[sebhc] H8 hardware request - docs, info

[Dave Dunfield]

>The Altair struck me (and many others, I think) as a diamond in the
>rough; a truly great design, but flawed in its implementation. It was
>the flaws that got in my way of making it really shine. Others, like
>you, managed to work around them.

>The Altair 8800 was *hard* to assemble. It had *hundreds* of loose wires
>connecting the boards. All those toggle switches were hand-wired. There
>were one-shots to adjust. The S-100 bus was poorly designed and had
>problems like an inadequate number of power and ground traces. The board
>layouts were bad, with not enough bypass capacitors, jumper wires and
>tacked-on fixes. You had to program it in binary. All of these can be
>dealt with by a skilled technician; but they are major roadblocks to a
>beginner.

I am reminded of a quote... I've forgotten the exact source, but it was
from one of the early people in aviation, and it goes something like:
"people look back at our designs and say they were impractical... but
you have one big advantage in looking back... You KNOW what an airplane
is supposed to look like - we did not".

MITS had no idea what a personal computer should look like - the Altair
is more like a minicomputer of the day. Lights, switches and bootstrapping by
manually loading binary code were how computers of the day worked, Ed and
company drew on their own experiences and information at hand.

Was it the "ultimate personal computer" - definately not. Was it the best
it could have been - nope. Was there room for improvement - plenty. But
does it warrent the title "terrible" - I don't think so, it worked as
expected, and was a lot more practical than anything else available in 1975.
Thats the only point I wish to make.


>The H8 is basically the same machine, but repackaged to make it far
>easier to build and use. As usual, Heath did a great job of writing the
>manuals so even a beginner could build it. The design was far cleaner;
>it probably took 10% of the time to build. The front panel was octal
>instead of binary, which was easier to learn. I think the H8 bus is
>better designed, so it is much easier to add memory or I/O boards.

My Altair came on the heels of several homebuilt wire-wrap computers, including
one that even *looked* like the Altair - complete with front panel and switches.
(how I wish I had kept that one - or at least a photo of it). At least the Altair
had printed circuit boards - Coming from this background, the Altair made a lot
of sense. Those wanting an off-the-shelf packaged appliance computer should have
waited for the TRS-80 or Apple - the industry was just not ready to provide that
yet. Yes, the H8 came closer two years later - but a couple of years after that
you could by an off-the-shelf system that you didn't have to build, with BASIC in
ROM and/or a boot disk --- does this imply that the H8 was a bad design... nope,
just at a different point on a very rapidly moving timeline.

Btw, the Altair front panel was laid out in octal grouping - this was natural for
the 8080 CPU chip, although coming from a mainframe background I have always preferred
and worked in hex.


>> Have you seen the Series-2 IMSAI?
>
>Yes. But I think they have taken a wrong turn. It's a lovely, powerful
>machine. But it's very expensive and complicated, and still can't
>compete with modern PCs.

Agreed - although I don't think the point is to compete with modern PC's.
(Thats why I dislike the notion of putting an ATX mainboard in it).



> ... Why use noisy high-power TTL when you can get quiet low-power HC?

Why do die-hard large scale model railroaders use "live steam" when they
could just tuck in a weed-wacker motor. To try and present as close an
approximation to the original and environment design as possible. This is
because their goal is to preserve the era of live steam - not to build a
better more modern locomotive.

Same is true for replica computers - otherwise all you really have is a
simulator in a box.


>Today's PCs are no longer "Personal Computers" -- they are appliances;
>inscrutible boxes that no one builds, no one programs, no one
>understands.
>
>Everyone has to start at the bottom and work their way up. You learn to
>ride a bicycle before a motorcycle. You fly a model airplane before a
>real one. And to really learn about electronics and computers, you have
>to start with something simple enough so you can truly understand it.
>
>If we expect today's kids to grow up to be tomorrow's computer
>designers, they need a way to get started on that long ladder up. The
>old Altair 8800, and H8, and other old computers gave us that ladder.
>Sure, they were "toys" by modern standards -- but we sure had a lot of
>fun (and learned a lot) playing with those toys!

Excellent sentiments, and ones that I share, however as I have been fairly
active in promoting "back to the basics" computer education for kids, I can
tell you it ain't goint to happen. Schools are turning out "applicance
operators", and that is exactly what 99% of the world wants. (ie: where the
money is).

For a while I ran a small "computer club" at out local school. I recall the
first time I took in my Altair and set it up, proudly giving a demonstration
of what "personal computing" was like in days gone by - The very first question
asked was "Why did anyone ever want a computer that wasn't any good?"

Kids are used to "video games" (even when they are called "operating systems"),
and in my opinion, an H8 or Altair simply isn't going to hold their interest
long enough for them to absorb any of the really good stuff that we learned.

So, I've taken a different approach, I use microcontrollers, robots, gadgets
and things that move and talk to keep kids interested. Essentially allowing
them to do things they can't do with a PC. Building a robot that can follow
a beam of light gives em a lot more low level skills than writing a visual
basic control for a web page...


As for the early machines.. I am actively collecting, repairing and preserving
as much of the original material as I can.


>My thought is an 'open source' design, that anyone can
>download and copy freely. Offer bare boards, or parts kits, or maybe
>even a complete kit if the market is there, but keep them reasonably
>priced. The whole point is to get people building, and learning, and
>having fun with computers again.

I like this idea - that way the individual can decide if he wants to build
a detailed model, or just a work-alike machine.


finally: Just to get this back on subject - it's clear that I need to spend
some "quality time" with my H8. One of my immediate goals is to be able to
check out the machine, and also to complete the original set of materials
that would have been distributed with it.

For this reason, I REALLY would like to find copies of the original software:

Here's the original request I posted to the classic computers mailing list,
if anyone can help provide copies of this material, I would appreciate it
very much.
-----------------------------------------------------------------------------
Hi, I've recently acquired a Heathkit H8, however I did not receive the
original software. I do have documentation for the following packages,
which all appear to be original Heathkit distributions on cassette tape:

   BUG-8 Console Debugger
   TED-8 Text Editor
   HASL-8 Assembly Language package
   Benton Harbor BASIC / Extended Benton Harbor BASIC

I'm looking for copies of the software. I'd love to obtain original Heathkit
tapes, however I would be happy just to obtain the binaries or even audio
recordings of the tapes.

If anyone can help, please contact me - thanks in advance.
-----------------------------------------------------------------------------

I'd also REALLY like to locate a disk controller for it - An original Heath
board would be ideal, but I'd be "almost as happy" with a working replica.

Regards,
Dave
-- 
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.

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