He shoots! He Boots! Heath Lives!

From: Roger Merchberger <zmerch_at_northernway.net>
Date: Fri Jul 11 23:19:39 1997

Whilst in a self-induced trance, Stacy C. Morang happened to blather:
>On Tue, 24 Jun 1997, Roger Merchberger wrote:

>> H-120-1. I'm assuming this is the model number.
>It is.

Uh... Update, folks! (and I gotta name this thing now... how about
"Heather"... 8-) Get it?!?

It boots! Did I mention that it came with one floppy disk stuck in the
bottom drive? This floppy was a boot floppy! And it still works! Joy! ;-)

>> Something tickled in my brain about those floppies, so as I lumbered around
>> in the dark in my newly-begun clean-ish basement (Eeeeek!) I found my old
>> non-working Atari 810 disk drive... and the mechs looked almost exact!
>> Would these happen to be the same mechanically, would anyone know?
>Probably not, the Z (or H) used standard SA-455? 360K ibm pc style drives

You're right, but they seem to format to only 320K (8 sectors/track, not 9)
with the DOS I do have, which is listed in the stats of the machine I
listed below... The broken drive *does* work! It's only the door that's
broken, so I sacrificed my Atari 810 (which was dead anyway) and the garage
door from it is exact! Yiippee!

>Top, I think. (I have one, but I only got it for the Winchester drive

Whaddya did with the rest? A few spare parts might be nice (or a color
tube, if yours had it... ;-)

>That is the monitor rom, and certain keys should do something more
>interesting, like
>C - color bars (if you have color video, otherwise b&w bars)
>B - boot prompt, pressing the right combo of numbers and fkeys selects
>the boot drive.
>D - dump memory

I don't doubt your memory, but I think this is a (prolly earlier) version
of the monitor rom... specs to follow. I fat-fingered *all* the keys on it,
and here's what works:

B -- boots. Accepts parameters of: 0, 1, 2, 3, and that tells it what
floppy to boot from. Plain B assumes floppy 0, which is top. Thanks! All
else beeps with invalid parameter, except "S", which appears to do nothing.
Would this be boot from the serial port, perchance?

V -- Version of the monitor rom, which is Version 1.02.

Nothing else worked...

>It will boot off of CP/M, MP/M, UCSD P-System, Concurrent CP/M, MS-DOS
>and others. If you find a generic version 1 or maybe 2 ms-dos it might
>boot, pc specific PC dos won't.

This thing came with a Version 1 Dos... here's the specs of the boot:

Z-DOS / MS-DOS BIOS Release 1.00 Version 1.02

Z-DOS / MS-DOS Release 1.00 Version 1.25
(C)Copyright 1982, Zenith Data Systems

Z-DOS / MS-DOS Command Release 1.00 Version 1.19

>The machine has an 8088 and an 8085 processor, and uses the appropriate
>one for the os in question.

I've pulled 'er apart to fix the floppy, and to clean the keyboard & all.
Sure enough, it has a NEC 8085A plastic, and an Intel 8088
like-eprom-whatever-you-call-it case. It presently has 128K RAM in it!


1. Whilst it's all apart, does anyone want me to snap pictures? I can...

2. How high can this rascal go in memory? I located 3 banks (9 each --
parity) of 64kx1 300ns DRAM, two of which are populated. Mathmatically,
that works to: 128K RAM. The third bank is empty. Can I pop in 9 more chips
without setting any jumpers/dipswitches? How about bigger DRAMS? (prolly
not... but it's worth an ask!) Still, 192K is still pretty good for a
machine from '82!

(also, on the question of jumpers... anyone have a tech-like manual for
this thing I could get a copy of... or at least a copy of the important

3. The video board which is based on the Motorola 68A45P video chip,
presently has 64K onboard for *just* the green section of the board. This
rascal can handle 192K Video Memory!!! Funky! ;^> (that is, if I'm reading
the boards right.... but CHKDSK doesn't return the added video memory, so
that'd seem correct.) Does the board support any form of graphics? I tried
the standard basic commands (ZBasic was on the floppy) but it seemed only
to work in text.

For this thing having 2 Intel-based processors, I'm surprised with the
amount of Motorola logic in this rascal! Prolly a 3rd of it is Moto,
including the 74 series chips! All of the important support chips, like the
video processor, the PIA's & UARTS, and all that jazz seem to be Moto.

Well folks, I havta say: This is one *sweet* machine! :-)

>I'm not sure what the licensing requirements are, however, I do have
>several OS's for the machine - I'm sure something can be worked out.

Did Heath/Zenith bundle an OS with the disk systems? If so, wouldn't I own
a license to own a copy of the included OS, as I own the machine? I'm not
sure how stuff like that works, especially on the old stuff.

>You're welcome, pity I'm so far behind in the mail...

No prob... I'm behind as well, as you can plainly see!

>So long, and keep your stick on the ice.

Ohhh, brrrr! I hope yer' talkin' Hockey!!! ;^>

Thanks again, and have a good weekend!
Roger "Merch" Merchberger
Roger Merchberger       | If at first you don't succeed,
Programmer, NorthernWay | nuclear warhead disarmament should *not*
zmerch_at_northernway.net  | be your first career choice.
Received on Fri Jul 11 1997 - 23:19:39 BST

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