Definition
Suspended Process
A suspended process is a process that has been swapped out of main memory (RAM) and moved to secondary storage (disk). In the Seven-State Process Model, these processes occupy the Ready/Suspend or Blocked/Suspend states.
A suspended process is not immediately available for execution on the CPU and requires a Swap In (activation) operation by the operating system before it can return to the Ready state.
Characteristics
- Location: Resides in the swap space on the disk rather than in RAM.
- Resources: Does not consume available physical memory, but its PCB typically remains in kernel memory so the OS can continue to manage it.
- State Changes: A process in the Blocked/Suspend state can still transition to Ready/Suspend if the event it was waiting for occurs while it is on disk.
Reasons for Suspension
The OS typically suspends processes to:
- Free up RAM for other active processes.
- Move a process that is blocked on a long-term event (e.g., waiting for user input) out of precious main memory.
- Fulfill a parent process request to pause a child for debugging or control purposes.