On Jul 29, 2020, at 6:52 PM, Eric Moore
<mooreericnyc at gmail.com> 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