Is it possible to have a main script (i will call it main.ksh) that executes say, 4 other scripts (sub_prog_1.ksh, sub_prog_2.ksh etc..) from within this main.ksh (simultaneously/in parallel), have them run in the background and communicate back to main.ksh when complete?

My guess is to use co-processes and do the communication between main and sub by redirecting output to a file descriptor which would be used by main. Is this correct?

the 4 sub-scripts would be calling and executing stored procedures and such, and it would be nice to have them execute concurrently. current setup uses a scheduling program (Maestro) to kick off jobs.

It is possible, but I would not use co-processes. I would just use background jobs.

The main script can remember the pid's of the background jobs that it launches. By doing "kill -0 $pid 2> /dev/null" and then checking the $? variable, it can monitor them to see if they are still running. The kill will do nothing except succeed if the process is still running. And it will fail if the process has exited. Since kill is a ksh built-in, this is not an expensive test.

It would be very hard for the background jobs to asyncronously notify the main script as they finish. If you really want to do that, you will need signal handlers. It is much better if the main script just polls the background jobs.