Wanted, Papertape Reader for Archiving Tapes
paulkoning at comcast.net
Tue Apr 28 11:29:58 CDT 2020
> On Apr 28, 2020, at 12:01 PM, Bill Degnan via cctech <cctech at classiccmp.org> wrote:
> Hi - COVID project.... I have been attempting to read some old Honeywell
> DDP-516 papertapes using the OP-80A or Teletype reader but it's inefficient
> and I don't want to damage the tapes. Does anyone have a reliable
> papertape reader for sale, or recommend one currently out there on Ebay,
> for the purpose of archiving papertapes of any kind safely and reliably. I
> have a reasonable budget. I have a lot of tapes that need to be archived,
> so I'd want one that I can interface with to capture into TAP files or what
> I would call a raw dump listing of the data in 8-bit Hex. MITS, SWTPc,
> Z80 stuf, PDP 8, PDP 11, Honeywell, etc.
> End goal is to load tapes into simH, PDPGUI, Altair/S-100, textfiles to
> display tapes. I want to be able to view the tape as it would be in Intel
> or Motorola format, etc. What does everyone else do?
> For example:
> Thanks for any advice.
I don't have a reader, or tapes that I need to read, but I've had some conversations with people who do.
Tape readers are not that hard to find but then you have to worry about interfacing. I've seen a few with RS232 output, that would be easy (just tie them to an RS232->USB adapter).
The concern I can see with many of them is that they tend to be built for speed, not for gentle handling. So you might see stepper motor drive, or fast spinning capstans plus brake blocks. Readers that can do 1000 cps and stop before the next character are impressive but not quite what we want here. Stepper motors are not quite as rough but still they accelerate and decelerate the tape for every frame, and typically they pull on the feed holes with a sprocket wheel.
If I needed to build one I'd probably construct a tape guide, adjustable to different tape widths (minimally 5, 7 or 8 track but perhaps 6 and 2 as well just for grins). Add the usual photocells. For transport, either just a driven takeup reel, or a capstan type drive. In either case, drive with a servomotor that's ramped up slowly and goes no faster than 100 cps or so. Then just capture the analog output signals from the 9 photocells and do the data recovery in software from those waveforms.
For the data format, my answer would be to capture each tape frame as 8 bits of binary data; decoding is then a further post-processing step.
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