Changeset f29b7faf in rtems-docs


Ignore:
Timestamp:
Feb 18, 2016, 5:22:15 AM (4 years ago)
Author:
Chris Johns <chrisj@…>
Branches:
4.11, master
Children:
bcd64c6
Parents:
25d55d4
git-author:
Chris Johns <chrisj@…> (02/18/16 05:22:15)
git-committer:
Amar Takhar <verm@…> (05/03/16 00:51:26)
Message:

Clean up.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • c_user/glossary.rst

    r25d55d4 rf29b7faf  
    33
    44:dfn:`active`
    5     A term used to describe an object
    6     which has been created by an application.
     5    A term used to describe an object which has been created by an application.
    76
    87:dfn:`aperiodic task`
    9     A task which must execute only at
    10     irregular intervals and has only a soft deadline.
     8    A task which must execute only at irregular intervals and has only a soft
     9    deadline.
    1110
    1211:dfn:`application`
    13     In this document, software which makes
    14     use of RTEMS.
     12    In this document, software which makes use of RTEMS.
    1513
    1614:dfn:`ASR`
     
    1816
    1917:dfn:`asynchronous`
    20     Not related in order or timing to
    21     other occurrences in the system.
     18    Not related in order or timing to other occurrences in the system.
    2219
    2320:dfn:`Asynchronous Signal Routine`
    24     Similar to a hardware
    25     interrupt except that it is associated with a task and is run in
    26     the context of a task.  The directives provided by the signal
     21    Similar to a hardware interrupt except that it is associated with a task
     22    and is run in the context of a task.  The directives provided by the signal
    2723    manager are used to service signals.
    2824
     
    3127
    3228:dfn:`awakened`
    33     A term used to describe a task that has
    34     been unblocked and may be scheduled to the CPU.
     29    A term used to describe a task that has been unblocked and may be scheduled
     30    to the CPU.
    3531
    3632:dfn:`big endian`
    37     A data representation scheme in which
    38     the bytes composing a numeric value are arranged such that the
    39     most significant byte is at the lowest address.
     33    A data representation scheme in which the bytes composing a numeric value
     34    are arranged such that the most significant byte is at the lowest address.
    4035
    4136:dfn:`bit-mapped`
    42     A data encoding scheme in which each bit
    43     in a variable is used to represent something different.  This
    44     makes for compact data representation.
     37    A data encoding scheme in which each bit in a variable is used to represent
     38    something different.  This makes for compact data representation.
    4539
    4640:dfn:`block`
     
    4842
    4943:dfn:`blocked task`
    50     The task state entered by a task which has been previously started and cannot
    51     continue execution until the reason for waiting has been satisfied.  Blocked
    52     tasks are not an element of the set of ready tasks of a scheduler instance.
     44    The task state entered by a task which has been previously started and
     45    cannot continue execution until the reason for waiting has been satisfied.
     46    Blocked tasks are not an element of the set of ready tasks of a scheduler
     47    instance.
    5348
    5449:dfn:`broadcast`
    55     To simultaneously send a message to a
    56     logical set of destinations.
     50    To simultaneously send a message to a logical set of destinations.
    5751
    5852:dfn:`BSP`
     
    6054
    6155:dfn:`Board Support Package`
    62     A collection of device
    63     initialization and control routines specific to a particular
    64     type of board or collection of boards.
     56    A collection of device initialization and control routines specific to a
     57    particular type of board or collection of boards.
    6558
    6659:dfn:`buffer`
    67     A fixed length block of memory allocated
    68     from a partition.
     60    A fixed length block of memory allocated from a partition.
    6961
    7062:dfn:`calling convention`
    71     The processor and compiler
    72     dependent rules which define the mechanism used to invoke
    73     subroutines in a high-level language.  These rules define the
    74     passing of arguments, the call and return mechanism, and the
    75     register set which must be preserved.
     63    The processor and compiler dependent rules which define the mechanism used
     64    to invoke subroutines in a high-level language.  These rules define the
     65    passing of arguments, the call and return mechanism, and the register set
     66    which must be preserved.
    7667
    7768:dfn:`Central Processing Unit`
    78     This term is equivalent to
    79     the terms processor and microprocessor.
     69    This term is equivalent to the terms processor and microprocessor.
    8070
    8171:dfn:`chain`
    82     A data structure which allows for efficient
    83     dynamic addition and removal of elements.  It differs from an
    84     array in that it is not limited to a predefined size.
     72    A data structure which allows for efficient dynamic addition and removal of
     73    elements.  It differs from an array in that it is not limited to a
     74    predefined size.
    8575
    8676:dfn:`cluster`
    8777    We have clustered scheduling in case the set of processors of a system is
    88     partitioned into non-empty pairwise disjoint subsets.  These subsets are called:dfn:`clusters`.  Clusters with a cardinality of one are partitions.  Each
    89     cluster is owned by exactly one scheduler instance.
     78    partitioned into non-empty pairwise disjoint subsets.  These subsets are
     79    called:dfn:`clusters`.  Clusters with a cardinality of one are partitions.
     80    Each cluster is owned by exactly one scheduler instance.
    9081
    9182:dfn:`coalesce`
    92     The process of merging adjacent holes into
    93     a single larger hole.  Sometimes this process is referred to as
    94     garbage collection.
     83    The process of merging adjacent holes into a single larger hole.  Sometimes
     84    this process is referred to as garbage collection.
    9585
    9686:dfn:`Configuration Table`
    97     A table which contains
    98     information used to tailor RTEMS for a particular application.
     87    A table which contains information used to tailor RTEMS for a particular
     88    application.
    9989
    10090:dfn:`context`
    101     All of the processor registers and
    102     operating system data structures associated with a task.
     91    All of the processor registers and operating system data structures
     92    associated with a task.
    10393
    10494:dfn:`context switch`
    105     Alternate term for task switch.
    106     Taking control of the processor from one task and transferring
    107     it to another task.
     95    Alternate term for task switch.  Taking control of the processor from one
     96    task and transferring it to another task.
    10897
    10998:dfn:`control block`
    110     A data structure used by the
    111     executive to define and control an object.
     99    A data structure used by the executive to define and control an object.
    112100
    113101:dfn:`core`
    114     When used in this manual, this term refers to
    115     the internal executive utility functions.  In the interest of
    116     application portability, the core of the executive should not be
    117     used directly by applications.
     102    When used in this manual, this term refers to the internal executive
     103    utility functions.  In the interest of application portability, the core of
     104    the executive should not be used directly by applications.
    118105
    119106:dfn:`CPU`
     
