[N8VEM: 16538] Building a first Homebrew Computer

[Andrew Bingham]

Hello,

I'm thinking of embarking on building one of the various computer designs
posted on this site, and have a few questions before I get started.

First, a little background on myself.... I was born in 1985, so most
vintage computers are older than I am. But my family wasn't into
technology when I was a child, so the first computer that we had was an
original IBM 5150 that was gifted to us...in 1994. 256 kB of ram, 1 DS and
1 SS drives, and the monochrome graphics adapter. Everything in the
original packaging, the 3-ring binder manuals, and copies of the IBM word
processor and such. In fact. the machine was used in an open house at the
IBM Plant in Burlington, Vermont as a display in the early to mid 80s -
there was a disk with it with programs and demos that were set up for the
public at the open house.

I loved that machine. The Model F keyboard, the satisfying "thwunk" of the
orange-red old-style power switch at the back right corner....
BASICA.EXE.... I taught myself BASIC from old books, and even wrote my own
nuclear reactor "simulator" program.

Eventually we "upgraded" to an Epson 8088 with the full 640k of RAM and a
CGA monitor.... and then a Northgate 286.... And finally, I managed to
convince my dad to buy a brand new PC instead of one a decade old, and I've
been on "current tech" ever since. (I still have the 5150, in all the
original IBM boxes, in storage back at my mom's place in VT. My youngest
sister managed to stick 2 5.25" floppies in drive A: and then broke off the
"close" tab on the drive trying to close it onto 2 of them, which removed
it from service.....sometime soon I think I'll have to fix it. It's
probably one of the nicest condition 5150s around these days, in the
original boxes for its entire life).

Anyway, I'm interested in building one of the systems that are part of the
general sphere of the N8VEM project "and friends". I'd like to recapture
some of the simplicity of those old machines and maybe experiment with
fusing them with modern technology like compactflash storage, ethernet, etc.

I have enough experience to be able to reliably build through-hole solder
components, and basic hardware/electronics debugging with a multimeter and
o-scope.

I'm leaning towards either
-The Xi 8088 based on my past experience with DOS and 8088s
-The Zeta based on it's relative simplicity and self-contained-ness and
ease of getting started - but I'd have to learn CP/M for the first time

Personally I'd love to go one iteration back in time and build an S-100
system because there are so many options as far as boards, but it looks
like the PCB availabiity is a bit more intermittent due to less demand
there. I like the idea of the S-100 8086 or 80286 running DOS.

Any thoughts on what to build would be greatly appreciated.

Andrew

[oscarv]

Andrew,

Post by Andrew Bingham
First, a little background on myself.... I was born in 1985, so most
vintage computers are older than I am. But my family wasn't into
technology when I was a child, so the first computer that we had was an
original IBM 5150 that was gifted to us...in 1994.

Well, I'd say that classifies as serious Vintage Computing roots!

The Model F keyboard
Ooh yes. Clickety Clack. I just upgraded to that keyboard again. At home -
in the office I'd get some noise complaints.

I'm leaning towards either

Post by Andrew Bingham
-The Xi 8088 based on my past experience with DOS and 8088s
-The Zeta based on it's relative simplicity and self-contained-ness and
ease of getting started - but I'd have to learn CP/M for the first time
Personally I'd love to go one iteration back in time and build an S-100
system because there are so many options as far as boards, but it looks
like the PCB availabiity is a bit more intermittent due to less demand
there. I like the idea of the S-100 8086 or 80286 running DOS.
Any thoughts on what to build would be greatly appreciated.

Very subjective answer:

I'd be biased in favour of the Zeta (if you want an all-in-one stand-alone
computer) or the N8VEM SBC (if you expect to add special functions).

With the Zeta, it really comes to its own when you add the ParPropPort
add-on board. You can hook it up to VGA, PS/2 keyboard (or go
clackety-clack with your Model F keyboard with a little adapter) and
experience the CP/M era that came just before your 5150 roots.

