Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bat.cis.ohio-state.edu!lum
From: lum@bat.cis.ohio-state.edu (Lum Johnson)
Newsgroups: comp.sys.next
Subject: Re: Op Environment vs Op System (was: NeXT not revolutionary enough?)
Message-ID: <27921@tut.cis.ohio-state.edu>
Date: 18 Nov 88 16:45:23 GMT
References: <471@wucs1.wustl.edu> <48@necbsd.NEC.COM> <26446@tut.cis.ohio-state.edu> <4833@polya.Stanford.EDU> <145@avsd.UUCP> <4163@encore.UUCP> <32289@bbn.COM>
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In article <32289@bbn.COM> jr@bbn.com (John Robinson) writes:
>In article <4163@encore.UUCP>, bzs@encore (Barry Shein) writes:
>>>
>>>I would assume that this functional division between the two [OS, "shell"]
>>>has been existent ever since OSes were designed, rather than conglomerated.
>>
>>[Please] show an operating system with this property before around 1970 when
>>Unix began this sort of thing.
>
>The TENEX "exec" was a program that you could ask the system to run for you,
>in an "inferior exec" if (for example) you wanted to suspend the interactive
>things you were doing and go off to look at a file or whatever.  This dates
>to about 1970.  Given the coincidence with Unix, howver, I suspect the idea
>has a common ancestor in either Multics or the SDS 940 operating system.
>I'll try to dig up more on this since it seems to be of interest.

The 'exec' was the program given to you on login, and you could "push" to
another invocation from the original or most other programs.  The analogy to
the 'shell' is very close indeed.

Both BBN TENEX and ATT UNIX were written in reaction to defects in the model
of time sharing accepted by Project MAC and exemplified by CTSS, MULTICS, and
TOPS-10.  TENEX, modeled mostly on DEC TOPS-10, was implemented on a Honeywell
machine, ported to Digital's pdp-10 when that was discontinued, and used by
Digital as the basis of TOPS-20.

The 'exec'/'shell' approach eased the burden of system debugging, maintenance,
and security, and made user control of different programs simultaneously
running in separate forks feasible.  It was a huge success.  I believe both
BBN and ATT made the same (or a very similar) discovery independently, almost
simultaneously.  BBN may have been earlier by a year.
-=-
-- 
Lum Johnson    lum@osu-20.ircc.ohio-state.edu    lum@tut.cis.ohio-state.edu
"You got it kid -- the large print giveth and the small print taketh away."
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