27 Feb
2009
27 Feb
'09
2:53 p.m.
On Thu, 26 Feb 2009 14:18:59 -0700 Mike Loewen wrote:
On Thu, 26 Feb 2009, Gordon JC Pearce wrote:
Umm if you store binary ... that is 80 bytes per card .. 46 feet per file.
Now how many dec tapes is that?
Errr, ISTR that a standard IBM, etc. punched card was 0.0065" thick rather than the
0.007" implied by the 0.178mm, BICBW. Also, since there are 12 rows per column, the
most efficient packing technique could store 120 bytes in the up to 960 "bits"
(hole positions) in the card.
Using those numbers, I came up with the following:
6,291,456 bytes / 120 = 52,428.8 cards (OK, 52,429)
52,429 * 0.0065 = 340.7885 inches or about 28.4 feet per file.
What an improvement. ;) (Is anyone else bored today?)
I also seem to recall that Univac or some other computer manufacturer actually used a 90
(?) column card for even better packing density. I'll leave that improved calculation
to someone who actually remembers how many columns those cards were blessed with.
Later,
Charlie Carothers
--
My email address is csquared3 at tx dot rr dot com
Didn't someone once work out that to store a
single MP3 you'd need a
stack of 80-column cards ten miles high?
Assuming a 6MB MP3 file and 40 bytes per card:
6 * 1048576 = 6291456 bytes
/ 40 bytes per card = 157286.4 (157285) cards
* .178mm card thickness = 27996.73 mm high
/ 25.4mm per inch = 1102.233465 inches
/ 12 = 91.85278871 (91.85) feet
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/