[TUHS] Algol68 vs. C at Bell Labs

Marc Rochkind rochkind at basepath.com
Fri Jul 1 03:57:10 AEST 2016

Dan Cross: "... even if they didn't use Unix directly, it was an existence
proof that such a thing was possible".

Indeed it was. IBM contracted with Interactive Systems (Heinz Lycklama's
company, in Santa Monica) to produce PC/IX, which was complete System 3 for
the IBM PC. 8088, 4.77MHz, and 512K of RAM (if I'm remembering the numbers
correctly). It was my primary development system for the first edition of
Advanced UNIX Programming.

As for why "IBM" didn't do something other than MS-DOS originally: It
depends what you mean by "IBM". The PC was not originally strategic,
although it might have become that way after a few years. It was just a
small group in Boca Raton (as I recall) that whipped it out pretty quickly.
MS-DOS was a good choice within the class of what then were known as
personal computer operating systems (CP/M being the leader for 8080/Z80
Intel systems).

I don't think PC/IX would have run on a floppy-only system. And, if it
would, it would have been a demonstration only--entirely impractical. IBM
didn't provide a PC with a hard drive until later, and that's when PC/IX
came along.

Don't forget that the IBM PC completely dominated office use where personal
computers were needed. A runaway success. That makes me think that the
technical solutions were correct for what the project was supposed to

When I tried to write responsive software for UNIX and UNIX-like OSes
running on PCs, I could never achieve good results because the display
support was inadequate. Typically, you treated the display like a terminal
(escape sequences). MS-DOS allowed me to write to display memory directly,
which what was made PC software so responsive.

To say it another way, UNIX on a PC was always just a port. No
consideration was given to providing support for the way PCs were actually
used. That didn't happen until Xerox PARC started to produce PCs (at a much
higher cost, of course). The first decent "PC" was the Macintosh SE. The
earlier Macs were dogs.


On Thu, Jun 30, 2016 at 11:07 AM, John Cowan <cowan at mercury.ccil.org> wrote:

> Dan Cross scripsit:
> > I've never understood why IBM didn't just write a real OS in a
> > high-level language instead of saddling the world with MS-DOS.
> I think because to IBM "a real OS" meant MVS.  The difference between
> Unix and MS-DOS simply wasn't visible to them.
> --
> John Cowan          http://www.ccil.org/~cowan        cowan at ccil.org
> Don't be so humble.  You're not that great.
>         --Golda Meir
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