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Ask HN: Forensic analysis for 50 year-old tape?

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Ask HN: Forensic analysis for 50 year-old tape?

#1

Post by passer_byer »

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.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#2

Post by News-Dog »

>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.

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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...>

Re: Ask HN: Forensic analysis for 50 year-old tape?

#3

Post by passer_byer »

News-Dog wrote: post #2

>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.wikipedi…

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?

Re: Ask HN: Forensic analysis for 50 year-old tape?

#4

Post by MaxPengwing »

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.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#5

Post by DrScump »

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.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#6

Post by passer_byer »

DrScump wrote: post #5

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…

This is very helpful. I’m guessing you have a copy of the Brown/Blue => Blue/Brown book.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#7

Post by passer_byer »

MaxPengwing wrote: post #4

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.

Great tip, thank you. Easy is relative. Lucky for me, I have kids who can get me going with a twitter account.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#8

Post by DrScump »

passer_byer wrote: post #6
DrScump wrote: post #5

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…

This is very helpful. I’m guessing you have a copy of the Brown/Blue => Blue/Brown book.

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.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#9

Post by raarts »

DrScump wrote: post #8
passer_byer wrote: post #6

Earlier quoted context omitted.

This is very helpful. I’m guessing you have a copy of the Brown/Blue => Blue/Brown book.

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.

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.

Re: Ask HN: Forensic analysis for 50 year-old tape?

#10

Post by pjmorris »

passer_byer wrote: post #3
News-Dog wrote: post #2

>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.wikipedi…

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?

Not GP, but 'IBM's 360 and Early 370 Systems', Pugh, Johnson, Palmer is solid.
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