Bitsavers size

Tony Duell ard.p850ug1 at
Fri Apr 21 13:00:39 CDT 2017

On Fri, Apr 21, 2017 at 6:24 PM, Rob Jarratt
<robert.jarratt at> wrote:
>> > My back of the envelope calculation comes to approximately
>> > 4 million miles of paper tape.
>> I think you're out by a factor of 10.... 267*10^9 bytes, divide by 10 as there are
>> 10 bytes to the inch on paper tape, and convert to miles. I get just over 400,000
>> miles.
> Agreed, I measured a piece of paper tape I have here and got a figure of 0.9 inches
> per 10 bytes, so clearly just a bit of finger trouble somewhere in my calculation.

I think you've made a fencepost error here. There will, indeed be 0.9" between
the centre line of one byte and that of the tenth byte after it. But
you are forgetting
to include the gap on one end of that block (if you see what I mean).

The holes on paper tape (at least the normal 5 level and 8 level
stuff, typesetter
tape may well be different) fall on a 0.1" matrix. I once made an emergency
splicing jig for paper tape using a bit of stripboard with some pins soldered
in. So there are exactly 10 characters per inch on paper tape.

> Still, almost enough for a round trip to the moon.



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