If a pipe is created before a fork command, it can be used to communicate between the parent and child processes. The dup function is normally used in Unix to duplicate a file handle into the standard input or standard output of a program about to be executed. Unix FD ports closes the first port, and duplicates the first port into the second port. For more information on these commands, please see their manual pages, or read a book on Unix programming. See below for a list of possible signals to send.
Threads are different from processes in that they share the same memory space and resources.
Isis allows you to create threads and run procedures in them. When the threads finish, you can retrieve the results of those applications, if desired. Threads in Isis are still under development and available for you to use on a trial basis only, and you must use a special interpreter called multi-isis . The thread interface is currently very simple. To create a new thread running a procedure, use the spawn operator, which will return a thread identifier or Null if an error occurred.