Although IBM cards were 80 columns wide, the last eight columns were
reserved for a sequence number in case the deck was dropped. The deck
could then be put back in order with a card sorter. That left 72 columns
for code and/or data...
Any 72 column monitors out there?
Nick
At 10:28 AM 7/31/02 +0200, you wrote:
>Certainly, screen dimensions were modelled after punched cards: There
>were 80 columns on a punched card, and once everybody was used to that
>line length, it was an obvious choice to make the screen just as wide -
>except for a couple of clever guys who made the screen 64 columns wide,
>which happens to be a power of two.
>
>40 columns was done on some home equipment. Reducing the number of
>columns also reduces the bandwidth required in the video path, so you
>were able to use a home TV instead of an expensive specialized monitor.
>
>I have heard that the gauge of today's railway tracks (1435mm or 4'
>8.5"), and hence even the dimensions of Space Shuttle's boosters go back
>to ancient Roman vehicles built to the width of two horse's backs, maybe
>true or maybe not. But, why did punched cards have just 80 columns?
>
>Regards,
>Andreas
>
>Louis Florit wrote:
> >
> > Yes, they are 80x24. I plan to scan one of them for netposterity. :)
> > Will post link when I get it done.
> >
> > Anyone know where the genesis of 80x24/40x24 screen dimensions (and quite
> > a few other devices) has its origination in? I remember my old dot matrix
> > epson used to be 80 columns wide, and most of the older 8 bit computers
> > had 40 or 80 cols by 24 or 25 rows. "But why?" he cried...
> >
> > Regards,
> > Louis
>
>--
>Andreas Freiherr
>Vishay Semiconductor GmbH, Heilbronn, Germany
>http://www.vishay.com
Received on Wed Jul 31 2002 - 10:58:01 BST