> On Jul 29, 2020, at 6:52 PM, Eric Moore <[email protected]> wrote:
>
> ...
> A couple notes:
>
> 1) My reader when set to lower baud rates physically stops and starts the
> reader. This jerks the tape and causes vibrations that can be severe at some
> speeds.
Some readers do this at all speeds. For example, any stepper motor is by
definition a start/stop drive at any speed. Fast optical readers may run
continuously if you let them, but that's worth a careful check. Especially
since some of the high speed readers have very serious brake systems, good for
their original application but not at all for our purposes. I've seen tape
readers specified at 1000 cps or better that are capable of stopping at any
point, starting up again, and reading the next character. So they are doing
100 inches per second and stopping within 1/20th of an inch. Ouch.
The best kind of archival tape readers would have an adjustable tape path so
you can read any of 5, 6, 7, or 8 channel tape. While 6 and 7 is uncommon it
does exist. 6 is probably least interesting, at least the only application I
know is typesetting, not computing.
I've been thinking a newly constructed optical tape reader with continuous
motion (no brakes), capstan drive, and slow ramp start/stop would be ideal and
with today's technology quite easy to make.
paul
