Gaps in the collection (was Re: rarest computers. )

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Tue Aug 3 23:18:23 2004

>
> My list:
>
> HP 9100A: Like Tony, I have a 9100B, but would like a 9100A for
> completeness. I wouldn't
> tear it apart like Tony does -- scares me to death just to think about
> it.

Why? Admittedly desoldering the 4 parts of the main ROM assembly from
each other was a bit worrying, but it all went back together in the end,
and I only had to do that once. Pulling it apart without a soldering iron
is something I do from time to time anyway (do a google search for the
pictures of me at the HPCC 2002 conference to see what I mean).

> Casio 14-A Relay Calculator: Yeah -- right. That'll happen :-)

Sounds interesting. I have a transistorised Casio (AL-1000), but nothing
earlier.

> Teletype ASR-33 or ASR-35: Maybe someday.

Are they that rare now? I have a couple of ASR33s, with the service manuals.

>
> Tektronix 4002A Terminal: A magical DVST beast with the best ^G tone
> ever implemented.

Off-thread [1], but an aspect of HP's wonderful design 30 years ago. I
have an HP9830, HP's first personal computer (It's called a calculator,
but you can type in BASIC programs, it has a 1-line alphanumeric display,
etc). It has a fixed-frequency beeper which sounds when there's an error,
etc. There's an output from the I/O interface board (actually, it's one
of the signals used for the magnetic card reader control on the 9810,
which uses the same CPU, but I digress) that's fed to a circuit on the
tape drive interface board. When said signal is asserted, you get a beep.
Fixed tone, fixed duratiin

Anyway, there's a little extra circuitry (transistor, a few passives) to
provided a simple amplitude envelope. Not just a sudden start/stop beep,
but one that tails away.

No real benefit from having this, but that _was_ HP for you.

[1] Off-thread means that I really should start a new thread, off-topic
means I shouldn't be posting it here at all :-).

-tony
Received on Tue Aug 03 2004 - 23:18:23 BST