31 Jul
2002
31 Jul
'02
4:01 a.m.
On Wed, 31 Jul 2002, Andreas Freiherr wrote:
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?
The physical dimensions of the punched cards were chosen to match dollar
bills, so that the processing hardware could make use of existing
subassemblies. I don't know why that particular hole to hole spacing was
chosen, but that combined with the size of the cards resulted in 80
column.