Zombie is actually a process still running, but we lost track of it. In other words, in the fork case, if the parent created a child that cannot exit on its own, say it has some sort of dead loop, whatever the dead loop is created by mistake or purposely, as a good practice, the parent process should kill the child process. Otherwise, the child becomes a zombie, as it will run forever, and it will have that seat in the process table forever.
Ehm, I beg to differ. A zombie process is not what you describe here. A zombie process is one that is no longer running (it has exited), but its parent has not yet collected its exit status, so the kernel keeps it around in the process table. What you describe is a runaway process, or even a perfectly normal daemon. Something like inetd or sendmail fits your description, and I do not think many people will call those zombies.
If a process exited, it will be removed from the process table, doesn't matter whether it is created by a parent process, or it runs on its own, as it is a process any way.
Except when its a child process - it exits but stays in the process table unless its parent collects its status.

Update: Added point about daemons.

YAU: After a chatterbox conversation with pg, we've decided that we're both right - different sources mean different things with 'zombie process'. YMMV.

CU
Robartes-

In reply to Re: Re: Re: open(KID, "-|") and wait()? by robartes
in thread open(KID, "-|") and wait()? by edan

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