> On Mar 1, 2026, at 5:23 PM, Jay Jaeger via cctalk <[email protected]>
> wrote:
>
> ...
> Having not used the CDC operating systems, I can't speak knowledgeably to
> them, but still, I can't imagine the master being on actual cards. Way too
> hard to manage changes.
I don't know about the earliest days. But when I worked with CDC NOS around
1975, everything (OS and applications) was handled by one of two rather similar
source control systems, MODIFY and UPDATE. These would maintain a "program
library" file, consisting of "decks" (individual programs), and you would feed
them a control deck identifying which deck(s) you wanted to extract and/or
change. For example, to assemble a program you'd run MODIFY to obtain a text
file containing the deck of that program, or possibly several decks if the
program was handled that way. That file would then be fed into the assembler.
That intermediate file had a compression scheme where spaces were run-length
encoded, similar to the IBM approach that was just mentioned. At CERL, there
was support for text files encoded that way, which were known as "squoze"
files. Over time that faded away, I'm not quite sure why.
UPDATE was basically the same. I never understood why there were two; perhaps
a legacy of the two main OS streams: MACE/KRONOS/NOS and SCOPE/NOS-BE. The
only UPDATE PL I ever ran into was for the 7054 (RP04-like) disk controller
firmware.
paul