CP/M is rather simple to master, certainly if you've grown up with DOS. PIP
instead of copy, and USER instead of subdirectories. That's the main
difference at the command line. CP/M is much more small-scale of course,
and that's the charm of it. Understanding the OS from its guts is much
easier than it is for DOS. And there's plenty of good software that eeks
out the maximum of 64K RAM. See this booklet (link - click first black
button there) <http://obsolescence.wix.com/obsolescence#!n8vemimage/c1v04>on some of the software that runs straight away on the Zeta/N8VEM SBC. But
my point would be - this gives you the history leading in to the 5150 you
know already.

But then, there's no right choice. I secretly plan an Xi build soon.

Going S-100 is arguably the Coolest Thing (if there is such a thing as Cool
in this hobby, not sure there is). But it becomes a much more ambitious
project with the power supply complications, finding a good case - I'd
reserve that for later on if the homebrewing bug does not recede...

Regards,

Oscar.

[Andrew Bingham]

At one point, the Epson Equity 1 8088 we had was hard crashing with memory
read errors every so often. So I used debug.exe to "read" different memory
locations until I isolated the crash to a single, narrow set of memory
addresses (I had a DOS book with an intro to assembly/debug.exe chapter)

Then I asked my dad go to a computer repair place. They gave him a giant
bag of old DIP memory chips they had pulled out of dead systems for free.
We went through the motherboard and pulled them one at a time and replaced
them with chips of the same capacity, until the error went away.

I think I was somewhere between 10-12....

I ended up going into mechanical engineering but the knowledge I gained
playing with the old machines is useful to me to this day in my job.

Andrew

Post by oscarv
Andrew,

Post by Andrew Bingham
First, a little background on myself.... I was born in 1985, so most
vintage computers are older than I am. But my family wasn't into
technology when I was a child, so the first computer that we had was an
original IBM 5150 that was gifted to us...in 1994.

Well, I'd say that classifies as serious Vintage Computing roots!
The Model F keyboard
Ooh yes. Clickety Clack. I just upgraded to that keyboard again. At home -
in the office I'd get some noise complaints.
I'm leaning towards either

Post by Andrew Bingham
-The Xi 8088 based on my past experience with DOS and 8088s
-The Zeta based on it's relative simplicity and self-contained-ness and
ease of getting started - but I'd have to learn CP/M for the first time
Personally I'd love to go one iteration back in time and build an S-100
system because there are so many options as far as boards, but it looks
like the PCB availabiity is a bit more intermittent due to less demand
there. I like the idea of the S-100 8086 or 80286 running DOS.
Any thoughts on what to build would be greatly appreciated.

I'd be biased in favour of the Zeta (if you want an all-in-one stand-alone
computer) or the N8VEM SBC (if you expect to add special functions).
With the Zeta, it really comes to its own when you add the ParPropPort
add-on board. You can hook it up to VGA, PS/2 keyboard (or go
clackety-clack with your Model F keyboard with a little adapter) and
experience the CP/M era that came just before your 5150 roots.
CP/M is rather simple to master, certainly if you've grown up with DOS.
PIP instead of copy, and USER instead of subdirectories. That's the main
difference at the command line. CP/M is much more small-scale of course,
and that's the charm of it. Understanding the OS from its guts is much
easier than it is for DOS. And there's plenty of good software that eeks
out the maximum of 64K RAM. See this booklet (link - click first black
button there)<http://www.google.com/url?q=http%3A%2F%2Fobsolescence.wix.com%2Fobsolescence%23!n8vemimage%2Fc1v04&sa=D&sntz=1&usg=AFQjCNGBgsypUsEC0S1ZnoiGCwJo1Rd0AA>on some of the software that runs straight away on the Zeta/N8VEM SBC. But
my point would be - this gives you the history leading in to the 5150 you
know already.
But then, there's no right choice. I secretly plan an Xi build soon.
Going S-100 is arguably the Coolest Thing (if there is such a thing as
Cool in this hobby, not sure there is). But it becomes a much more
ambitious project with the power supply complications, finding a good case
- I'd reserve that for later on if the homebrewing bug does not recede...
Regards,
Oscar.

