# Revision History {#rtos_revisionHistory}

<table class="cmtable" summary="Revision History">
    <tr>
      <th>Version</th>
      <th>Description</th>
    </tr>
    <tr>
      <td>V2.3.0</td>
      <td>
         Added provisional support for processor affinity in SMP systems:
         - \ref osThreadAttr_t :: affinity_mask
         - \ref osThreadSetAffinityMask, \ref osThreadGetAffinityMask
      </td>
    </tr>
    <tr>
      <td>V2.2.0</td>
      <td>
        Added support for Process Isolation (Functional Safety):
         - Kernel Management: \ref osKernelProtect, \ref osKernelDestroyClass
         - Thread Management: \ref osThreadGetClass, \ref osThreadGetZone,<br>
           \ref osThreadSuspendClass, \ref osThreadResumeClass, \ref osThreadTerminateZone,<br>
           \ref osThreadFeedWatchdog, \ref osThreadProtectPrivileged
         - Thread attributes: \ref osThreadZone, \ref osThreadUnprivileged, \ref osThreadPrivileged
         - Object attributes: \ref osSafetyClass
         - Handler functions: \ref osWatchdogAlarm_Handler
         - Zone Management: \ref osZoneSetup_Callback
         - Exception Faults: \ref osFaultResume

        Additional functions allowed to be called from Interrupt Service Routines:
         - \ref osThreadGetName, \ref osEventFlagsGetName, \ref osTimerGetName, \ref osMutexGetName, \ref osSemaphoreGetName, \ref osMemoryPoolGetName, \ref osMessageQueueGetName
      </td>
    </tr>
    <tr>
      <td>V2.1.3</td>
      <td>
        Additional functions allowed to be called from Interrupt Service Routines:
         - \ref osThreadGetId
     </td>
    </tr>
    <tr>
      <td>V2.1.2</td>
      <td>
        Additional functions allowed to be called from Interrupt Service Routines:
         - \ref osKernelGetInfo, \ref osKernelGetState
     </td>
    </tr>
    <tr>
      <td>V2.1.1</td>
      <td>
        Additional functions allowed to be called from Interrupt Service Routines:
         - \ref osKernelGetTickCount, \ref osKernelGetTickFreq
         
        Changed Kernel Tick type to uint32_t:
         - updated: \ref osKernelGetTickCount, \ref osDelayUntil
     </td>
    </tr>
    <tr>
      <td>V2.1.0</td>
      <td>
        Support for critical and uncritical sections (nesting safe):
         - updated: \ref osKernelLock, \ref osKernelUnlock
         - added: \ref osKernelRestoreLock

        Updated \ref CMSIS_RTOS_ThreadFlagsMgmt "Thread Flags" and \ref CMSIS_RTOS_EventFlags "Event Flags":
         - changed flags parameter and return type from int32_t to uint32_t
     </td>
    </tr>
    <tr>
      <td>V2.0.0</td>
      <td>
        New API Version 2.0 available. 
         - See \ref CMSIS_RTOS for a detailed function reference.
     </td>
    </tr>
    <tr>
      <td>V1.02 - only documentation changes</td>
      <td>
      Added: Overview of the \ref rtosValidation "CMSIS-RTOS Validation" Software Pack.\n
      Clarified: Behavior of \ref CMSIS_RTOS_TimeOutValue.
     </td>
    </tr>
    <tr>
      <td>V1.02</td>
      <td>Added: New control functions for short timeouts in microsecond resolution \b osKernelSysTick,
      \b osKernelSysTickFrequency, \b osKernelSysTickMicroSec.\n
      Removed: osSignalGet.
     </td>
    </tr>fv
    <tr>
      <td>V1.01</td>
      <td>Added capabilities for C++, kernel initialization and object deletion.\n
      Prepared for C++ class interface. In this context to \em const attribute has been moved from osXxxxDef_t typedefs to
      the osXxxxDef macros.\n
      Added: \ref osTimerDelete, \ref osMutexDelete, \ref osSemaphoreDelete .\n
      Added: \ref osKernelInitialize that prepares the kernel for object creation.\n
      </td>
    </tr>
    <tr>
      <td>
      V1.00</td>
      <td>First official Release.\n
      Added: \ref osKernelStart; starting 'main' as a thread is now an optional feature.\n
      Semaphores have now the standard behavior.\n
      \b osTimerCreate does no longer start the timer. Added: \ref osTimerStart (replaces osTimerRestart).\n
      Changed: osThreadPass is renamed to \ref osThreadYield.
      </td>
    </tr>
    <tr>
      <td>V0.02</td>
      <td>Preview Release.</td>
    </tr>
</table>