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From: cik@l.cc.purdue.edu (Herman Rubin)
Newsgroups: comp.misc
Subject: Re: Punched Cards
Summary: Why 72 columns?
Message-ID: <2219@l.cc.purdue.edu>
Date: 6 Jun 90 15:05:20 GMT
References: <12546@netcom.UUCP> <220@taumet.COM> <12573@netcom.UUCP> <1208@mplvax.EDU>
Organization: Purdue University Statistics Department
Lines: 27

In article <1208@mplvax.EDU>, cdl@mplvax.EDU (Carl Lowenstein) writes:
> 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.

A little background:  punched cards were read initially a row at a time,
from the bottom (9) row up.  When a card was sent to a computer, it was
the left side of the 9's row, the right side, etc.

Fortran was designed for the IBM 704, which was a 36-bit machine.  The 
card-reading hardware for this machine could not read the right 8 columns
of the card.
-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907
Phone: (317)494-6054
hrubin@l.cc.purdue.edu (Internet, bitnet)	{purdue,pur-ee}!l.cc!cik(UUCP)