[TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?)

[Douglas McIlroy <douglas.mcilroy@dartmouth.edu>]

Many tree and dag pipe notations have been proposed. Marc's was one of
the first. I devised one myself, but didn't like it enough to publish
it even as a TM. A recent one is Spinellis's dgsh. More elaborate
networks with feedback loops evolve for power-series computation. The
idea of implementing cellular automata as arrays of processes with
nearest neighbors connected by pipes was suggested early on, but I've
never seen such an arrangement implemented--it would be hideously
slow.

I once wrote a general plumber that worked from a connection list:
connect fd m in process A to fd n in process B. The main challenge was
to find an order of hooking things up so that the number of live file
descriptors in the plumber didn't exceed the system limit.

Doug