[Sergey]

Oscar:

Is it your site (http://obsolescence.wix.com/obsolescence)? I am VERY
impressed. Extremely informative...
The demo disk is especially useful. I wanted to build something like this
myself :-)
... I also owned a Suzuki Swift '85... it was a nice car (for my student
years anyway)...

Andrew:
For the beginning I'd start either with Zeta SBC or N8VEM SBC V2 they are
much simpler systems than Xi 8088. Also they could work standalone with a
terminal, while for Xi 8088 you'll need to find or build various additional
hardware: display controller, floppy/hard disk controllers, backplane, etc.
But then if you're feeling nostalgic for a 8088 system - Xi 8088 is a good
choice.

Choosing between Zeta SBC and N8VEM SBC - In my own (very biased) opinion
Zeta SBC is easier to build, but then N8VEM SBC is much more extendable.
Depends what you want to do with the system.

Thanks,
Sergey

Post by oscarv
Andrew,

Post by Andrew Bingham
First, a little background on myself.... I was born in 1985, so most
vintage computers are older than I am. But my family wasn't into
technology when I was a child, so the first computer that we had was an
original IBM 5150 that was gifted to us...in 1994.

Well, I'd say that classifies as serious Vintage Computing roots!
The Model F keyboard
Ooh yes. Clickety Clack. I just upgraded to that keyboard again. At home -
in the office I'd get some noise complaints.
I'm leaning towards either

Post by Andrew Bingham
-The Xi 8088 based on my past experience with DOS and 8088s
-The Zeta based on it's relative simplicity and self-contained-ness and
ease of getting started - but I'd have to learn CP/M for the first time
Personally I'd love to go one iteration back in time and build an S-100
system because there are so many options as far as boards, but it looks
like the PCB availabiity is a bit more intermittent due to less demand
there. I like the idea of the S-100 8086 or 80286 running DOS.
Any thoughts on what to build would be greatly appreciated.

I'd be biased in favour of the Zeta (if you want an all-in-one stand-alone
computer) or the N8VEM SBC (if you expect to add special functions).
With the Zeta, it really comes to its own when you add the ParPropPort
add-on board. You can hook it up to VGA, PS/2 keyboard (or go
clackety-clack with your Model F keyboard with a little adapter) and
experience the CP/M era that came just before your 5150 roots.
CP/M is rather simple to master, certainly if you've grown up with DOS.
PIP instead of copy, and USER instead of subdirectories. That's the main
difference at the command line. CP/M is much more small-scale of course,
and that's the charm of it. Understanding the OS from its guts is much
easier than it is for DOS. And there's plenty of good software that eeks
out the maximum of 64K RAM. See this booklet (link - click first black
button there) <http://obsolescence.wix.com/obsolescence#!n8vemimage/c1v04>on some of the software that runs straight away on the Zeta/N8VEM SBC. But
my point would be - this gives you the history leading in to the 5150 you
know already.
But then, there's no right choice. I secretly plan an Xi build soon.
Going S-100 is arguably the Coolest Thing (if there is such a thing as
Cool in this hobby, not sure there is). But it becomes a much more
ambitious project with the power supply complications, finding a good case
- I'd reserve that for later on if the homebrewing bug does not recede...
Regards,
Oscar.

[oscarv]

Sergey,

Post by Sergey
Is it your site (http://obsolescence.wix.com/obsolescence)? I am VERY
impressed. Extremely informative...

Well... You're probably only impressed because you don't know the Wix web
site service - it's one of these point & click web design hosts. Great
looks without doing much yourself. It is very Uncool not to do the whole
HTML setup yourself but I was lazy and wanted to spend my time on writing
content, not HTML code.

The demo disk is especially useful. I wanted to build something like this

Post by Sergey
myself :-)

I should release a new version asap - I now also added the full Z-System
(which really transforms the OS experience on the Zeta/N8VEM, it really is
amazing) and need to bring the disk image generation under Wayne Warthen's
batch code structure.

... I also owned a Suzuki Swift '85... it was a nice car (for my student

Post by Sergey
years anyway)...

Ah, the Swift... great little car - I wish I still had it. But safety-wise,
better to forget about it. The last seconds of driving it taught me the
benefits of owning full-size cars :)

Regards,

Oscar.