Groups > comp.arch > #2021

Re: History of byte addressing

From	Anne & Lynn Wheeler <lynn@garlic.com>
Newsgroups	comp.arch
Subject	Re: History of byte addressing
Date	2011-06-03 09:48 -0400
Organization	Wheeler&Wheeler
Message-ID	<m3fwnrrpoa.fsf@garlic.com> (permalink)
References	<is8ons$jiv$1@gal.iecc.com> <c5816f6d-8ccb-4629-ad7f-84770c220a25@v31g2000vbs.googlegroups.com>

Show all headers | View raw

Alex McDonald <blog@rivadpm.com> writes:
> Perhaps (and I must admit to speculating here) BCD, EBCDIC and the
> 80column punch card played a part when used in column mode. Some early
> IBM machines used row mode (1 row for two 36bit words, giving the 72
> data columns that became just about a standard in column mode too),
> but lots of punchholes per row or column gave the cards less than an
> ideal stiffness.  I only vaguely remember machines with row mode
> binary cards.
>
> The commonly adopted maximum punch was 3 in a column, one in 3 of rows
> 12, 11, 0, one or two for 1-9 (the 8 or 9 was the 3rd punch) giving a
> 6bit BCD encoding. EBCDIC extended that to more holes/column with
> backward compatibility with 6bit BCD (hence the discontinuous nature
> of the A-Z encodings), but that was a later development (1977??) and
> used 4 punches for the extended bits; 5 for some really obscure
> encodings. I do remember that hand keypunches were difficult to use
> beyond 3 punches per column.
>
> Perhaps 8bits was the maximum encodable without causing backward
> compatibility problems and having too many holes in a card? Perhaps.

punch card 80 columns and 12 rows; 360 (announced 1964, with 8bit
"bytes" rather than 6bit "bytes) extended 6-bit BCD to (single) 8-bit
EBCDIC punch card encoding (eliminating column binary encoding).

my 1st programming job at univ. was porting 1401 MPIO (card->tape &
tape->printer/punch; where 1401 acted as front end for 709; that
normally ran tape->tape) to 360/30; the 360/30 had 1401 hardware
emulation mode (that would directly run MPIO) ... so it apparently was
univ. was just gettting familiarity with 360 as part of planned
transition to replace 709/1401 with 360/67. I got to design&implement my
own monitor, device drivers, interrupt handler, storage management,
error recovery, multitasking (concurrent card->tape while
tape->printer/punch), etc.

input cards could either be (6-bit) BCD or column binary. ... basically
"column binary" was two six-bit "bytes" per column rather than 6-bit
BCD.  I would read "BCD" ... if got an error (reader would generate
error if there were any columns with punch hole combinations not
valid/defined for BCD) reread as column binary ... before doing
feed-selectstacker. on 360, the two six-bit bytes would be stored in two
eight-bit bytes (80 column binary card would occupy 160bytes). bytes
would then be written to 7-track tape (6bit byte plus parity).
going tape->punch ... had to recognized whether to punch 80byte BCD or
160byte column binary.

i have done a Q&D conversion of IOS3270 "green card" to html
http://www.garlic.com/~lynn/gcard.html

lists for newer generation reader/punch I/O command codes, but mostly
same for old 360 2540 reader/punch
http://www.garlic.com/~lynn/gcard.html#23

read-only: 11D0F010  ; "D" =0 ebcdic, =1 "card image", aka column binary

and for (old) 7-track tape
http://www.garlic.com/~lynn/gcard.html#25

-- 
virtualization experience starting Jan1968, online at home since Mar1970

Thread

History of byte addressing John Levine <johnl@iecc.com> - 2011-06-02 19:36 +0000
  Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-02 20:38 +0100
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 08:05 -0700
  Re: History of byte addressing Alex McDonald <blog@rivadpm.com> - 2011-06-03 05:26 -0700
    Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-03 09:48 -0400
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 07:49 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 10:56 -0700
  Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-04 10:59 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-04 15:01 -0700
      Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-04 22:53 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:40 -0700
    Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-05 06:10 +0000
      Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:00 -0700
        Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:04 -0700
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:36 -0700
            Re: History of byte addressing "Paul A. Clayton" <paaronclayton@gmail.com> - 2011-06-05 11:00 -0700
              Re: History of byte addressing Morten Reistad <first@last.name> - 2011-06-05 21:42 +0200
                Re: History of byte addressing anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-06-06 17:03 +0000
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-06 23:55 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:26 -0700
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-07 05:08 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-07 03:26 -0700
                Re: History of byte addressing Roberto Waltman <usenet@rwaltman.com> - 2011-07-05 20:00 -0400
                Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-06 00:15 +0000
              Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-05 16:18 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:10 -0700
              Re: History of byte addressing torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-06-07 10:50 +0200
                Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:02 +0200
              Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 15:51 +0200
            Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-05 13:43 -0600
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:12 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 02:04 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-05 23:49 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 13:34 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-06 10:49 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-06 22:42 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-07 07:37 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:22 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-11 09:56 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-11 14:59 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-11 18:52 -0600
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-12 12:40 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-11 15:05 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 13:10 -0600
                Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-06 16:41 -0400
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:13 -0700
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 23:50 -0600
                Re: History of byte addressing Jim Haynes <jhaynes@alumni.uark.edu> - 2011-06-07 10:01 -0500
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 13:09 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 14:03 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 05:16 -0600
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:44 -0700
        Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 05:00 +0000
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:11 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:00 +0100
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:16 -0700
            Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 01:01 -0700
              Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:30 +0100
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 10:34 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:29 -0700
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 15:21 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:23 -0700
                Re: History of byte addressing MitchAlsup <MitchAlsup@aol.com> - 2011-06-07 08:01 -0700
                Re: alignment, was History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 18:33 +0000
                Re: alignment, was History of byte addressing nmm1@cam.ac.uk - 2011-06-06 19:30 +0100
                Re: alignment, was History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-06 15:32 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:11 -0700
          Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-06 06:48 -0700
            Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-03 16:13 +0000
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 09:10 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:23 +0200
    Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:26 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:25 +0200
    Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:45 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:48 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:59 +0200
        Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 17:05 +0200
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-18 15:43 -0700
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:14 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:40 -0700
      Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 04:28 -0700
        Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 13:38 +0100
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 06:47 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 14:16 +0100
        Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:53 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:36 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:50 -0700
          Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-07-04 19:46 +0000
            Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 15:29 -0700
              Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-05 00:02 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:47 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:54 -0700

csiph-web