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