Yes, that sounds about right. LSX and MX used older versions of UNIX
and binary licensing from WE was not yet available.
Heinz
On 2021-04-07 00:52, Paul Ruizendaal via TUHS wrote:
I developed
LSX at Bell Labs in Murray Hill NJ in the 1974-1975
timeframe.
An existing C compiler made it possible without too much effort. The
UNIX
source was available to Universities by then. I also developed
Mini-UNIX
for the PDP11/10 (also no memory protection) in the 1976 timeframe.
This source code was also made available to Universities, but the
source
code for LSX was not.
Peter Weiner, the founder of INTERACTIVE Systems Corp.(ISC) in June
1977,
the first commercial company to license UNIX source from Western
Electric for $20,000. Binary licenses were available at the same time.
I joined ISC in May of 1978 when ISC was the first company to offer
UNIX support services to third parties. There was never any talk about
licensing UNIX source code from Western Electric (WE) from the
founding
of ISC to when the Intel 8086 micro became available in 1981.
DEC never really targeted the PC market with the LSI-11 micro,
and WE never made it easy to license binary copies of the UNIX
source code, So LSX never really caught on in the commercial market.
ISC was in the business of porting the UNIX source code to other
computers, micro to mainframe, as new computer architectures
were developed.
Heinz
The Wikipedia page for ISC has the following paragraphs:
"Although observers in the early 1980s expected that IBM would choose
Microsoft Xenix or a version from AT&T Corporation as the Unix for its
microcomputer, PC/IX was the first Unix implementation for the IBM PC
XT available directly from IBM. According to Bob Blake, the PC/IX
product manager for IBM, their "primary objective was to make a
credible Unix system - [...] not try to 'IBM-ize' the product. PC-IX
is System III Unix." PC/IX was not, however, the first Unix port to
the XT: Venix/86 preceded PC/IX by about a year, although it was based
on the older Version 7 Unix.
The main addition to PC/IX was the INed screen editor from ISC. INed
offered multiple windows and context-sensitive help, paragraph
justification and margin changes, although it was not a fully fledged
word processor. PC/IX omitted the System III FORTRAN compiler and the
tar file archiver, and did not add BSD tools like vi or the C shell.
One reason for not porting these was that in PC/IX, individual
applications were limited to a single segment of 64 kB of RAM.
To achieve good filesystem performance, PC/IX addressed the XT hard
drive directly, rather than doing this through the BIOS, which gave it
a significant speed advantage compared to MS-DOS. Because of the lack
of true memory protection in the 8088 chips, IBM only sold single-user
licenses for PC/IX.
The PC/IX distribution came on 19 floppy disks and was accompanied by
a 1,800-page manual. Installed, PC/IX took approximately 4.5 MB of
disk space. An editorial by Bill Machrone in PC Magazine at the time
of PC/IX's launch flagged the $900 price as a show stopper given its
lack of compatibility with MS-DOS applications. PC/IX was not a
commercial success although BYTE in August 1984 described it as "a
complete, usable single-user implementation that does what can be done
with the 8088", noting that PC/IX on the PC outperformed Venix on the
PDP-11/23.”
It seems like Venix/86 came out in Spring 1983 and PC/IX in Spring
1984. I guess by then RAM had become cheap enough that running in 64KB
of core was no longer a requirement and LSX and MX did not make sense
anymore. Does that sound right?