8 Jan
2025
8 Jan
'25
11:20 a.m.
I've got a 7 track tape here that was written on a PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names.
Does anyone have information on the mini-dump structure?
TIA
Chuck
8 Jan
8 Jan
1:13 p.m.
There are some good FB groups specific to DEC and PDP11 with thousands of members and lots
of knowledge.
Here's one https://www.facebook.com/groups/40651613978
-rA
________________________________
From: Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
Sent: Wednesday, January 8, 2025 1:20 PM
To: CCtalk <cctalk(a)classiccmp.org>
Cc: Chuck Guzis <cclist(a)sydex.com>
Subject: [cctalk] PDP-10 TENEX mini-dump format
I've got a 7 track tape here that was written on a PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names.
Does anyone have information on the mini-dump structure?
TIA
Chuck
1:16 p.m.
Too bad it is Facebook. I’m sure there are people here or on discord who would know
Sent from my iPhone
On Jan 8, 2025, at 4:13 PM, roger arrick via cctalk
<cctalk(a)classiccmp.org> wrote:
There are some good FB groups specific to DEC and PDP11 with thousands of members and
lots of knowledge.
Here's one https://www.facebook.com/groups/40651613978
-rA
________________________________
From: Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
Sent: Wednesday, January 8, 2025 1:20 PM
To: CCtalk <cctalk(a)classiccmp.org>
Cc: Chuck Guzis <cclist(a)sydex.com>
Subject: [cctalk] PDP-10 TENEX mini-dump format
I've got a 7 track tape here that was written on a PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names.
Does anyone have information on the mini-dump structure?
TIA
Chuck
2:55 p.m.
Also try the DEC Forum at vcfed.org.
On 1/8/2025 3:13 PM, roger arrick via cctalk wrote:
There are some good FB groups specific to DEC and
PDP11 with thousands of members and lots of knowledge.
Here's one https://www.facebook.com/groups/40651613978
-rA
________________________________
From: Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
Sent: Wednesday, January 8, 2025 1:20 PM
To: CCtalk <cctalk(a)classiccmp.org>
Cc: Chuck Guzis <cclist(a)sydex.com>
Subject: [cctalk] PDP-10 TENEX mini-dump format
I've got a 7 track tape here that was written on a PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names.
Does anyone have information on the mini-dump structure?
TIA
Chuck
3 p.m.
On 1/8/25 13:13, roger arrick via cctalk wrote:
There are some good FB groups specific to DEC and
PDP11 with thousands of members and lots of knowledge.
Here's one https://www.facebook.com/groups/40651613978
Maybe, but I'm not a facebooker. Is there any good TWENEX/TOPS-20
documentation around that might have the information?
--Chuck
6:40 p.m.
Date: Wed, 8 Jan 2025 21:13:36 +0000
From: roger arrick via cctalk <cctalk(a)classiccmp.org>
There are some good FB groups specific to DEC and
PDP11 with thousands of
members and lots of knowledge.
Chuck asked about the PDP-10, a 36 bit mainframe system from DEC, rather than
the PDP-11, a 16 bit minicomputer from the same company. The two systems have
nothing in common besides the naming convention.
Rich
7:22 p.m.
Date: Wed, 08 Jan 2025 19:20:33 +0000 (UTC)
From: Chuck Guzis via cctalk <cctalk(a)classiccmp.org>
I've got a 7 track tape here that was written on a
PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names.
Does anyone have information on the mini-dump
structure?
Chuck,
I never got the opportunity to use TENEX, so never encountered "mini-dump"
format tapes. However, a quick browse through the TENEX manuals at Bitsavers
tunred up a program called TAINT which accompanied TENEX but was intended for
execution on Tops-10, specifically to read mini-dump tapes under the DEC OS.
This program does not appear in Tim Shoppa's archive of PDP-10 tapes (not
surprising, since most of them are DEC images).
I asked a friend who is not on the list if he was familiar with anything TENEX
(he was a systems programmer for SAIL), but he did not know.
A 7 track tape should have the 36 data bits across 6 frames, unlike the 9 track
usage of 5x8 with zero padding in the 5th.
Someone familiar with the TENEX file system (i. e., TOPS-20 lite) should be
able to decipher the block headers easily enough. There's at least one of us
on the list.
Rich
...still programming PDP-10 systems for money in the 21st Century...
8:23 p.m.
On 1/8/25 19:22, Rich Alderson via cctalk wrote:
A 7 track tape should have the 36 data bits across 6
frames, unlike the 9 track
usage of 5x8 with zero padding in the 5th.
Someone familiar with the TENEX file system (i. e., TOPS-20 lite) should be
able to decipher the block headers easily enough. There's at least one of us
on the list.
I'm familiar with the data format; back around 1975, a DEC CE friend
smuggled a tape (don't recall if it was 7 or 9 track) of Colossal Cave
Adventure to me. I figured out the 36 bit 5 x 7bit character scheme
back then and got the thing running on a Cyber 74 running SCOPE. Darned
thing spread like wildfire at SVLOPS to the extent that COMSOURCE wrote
a "search and destroy" program.
Did Tenex employ the Rad50 file naming scheme?
--Chuck
11:17 p.m.
Rich Alderson wrote:
> Someone familiar with the TENEX file system (i. e., TOPS-20 lite)
I also jotted down some notes about the TENEX file system:
https://gunkies.org/wiki/TENEX_file_system_layout
I don't know what the internals of the TOPS-20 file system look like,
but supposedly DEC rewrote or replaced the TENEX code. Among other
things, TOPS-20 supports subdirectories, but TENEX doesn't.
Chuck Guzis wrote:
Did Tenex employ the Rad50 file naming scheme?
No, file names are in ASCII. Other PDP-10 operating systems use SIXBIT,
not RAD50.
11:06 p.m.
Chuck Guzis wrote:
I've got a 7 track tape here that was written on a
PDP-10 TENEX setup.
It's identified as a "mini-dump" tape. I can extract the data (PDP-10
5 char/word) successfully, but the format of the block headers (seems to
be about 6 words) eludes me. I'd like to be able to use the original
file names. Does anyone have information on the mini-dump structure?
Yes. I wrote this by combining various documents, MINI-DUMPER and
DUMPER sources, and testing. It includes both MINI-DUMPER and DUMPER.
https://gunkies.org/wiki/DUMPER_tape_format
I wrote a program to read and write such tapes:
https://github.com/larsbrinkhoff/pdp10-its-disassembler/blob/master/dumper.c
I haven't tested extracting a MINI-DUMPER tape, because I don't have any
samples. I have created tape images, and tested reading them from
inside TENEX.
28
days inactive
28
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10 comments
6 participants
participants (6)
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Christopher Zach -
Chuck Guzis -
Lars Brinkhoff -
Mike Katz -
Rich Alderson -
roger arrick