On Mon, 2024-12-23 at 13:16 +0000, Donald Whittemore via cctalk wrote: > I thought the whole idea of the middle pocket on the 2540 was to > allow a master deck to be read in and fed to the middle pocket. A > total card in the deck could be selected into read pocket 1 and a new > total card punched and fed to the middle pocket merging it into the > master deck in the right place.
The "2/8" center stacker on the 2540, modeled on the 1402 or maybe a 1402 with a different cover, worked for both the reader and punch. But the reader and punch operate at different speeds. It was not recommended to stack from both the reader and punch into the center stacker, but it could be done if appropriate timing loops were included. This could be useful if your 1401 had the "read punch feed" feature and your computer room didn't have a model 88 collator. > A fun reader was the 2501. The card read in 9 edge first then changed > direction and passed by the light based reader column 1 first and > then shot up into the stacker. The card was stopped by 2 fingers > hanging down. Tape the fingers up out of the way, run a program that > read cards and you could have a game of 2000 card pickup in 2 > minutes. Cleanup was a pain. 😊 > https://en.wikipedia.org/wiki/IBM_2501 It sounds like the 2501 was the same as 1442 model 4, a read-only version of other models of the 1442. Models 1, 2, and 3 were read-and- then-punch machines. The punch station was downstream from the read station. So it was possible to read a card, then punch stuff onto the same card — usually in blank columns. Programs that would do things like read details and punch summaries were difficult with 1442, but not with the 1402.
