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foone
Wanna see some old-ass RAM? This is a magnetostrictive delay line memory unit from a Iskra 122 calculator. This stores about 128 bytes.
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foone Jul 5
Replying to @Foone
The way it works: there's little pieces of magnetostrictive metal at each end of the wire. an electromagnet causes it to contract or expand, causing a torsion wave to travel down the wire at the speed of sound in the material. It's then regenerated at the other end.
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foone Jul 5
Replying to @Foone
so you can store data in these waves by encoding it into left or right twists. This was an improvement on the earlier mercury delay lines, and were more reliable than early tube/valve memory systems.
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foone Jul 5
Replying to @Foone
This one's from 1973, and the Iskra 122 calculator was made from 1972-1978. In the west this type of memory was only used through the 60s, but apparently it survived in some applications in the USSR until the 70s.
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foone Jul 5
Replying to @Foone
Here's the calculator it was used in. Check out that sixteen-digit nixie-tube display! sweeet. from
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foone Jul 5
Replying to @Foone
Also, notice the .su in that domain name? Yep, that's the Soviet Union. They got their own top level domain shortly before breaking up, but it's been kept around for reasons. Here's the memory units on the calculator. Looks like they slide under the PCBs in the back?
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Jana Eggers Jul 5
Replying to @Foone
Do you know the size of this and the resulting calculator?
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Coffee (Xythar says so) Jul 5
Replying to @Foone
These buttons feel very good by the way! We had one of these but then it died and back in 1995 people somehow did not really consider these valuable
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foone Jul 5
Replying to @jeggers
not exactly, but you can sorta tell from the pictures of the calculator. It's a big one: This unit is about 12cm/5in across, and it seems the calculator had two of them side-by-side.
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foone Jul 5
Replying to @Foone
anyway, this one is on ebay if you'd like one.
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foone Jul 5
Replying to @Xiatian
yeah, one of the first results when I was trying to find more info was someone saying this wasn't at all valuable. I don't exactly agree! but I can see why they'd become unrepairable fast. this was old-ass technology when it was first built!
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pupper!!! Jul 5
Replying to @Foone
To be sure, are we talking bytes or bits here?
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foone Jul 5
Replying to @PurpleDug_
Bytes. It stores 900 bits
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windfall.apples Jul 5
Replying to @Foone
Wait, "about" 128 bytes? Were there variations in capacity?
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foone Jul 5
Replying to @windfallapples
Nah, just it was 900 bits, which doesn't divide evenly into bytes, and is actually 112.5 bytes
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Vin 💜 Jul 5
Replying to @Foone
I wonder if this could work on an Atari 2600, considering it uses the same amount.
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foone Jul 5
Replying to @VinsCool022
probably not. The latency on this thing was insane, like 500ms to read a bit. the atari 2600 most likely cannot handle that kind of delay.
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Carl Johnstone Jul 6
Replying to @Foone @windfallapples
Did it even use 8-bit bytes?
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foone Jul 6
No clue! I was just "translating" to bytes to make the number easier to understand
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matya Jul 6
Replying to @Foone
and will continue for the next 50 years to work (I assume).
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