They were valid column binary.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Steve Smith [sasd...@gmail.com] Sent: Tuesday, June 2, 2020 5:06 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Punched cards and character set That's plausible, I think. While there are plenty of adjacent punches in the full 256-characters, I'm sure most cards were mostly alphanumeric only, and it might pay to make them as strong as possible. I remember seeing some cards that were punched in every position; those were very delicate, and definitely couldn't survive a pass through a card reader, regardless of the fact they had no validity at all. sas On Tue, Jun 2, 2020 at 4:55 PM Jesse 1 Robinson <jesse1.robin...@sce.com> wrote: > I haven't seen this mentioned. The punch card codes for letters went like > this: > > A - I rows 1 - 9 > J - R rows 1 - 9 > S - Z rows 2 - 9 > > So why was S assigned to row 2 instead of row 1? The answer I was taught > was that row 1 was too close to an adjacent location. The punching/reading > devices and card stock of the day could not reliably handle punches that > close together, so row 1 was skipped for the third alphabetic sequence. > > What's amusing is that this pattern was carried over to EBCDIC. The code > for S likewise skips a possible combination: D9 to E2; 'E1' is not assigned > to an alphabetic character. > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
