -application to RTEMS. - -@item Giant lock -The @dfn{Giant lock} is a recursive SMP lock protecting most parts of the -operating system state. Virtually every operating system service must acquire -and release the Giant lock during its operation. - -@item global -An object that has been created with the -GLOBAL attribute and exported to all nodes in a multiprocessor -system. - -@item 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. - -@item 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. - -@item heap -A data structure used to dynamically allocate -and deallocate variable sized blocks of memory. - -@item heir task -A task is an @dfn{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. - -@item heterogeneous -A multiprocessor computer system composed of dissimilar processors. - -@item homogeneous -A multiprocessor computer system composed of a single type of processor. - -@item ID -An RTEMS assigned identification tag used to -access an active object. - -@item IDLE task -A special low priority task which assumes -control of the CPU when no other task is able to execute. - -@item interface -A specification of the methodology used -to connect multiple independent subsystems. - -@item internal address -The address used to access -dual-ported memory by the node which owns the memory. - -@item interrupt -A hardware facility that causes the CPU -to suspend execution, save its status, and transfer control to a -specific location. - -@item 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. - -@item Interrupt Service Routine -An ISR is invoked by the -CPU to process a pending interrupt. - -@item I/O -An acronym for Input/Output. - -@item ISR -An acronym for Interrupt Service Routine. - -@item kernel -In this document, this term is used as a -synonym for executive. - -@item list -A data structure which allows for dynamic -addition and removal of entries. It is not statically limited -to a particular size. - -@item 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. - -@item 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. - -@item local operation -The manipulation of an object which -resides on the same node as the calling task. - -@item logical address -An address used by an application. -In a system without memory management, logical addresses will -equal physical addresses. - -@item loosely-coupled -A multiprocessor configuration -where shared memory is not used for communication. - -@item major number -The index of a device driver in the -Device Driver Table. - -@item manager -A group of related RTEMS' directives which -provide access and control over resources. - -@item memory pool -Used interchangeably with heap. - -@item message -A sixteen byte entity used to communicate -between tasks. Messages are sent to message queues and stored -in message buffers. - -@item message buffer -A block of memory used to store -messages. - -@item message queue -An RTEMS object used to synchronize -and communicate between tasks by transporting messages between -sending and receiving tasks. - -@item Message Queue Control Block -A data structure associated with each message queue used by RTEMS -to manage that message queue. - -@item minor number -A numeric value passed to a device -driver, the exact usage of which is driver dependent. - -@item 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. - -@item MPCI -An acronym for Multiprocessor Communications -Interface Layer. - -@item multiprocessing -The simultaneous execution of two -or more processes by a multiple processor computer system. - -@item multiprocessor -A computer with multiple CPUs -available for executing applications. - -@item Multiprocessor Communications Interface Layer -A set -of user-provided routines which enable the nodes in a -multiprocessor system to communicate with one another. - -@item Multiprocessor Configuration Table -The data structure defining the characteristics of the multiprocessor -target system with which RTEMS will communicate. - -@item 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. - -@item mutual exclusion -A term used to describe the act of -preventing other tasks from accessing a resource simultaneously. - -@item nested -A term used to describe an ASR that occurs -during another ASR or an ISR that occurs during another ISR. - -@item node -A term used to reference a processor running -RTEMS in a multiprocessor system. - -@item non-existent -The state occupied by an uncreated or -deleted task. - -@item 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. - -@item 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. - -@item 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. - -@item operating system -The software which controls all -the computer's resources and provides the base upon which -application programs can be written. - -@item overhead -The portion of the CPUs processing power -consumed by the operating system. - -@item packet -A buffer which contains the messages passed -between nodes in a multiprocessor system. A packet is the -contents of an envelope. - -@item partition -An RTEMS object which is used to allocate -and deallocate fixed size blocks of memory from an dynamically -specified area of memory. - -@item partition -Clusters with a cardinality of one are @dfn{partitions}. - -@item Partition Control Block -A data structure associated -with each partition used by RTEMS to manage that partition. - -@item pending -A term used to describe a task blocked -waiting for an event, message, semaphore, or signal. - -@item periodic task -A task which must execute at regular -intervals and comply with a hard deadline. - -@item physical address -The actual hardware address of a -resource. - -@item 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. - -@item pool -A collection from which resources are -allocated. - -@item portability -A term used to describe the ease with -which software can be rehosted on another computer. - -@item posting -The act of sending an event, message, -semaphore, or signal to a task. - -@item preempt -The act of forcing a task to relinquish the -processor and dispatching to another task. - -@item 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. - -@item priority boosting -A simple approach to extend the priority inheritance protocol for clustered -scheduling is @dfn{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. - -@item 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. - -@item 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. - -@item processor utilization -The percentage of processor -time used by a task or a set of tasks. - -@item proxy -An RTEMS control structure used to represent, -on a remote node, a task which must block as part of a remote -operation. - -@item Proxy Control Block -A data structure