19-07-2012, 04:27 PM
OPERATING SYSTEMS SCHEDULING
[attachment=28110]
CPU SCHEDULING
Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves:
switching context
switching to user mode
jumping to the proper location in the user program to restart that program
Dispatch latency – time it takes for the dispatcher to stop one process and start another running
MULTIPLE PROCESSOR SCHEDULING:
Different rules for homogeneous or heterogeneous processors.
Load sharing in the distribution of work, such that all processors have an equal amount to do.
Each processor can schedule from a common ready queue ( equal machines ) OR can use a master slave arrangement.
Real Time Scheduling:
Hard real-time systems – required to complete a critical task within a guaranteed amount of time.
Soft real-time computing – requires that critical processes receive priority over less fortunate ones.
[attachment=28110]
CPU SCHEDULING
Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves:
switching context
switching to user mode
jumping to the proper location in the user program to restart that program
Dispatch latency – time it takes for the dispatcher to stop one process and start another running
MULTIPLE PROCESSOR SCHEDULING:
Different rules for homogeneous or heterogeneous processors.
Load sharing in the distribution of work, such that all processors have an equal amount to do.
Each processor can schedule from a common ready queue ( equal machines ) OR can use a master slave arrangement.
Real Time Scheduling:
Hard real-time systems – required to complete a critical task within a guaranteed amount of time.
Soft real-time computing – requires that critical processes receive priority over less fortunate ones.