A Few Facts About the LGP-30


The Librascope/Royal McBee LGP-30, an early computer, is now best remembered for being the computer at the heart of The Story of Mel: drum memory, one-plus-one addressing, index register, and all. (The “free verse” version is better-known, and I think better.)

But did you know that Mel was real?

Also, did you know that the LGP-30 used non-standard hexadecimal? Perhaps you are asking yourself how hexadecimal could possibly be non-standard: there are sixteen digits, right? Well, yes, but in our modern computers, those digits are:

 0 1 2 3 4 5 6 7 8 9 A B C D E F

Whereas, on the LGP-30, they were:

 0 1 2 3 4 5 6 7 8 9 F G J K Q W

Makes sense, right? It’s related to the layout of the LGP’s Flexowriter—you can see the lower-case letters continuing the stride of the decimal digits—though that layout is itself a baroque marvel that has the same character serve as a lower-case “l” and as the digit “1”.

With such an unlikely sequence of letters, one needs a mnemonic. According to Wikipedia, the canonical one was “FiberGlass Javelins Kill Quite Well.” But according to M. Mitchell Waldrop’s biography, J.C.R. Licklider preferred “For God and Jesus Christ, Quit Worrying.” The observant reader will have noticed that the mnemonic only works if you treat “Christ” as though it started with a K.

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