Unix IPC

[Dan Klein]

Clearly, the signalling mechanism currently in Unix is far from optimal
for anything other than the most simpleminded IPC.  The mailbox approach
is reasonable, but tricky, since you need to have a way of passing the
names of the mailbox (for which you need IPC already), or just making it
an open file which gets transferred via exec.

There is one advantage to signals which cannot be overlooked in this
discussion: they have the ability to interrupt you.  Pipes do not.  Perhaps
having a VMS style AST to interrupt you on file/terminal activity is the
way to go. This way you get notice when a communicating process has something
to say, or you can simply poll things.  This makes useful programs (like
multi-player interactive games) easy to write.  They just do their real-time
things until the player changes some state by issuing a command.

(Sorry for the stream of consciousness...)