Process Scheduling 1 read operating system concepts 6

When a process enters the system, it will be addedJob Queue. This queue includes all processes in the system. Processes that reside in the memory ready for running are saved inReady queueTable. This queue is usually stored in the form of a linked list. Its header node includes pointers pointing to the first and last PCB blocks of the linked list. You can add a pointer field for each PCB to point to the Next PCB of the ready queue.

The operating system also has other queues. After a CPU is allocated to a process, it starts to execute and eventually completes, exits, or is interrupted, or waits for a specific event, such as the completion of an I/O Request. For I/O requests, this request may be a dedicated tape drive or shared device (such as a disk ). Because the system has many processes, the disk may be busy with the I/O requests of other processes, so the process may need to wait for the disk. The list of processes waiting for a specific I/O device is calledDevice queue.