    121108
    122109:dfn:`critical section`
    123     A section of code which must be
    124     executed indivisibly.
     110    A section of code which must be executed indivisibly.
    125111
    126112:dfn:`CRT`
    127     An acronym for Cathode Ray Tube.  Normally used
    128     in reference to the man-machine interface.
     113    An acronym for Cathode Ray Tube.  Normally used in reference to the
     114    man-machine interface.
    129115
    130116:dfn:`deadline`
    131     A fixed time limit by which a task must
    132     have completed a set of actions.  Beyond this point, the results
    133     are of reduced value and may even be considered useless or
    134     harmful.
     117    A fixed time limit by which a task must have completed a set of actions.
     118    Beyond this point, the results are of reduced value and may even be
     119    considered useless or harmful.
    135120
    136121:dfn:`device`
    137     A peripheral used by the application that
    138     requires special operation software.  See also device driver.
     122    A peripheral used by the application that requires special operation
     123    software.  See also device driver.
    139124
    140125:dfn:`device driver`
    141     Control software for special
    142     peripheral devices used by the application.
     126    Control software for special peripheral devices used by the application.
    143127
    144128:dfn:`directives`
    145     RTEMS' provided routines that provide
    146     support mechanisms for real-time applications.
     129    RTEMS' provided routines that provide support mechanisms for real-time
     130    applications.
    147131
    148132:dfn:`dispatch`
    149     The act of loading a task's context onto
    150     the CPU and transferring control of the CPU to that task.
     133    The act of loading a task's context onto the CPU and transferring control
     134    of the CPU to that task.
    151135
    152136:dfn:`dormant`
    153     The state entered by a task after it is
    154     created and before it has been started.
     137    The state entered by a task after it is created and before it has been
     138    started.
    155139
    156140:dfn:`Device Driver Table`
    157     A table which contains the
    158     entry points for each of the configured device drivers.
     141    A table which contains the entry points for each of the configured device
     142    drivers.
    159143
    160144:dfn:`dual-ported`
    161     A term used to describe memory which
    162     can be accessed at two different addresses.
     145    A term used to describe memory which can be accessed at two different
     146    addresses.
    163147
    164148:dfn:`embedded`
    165     An application that is delivered as a
    166     hidden part of a larger system.  For example, the software in a
    167     fuel-injection control system is an embedded application found
    168     in many late-model automobiles.
     149    An application that is delivered as a hidden part of a larger system.  For
     150    example, the software in a fuel-injection control system is an embedded
     151    application found in many late-model automobiles.
    169152
    170153:dfn:`envelope`
    171     A buffer provided by the MPCI layer to
    172     RTEMS which is used to pass messages between nodes in a
    173     multiprocessor system.  It typically contains routing
    174     information needed by the MPCI.  The contents of an envelope are
    175     referred to as a packet.
     154    A buffer provided by the MPCI layer to RTEMS which is used to pass messages
     155    between nodes in a multiprocessor system.  It typically contains routing
     156    information needed by the MPCI.  The contents of an envelope are referred
     157    to as a packet.
    176158
    177159:dfn:`entry point`
    178     The address at which a function or task
    179     begins to execute.  In C, the entry point of a function is the
    180     function's name.
     160    The address at which a function or task begins to execute.  In C, the entry
     161    point of a function is the function's name.
    181162
    182163:dfn:`events`
    183     A method for task communication and
    184     synchronization. The directives provided by the event manager
    185     are used to service events.
     164    A method for task communication and synchronization. The directives
     165    provided by the event manager are used to service events.
    186166
    187167:dfn:`exception`
     
    190170:dfn:`executing task`
    191171    The task state entered by a task after it has been given control of the
    192     processor.  On SMP configurations a task may be registered as executing on more
    193     than one processor for short time frames during task migration.  Blocked tasks
    194     can be executing until they issue a thread dispatch.
     172    processor.  On SMP configurations a task may be registered as executing on
     173    more than one processor for short time frames during task migration.
     174    Blocked tasks can be executing until they issue a thread dispatch.
    195175
    196176:dfn:`executive`
    197     In this document, this term is used to
    198     referred to RTEMS.  Commonly, an executive is a small real-time
    199     operating system used in embedded systems.
     177    In this document, this term is used to referred to RTEMS.  Commonly, an
     178    executive is a small real-time operating system used in embedded systems.
    200179
    201180:dfn:`exported`
    202     An object known by all nodes in a
    203     multiprocessor system.  An object created with the GLOBAL
    204     attribute will be exported.
     181    An object known by all nodes in a multiprocessor system.  An object created
     182    with the GLOBAL attribute will be exported.
    205183
    206184:dfn:`external address`
    207     The address used to access
    208     dual-ported memory by all the nodes in a system which do not own
    209     the memory.
     185    The address used to access dual-ported memory by all the nodes in a system
     186    which do not own the memory.
    210187
    211188:dfn:`FIFO`
     
