John Cowan <cowan@locke.ccil.org> writes on Tue, 4 Jul 2000 11:26:59 -0800
(GMT-0800):
>> I think that TOPS-10 was the first OS to use this convention [1A SUB ==
>> end-of-file]
I worked for a dozen years on a TOPS-20 system, and never saw that, so
I don't think TOPS-10 had that characteristic. The PDP-10 CPU allowed
byte sizes from 1 to 36, and TOPS-n supported files with all of those
sizes, so designation of a specific character to denote end-of-file is
impossible.
However, Gary Kildall's CP/M did use 1A SUB for end-of-file marks, and
as far as I know, Microsoft/IBM DOS borrowed that practice, and many
other things, from it.
There may be even older systems with this `feature': the Emacs
jargon.info file (the online form of Raymond & Steele's New Hackers'
Dictionary) says this:
>> ...
>> :CP/M:: /C-P-M/ /n./ [Control Program/Monitor; later
>> {retcon}ned to Control Program for Microcomputers] An early
>> microcomputer {OS} written by hacker Gary Kildall for 8080- and
>> Z80-based machines ...
>> Many of CP/M's features and conventions strongly resemble those of
>> early {DEC} operating systems such as {{TOPS-10}}, OS/8, RSTS, and
>> RSX-11.
>> ...
Perhaps someone out there has some 1970s-vintage manuals still on
their shelf that could provide further clarification.
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