Subject: Re: Mark-8 Minicomputer Kit on E-bay

From: "Jim Kearney" <[email-masked]>
Date: Thu Mar 13 14:35:56 2003

>From: "Heinz Wolter" <[email-masked]>
> Parts?- not quite so trivial to find. 8008's go on ebay often - but do
they
> work?
> Though you might salvage a plastic 8008 from an 11/34 or pdp8a (??)

'New' and working 8008's are not that hard to come by.  I recently bought 15
of them for a project (http://www.jkearney.com/tiny8demo/) and could get
more if necessary.  Not cheap, though.

> If you were building a totally modern work alike - an all fpga solution -
cpu+rom+ram
> would be more interesting than yet another 8008 using LS/HC TTL and CMOS
static rams.
> 8008 on a PLD anyone?

This would be a fun project.  I did a design (but haven't built) of a Mark-8
using an FPGA and an 8008.  The 8008 could be omitted and implemented in the
FPGA, but I think it's fun to use the actual old processors:
http://www.jkearney.com/8008/uMark8.htm

Jim

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From: "Jim Kearney" <[email-masked]>
Date: Thu Mar 13 14:37:07 2003

>From: "ben franchuk" <[email-masked]>
> I still would like to know how you debounce the
> front pannel.

Look at the VHDL file debounce.vhd.  It is a simple but effective digital
debouncer.

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From: "Jim Kearney" <[email-masked]>
Date: Thu Mar 13 14:38:33 2003

> Look at the VHDL file debounce.vhd.  It is a simple but effective digital

p.s. check out this Maxim appnote:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/287/ln/en

It's an implementation of the same idea.

---

From: Ethan Dicks <[email-masked]>
Date: Thu Mar 13 14:42:32 2003

> > Though you might salvage a plastic 8008 from an 11/34 or pdp8a (??)

I have a ceramic 8008 on an 11/34 console board sitting in a pile.  I
could certainly borrow it for this application.  I've been thinking of
a Mark-8, but I will probably never have enough time to build an original.
This one (or the uMark8) sounds feasible.
 
> 'New' and working 8008's are not that hard to come by.  I recently bought
> 15 of them for a project (http://www.jkearney.com/tiny8demo/) and could
> get more if necessary.  Not cheap, though.

How much is "not cheap"?  $50?  More?

Would you consider a group buy of the Tiny-8 design?  I doubt I'd want to
build one at prototype-PCB costs.

-ethan

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From: "Jim Kearney" <[email-masked]>
Date: Thu Mar 13 14:42:44 2003

>Ethan Dicks wrote:

The last quote I had (a few months ago) was $40 ea for NOS C8008's in 20
qty.

> Would you consider a group buy of the Tiny-8 design?  I doubt I'd
> want to build one at prototype-PCB costs.

Sure, and since the fab still has the masks etc. saved (I hope), there would
be no NRE, so they would only cost around $15 each in qty 20.  I also have a
stock of most of the parts with datecodes <= 1980.

What happened last time was that I sold one on eBay and got a number of
private orders in addition due to the auction's advertising effect.

Jim

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From: Dan Veeneman <[email-masked]>
Date: Thu Mar 13 14:47:53 2003

At 10:44 AM 3/12/03 -0800, you wrote:
>Point taken but even if you were to build a Mark-1 you'd really only need
>the original issues of Radio-Electronics.  You can get those for under
>$200 on eBay or free if you find someone willing to scan the pages.  With
>the exception of the 8008, the rest is trivial.

I have the original Radio-Electronics issue (July 1974) with the Mark-8
article by Jonathan A. Titus.  I'll be happy to sell it someone for $200.

The article itself is only five pages.  Readers were asked to send $5
plus postage to R-E in New York to receive a 52-page package of
"complete construction details, more data on how it works, a group
of eight experiments you can perform with the computer and other
important information."

Jon Titus' article goes on to describe the six different modules
(Main CPU, Memory Address, Input Mux, Memory, Output and Readout)
and an interface to the TV Typewriter (from R-E, September 1973).
It also provides a parts list, power requirements (+5 VDC at 3 amps
and -9 VDC at 1.5 amps), and a software example.

It's all interesting reading and goes in to a fair amount of detail,
but construction would require the 52-page plans, not just the
R-E article.

As a point of reference, the parts list indicates that a complete set of
circuit boards were available from "Techniques, Inc." of Englewood,
New Jersey, for $47.50.

Regarding the 8008 microprocessor, the article has a footnote:

For more detailed data on the Microprocessor IC write to
Intel Corp., 3065 Bowers Ave., Santa Clara, Calif. 95051 - ask for a
copy of "8008, 8-Bit Parallel Central Processor Unit-Users Manual."
This manual was offered free at the time this article went to press.

Hope this helps.

Cheers,

Dan
www.decodesystems.com/wanted.html

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From: "Heinz Wolter" <[email-masked]>
Date: Thu Mar 13 14:48:04 2003

From: "Vintage Computer Festival" <[email-masked]>

> the exception of the 8008, the rest is trivial.

wrong.
the original magazine articles and pcb patterns contained several mistakes.
Parts?- not quite so trivial to find. 8008's go on ebay often - but do they
work?
Though you might salvage a plastic 8008 from an 11/34 or pdp8a (??)
keyboard console, the signetics 8267 and 8263 parts might not be that easy
to
come by. 1101 srams will also be a bit diffcult to find. the rest of the
jellybean
logic may be found by scrounging old boards, but forget Digikey and the
like.

I bought a basic kit- thankfully, the hard to get parts were provided, as
well as scans
of the mag articles including the corrections, and Mark-8 users group
newsletters.
If someone is interested in building boards or wirewrapping- feel free to
contact
me - perhaps we can put the files up somewhere. But for me, it was well
worth
my time and money to get the "modern" kit and not dick around looking for
parts.
Having paid less than 200$ for the basic kit incl pcbs and core chips, this
makes much
more sense to me than paying 200$ for magazines only. If you were building a
totally
modern work alike - an all fpga solution - cpu+rom+ram would be more
interesting
than yet another 8008 using LS/HC TTL and CMOS static rams. 8008 on a PLD
anyone?
H

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From: ben franchuk <[email-masked]>
Date: Thu Mar 13 14:48:15 2003

> http://www.jkearney.com/8008/uMark8.htm

Nice design , too bad the schematic is not PDF.
I still would like to know how you debounce the
front pannel.This looks to the best of both worlds
as a DUD 8008 could even be used and it would still work.

Ben.