29 Jul
2021
29 Jul
'21
6:16 a.m.
One of those magnetic fluid tape checking devices would show the bits very easily at that
density (or even a lot higher).
It seems to me this sort of thing should be no problem at all for the various general
purpose tape reading machines that have been built, especially the ones with MR heads. So
long as the reader has heads that land reasonably well on the recorded tracks, the rest is
just software.
Part of the software work would be reverse engineering the recording format -- NRZ or NRZI
or whatever, bit layout and character set encoding, file encoding. The encoding of
formatting control information will probably be guesswork, but recovering most of the
plain text should be doable.
paul
On Jul 29, 2021, at 4:58 AM, Dave Wade G4UGM via
cctalk <cctalk at classiccmp.org> wrote:
Cory,
Its only recorded at around 25BPI so I don't thing it would be too hard to decode.
Given its a character at a time, I suspect some iron filings or similar would reveal the
codes and track spacing and with a bit of luck you could find a head that would read the
data...
I am sure we used to have some when we had real tapes.
Dave
-----Original Message-----
From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Cory
Heisterkamp via cctalk
Sent: 29 July 2021 00:37
To: General Discussion: On-Topic Posts <cctech at classiccmp.org>
Subject: Reading MT/ST Tapes
This is a bit of a long shot, but is anyone aware of a successful method to read
IBM Selectric MT/ST tapes? A museum in Australia has a box of them and are
interested in the contents.
I'm fairly involved in the global Selectric community and while 1 or 2 MT/ST?s
exist, they?re non-functional. I know IBM offered a 2495 Tape Reader for the
IBM 360, which could be a starting point with modification, but I suspect
those are even scarcer than the MT/ST itself.
Even the encoding format appears to be a bit of a secret. Recording is
character-by-character, tape spacing controlled by sprocket holes along one
edge.
https://obsoletemedia.org/ibm-mtst/ <https://obsoletemedia.org/ibm-
mtst/?fbclid=IwAR28c5ej69AlF0os1PcykpHCh0Q_yz5BXbnUSi9UID-
4pY6GU3wLxZXFhDI>
Thanks- Cory