23 Dec
2024
23 Dec
'24
2:37 p.m.
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.