...do extra or better than other IPC modules?

The impetus/reasons are usually listed in the documentation, otherwise there is no real way to know :) other than to compare interfaces , and then a code review

Usually, IPC modules tend to also work on Win32/Windows ... while Proc:: modules generally don't work on win32 ... almost all fork/forking/forkness idioms of unix/linux don't apply to win32 because win32 doesn't have fork perl emulates it, poorly, so IPC:... need win32 specific loops ... complicates the codebase, and sometimes limits the interface

Also, Proc-Simple first released 05/22/96 which was before perl 5.003 -- Proc-Simple should live :D

Is there any difference between controlling background processes and simple foreground proceses?

foreground/background is a user gui/shell perspective , the process is exactly the same

when you start a process from a shell, its in the foreground, it blocks the shell from accepting any new commands

unless the process is started in the background, or you put it into the background via shell command (IIRC ctr+b? ), then the shell will accept new commands and start new processes while the now backgrounded process is still running

Another way that the nomenclature is commonly used is to say that “foreground” activities occur spontaneously and at the user’s behest, while “background” activities are commonly beefier, performed on behalf of the community at large, longer-running, and therefore commonly handled by a group of batch-service processes (on the same or on different computers), who are servicing some kind of request-queue and posting their results [files ...] to some kind of results queue.   In other words, “batch jobs.”   (There’s a third category, “servers,” or “daemons,” to generally denote processes that are running all the time.)

At this point, I would suggest that you consider your overall requirement carefully, and, feel free to discuss it here.   There are, today, many good CPAN libraries which address this sort of requirement at a very high level ... POE and RPC::Any come readily to mind ... that might take you much farther, much faster, towards a robust solution for your requirement, than your initial gropings might suggest.   If you describe now what you need to do, and the environment in which you need to do it, someone [else] here will probably hand back excellent suggestions within a matter of hours or minutes, drawn directly from their personal experience.   So, I’d start there.