Two of the EBCDIC design constraints were 1. Preserve the punch combinations for common characters 2. Map numeric punches into the corresponding 4-bit numbers
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Jesse 1 Robinson [jesse1.robin...@sce.com] Sent: Tuesday, June 2, 2020 4:54 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Punched cards and character set 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. . . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW robin...@sce.com -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Paul Gilmartin Sent: Tuesday, June 2, 2020 12:43 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: (External):Re: Punched cards and character set CAUTION EXTERNAL EMAIL On Tue, 2 Jun 2020 15:14:33 -0400, Tony Harminc wrote: > >Some card readers supported Column Binary or Card Image mode, and in >this case a card record was 160 bytes with each column mapped to the >low-order 6 bits of two adjacent bytes. I think there were some other >variations for this mapping. > A colleague, steeped in CDC 6400 lore, got a Ph.D. from U. of Colo. and took a job with IBM. He took his personal source library of utilities on CDC binary cards, two 6-bit characters per column, intending that his first learning experience with s/360 assembler would be deciphering and translating CDC=>EBCDIC. He could not get access to any IBM reader with the column binary feature. >Code Pages as we know them today have their roots a good deal later >than punched cards. At least in the IBM mainframe world, they came from >the 3270 devices, which were initially US-centric, with only upper case >English (unaccented Latin) letters. Almost immediately local variants >were field developed in many countries to provide characters needed. In >many - maybe most - cases the character assignments clashed, and >because of the 3270 addressing architecture, positions below X'40' were >not available. > Don't forget lower case. But I guess IBM did. Alas. See: https://secure-web.cisco.com/1uJJ4M0JM1Y-6cjjSrqrtZK-RS4l7JewSbteKoXbnnRb_fSkDH6GUJB3x-jlpEHa8hFLSz1P4TQqhKEAg6WYcGF2PtfLXBH57i9jg0LN0lHRkwEi-hNstlRkEMoxMsLZ6i-qz6z2ycvsSKDVSsCv_nubHVHLqpwuB7v9lRx-T17ESHt9b5keSghXnVQ48zKA7C4mgrnPaX719sD5gq0RhgK1bwAJgeYJWAXP_-2K_F0cxn1kVg1LaW0352v5Ggn6CTK_iEsgoltIYC0mVsNOWKtjIiU-SlxIXTe7IhkfACbW2k2gk_cjjc-RYxunAHFCEKVsnL_sJPUu_utx_GoG2byrbk2DNjhuttPtWhjVHbihFLWjj3CTh5uTosaRSe_Zl6t0Lx2GewctGij77Dy4f8EXBNdXljWEHlANSMw3QO4E_h4idixxSEfDN_3aIdIhU/https%3A%2F%2Fweb.archive.org%2Fweb%2F20180513204153%2Fhttp%3A%2F%2Fwww.bobbemer.com%2FP-BIT.HTM >A very good historic reference for how this developed is the 1989 SHARE >"ASCII and EBCDIC Character Set and Code Issues in Systems Application >Architecture" report by the ASCII / EBCDIC Character Set Task Force. To >make their point, they used the short name "SHARE ÆCS Report". I have a >scanned copy if you can't find it online somewhere. >Parts of this became input into the design of UNICODE. -- gil ---------------------------------------------------------------------- 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
