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.
My EECO does this, runs the tape through in short bursts and buffers it so not much point
in trying to go easy on the tape by running it at a low baud rate.
Paul's reader idea sounds fine. I have a super simple idea, how about a 3D-printed
guide with a geared hand crank and a bracket for attaching a mobile phone looking down at
tape running through the guide below it. Then set it to record video and crank away at a
steady rate. The crank has a meter or moving widget to add additional means of tracking.
At a later stage some video processing could read the pattern from the video. There would
undoubtedly be a python library for that. It would capture the label and other
labelling nicely too.