    216193
    217194:dfn:`floating point coprocessor`
    218     A component used in
    219     computer systems to enhance performance in mathematically
    220     intensive situations.  It is typically viewed as a logical
     195    A component used in computer systems to enhance performance in
     196    mathematically intensive situations.  It is typically viewed as a logical
    221197    extension of the primary processor.
    222198
    223199:dfn:`freed`
    224     A resource that has been released by the
    225     application to RTEMS.
     200    A resource that has been released by the application to RTEMS.
    226201
    227202:dfn:`Giant lock`
    228203    The :dfn:`Giant lock` is a recursive SMP lock protecting most parts of the
    229     operating system state.  Virtually every operating system service must acquire
    230     and release the Giant lock during its operation.
     204    operating system state.  Virtually every operating system service must
     205    acquire and release the Giant lock during its operation.
    231206
    232207:dfn:`global`
    233     An object that has been created with the
    234     GLOBAL attribute and exported to all nodes in a multiprocessor
    235     system.
     208    An object that has been created with the GLOBAL attribute and exported to
     209    all nodes in a multiprocessor system.
    236210
    237211:dfn:`handler`
    238     The equivalent of a manager, except that it
    239     is internal to RTEMS and forms part of the core.  A handler is a
    240     collection of routines which provide a related set of functions.
    241     For example, there is a handler used by RTEMS to manage all
    242     objects.
     212    The equivalent of a manager, except that it is internal to RTEMS and forms
     213    part of the core.  A handler is a collection of routines which provide a
     214    related set of functions.  For example, there is a handler used by RTEMS to
     215    manage all objects.
    243216
    244217:dfn:`hard real-time system`
    245     A real-time system in which a
    246     missed deadline causes the worked performed to have no value or
    247     to result in a catastrophic effect on the integrity of the
    248     system.
     218    A real-time system in which a missed deadline causes the worked performed
     219    to have no value or to result in a catastrophic effect on the integrity of
     220    the system.
    249221
    250222:dfn:`heap`
    251     A data structure used to dynamically allocate
    252     and deallocate variable sized blocks of memory.
     223    A data structure used to dynamically allocate and deallocate variable sized
     224    blocks of memory.
    253225
    254226:dfn:`heir task`
    255     A task is an :dfn:`heir` if it is registered as an heir in a processor of the
    256     system.  A task can be the heir on at most one processor in the system.  In
    257     case the executing and heir tasks differ on a processor and a thread dispatch
    258     is marked as necessary, then the next thread dispatch will make the heir task
    259     the executing task.
     227    A task is an :dfn:`heir` if it is registered as an heir in a processor of
     228    the system.  A task can be the heir on at most one processor in the system.
     229    In case the executing and heir tasks differ on a processor and a thread
     230    dispatch is marked as necessary, then the next thread dispatch will make
     231    the heir task the executing task.
    260232
    261233:dfn:`heterogeneous`
     
    266238
    267239:dfn:`ID`
    268     An RTEMS assigned identification tag used to
    269     access an active object.
     240    An RTEMS assigned identification tag used to access an active object.
    270241
    271242:dfn:`IDLE task`
    272     A special low priority task which assumes
    273     control of the CPU when no other task is able to execute.
     243    A special low priority task which assumes control of the CPU when no other
     244    task is able to execute.
    274245
    275246:dfn:`interface`
    276     A specification of the methodology used
    277     to connect multiple independent subsystems.
     247    A specification of the methodology used to connect multiple independent
     248    subsystems.
    278249
    279250:dfn:`internal address`
    280     The address used to access
    281     dual-ported memory by the node which owns the memory.
     251    The address used to access dual-ported memory by the node which owns the
     252    memory.
    282253
    283254:dfn:`interrupt`
    284     A hardware facility that causes the CPU
    285     to suspend execution, save its status, and transfer control to a
    286     specific location.
     255    A hardware facility that causes the CPU to suspend execution, save its
     256    status, and transfer control to a specific location.
    287257
    288258:dfn:`interrupt level`
    289     A mask used to by the CPU to
    290     determine which pending interrupts should be serviced.  If a
    291     pending interrupt is below the current interrupt level, then the
    292     CPU does not recognize that interrupt.
     259    A mask used to by the CPU to determine which pending interrupts should be
     260    serviced.  If a pending interrupt is below the current interrupt level,
     261    then the CPU does not recognize that interrupt.
    293262
    294263:dfn:`Interrupt Service Routine`
    295     An ISR is invoked by the
    296     CPU to process a pending interrupt.
     264    An ISR is invoked by the CPU to process a pending interrupt.
    297265
    298266:dfn:`I/O`
     
