Controlling started tasks
A started task, like a job, is a basic unit of work for the system. However, started tasks differ from jobs in that started tasks are always demand-selected; that is, the operator or a program must take action to initiate a started task.
There are several ways to initiate started tasks:
- With a START command.
- Via TSO/E logons. For information on using TSO/E logons, refer to the TSO/E publications.
- With ASCRE (address space create) macros in programs. For information on how to use the ASCRE macro, refer to z/OS MVS Programming: Extended Addressability Guide.
Both the START command and the ASCRE macro create an address space. A START command and an ASCRE macro started via a START command each will look for a program that has a procedure in SYS1.PROCLIB; that program will be the first to run in the ASCRE-created address space. Essentially, using ASCRE is similar to a started task.
For a started task, the system:
- Locates the JCL that starts the task
- Defines the task's address space
- Processes the JCL.
For a started task, operators can do the following:
| Task | For information, refer to: |
|---|---|
| Cancel the started task | CANCEL command |
| Display status about the started task | DISPLAY command |
| Force the started task | FORCE command |
| Modify the started task | MODIFY command |
| Name the started task | "START Command" Starting a system task from a console (JOBNAME= parameter) |
| Start the started task | "START Command" Starting a system task from a console |
| Stop the started task | STOP command |