Well bitsavers is probably your best bet. I would look at any ibm doc for os/360 and TSS/360. Then look at the DEC docs for Tops-10 and the distro library's. Tops-20 I would have expected but maybe not as by the VMS and more closed culture had begun at DEC but because it was based on Tenex (from BBN) might have been available with full sources.

IIRC early versions of RT-11 was distributed as a binary but the sources were readily available. I know I have seen them. Some of the first assembler based driver code I ever looked was from RT11 (the TC11 driver)

TSS/8 was in PDP-8 source originally from CMU but DEC made it a product. That was source which I think I have somewhere from the paper tape swapping hack.

I never looked for or built OS/8 but I have to believe it was distributed as source from DEC

As I said I would suggest bit savers.

On Tue, Nov 10, 2020 at 7:06 PM Greg 'groggy' Lehey <grog@lemis.com> wrote:

On Tuesday, 10 November 2020 at 18:45:15 -0500, Clem Cole wrote:
> On Tue, Nov 10, 2020 at 6:11 PM Greg 'groggy' Lehey <grog@lemis.com> wrote:
>
>> I'm currently reviewing a paper about Unix and Linux, and I made the
>> comment that in the olden days the normal way to build an OS image for
>> a big computer was from source. Now I've been asked for a reference,
>> and I can't find one! Can anybody help?
>
> Mumble -- For IBM and DEC in the 60s and early 70s, the manufactures
> distributed the (assembler) sources to the OS and we could (and did)
> build from source but usually just built parts.

Right, this is my recollection.

> Remember, the target was the manufacturers HW so they were not
> giving away much.

Again, my assessment.

The real issue is: where can I find a reference? Google brings up so
many false positives that it's not worth the trouble, and Wikipedia's
pages on "System generation" are too vague.

Greg
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