    303271
    304272:dfn:`kernel`
    305     In this document, this term is used as a
    306     synonym for executive.
     273    In this document, this term is used as a synonym for executive.
    307274
    308275:dfn:`list`
    309     A data structure which allows for dynamic
    310     addition and removal of entries.  It is not statically limited
    311     to a particular size.
     276    A data structure which allows for dynamic addition and removal of entries.
     277    It is not statically limited to a particular size.
    312278
    313279:dfn:`little endian`
    314     A data representation scheme in which
    315     the bytes composing a numeric value are arranged such that the
    316     least significant byte is at the lowest address.
     280    A data representation scheme in which the bytes composing a numeric value
     281    are arranged such that the least significant byte is at the lowest address.
    317282
    318283:dfn:`local`
    319     An object which was created with the LOCAL
    320     attribute and is accessible only on the node it was created and
    321     resides upon.  In a single processor configuration, all objects
    322     are local.
     284    An object which was created with the LOCAL attribute and is accessible only
     285    on the node it was created and resides upon.  In a single processor
     286    configuration, all objects are local.
    323287
    324288:dfn:`local operation`
    325     The manipulation of an object which
    326     resides on the same node as the calling task.
     289    The manipulation of an object which resides on the same node as the calling
     290    task.
    327291
    328292:dfn:`logical address`
    329     An address used by an application.
    330     In a system without memory management, logical addresses will
    331     equal physical addresses.
     293    An address used by an application.  In a system without memory management,
     294    logical addresses will equal physical addresses.
    332295
    333296:dfn:`loosely-coupled`
    334     A multiprocessor configuration
    335     where shared memory is not used for communication.
     297    A multiprocessor configuration where shared memory is not used for
     298    communication.
    336299
    337300:dfn:`major number`
    338     The index of a device driver in the
    339     Device Driver Table.
     301    The index of a device driver in the Device Driver Table.
    340302
    341303:dfn:`manager`
    342     A group of related RTEMS' directives which
    343     provide access and control over resources.
     304    A group of related RTEMS' directives which provide access and control over
     305    resources.
    344306
    345307:dfn:`memory pool`
     
    347309
    348310:dfn:`message`
    349     A sixteen byte entity used to communicate
    350     between tasks.  Messages are sent to message queues and stored
    351     in message buffers.
     311    A sixteen byte entity used to communicate between tasks.  Messages are sent
     312    to message queues and stored in message buffers.
    352313
    353314:dfn:`message buffer`
    354     A block of memory used to store
    355     messages.
     315    A block of memory used to store messages.
    356316
    357317:dfn:`message queue`
    358     An RTEMS object used to synchronize
    359     and communicate between tasks by transporting messages between
    360     sending and receiving tasks.
     318    An RTEMS object used to synchronize and communicate between tasks by
     319    transporting messages between sending and receiving tasks.
    361320
    362321:dfn:`Message Queue Control Block`
    363     A data structure associated with each message queue used by RTEMS
    364     to manage that message queue.
     322    A data structure associated with each message queue used by RTEMS to manage
     323    that message queue.
    365324
    366325:dfn:`minor number`
    367     A numeric value passed to a device
    368     driver, the exact usage of which is driver dependent.
     326    A numeric value passed to a device driver, the exact usage of which is
     327    driver dependent.
    369328
    370329:dfn:`mode`
    371     An entry in a task's control block that is
    372     used to determine if the task allows preemption, timeslicing,
    373     processing of signals, and the interrupt disable level used by
    374     the task.
     330    An entry in a task's control block that is used to determine if the task
     331    allows preemption, timeslicing, processing of signals, and the interrupt
     332    disable level used by the task.
    375333
    376334:dfn:`MPCI`
    377     An acronym for Multiprocessor Communications
    378     Interface Layer.
     335    An acronym for Multiprocessor Communications Interface Layer.
    379336
    380337:dfn:`multiprocessing`
    381     The simultaneous execution of two
    382     or more processes by a multiple processor computer system.
     338    The simultaneous execution of two or more processes by a multiple processor
     339    computer system.
    383340
    384341:dfn:`multiprocessor`
    385     A computer with multiple CPUs
    386     available for executing applications.
     342    A computer with multiple CPUs available for executing applications.
    387343
    388344:dfn:`Multiprocessor Communications Interface Layer`
    389     A set
    390     of user-provided routines which enable the nodes in a
    391     multiprocessor system to communicate with one another.
     345    A set of user-provided routines which enable the nodes in a multiprocessor
     346    system to communicate with one another.
    392347
    393348:dfn:`Multiprocessor Configuration Table`
     
