Re: time-sharing history, Privilege Levels Below User

John Levine <johnl@taugh.com> writes:

In any event, I'd find the second article I linked to, the VM history
written by IBMers who were there, more credible than some random third
party magazine. CMS really was written at the same time as CP, and
they always intended them to work together as a time-sharing system.

Some of the MIT CTSS/7094 people went to the 5th flr to do Multics;
others went to the science center on the 4th flr to do virtual machines,
internal network, invent GML in 1969, other interactive applications.

cambridge science center wanted a 360/50 to add virtual memory to
... but all the spare 360/50s were going to FAA ATC project ... and they
had to settle for 360/40. (virtual machine) CP/40 (running on bare
hardware using hardware virtual memory mods _ was developed in parallel
with CMS (running on bare 360/40). When CP/40 virtual machines was
operational, they then could run CMS in CP/40 virtual machines.

Melinda history
http://www.leeandmelindavarian.com/Melinda#VMHist
and CP/40
http://www.leeandmelindavarian.com/Melinda/JimMarch/CP40_The_Origin_of_VM370.pdf
my OCR from Comeau's original paper
https://www.garlic.com/~lynn/cp40seas1982.txt

CP/40 morphs into CP/67 when 360/67 standard with virtual memory becomes
available. I was responsible for OS/360 running on 360/67 (as 360/65),
univ shutdown datacenter on weekends and I had datacenter dedicated for
48hrs straight). CSC came out Jan1968 to install CP/67 (3rd install
after CSC itself and MIT Lincoln Labs) ,,, and I mostly played with it
during my weekend dedicated time. First couple months was rewritting
pathlengths for running OS/360 in virtual machine. Benchmark was OS/360
jobstream that ran 322secs on real machine. Started out 858secs in
virtual machine (CP67 CPU 534secs) .... after few months got CP67 CPU
down to 113secs. I then rewrite time-sharing system scheduling and
dispatching, page I/O and page replacement, I/O arm scheduling, etc.

I'v joked that original CP/67 scheduling delivered to univ (and I
completely replaced) ... looked a lot like Unix scheduling that I first
saw 15yrs later. Also 1st install at univ (jan1968) had CP67 source in
OS/360 datasets ... it wasn't until a few months later that they moved
source to CMS files. After I graduated and joined science center, one of
my hobbies was enhanced production operating systems for internal
datacenters.

CP-67
https://en.wikipedia.org/wiki/CP-67
CP/CMS
https://en.wikipedia.org/wiki/CP/CMS
History of CP/CMS
https://en.wikipedia.org/wiki/History_of_CP/CMS
Cambridge Scientific Center
https://en.wikipedia.org/wiki/Cambridge_Scientific_Center

when it was decided to add virtual memory to all 370s, it was also
decided to rewrite CP67 for VM370, simplifying and/or dropping lots of
features (also renaming Cambridge Monitor System to Conversational
Monitor System and crippling its ability to run on real machine).

1974, I start migrating lots of original CP67 stuff (lots that I had
done as undergraduate) to VM370 Release2 base for an enhanced internal
CSC/VM (including for world-wide online sales&marketing support HONE
systems).  Then in 1975 I upgrade to VM370 Release3 base and add the
CP67 multiprocessor support (one of the things dropped in CP67->VM370)
... originally for US consolidated HONE complex so they could add 2nd
processor to each of their systems (all the US HONE systems had been
consolidated in Palo Alto, trivia: when FACEBOOK 1st moved into silicon
valley, it was into new bldg built next door to the former US
consolidated HONE datacenter).

--
virtualization experience starting Jan1968, online at home since Mar1970