How is checkpoint/restart different than SIGSTOP/SIGCONT?
Putting a process to sleep (via the SIGSTOP signal) implies stopping its execution. Taking a checkpoint writes a snapshot of a process to disk: the process may either be allowed to continue running after the checkpoint is complete, or you can kill the process to release all of its resources . With sleep, a process’s resources are not all fully released (such as virtual memory, network connections, process id, etc.). Checkpointing then killing a process fully releases all system resources. Restarts from checkpoint files can be used across machine reboots, and/or even on different machines than the one that the checkpoint was taken on. This is not true for SIGCONT.
