[TUHS] Etymology of shell

John Cowan cowan at mercury.ccil.org
Sat Dec 26 12:44:08 AEST 2015

Warren Toomey scripsit:

> So what is the etymology of "shell", then? I see that Multics has a
> shell. Was the CTSS user interface also called a shell?

I can't speak to CTSS, but my understanding is that the Multics shell was
a shell in the same sense as an expert-system shell: that is, a fixed
piece of code into which other code was loaded in order to customize
it to do something.  Rather than starting another process, the Multics
shell mapped the executable program the user requested into its own
space, as is done with shared libraries today, and then jumped into it.
The equivalent of exit() simply jumped back to the shell code.

John Cowan          http://www.ccil.org/~cowan        cowan at ccil.org
The present impossibility of giving a scientific explanation is no proof
that there is no scientific explanation. The unexplained is not to be
identified with the unexplainable, and the strange and extraordinary
nature of a fact is not a justification for attributing it to powers
above nature.  --The Catholic Encyclopedia, s.v. "telepathy" (1913)

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