    396351
    397352:dfn:`multitasking`
    398     The alternation of execution amongst a
    399     group of processes on a single CPU.  A scheduling algorithm is
    400     used to determine which process executes at which time.
     353    The alternation of execution amongst a group of processes on a single CPU.
     354    A scheduling algorithm is used to determine which process executes at which
     355    time.
    401356
    402357:dfn:`mutual exclusion`
    403     A term used to describe the act of
    404     preventing other tasks from accessing a resource simultaneously.
     358    A term used to describe the act of preventing other tasks from accessing a
     359    resource simultaneously.
    405360
    406361:dfn:`nested`
    407     A term used to describe an ASR that occurs
    408     during another ASR or an ISR that occurs during another ISR.
     362    A term used to describe an ASR that occurs during another ASR or an ISR
     363    that occurs during another ISR.
    409364
    410365:dfn:`node`
    411     A term used to reference a processor running
    412     RTEMS in a multiprocessor system.
     366    A term used to reference a processor running RTEMS in a multiprocessor
     367    system.
    413368
    414369:dfn:`non-existent`
    415     The state occupied by an uncreated or
    416     deleted task.
     370    The state occupied by an uncreated or deleted task.
    417371
    418372:dfn:`numeric coprocessor`
    419     A component used in computer
    420     systems to enhance performance in mathematically intensive
    421     situations.  It is typically viewed as a logical extension of
    422     the primary processor.
     373    A component used in computer systems to enhance performance in
     374    mathematically intensive situations.  It is typically viewed as a logical
     375    extension of the primary processor.
    423376
    424377:dfn:`object`
    425     In this document, this term is used to refer
    426     collectively to tasks, timers, message queues, partitions,
    427     regions, semaphores, ports, and rate monotonic periods.  All
    428     RTEMS objects have IDs and user-assigned names.
     378    In this document, this term is used to refer collectively to tasks, timers,
     379    message queues, partitions, regions, semaphores, ports, and rate monotonic
     380    periods.  All RTEMS objects have IDs and user-assigned names.
    429381
    430382:dfn:`object-oriented`
    431     A term used to describe systems
    432     with common mechanisms for utilizing a variety of entities.
    433     Object-oriented systems shield the application from
     383    A term used to describe systems with common mechanisms for utilizing a
     384    variety of entities.  Object-oriented systems shield the application from
    434385    implementation details.
    435386
    436387:dfn:`operating system`
    437     The software which controls all
    438     the computer's resources and provides the base upon which
    439     application programs can be written.
     388    The software which controls all the computer's resources and provides the
     389    base upon which application programs can be written.
    440390
    441391:dfn:`overhead`
    442     The portion of the CPUs processing power
    443     consumed by the operating system.
     392    The portion of the CPUs processing power consumed by the operating system.
    444393
    445394:dfn:`packet`
    446     A buffer which contains the messages passed
    447     between nodes in a multiprocessor system.  A packet is the
    448     contents of an envelope.
     395    A buffer which contains the messages passed between nodes in a
     396    multiprocessor system.  A packet is the contents of an envelope.
    449397
    450398:dfn:`partition`
    451     An RTEMS object which is used to allocate
    452     and deallocate fixed size blocks of memory from an dynamically
    453     specified area of memory.
     399    An RTEMS object which is used to allocate and deallocate fixed size blocks
     400    of memory from an dynamically specified area of memory.
    454401
    455402:dfn:`partition`
     
    457404
    458405:dfn:`Partition Control Block`
    459     A data structure associated
    460     with each partition used by RTEMS to manage that partition.
     406    A data structure associated with each partition used by RTEMS to manage
     407    that partition.
    461408
    462409:dfn:`pending`
    463     A term used to describe a task blocked
    464     waiting for an event, message, semaphore, or signal.
     410    A term used to describe a task blocked waiting for an event, message,
     411    semaphore, or signal.
    465412
    466413:dfn:`periodic task`
    467     A task which must execute at regular
    468     intervals and comply with a hard deadline.
     414    A task which must execute at regular intervals and comply with a hard
     415    deadline.
    469416
    470417:dfn:`physical address`
    471     The actual hardware address of a
    472     resource.
     418    The actual hardware address of a resource.
    473419
    474420:dfn:`poll`
    475     A mechanism used to determine if an event has
    476     occurred by periodically checking for a particular status.
    477     Typical events include arrival of data, completion of an action,
    478     and errors.
     421    A mechanism used to determine if an event has occurred by periodically
     422    checking for a particular status.  Typical events include arrival of data,
     423    completion of an action, and errors.
    479424
    480425:dfn:`pool`
    481     A collection from which resources are
    482     allocated.
     426    A collection from which resources are allocated.
    483427
    484428:dfn:`portability`
    485     A term used to describe the ease with
    486     which software can be rehosted on another computer.
     429    A term used to describe the ease with which software can be rehosted on
     430    another computer.
    487431
    488432:dfn:`posting`
    489     The act of sending an event, message,
    490     semaphore, or signal to a task.
     433    The act of sending an event, message, semaphore, or signal to a task.
    491434
    492435:dfn:`preempt`
    493     The act of forcing a task to relinquish the
    494     processor and dispatching to another task.
     436    The act of forcing a task to relinquish the processor and dispatching to
     437    another task.
    495438
    496439:dfn:`priority`
    497     A mechanism used to represent the relative
    498     importance of an element in a set of items.  RTEMS uses priority
    499     to determine which task should execute.
     440    A mechanism used to represent the relative importance of an element in a
     441    set of items.  RTEMS uses priority to determine which task should execute.
    500442
    501443:dfn:`priority boosting`
    502444    A simple approach to extend the priority inheritance protocol for clustered
    503     scheduling is :dfn:`priority boosting`.  In case a mutex is owned by a task of
    504     another cluster, then the priority of the owner task is raised to an
     445    scheduling is :dfn:`priority boosting`.  In case a mutex is owned by a task
     446    of another cluster, then the priority of the owner task is raised to an
    505447    artificially high priority, the pseudo-interrupt priority.
    506448
    507449:dfn:`priority inheritance`
    508     An algorithm that calls for
    509     the lower priority task holding a resource to have its priority
    510     increased to that of the highest priority task blocked waiting
    511     for that resource.  This avoids the problem of priority
    512     inversion.
     450    An algorithm that calls for the lower priority task holding a resource to
     451    have its priority increased to that of the highest priority task blocked
     452    waiting for that resource.  This avoids the problem of priority inversion.
    513453
    514454:dfn:`priority inversion`
    515     A form of indefinite
    516     postponement which occurs when a high priority tasks requests
    517     access to shared resource currently allocated to low priority
    518     task.  The high priority task must block until the low priority
    519     task releases the resource.
     455    A form of indefinite postponement which occurs when a high priority tasks
     456    requests access to shared resource currently allocated to low priority
     457    task.  The high priority task must block until the low priority task
     458    releases the resource.
    520459
    521460:dfn:`processor utilization`
    522     The percentage of processor
    523     time used by a task or a set of tasks.
     461    The percentage of processor time used by a task or a set of tasks.
    524462
    525463:dfn:`proxy`
    526     An RTEMS control structure used to represent,
    527     on a remote node, a task which must block as part of a remote
    528     operation.
     464    An RTEMS control structure used to represent, on a remote node, a task
     465    which must block as part of a remote operation.
    529466
    530467:dfn:`Proxy Control Block`
    531     A data structure associated
    532     with each proxy used by RTEMS to manage that proxy.
     468    A data structure associated with each proxy used by RTEMS to manage that
     469    proxy.
    533470
    534471:dfn:`PTCB`
     
