Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!ucsd!mplvax!cdl
From: cdl@mplvax.EDU (Carl Lowenstein)
Newsgroups: comp.misc
Subject: Re: Punched Cards
Message-ID: <1208@mplvax.EDU>
Date: 5 Jun 90 15:50:18 GMT
References: <12546@netcom.UUCP> <220@taumet.COM> <12573@netcom.UUCP> <898@nlsun1.oracle.nl> <1990May29.132631.2253@pdn.paradyne.com> <1990May30.065025.25861@diku.dk> <1990Jun1.211352.4749@unhtel.uucp> <5157@stpstn.UUCP> <124@bohra.cpg.oz>
Reply-To: cdl@mplvax.ucsd.edu.UUCP (Carl Lowenstein)
Organization: U.C. San Diego, Marine Physical Laboratory
Lines: 32

In article <124@bohra.cpg.oz> ejp@bohra.cpg.oz.au (Esmond Pitt) writes:
>In article <5157@stpstn.UUCP> lerman@stpstn.UUCP (Ken Lerman) writes:
>>In the "Good Old Days", Fortran was punched in columns 1-72 of the 80
>>column card with 73-80 used for (an optional) sequence number.
>
>So was COBOL, assembler, ... It was a Hollerith card convention.
>

Oh, well, try to dredge up facts rather than conjectures.

For some large computer (probably 7030 Stretch) IBM made a 72-bit core
memory.  At the same time they made a card reader that could read
72-bit binary data a row at a time across the card to load this
memory.

As a follow-on, the 72-bit memory got used in 36-bit computers, thus
giving automatic 1-word memory readahead.  And the 72-column card
reader went along for the ride.

Since it was probably the fastest card reader going at the time, it was
also used for reading in column-oriented data like Hollerith card codes
(characters), despite the software penalty of having to transpose the
matrix of bits (corner-turning).  But the last 8 columns never made it
into the computer because there wasn't any hardware to read them.

To make lemonade out of this particular lemon, the convention of
columns 73-80 for sequence numbers was devised.

-- 
        carl lowenstein         marine physical lab     u.c. san diego
        {decvax|ucbvax} !ucsd!mplvax!cdl              cdl@mpl.ucsd.edu
                                                  clowenstein@ucsd.edu