RTEMS 4.5.0 On-Line Library

Task Manager Task Manager Task States

RTEMS ITRON 3.0 API User's Guide

1.2.4: Task Manager Task States

A task may exist in one of the following five states:

RUN - Currently scheduled to the CPU
READY - May be scheduled to the CPU
Wait - Unable to be scheduled to the CPU
- (Specific) WAIT - The task is issued a command to wait on a condition
- SUSPEND - Another task suspended execution of the task
- WAIT-SUSPEND - Both the WAIT and SUSPEND states apply
DORMANT - Created task that is not started
NON-EXISTENT - Uncreated or deleted task

An active task may occupy the RUN, READY, Wait or DORMANT state, otherwise the task is considered NON-EXISTENT. One or more tasks may be active in the system simultaneously. Multiple tasks communicate, synchronize, and compete for system resources with each other via system calls. The multiple tasks appear to execute in parallel, but actually each is dispatched to the CPU for periods of time determined by the scheduling algorithm. The scheduling of a task is based on its current state and priority.

RTEMS ITRON 3.0 API User's Guide