    539476
    540477:dfn:`quantum`
    541     The application defined unit of time in
    542     which the processor is allocated.
     478    The application defined unit of time in which the processor is allocated.
    543479
    544480:dfn:`queue`
     
    550486:dfn:`ready task`
    551487    A task occupies this state when it is available to be given control of a
    552     processor.  A ready task has no processor assigned.  The scheduler decided that
    553     other tasks are currently more important.  A task that is ready to execute and
    554     has a processor assigned is called scheduled.
     488    processor.  A ready task has no processor assigned.  The scheduler decided
     489    that other tasks are currently more important.  A task that is ready to
     490    execute and has a processor assigned is called scheduled.
    555491
    556492:dfn:`real-time`
    557     A term used to describe systems which are
    558     characterized by requiring deterministic response times to
    559     external stimuli.  The external stimuli require that the
    560     response occur at a precise time or the response is incorrect.
     493    A term used to describe systems which are characterized by requiring
     494    deterministic response times to external stimuli.  The external stimuli
     495    require that the response occur at a precise time or the response is
     496    incorrect.
    561497
    562498:dfn:`reentrant`
    563     A term used to describe routines which do
    564     not modify themselves or global variables.
     499    A term used to describe routines which do not modify themselves or global
     500    variables.
    565501
    566502:dfn:`region`
    567     An RTEMS object which is used to allocate
    568     and deallocate variable size blocks of memory from a dynamically
    569     specified area of memory.
     503    An RTEMS object which is used to allocate and deallocate variable size
     504    blocks of memory from a dynamically specified area of memory.
    570505
    571506:dfn:`Region Control Block`
    572     A data structure associated
    573     with each region used by RTEMS to manage that region.
     507    A data structure associated with each region used by RTEMS to manage that
     508    region.
    574509
    575510:dfn:`registers`
    576     Registers are locations physically
    577     located within a component, typically used for device control or
    578     general purpose storage.
     511    Registers are locations physically located within a component, typically
     512    used for device control or general purpose storage.
    579513
    580514:dfn:`remote`
    581     Any object that does not reside on the local
    582     node.
     515    Any object that does not reside on the local node.
    583516
    584517:dfn:`remote operation`
    585     The manipulation of an object
    586     which does not reside on the same node as the calling task.
     518    The manipulation of an object which does not reside on the same node as the
     519    calling task.
    587520
    588521:dfn:`return code`
    589     Also known as error code or return
    590     value.
     522    Also known as error code or return value.
    591523
    592524:dfn:`resource`
    593     A hardware or software entity to which
    594     access must be controlled.
     525    A hardware or software entity to which access must be controlled.
    595526
    596527:dfn:`resume`
    597     Removing a task from the suspend state.  If
    598     the task's state is ready following a call to the ``rtems_task_resume``
    599     directive, then the task is available for scheduling.
     528    Removing a task from the suspend state.  If the task's state is ready
     529    following a call to the ``rtems_task_resume`` directive, then the task is
     530    available for scheduling.
    600531
    601532:dfn:`return code`
    602     A value returned by RTEMS directives to
    603     indicate the completion status of the directive.
     533    A value returned by RTEMS directives to indicate the completion status of
     534    the directive.
    604535
    605536:dfn:`RNCB`
     
    607538
    608539:dfn:`round-robin`
    609     A task scheduling discipline in which
    610     tasks of equal priority are executed in the order in which they
    611     are made ready.
     540    A task scheduling discipline in which tasks of equal priority are executed
     541    in the order in which they are made ready.
    612542
    613543:dfn:`RS-232`
     
    615545
    616546:dfn:`running`
    617     The state of a rate monotonic timer while
    618     it is being used to delineate a period.  The timer exits this
    619     state by either expiring or being canceled.
     547    The state of a rate monotonic timer while it is being used to delineate a
     548    period.  The timer exits this state by either expiring or being canceled.
    620549
    621550:dfn:`schedulable`
    622     A set of tasks which can be guaranteed
    623     to meet their deadlines based upon a specific scheduling
    624     algorithm.
     551    A set of tasks which can be guaranteed to meet their deadlines based upon a
     552    specific scheduling algorithm.
    625553
    626554:dfn:`schedule`
    627     The process of choosing which task should
    628     next enter the executing state.
     555    The process of choosing which task should next enter the executing state.
    629556
    630557:dfn:`scheduled task`
    631558    A task is :dfn:`scheduled` if it is allowed to execute and has a processor
    632     assigned.  Such a task executes currently on a processor or is about to start
    633     execution.  A task about to start execution it is an heir task on exactly one
    634     processor in the system.
     559    assigned.  Such a task executes currently on a processor or is about to
     560    start execution.  A task about to start execution it is an heir task on
     561    exactly one processor in the system.
    635562
    636563:dfn:`scheduler`
     
