7 Feb
2026
7 Feb
'26
1:35 a.m.
On 07/02/2026 03:51, Steve Lewis wrote:
Dave,
Page 439 of that document you linked has a nice chart of "integrated
emulators that run execute under VM/370" - now I do recall one of the
"famous" things about the prior S/360 was it could emulate 1401 and
other IBM systems. Then later on, more systems to emulate would be
the 709-series. Ok, so VM/370 is more like what we might today
call a Hypervisor? So the "it looks like whatever you want" comment
makes sense.
You don't need VM to emulate a 1401, I believe the 1401 emulator ran
under MVS as well, or I think on some S/360 machines you could load 1401
microcode.
So yes VM itself is what today we would call a hypervisor. It creates
virtual machines and each virtual machine is pretty much totally isolated.
But CMS was provided as source code, and in the early days it was very
limited so sites made many modifications.
I suppose what I'm after is more a visual on the
usage of CMS, DOS/VS
or OS/VS1 ( OS's that one would only use on an S/370 ? )
There was also MTS and MUSIC plus a few other TSO and CICS replacements.
I put a couple reference images here on what I have
about CTSS and
TOPS-10 (CTSS is from a modern-day emulators, TOPS-10 is from one of
their manuals so its from in 1970). I see how you mean VM/370 isn't
quite the same nature (not "just an OS" but an enterprise thing like
for airlines, banks, financial brokers -- and the virtualization
helped in testing/deploying new systems -- that maybe had newer OS's
-- without disrupting operational systems?)
https://github.com/voidstar78/OS_NOTES
OK I can do something similar for VM and CMS but got a busy day here:-
https://www.scienceandindustrymuseum.org.uk/whats-on/meet-baby
(yes thats me, the rest of the team are camera shy)
- Steve
Dave
On Fri, Feb 6, 2026 at 10:00 AM David Wade <dave.g4ugm(a)gmail.com> wrote:
On 06/02/2026 14:55, Steve Lewis wrote:
Thanks Dave, the 3270 terminal screen makes
sense. Or to make
use of
the system and resources, you'd remote to it
using a 3270.
So it may have been at a time no one thought to snap a
photograph of
any of those 3270s in use (not just a "room
full of 3270's" kind of
photo - but of the actual screen, showing whatever it was they were
doing; managing tape/disk resources, files, users, or running
APL or
something. That's more what I was looking
for, when you "used
VM/370
{or remoted into it}, this is what it looked
like."
Generally thats not what you did with VM/370. You edited,
compiled, and
ran programs....
There had to be some kind of installer? Or maybe I'm viewing it
wrong
- they (a business) didn't just buy a S/370
then decide what OS to
install. But rather it was a packaged prepared by IBM, so maybe it
was pre-installed with VM/370 and configured to whatever the
arrangement/contract was?
For VM you usually got a "starter system" on a tape. There was a
different tape for each disk type. The first file on the tape is the
standalone disk dump and restore program, DDR. So you IPL (boot) from
this tape, and use DDR to restore the starter system to DASD (disk).
You usually needed three packs. The first time you IPL the restored
starter system it asks you some basic config questions, and you then
have a working system that you can use to restore the rest of the
VM/370, load and apply service (fixes) , and configure to your exact
hardware set-up.
I expect at 522 pages this manual which covers install and
congigureis a
tad bigger than the one for other systems...
https://bitsavers.org/pdf/ibm/370/VM/370/Release_6/GC20-1801-10_VM370_Sysge…
Or a way to say "when someone used a S/370
{or CMS}, this is
what the
console content looked like" (printed, or by
that time yea probably
more likely a CRT).
It looked like whatever you wanted. The samples in the previous
e-mail
are typical...
“The Origin of the VM/370 Time-Sharing System” –
R.J. Creasy
gives a
little bit of a description on those components
CP, CMS, and RSCS.
But no photo/image yet of a terminal with content to identify
"yeah,
see they are using a S/370 there" (maybe its
listing disk packs,
tapes, memory resources, etc?) I got something like this for the
earlier CTSS and TOPS-10.
pass me what you have for that so I can see what a VM Equivalent
might
be. The definitive thing on a users 3270 is the status bottom right
which on a pukka system which usually reads "VM READ VM/370" but can
also start "RUNNING", "HOLDING" "CP READ".
-Steve
Dave