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

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