punching paper tape

Eric Moore mooreericnyc at gmail.com
Fri Mar 26 15:53:12 CDT 2021

For short tapes, running it through a rotary paper cutter rig would let you
cut it down to the right width. Problem is you could not use anything but a
custom built or modified reader. Leaving the MSB 0 would get you accurate 7
bit bytes/words with 8 bit byte alignment for simplified reading and
storing of files on modern systems, and allow usage of common punches and

I would suggest punching a number of 8 level tapes, then taking a few and
cutting them down so you have readable tapes, and then historically
accurate tapes for demonstration/display purposes.


On Fri, Mar 26, 2021, 3:43 PM Guy Fedorkow <fedorkow at mit.edu> wrote:

> Paul,
>   You are correct, the Whirlwind tape was only seven tracks wide, with
> the same pitch as what became eight-track tape.
> http://www.bitsavers.org/pdf/mit/whirlwind/Whirlwind_Paper_Tape_Format.pdf
>   I'll admit that I was expecting it to be hard to find someone with an
> eight-track punch and blank tape, without even trying for seven track...
> There are a few of the original Flexowriters out there somewhere, but
> I'm certainly not going to try using one.  The tape is for "pedagogical"
> purposes, so indeed seven would be better than eight, but eight will do
> fine.
>   But if you can suggest a way to punch a seven track paper tape, I'm
> glad to give it a try!
>   And if we do end up with eight track tape, I'll be sure to add an
> attaboy for anyone else who notices!
>   Thanks!
> /guy
> On 3/26/2021 4:02 PM, Paul Koning wrote:
> >
> >> On Mar 26, 2021, at 3:31 PM, Guy Fedorkow via cctalk <
> cctalk at classiccmp.org> wrote:
> >>
> >> wow, what format?
> >>   The codes I'm punching should line up with a long-dead machine,
> >> Whirlwind from MIT, so I think you'd consider them to be 7-track binary,
> >> i.e., same size as an 8-track teletype tape with one track blank, but no
> >> recognizable coding like ASCII.
> > Some machines used 7-track paper tape that is narrower than 8 track
> tape.  I thought Whirlwind was one of those.
> >
> >       paul
> >
> >

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