    638565    subset of its set of ready tasks.  So it manages access to the processor
    639566    resource.  Various algorithms exist to choose the tasks allowed to use a
    640     processor out of the set of ready tasks.  One method is to assign each task a
    641     priority number and assign the tasks with the lowest priority number to one
    642     processor of the set of processors owned by a scheduler instance.
     567    processor out of the set of ready tasks.  One method is to assign each task
     568    a priority number and assign the tasks with the lowest priority number to
     569    one processor of the set of processors owned by a scheduler instance.
    643570
    644571:dfn:`scheduler instance`
    645572    A :dfn:`scheduler instance` is a scheduling algorithm with a corresponding
    646     context to store its internal state.  Each processor in the system is owned by
    647     at most one scheduler instance.  The processor to scheduler instance assignment
    648     is determined at application configuration time.  See `Configuring a System`_.
     573    context to store its internal state.  Each processor in the system is owned
     574    by at most one scheduler instance.  The processor to scheduler instance
     575    assignment is determined at application configuration time.  See
     576    `Configuring a System`_.
    649577
    650578:dfn:`segments`
    651     Variable sized memory blocks allocated
    652     from a region.
     579    Variable sized memory blocks allocated from a region.
    653580
    654581:dfn:`semaphore`
    655     An RTEMS object which is used to
    656     synchronize tasks and provide mutually exclusive access to
    657     resources.
     582    An RTEMS object which is used to synchronize tasks and provide mutually
     583    exclusive access to resources.
    658584
    659585:dfn:`Semaphore Control Block`
    660     A data structure associated
    661     with each semaphore used by RTEMS to manage that semaphore.
     586    A data structure associated with each semaphore used by RTEMS to manage
     587    that semaphore.
    662588
    663589:dfn:`shared memory`
    664     Memory which is accessible by
    665     multiple nodes in a multiprocessor system.
     590    Memory which is accessible by multiple nodes in a multiprocessor system.
    666591
    667592:dfn:`signal`
    668     An RTEMS provided mechanism to communicate
    669     asynchronously with a task.  Upon reception of a signal, the ASR
    670     of the receiving task will be invoked.
     593    An RTEMS provided mechanism to communicate asynchronously with a task.
     594    Upon reception of a signal, the ASR of the receiving task will be invoked.
    671595
    672596:dfn:`signal set`
    673     A thirty-two bit entity which is used to
    674     represent a task's collection of pending signals and the signals
    675     sent to a task.
     597    A thirty-two bit entity which is used to represent a task's collection of
     598    pending signals and the signals sent to a task.
    676599
    677600:dfn:`SMCB`
     
    680603:dfn:`SMP locks`
    681604    The :dfn:`SMP locks` ensure mutual exclusion on the lowest level and are a
    682     replacement for the sections of disabled interrupts.  Interrupts are usually
    683     disabled while holding an SMP lock.  They are implemented using atomic
    684     operations.  Currently a ticket lock is used in RTEMS.
     605    replacement for the sections of disabled interrupts.  Interrupts are
     606    usually disabled while holding an SMP lock.  They are implemented using
     607    atomic operations.  Currently a ticket lock is used in RTEMS.
    685608
    686609:dfn:`SMP barriers`
    687610    The :dfn:`SMP barriers` ensure that a defined set of independent threads of
    688611    execution on a set of processors reaches a common synchronization point in
    689     time.  They are implemented using atomic operations.  Currently a sense barrier
    690     is used in RTEMS.
     612    time.  They are implemented using atomic operations.  Currently a sense
     613    barrier is used in RTEMS.
    691614
    692615:dfn:`soft real-time system`
    693     A real-time system in which a
    694     missed deadline does not compromise the integrity of the system.
     616    A real-time system in which a missed deadline does not compromise the
     617    integrity of the system.
    695618
    696619:dfn:`sporadic task`
    697     A task which executes at irregular
    698     intervals and must comply with a hard deadline.  A minimum
    699     period of time between successive iterations of the task can be
    700     guaranteed.
     620    A task which executes at irregular intervals and must comply with a hard
     621    deadline.  A minimum period of time between successive iterations of the
     622    task can be guaranteed.
    701623
    702624:dfn:`stack`
    703     A data structure that is managed using a Last
    704     In First Out (LIFO) discipline.  Each task has a stack
    705     associated with it which is  used to store return information
    706     and local variables.
     625    A data structure that is managed using a Last In First Out (LIFO)
     626    discipline.  Each task has a stack associated with it which is used to
     627    store return information and local variables.
    707628
    708629:dfn:`status code`
    709     Also known as error code or return
    710     value.
     630    Also known as error code or return value.
    711631
    712632:dfn:`suspend`
    713     A term used to describe a task that is not
    714     competing for the CPU because it has had a ``rtems_task_suspend`` directive.
     633    A term used to describe a task that is not competing for the CPU because it
     634    has had a ``rtems_task_suspend`` directive.
    715635
    716636:dfn:`synchronous`
    717     Related in order or timing to other
    718     occurrences in the system.
     637    Related in order or timing to other occurrences in the system.
    719638
    720639:dfn:`system call`
    721     In this document, this is used as an
    722     alternate term for directive.
     640    In this document, this is used as an alternate term for directive.
    723641
    724642:dfn:`target`
    725     The system on which the application will
    726     ultimately execute.
     643    The system on which the application will ultimately execute.
    727644
    728645:dfn:`task`
    729646    A logically complete thread of execution.  It consists normally of a set of
    730     registers and a stack.  The terms :dfn:`task` and :dfn:`thread` are synonym in
    731     RTEMS.  The scheduler assigns processors to a subset of the ready tasks.
     647    registers and a stack.  The terms :dfn:`task` and :dfn:`thread` are synonym
     648    in RTEMS.  The scheduler assigns processors to a subset of the ready tasks.
    732649
    733650:dfn:`Task Control Block`
    734     A data structure associated with
    735     each task used by RTEMS to manage that task.
     651    A data structure associated with each task used by RTEMS to manage that
     652    task.
    736653
    737654:dfn:`task migration`
    738     :dfn:`Task migration` happens in case a task stops execution on one processor
    739     and resumes execution on another processor.
     655    :dfn:`Task migration` happens in case a task stops execution on one
     656    processor and resumes execution on another processor.
    740657
    741658:dfn:`task processor affinity`
     
