Safe State
- When
a process requests an available resource, system must decide if immediate
allocation leaves the system in a safe state.
- System
is in safe state if there exists a safe sequence of all processes.
- Sequence
<P1, P2, …, Pn> is
safe if for each Pi, the resources that Pi can still request can be satisfied by currently
available resources + resources held by all the Pj, with j<I.
- If Pi resource
needs are not immediately available, then Pi can wait until all Pj have
finished.
- When Pj is finished, Pi can obtain needed resources, execute,
return allocated resources, and terminate.
- When Pi terminates, Pi+1 can obtain its needed resources, and so
on.
No comments:
Post a Comment