NCL Concepts › Execute NCL Processes Concurrently

Execute NCL Processes Concurrently

You can use the START command to invoke an NCL process that will execute concurrently with other NCL processes that are invoked with the EXEC or START command from the same window (that is, in the same processing environment).

This means that if you enter:

START     PROC1
START     PROC2

from the OCS window command line, a process is invoked to execute the procedure PROC1 immediately, and the second process is also invoked to execute PROC2 immediately. You can use the START command to execute many independent NCL processes at the same time in the same NCL environment.

Concurrent execution of processes lets you have slave processes running on your behalf doing different tasks. For example, a process could execute NCL procedures that monitor the status of particular resources at regular intervals and communicate with your OCS window only when something is found to be wrong.

The default maximum number of NCL processes that can be executing concurrently for any user is 128.

The concurrent stream of NCL processes executes in parallel with the serial stream.

If you enter:

EXEC     PROC1
EXEC     PROC2
START    PROC3
START    PROC4

from the OCS window command line, PROC1 executes at once on the serial stream and PROC2 is queued waiting for PROC1 to finish. However, PROC3 and PROC4 start at once on the concurrent stream and therefore execute at the same time as PROC1.