    743660
    744661:dfn:`task switch`
    745     Alternate terminology for context
    746     switch.  Taking control of the processor from one task and given
    747     to another.
     662    Alternate terminology for context switch.  Taking control of the processor
     663    from one task and given to another.
    748664
    749665:dfn:`TCB`
     
    751667
    752668:dfn:`thread dispatch`
    753     The :dfn:`thread dispatch` transfers control of the processor from the currently
    754     executing thread to the heir thread of the processor.
     669    The :dfn:`thread dispatch` transfers control of the processor from the
     670    currently executing thread to the heir thread of the processor.
    755671
    756672:dfn:`tick`
    757     The basic unit of time used by RTEMS.  It is a
    758     user-configurable number of microseconds.  The current tick
    759     expires when the ``rtems_clock_tick``
     673    The basic unit of time used by RTEMS.  It is a user-configurable number of
     674    microseconds.  The current tick expires when the ``rtems_clock_tick``
    760675    directive is invoked.
    761676
    762677:dfn:`tightly-coupled`
    763     A multiprocessor configuration
    764     system which communicates via shared memory.
     678    A multiprocessor configuration system which communicates via shared memory.
    765679
    766680:dfn:`timeout`
    767     An argument provided to a number of
    768     directives which determines the maximum length of time an
    769     application task is willing to wait to acquire the resource if
    770     it is not immediately available.
     681    An argument provided to a number of directives which determines the maximum
     682    length of time an application task is willing to wait to acquire the
     683    resource if it is not immediately available.
    771684
    772685:dfn:`timer`
    773     An RTEMS object used to invoke subprograms at
    774     a later time.
     686    An RTEMS object used to invoke subprograms at a later time.
    775687
    776688:dfn:`Timer Control Block`
    777     A data structure associated
    778     with each timer used by RTEMS to manage that timer.
     689    A data structure associated with each timer used by RTEMS to manage that
     690    timer.
    779691
    780692:dfn:`timeslicing`
    781     A task scheduling discipline in which
    782     tasks of equal priority are executed for a specific period of
    783     time before being preempted by another task.
     693    A task scheduling discipline in which tasks of equal priority are executed
     694    for a specific period of time before being preempted by another task.
    784695
    785696:dfn:`timeslice`
    786     The application defined unit of time in
    787     which the processor is allocated.
     697    The application defined unit of time in which the processor is allocated.
    788698
    789699:dfn:`TMCB`
     
    791701
    792702:dfn:`transient overload`
    793     A temporary rise in system
    794     activity which may cause deadlines to be missed.  Rate Monotonic
    795     Scheduling can be used to determine if all deadlines will be met
    796     under transient overload.
     703    A temporary rise in system activity which may cause deadlines to be missed.
     704    Rate Monotonic Scheduling can be used to determine if all deadlines will be
     705    met under transient overload.
    797706
    798707:dfn:`user extensions`
    799     Software routines provided by the
    800     application to enhance the functionality of RTEMS.
     708    Software routines provided by the application to enhance the functionality
     709    of RTEMS.
    801710
    802711:dfn:`User Extension Table`
    803     A table which contains the
    804     entry points for each user extensions.
     712    A table which contains the entry points for each user extensions.
    805713
    806714:dfn:`User Initialization Tasks Table`
    807     A table which
    808     contains the information needed to create and start each of the
    809     user initialization tasks.
     715    A table which contains the information needed to create and start each of
     716    the user initialization tasks.
    810717
    811718:dfn:`user-provided`
    812     Alternate term for user-supplied.
    813     This term is used to designate any software routines which must
    814     be written by the application designer.
     719    Alternate term for user-supplied.  This term is used to designate any
     720    software routines which must be written by the application designer.
    815721
    816722:dfn:`user-supplied`
    817     Alternate term for user-provided.
    818     This term is used to designate any software routines which must
    819     be written by the application designer.
     723    Alternate term for user-provided.  This term is used to designate any
     724    software routines which must be written by the application designer.
    820725
    821726:dfn:`vector`
    822     Memory pointers used by the processor to
    823     fetch the address of routines which will handle various
    824     exceptions and interrupts.
     727    Memory pointers used by the processor to fetch the address of routines
     728    which will handle various exceptions and interrupts.
    825729
    826730:dfn:`wait queue`
    827     The list of tasks blocked pending the
    828     release of a particular resource.  Message queues, regions, and
    829     semaphores have a wait queue associated with them.
     731    The list of tasks blocked pending the release of a particular resource.
     732    Message queues, regions, and semaphores have a wait queue associated with
     733    them.
    830734
    831735:dfn:`yield`
    832736    When a task voluntarily releases control of the processor.
    833 
Note: See TracChangeset for help on using the changeset viewer.