THE best find of the weekend!

From: John Chris Wren <jcwren_at_jcwren.com>
Date: Sun Feb 10 21:27:05 2002

[snip]

>
> Speaking of Daisy Wheel printers... I prefer to use a daisy wheel for
> printing plain text stuff. Currently, I have a DIABLO 630 and am
> having real
> difficulty talking to it. Seems like when I try to print anything, I get
> buffer overruns, the wrong chatracters printed, and all kind of other
> errors. I have tried every possible combination of comm settings, flow
> control, etc... to no avail. Does anyone know where I can find
> the specs for
> setup and handshaking for this printer.
>
> See ya,
> SteveRob
>

        Years ago, I used to have a Diablo Hytype-I that was interfaced to my CP/M
system via a GPIO card. I originally wrote the print program in assembly,
but re-wrote it in C (my first C program! Using the Aztec C compiler,
IIRC). It wound up being 3 times faster, since it was easier to overlap the
platen, carriage and print wheel motion. That ol' thing would hammer along,
printing out proportionally spaced documents all day.

        Then it started getting sick. I had schematics for it, but wasn't a smart
enough electrical engineer to fix it (I was 16). The thing would be merrily
printing along, and all of a sudden decide the head wasn't where it thought
was, or that it wanted to move the carriage 14" to the left, when it was at
the 6" position.

        As people who've owned Hytypes will attest, this was the first printer
(that I'm aware of) that used ramped acceleration to move the head. If you
were at position 0, and wanted to move to the 14" position, it would ramp up
the head up to speed in the first 2" (arbitrary number, I don't remember the
actual ramp values), cruise at full speed to 13", then deaccelerate in the
last inch. It was a wonderously smooth movement.

        Except for when it got confused. If it was at the 6" mark and thought it
was at the 14" mark, it would ramp the head up, and *boom* smash into the
left margin at full cruise missile speed. If you had your fingers in the
way, you'd have a bloody mess. This sudden stop at max cruise usually
caused the printer to jump about 4" to the left. You may remember these
things weighed about 35 pounds, and when you can move 35 pounds on non-skid
feet 4" into the left, you *know* it had some kinetic energy.

        Alas, I was young, foolish, and wanted a PC. This thing was in the way of
where my new found PC would go, and since no one could seem to help me
repair it (in spite of having the 11" x 14" big orange covered server
manual), it was eventually disposed of.

        One this I never did while I had it was turn it into a scanner. With that
high resolution stepping (for the period), it would have made a fairly
decent, albiet coarse, B&W scanner. I remember poring over the TI CCD
imagers, trying to figure a way to make it work.

        Ah, would I like to have my old (working) Diablo HyType-I back. That was a
slick piece of printer.

        --John
Received on Sun Feb 10 2002 - 21:27:05 GMT