29 Jul
2020
29 Jul
'20
6:17 p.m.
Absolutely would be good to have. I would prefer a slow smooth pull through
the reader than slow and jerky or fast and smooth which are my current
options.
There are some kit paper tape readers out there that just need a pinch
roller added to be ideal.
On 5, 6, and 7 bit tape, I believe the DSI NC2400 which a number of people
have is adjustable width. That said, a kit that came with a variable width
optical read head and a variable speed smooth pinch roller with an RS232
interface would likely find a market with hobbyists. No hard brake needed
for archival purposes, but definitely a softer break to fairly quickly stop
the tape if something goes wrong.
-Eric
On Wed, Jul 29, 2020, 19:43 Paul Koning <paulkoning at comcast.net> wrote:
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