associated -with each proxy used by RTEMS to manage that proxy. - -@item PTCB -An acronym for Partition Control Block. - -@item PXCB -An acronym for Proxy Control Block. - -@item quantum -The application defined unit of time in -which the processor is allocated. - -@item queue -Alternate term for message queue. - -@item QCB -An acronym for Message Queue Control Block. - -@item 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. - -@item 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. - -@item reentrant -A term used to describe routines which do -not modify themselves or global variables. - -@item region -An RTEMS object which is used to allocate -and deallocate variable size blocks of memory from a dynamically -specified area of memory. - -@item Region Control Block -A data structure associated -with each region used by RTEMS to manage that region. - -@item registers -Registers are locations physically -located within a component, typically used for device control or -general purpose storage. - -@item remote -Any object that does not reside on the local -node. - -@item remote operation -The manipulation of an object -which does not reside on the same node as the calling task. - -@item return code -Also known as error code or return -value. - -@item resource -A hardware or software entity to which -access must be controlled. - -@item resume -Removing a task from the suspend state. If -the task's state is ready following a call to the -@code{@value{DIRPREFIX}task_resume} -directive, then the task is available for scheduling. - -@item return code -A value returned by RTEMS directives to -indicate the completion status of the directive. - -@item RNCB -An acronym for Region Control Block. - -@item round-robin -A task scheduling discipline in which -tasks of equal priority are executed in the order in which they -are made ready. - -@item RS-232 -A standard for serial communications. - -@item 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. - -@item schedulable -A set of tasks which can be guaranteed -to meet their deadlines based upon a specific scheduling -algorithm. - -@item schedule -The process of choosing which task should -next enter the executing state. - -@item scheduled task -A task is @dfn{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. - -@item scheduler -A @dfn{scheduler} or @dfn{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. - -@item scheduler instance -A @dfn{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. @xref{Configuring a System -Configuring Clustered Schedulers}. - -@item segments -Variable sized memory blocks allocated -from a region. - -@item semaphore -An RTEMS object which is used to -synchronize tasks and provide mutually exclusive access to -resources. - -@item Semaphore Control Block -A data structure associated -with each semaphore used by RTEMS to manage that semaphore. - -@item shared memory -Memory which is accessible by -multiple nodes in a multiprocessor system. - -@item 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. - -@item 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. - -@item SMCB -An acronym for Semaphore Control Block. - -@item SMP locks -The @dfn{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. - -@item SMP barriers -The @dfn{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. - -@item soft real-time system -A real-time system in which a -missed deadline does not compromise the integrity of the system. - -@item 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. - -@item 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. - -@item status code -Also known as error code or return -value. - -@item suspend -A term used to describe a task that is not -competing for the CPU because it has had a -@code{@value{DIRPREFIX}task_suspend} directive. - -@item synchronous -Related in order or timing to other -occurrences in the system. - -@item system call -In this document, this is used as an -alternate term for directive. - -@item target -The system on which the application will -ultimately execute. - -@item task -A logically complete thread of execution. It consists normally of a set of -registers and a stack. The terms @dfn{task} and @dfn{thread} are synonym in -RTEMS. The scheduler assigns processors to a subset of the ready tasks. - -@item Task Control Block -A data structure associated with -each task used by RTEMS to manage that task. - -@item task migration -@dfn{Task migration} happens in case a task stops execution on one processor -and resumes execution on another processor. - -@item task processor affinity -The set of processors on which a task is allowed to execute. - -@item task switch -Alternate terminology for context -switch. Taking control of the processor from one task and given -to another. - -@item TCB -An acronym for Task Control Block. - -@item thread dispatch -The @dfn{thread dispatch} transfers control of the processor from the currently -executing thread to the heir thread of the processor. - -@item tick -The basic unit of time used by RTEMS. It is a -user-configurable number of microseconds. The current tick -expires when the @code{@value{DIRPREFIX}clock_tick} -directive is invoked. - -@item tightly-coupled -A multiprocessor configuration -system which communicates via shared memory. - -@item 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. - -@item timer -An RTEMS object used to invoke subprograms at -a later time. - -@item Timer Control Block -A data structure associated -with each timer used by RTEMS to manage that timer. - -@item 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. - -@item timeslice -The application defined unit of time in -which the processor is allocated. - -@item TMCB -An acronym for Timer Control Block. - -@item 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. - -@item user extensions -Software routines provided by the -application to enhance the functionality of RTEMS. - -@item User Extension Table -A table which contains the -entry points for each user extensions. - -@item User Initialization Tasks Table -A table which -contains the information needed to create and start each of the -user initialization tasks. - -@item user-provided -Alternate term for user-supplied. -This term is used to designate any software routines which must -be written by the application designer. - -@item user-supplied -Alternate term for user-provided. -This term is used to designate any software routines which must -be written by the application designer. - -@item vector -Memory pointers used by the processor to -fetch the address of routines which will handle various -exceptions and interrupts. - -@item 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. - -@item yield -When a task voluntarily releases control of the processor. - -@end table - |