On Fri, Apr 9, 2021 at 11:34 PM Ed Bradford <egbegb2 at gmail.com> wrote:

> Why did a Ph.D., an academic, and a computer scientist not know about UNIX
> in 1974 or so? 1976? In 1976, some (many?) universities had source code.
>

Some knowns/givens at the time ...
1.) He was a language/compiler type person -- he had created PL/M and that
was really what he was originally trying to show off.  As I understand it
and has been reported in other interviews, originally CP/M was an attempt
to show off what you could do with PL/M.
2.) The 8080/Z80 S-100 style machines we quite limited, they had very
little memory, no MMU, and extremely limited storage in the 8" floppies
3.) He was familiar with RT/11 and DOS-11, many Universities had it on
smaller PDP-11s as they ran on an 11/20 without an MMU also with limited
memory, and often used simple (primarily tape) storage (DECtape and
Cassette's) as the default 'laboratory' system, replacing the earlier PDP-8
for the same job which primarily ran DOS-8 in those settings.
4.) Fifth and Sixth Edition of Unix was $150 for university but to run it,
it took a larger at least 11/40 or 45, with a minimum of 64Kbytes to boot
and really need the full 256Kbytes to run acceptably and the cost of a 2.5M
byte RK05 disk was much greater per byte than tape -- thus the base system
it took to run it was at least $60K (in 1975 dollars) and typically cost
about two to four times that in practice.   Remember the cost of
acquisition of the HW dominated many (most) choices.

*I**'ll take a guess, but it is only that.*  I *suspect* he saw the S-100
system as closer to a PDP-11/20 'lab' system than as a small
timesharing machine.  He set out with CP/M to duplication the functionality
from RT/11.  He even the naming of the commands was the same as what DEC
used (*e.g.* PIP) and used the basic DEC style command syntax and parsing
rules.