Checkpoint and restart processing

In programs, checkpoints can be set by means of the WRCPT macro; when a checkpoint is encountered, the program status, the system environment, etc. are written into a checkpoint file. For large tape files, automatic writing of checkpoints can be specified using the FILE macro (operand CHKPT) or ADD-FILE-LINK command (operand CHECKPOINT-WRITE).

If a program is aborted, it can be restarted from one of these checkpoints with the aid of the RESTART-PROGRAM command.