[HN Gopher] Ask HN: Forensic analysis for 50 year-old tape?
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Ask HN: Forensic analysis for 50 year-old tape?
Im posting for a friend who moved recently. He found a magnetic
tape that was written over 50 years ago. He says, if he recalls
correctly, the tape would have contained 2 file, EBCDIC encoded,
written by an IBM utility using a tape sub-system attached to a
s/360 processor running MVS. Assume the IBM guys have this setup
in some dusty basement in upstate New York. This is a 2 part
question. What is the best method for attempting to read this mag
tape? That's the main question. Second, what is the probability of
success here? Assume the tape was kept in a climate controlled
home.
Author : passer_byer
Score : 28 points
Date : 2022-06-30 04:55 UTC (18 hours ago)
| News-Dog wrote:
| _> 50 yr old tape<_ = circa:1972 vintage Tape
|
| search: _> 'magnetic tape restoration'<_ @DDG :
| <https://html.duckduckgo.com/html/?q='magnetic tape restorati...>
|
| The chances of reading the data will depend on several factors;
| 1. The tape-stock (base and binder stability), the stored
| temperature, humidity and magnetic field exposure. 2.
| A working and aligned reader.
|
| Background.
|
| The IBM System/360 (S/360) :
| https://en.m.wikipedia.org/wiki/IBM_System/360
|
| Is a family of mainframe computer systems that was announced by
| IBM on April 7 1964, and delivered between 1965 & 1978.
|
| --
|
| Extended Binary Coded Decimal Interchange Code (EBCDIC ) :
| https://en.m.wikipedia.org/wiki/EBCDIC
|
| Is an eight-bit character encoding used mainly on IBM mainframe
| and IBM midrange computer operating systems.
|
| --
|
| Also See;
|
| search: _> 'NASA call for Moon tapes'<_ @DDG :
| <https://html.duckduckgo.com/html/?q='NASA call for Moon tape...>
| passer_byer wrote:
| I'm guessing you also have a book recommendation on the history
| of the 360 architecture. Excluding Watson's bio and "Mythical
| Man Month", what book should I read next?
| pjmorris wrote:
| Not GP, but 'IBM's 360 and Early 370 Systems', Pugh, Johnson,
| Palmer is solid.
| MaxPengwing wrote:
| I think you should reach out to Jason Scott over at the Internet
| Archive. He's been involved with helping people get old stuff off
| of old media before and if he doesn't have the tech and know how,
| chances are high he knows who to ask.
|
| He's very easy to reach on Twitter, @textfiles.
| passer_byer wrote:
| Great tip, thank you. Easy is relative. Lucky for me, I have
| kids who can get me going with a twitter account.
| toomuchtodo wrote:
| email jason at textfiles dot com
| tgflynn wrote:
| I'm guessing that would be one of the old reel to reel tapes. I
| think the hardest part (assuming the tape is intact) would be
| finding a working tape reader. From pictures I've seen I think
| those were real beasts, in cabinets as large as the mainframe
| itself. The Computer History Museum in Mountain View CA is one of
| the few places that might have one.
|
| Otherwise you might be able to build your own tape reader. You
| could probably make it a lot smaller and simpler than the
| original machines since throughput wouldn't really be an issue.
| Still it would probably be quite an engineering project.
| h2odragon wrote:
| I have a couple of 4U 9 track tape drives with centronics SCSI
| interfaces. Pulled from 90s Sun gear from ex Federal
| deployment. Government stuck with tape for a long time.
|
| One of them ran in 1999, at least, but they've been in the barn
| since.
|
| rebuilding that to functional might be harder than making some
| hacked up sensor to run tape through.
| EvanAnderson wrote:
| This probably isn't going to help the poster specifically but
| it's an excuse to share a good presentation from Vintage Computer
| Fest West 2020 re: magnetic tape restoration:
| https://www.youtube.com/watch?v=sKvwjYwvN2U
|
| The presentation explores using software to digitize and analyze
| the analog signal generated by the flux transitions on the tape
| to reconstruct the data. Essentially, it's moving the digital
| portion of the tape drive into a software domain and doing signal
| processing. Software-defined radio kind of stuff, to some extent.
|
| The presenter had a tape from his college days in the 1960s,
| stored in less than ideal environmental conditions, that he
| wanted to read. (I believe the presenter's tape was also from an
| S/360. I guess maybe, if the rig the presenter used to read his
| tape still exists, this might be of use to the poster.)
|
| The presentation gets into some work applying these techniques to
| reconstruct tapes recovered from the Whirlwind project, too.
| mavu wrote:
| Contact this guy: https://www.youtube.com/c/CuriousMarc
|
| If he does not have a machine capable of reading the tapes in his
| house/museeum, he will know someone who has.
|
| (and as a bonus, the recovery might end up as a entertaining
| youtube video)
| troupe wrote:
| I'm curious if there is something valuable on this or if you are
| just doing this for the challenge.
| ChrisMarshallNY wrote:
| There is a pretty marvelous woman, named Marianne Bellotti. She
| probably couldn't help you directly, but she's a total "old
| computer" nerd.
|
| https://www.marianne-bellotti.com
|
| I do not have contact info for her, and she has no idea who I am,
| so you're on your own...
| DrScump wrote:
| Aside from the physical encoding, note the conventions for IBM
| tape file sequence and labeling:
|
| https://www.ibm.com/docs/en/zvse/6.2?topic=SSB27H_6.2.0/fa2m...
|
| You can bypass default label assumptions and label processing
| using JCL directives like BLP, NL, etc.
|
| When I was in mainframe operations and at times ran the
| Production Control Center (triage), I rescued some systems from
| being rerun due to clobbered labels by altering JCL.
| passer_byer wrote:
| This is very helpful. I'm guessing you have a copy of the
| Brown/Blue => Blue/Brown book.
| DrScump wrote:
| I'm not familiar with that description. I worked as a 370
| series (370/3033/308x/309x) OS/MVS computer operator in the
| 80s, before programming.
| raarts wrote:
| I worked as an 370 ACP/TPF Assembly Language Programmer in
| the 80s. I think this is referring to Gary DeWard Brown who
| wrote books about assembly language and JCL for example.
| Don't remember if they were blue though.
| saltypal wrote:
| Email George Blood LP (https://www.georgeblood.com/), they have
| support to read like 100+ old magnetic formats and are wonderful
| pros.
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