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A comment on LGP-30 found in basement, the same model of drum computer programmed by “Mel”. Parent comment

Re:LGP-30 found in basement, the same model of drum computer... by jgrahamc on Tuesday November 08, 2022 @03:20AM (#33517064)
FGJKQW makes sense because almost all the rest of the alphabet was used for the instruction set (one letter per instruction) so these were left over.

For the life of me, I can't figure out why ORDVAC use KSNJFL. If you Google around you'll find the claim that this was because in figure shift mode the input teletype produced 01010 to 01111 in binary on the tape for those letters. Except, I can't find a 5 level code that actually conforms to that. It's certainly not Baudot as some claim. And if you look at the manual the claim about figure shift isn't even true for the actual code used. https://www.ideals.illinois.edu/items/55048

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Re:LGP-30 found in basement, the same model of drum computer... by kps on Tuesday November 08, 2022 @09:34AM (#33519362)
> https://www.ideals.illinois.edu/items/55048

On p4 the code has KSNJFL punch binary 10–15. It starts with a permutation of Baudot ITA2 (notice the QWERTYUIOP/1234567890) to make 0–9 punch their values.

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Re:LGP-30 found in basement, the same model of drum computer... by jgrahamc on Tuesday November 08, 2022 @01:08PM (#33522137)
Yes. But why that permutation? And although there is a relationship (like Q and 1 being on the same key) there isn't a relationship with Baudot or ITA2 (e.g. Q/1 isn't 00001 it's 11101).
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Re:LGP-30 found in basement, the same model of drum computer... by kps on Tuesday November 08, 2022 @01:54PM (#33522753)
In case you're not already aware (and/or for readers who aren't, because I wasn't yesterday), they made substantial modifications to Model 15 Teletypes to get their chosen coding and key layout (numeric-pad-like rather than QWERTY), including modifying and permuting levers, type bars, and keycaps. It could be that KSNJFL was somehow most convenient in that respect, though it's hard to imagine.

https://archive.org/details/modificationofte56mill

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Re:LGP-30 found in basement, the same model of drum computer... by jgrahamc on Tuesday November 08, 2022 @04:09PM (#33524328)
Yeah. It's pretty interesting because they clearly did this super intentionally. As you say they moved everything around. Since they are using the existing keycaps which have Q/1, W/2 etc. they lose QWERTYUIOP but they've still got ASDFGHJKLZXCVBNM from which to get the hex digits.
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