Reading PDP-8 paper tapes

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sun Jun 29 17:00:59 2003

> Hi Pete! Just to introduce myself to the folks here; I was an Acorn

Welcome aboard!

> system programmer for several years which is how I know Pete, and
> I subbed to this list a couple of days ago - although my interest here
> is actually in older stuff, I *do* have an absolute sh*tload of old
> Acorn systems and boards that I've been trudging around for years
> and I'll be glad to help with Acorn info when I can. Any of the
> Acorn kit that I have which anyone needs, they're welcome to it -
> I'll never use it again, I just wanted to save it from the dumper...

I have a couple of Acorn Systems (one 6502, the other 6809-based). I am
always looking for any of the more unusual I/O cards for them....

> Anyway, yes, we have a significant collection of paper tapes which
> I used to use personally around '76-78, at which point they were
> donated to the Royal Scottish Museum. Unfortunately the curators

Argh!

> won't let us take them off the premises now in order to read them,
> so we need to take a reader of some description into their warehouse
> along with a portable PC. Even a serial ASR33 would do, although
> it would be a heavy lift! We're pretty desparate here...

I would recoemnd against using an ASR33 or any other sprocket-fed reader.
Too much risk of damaging the tapes....

Try to find a Trend USR or HSR, or some other capstan-fed reader with
optical sensing of all the holes including the sprocket track. Those
readers are remarkably kind to tapes, even if you get a snarl-up. They
are not _trivial_ to interface to a PC (the interface is one TTL level
signal per track, including the sprocket track, and signals to start the
tape moving, etc -- you need to add logic to get it to step one character
at a time if that's what you want to do -- but it _will_ stop on a
character), but it's not impossible to do that either.

The only problem is finding one. I have several of them, but (a) I'm in
London and (b) they're all linked to rather larger machines...

-tony
Received on Sun Jun 29 2003 - 17:00:59 BST