Magnetic card data recovery -- is it possible, and if so, how?
April 7, 2016 8:04 AM   Subscribe

I received a box of Scotch Brand MC/ST 530 Magnetic Cards. There is probably data on them. How, if possible, do I retrieve it?

Extended background info: I work as an archivist, and this box of cards came in with a new accession with the sticky note "what are these???" Here are three different angles of the box in full violet glory: 1 2 3

My best (internet research-based) guess is that they're magnetic data cards used in a typewriter, probably a Selectric. So I'm most interested in whether it's possible to get whatever data is stored in them off these cards and into another format. How do I do this?

Like most archives, our means are limited, so I'm looking for the most cost-effective method possible. What are my possible options? Should I try to find a Selectric? Or is that for entry only, and won't help with any data display/recovery?

Shipping out to a data recovery service might be a possibility (again: cost versus is this data really valuable/how can we know it's valuable if we don't know what it is, etc, argh). I welcome any recommendations for specific vendors, or any listservs with experts in this area. I haven't yet posted to SAA's list, although that's on my list -- I have searched their archives on this format, though, and only found people with the same issue I have. Plenty of cards, no way to read/recover. I'm woefully ignorant about this particular technology, so any clarifications on how people used the magnetic cards will help, too! Thanks.
posted by pepper bird to Technology (9 answers total) 6 users marked this as a favorite
 
Here's a non-destructive low-tech way to literally see if there's data on the cards.

If that proves fruitful, you may just be able to read it off visually, depending on density and how many cards you have.
posted by odinsdream at 8:16 AM on April 7, 2016 [2 favorites]


I'm probably not telling you anything you don't already know, but just in case:

At minimum you'd need a reader and some sort of forensic software to image the disks and display it as something human-readable. The forensic software bit is probably the easiest part to get -- see (Bitcurator and BitCreator Consortium--the people involved in this have the most advanced knowledge of this sort of thing in the field). Finding a drive that will read this specific card/disc as will probably be the more expensive/time consuming thing. Beyond archivists the people I am most aware being pioneers in this work are law enforcement and people in the saving retro videogame community.

But...the biggest question may be, how important do you think the data on these may be? There's probably not a ton of data on each disk, and if it's a typewriter disk, there are likely printed copies of the data already. Also, I don't know the circumstances of this accession or collection, but in my experience (dealing with congressional records from the 1960s-1990s) disks still-in-boxes are more often than not unused.

Again, I do recommend checking with the people associated with BitCurator if you have not already.
posted by theefixedstars at 8:22 AM on April 7, 2016


Crikey. Those were everywhere in the richer offices in 1980. Yes indeed it was a Selectric. The Mag Card Typewriter (which was what it was called) was a standard Selectric typewriter connected by a thick cable to a unit about the size of a credenza. It was the word processor of its day—the cards were the data storage (read and write from the typewriter) and could incorporate variable text and suchlike. Given that they were made by IBM, there should still be functioning ones around, although I quite see your problems finding one—and you'd need an operator or at least a manual. BTW, each card could hold two to three pages of text, so we are not talking about a lot of data.
posted by Logophiliac at 8:49 AM on April 7, 2016


You could probably find an EE student to write code to do this as a class project / undergrad thesis. Maybe they can do it nondestructively just using a picture of the iron filings.
posted by miyabo at 9:16 AM on April 7, 2016


This article gives you a bit of technical detail on the encoding used on the cards.
posted by jferg at 10:08 AM on April 7, 2016


It doesn't look the computer history museum has one of these typewriters.

There are several folks on youtube with these machines. Maybe send messages to folks on youtube and see if any of them are nearby?

@miyabo I would guess that the optical method will not work-- the cards are 82.55x187.325mm or 15464mm^2. I read somewhere that the capacity for these cards is 8,000 characters or about 2 characters per mm^2. There are ~76 characters/punctuation (14 punctuation, 26 uppercase, 26 lowercase, 10 numbers) in english; if you include tab, space, & linebreak that gets you up to 79. To encode a number between 1 and 79 you need 7 bits (ie 79 = 1001111) that means you'd need 14 total bits per mm^2 that means 0.07mm per bit or in the range of the width of a human hair. This makes some pretty big assumptions.
posted by gregr at 10:23 AM on April 7, 2016 [2 favorites]


Searching Selectric Ii for sale found some possibilities. (Is that the model you would need?) Here is one.

http://vintagestockpile.com/typewriters/
posted by SemiSalt at 2:23 PM on April 7, 2016


Many thanks to all of you! Plenty of info here to help me make an informed decision and better frame a recommendation to my supervisor for whether or not we should spend time and money on these cards. Especially helpful to see a video of the card reader AND the typewriter in action -- I was thinking (like SemiSalt suggested) that I could get away with purchasing a typewriter, but I didn't understand the full process.
posted by pepper bird at 9:22 AM on April 12, 2016


Gonna mark this resolved, but please feel free to memail me if you have some incredible magnetic typewriter card info you want to share! Thanks again.
posted by pepper bird at 9:23 AM on April 12, 2016


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