[its-hackers] Fwd: [PDP-10/its] Use the CH11 Chaosnet address (#2038)

Lars Brinkhoff lars at nocrew.org
Wed Jun 23 19:12:27 CEST 2021

Jack Haverty wrote:
> Just curious --- has anyone found source code for DSKDMP?   Back in the
> mid-70s, I recall an incident where someone asked for a copy of DSKDMP to
> use on some new machine, and was surprised to learn that there wasn't any
> source file.   Maybe there once was such a file, but over the years DSKDMP
> had been extensively modified and new features added, all by simply writing
> new code in DDT and saving the binary image.   So there was no source file
> for the DSKDMP we used on MIT-DM, at least at that time.

I could well believe this was true at some point.  Unfortunately the
backup records are not in a good shape, so we don't have much evidence
to go on.  Here are all DSKDMP source files I can see that were backed
up on DM.  This is just information from the .TAPE database; we don't
have the files themselves.

 SAENG   DSKDMP  109    1975-01-15 12:12:12
 SAENG   DSKDMP  132    1976-04-23 07:36:56
 SAENG   DSKDMP  134    1976-04-24 23:46:12
 SAENG   DSKDMP  144    1976-08-09 01:40:50
 SYSTEM  DSKDMP  151    1977-04-02 21:00:57
 SYSTEM  DSKDMP  155    1978-08-22 02:16:00
 SYSTEM  DSKDMP  154    1978-03-16 04:05:16
 SYSTEM  DSKDMP  156    1979-09-05 20:45:27
 SYSTEM  DSKDMP  157    1979-10-18 06:38:41

The first observation I make is that DM stored source files in a
directory called SAENG.  This is unique to DM.  I'm guessing it means
"Stand-Alone English files".

Secondly, there is a decent progression of file versions from 132 to
157.  There *is* a decided jump from 109 to 132 and timestamps have them
separated by more than a year.  We can imagine this to be consistent
with your mid-70s incident, but that's a rather flimsy assumption.

I understand Scott Cutler was one of the people who worked on attaching
disks to DM, using the new Mathlab PDP-10 for testing and bringup since
it conveniently had the same kind of DEC disk controller.

Outside Dynamic Modeling we have good coverage of source files for
DSKDMP going all the way back to 1971 were it seems George Mitchell and
Fred Wright were involved with (creating?) early versions.  It seems not
long before that MACDMP was used to boot ITS.

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