On the Emulation of TU58s

Ian S. King isking at uw.edu
Tue Jun 16 11:51:59 CDT 2015

Mark, I've thought of that for my HP 9845, too.  Sure would be nice to
fabricate something that's flexible hardware that can be programmed for the
peculiarities of various implementations.  I'll put it on my list of things
to do once I'm done with my dissertation.  :-)

On Tue, Jun 16, 2015 at 4:21 PM, Paul Koning <paulkoning at comcast.net> wrote:

> > On Jun 16, 2015, at 12:10 PM, tony duell <ard at p850ug1.demon.co.uk>
> wrote:
> >
> >>
> >> As long as we're talking philosophy, what do y'all think about
> emulating the TU58 drive, vs. emulating the TU58 > *tape*?
> >>
> >> I cannot properly express my opinion of that tape cartridge design even
> if I violate list rules about use of
> >> profanity. But the drive itself isn't all that bad, aside from not
> having enough motors to manipulate a
> >> well-designed tape cartridge mechanism.
> >
> > The tape cartridge (along with QIC cartridges, etc) is an interesting
> design. Of course the general problem is
> > to run the tape at constant linear speed past the head while winding it
> off one reel onto the other. In general
> > there have been 3 solutions to this.
> Another solution is to avoid the problem entirely by not requiring
> constant linear speed.  That’s what DECtape (the real one) does.
> >
> > One is to drive the tape itself using a capstan and maybe a pinch
> roller. Then have the takeup spool
> > driven too fast with a slipping clutch in-line. And a weak brake on the
> supply spool. This of course is what
> > was done in audio recorders (reel to reel and cassette), Video recorders
> (ditto), etc.
> Or a variant: drive the takeup reel with a controlled torque motor and no
> slip clutch.  I think professional grade tape decks may have been built
> that way.
>         paul

Ian S. King, MSIS, MSCS, Ph.D. Candidate
The Information School <http://ischool.uw.edu>

Archivist, Voices From the Rwanda Tribunal <http://tribunalvoices.org>
Value Sensitive Design Research Lab <http://vsdesign.org>

University of Washington

There is an old Vulcan saying: "Only Nixon could go to China."

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