[COFF] [TUHS] Memory management in Dennis Ritchie's C Compiler

[Paul Winalski]

On 8/19/20, Clem Cole <clemc at ccc.com> wrote:
> small update ... see below..
>
> On Wed, Aug 19, 2020 at 1:39 PM Paul Winalski <paul.winalski at gmail.com>
> wrote:
>
>> In the IBM System/360 world, the first machine with Dynamic Address
>> Translation (DAT, the hardware that implements virtual->physical
>> address transiation via page tables) was the S/360 model 67.
>
> Called the Data Address Translator (DAT) box.  I still have my 'TILT' deck
> which is an IPL program that used diagnose instructions to spell TILT in
> the lights on the DAT box and ring the console bell, which on a 360 was a
> fire alarm.
>
> BTW: the 67 had 8 32 bit TLB entries, built out of ECL flip-flops.

The various OS/VS variants for S/370 were way late.  IBM was forced to
release the models 155 and 165 before OS/VS was available.  The
decided to take the opportunity to stick it to the third-party leasing
companies.  The S/370 models 155 and 165 were released without DAT
boxes.  The third-party leasers gobbled them up.  The third S/370, the
model 145, had to be released with the DAT hardware and microcode
because the IBM 1400 emulator needed it.  Then OS/VS was finally
ready.  For the model 145 DAT support just worked.  For the 155 and
165, a DAT box could be added to turn them into the 155-II and 165-II.
If you leased your machine from IBM, you got the upgrade for free.  If
you had bought the machine, you had to pay through the nose to get a
DAT box.

>>   The only
>> IBM OS to use it was CP/67, the virtual machine forerunner of VM/370.
>>
> Careful, TSS used it first actually and shipped before CP/67 - but it had a
> number of issues.
> CMU would work to fix them and Michigan would start and rewrite, creating
> MTS (which was not an IBM product but TSS was and shipped into the early
> 1980s).

I forgot all about TSS.

> I just did a review of a book that I'll find out when it supposed to hit
> the streets by some tech historians in the UK.   I reviewed the chapter
> where CTSS begets, Multics and TSS,  beget UNIX and MTS respectfully.
>  Basically the name of the chapter is the rise of idea of timesharing.
>  [No worries, the DEC world is in the book also, but follows a different
> thread - this is looking at the fight at IBM and GE between commercial
> batch and timesharing].

GECOS was GE's commercial batch OS, IIRC.  Dartmouth Time-Sharing
System (DTSS) ran on the GE 635.

-Paul W.