I have a duplicate copy of "The Computer Technician's Handbook",
by Brice Ward, TAB No. 554, 1971.
The first half of the book is a convetional treatment of basic
digital logic theory, logic families, and such, with an emphasis
on the 8200 series. The second half of the book is more interesting.
It is a "case study" of the Computer Automation PDC 808, complete
with a description of the architecture, logic diagrams, a detailed
walkthrough, timing diagrams, scope waveforms, etc. Much of it
looks like it was probably lifted from the manufacturer's service
manuals. The PDC 808 was an 8-bit minicomputer (yes, 8-bit)
introduced in 1968. It appears to have a family resemblance to the
16-bit PDC 816, and more closely resembles the traditional 16-bit
"stretched PDP-8" minicomputer style rather than most of the later
8-bit architectures seen in microprocessors.
The bookseller rated this book in "very good" condition. It is clean
with a tight binding, with some wear on the cover and a small crease.
I paid $7.00 for it. I'll sell it for that plus shipping.
--Bill
Hey,
I ran accross one of your newsgroup posts on the internet the other day. I
bought a northgate ZX off Ebay, and have found it difficult to find the A/C
Adapter, can you give me any advice to locate one for sale, or perhaps where
to buy the connector, so far, It seems nobody has anything compatible which
would power the computer.
Now I guess I know why the guy selling it was so eager to get rid of it,
lol....
Thanks for your help, Michael
_________________________________________________________________
Don’t just search. Find. Check out the new MSN Search!
http://search.msn.click-url.com/go/onm00200636ave/direct/01/
I think Sellam absolutely did the right thing!!! A number of people here
in Santa Barbara have passed away with significant classic computer
related items. For one example, many of the IBM 1130 and Burroughs
manuals that Al has scanned came from someone who had worked with these
things for close to 40 years. *ALL* of those manuals were destined for
the recycle bin. The only reason they got saved was a friend of mine
called me after he saw them when he was picking up other equipment
there. I called his wife and was invited to come over and take what I
wanted (I took everything!) When I saw her again a couple of months ago,
his wife was very happy to hear that they have proved useful to others.
A friend of mine passed away many years ago, and I was called to see if
I would help with the stuff. He had been involved with microcomputers
>from the first, and his father knew nothing of the value of this stuff.
Of course, at that point in time, a lot of classic stuff was still
deemed junk and went to that great storage space in the sky. Out of that
came an almost complete set of (can't remember the name right now)
cassette programs for the TRS-80 that were mailed out on a subscription
basis along with many of the docs and associated correspondence (he was
also an editor for a bit.) There were also boxes of documentation for
other now classic computers.
There are many such stories by myself and others on this list. I don't
know where you and your wife are coming from, but the main focus of most
of us on this list is saving classic computer related hardware,
software, docs, etc. And many of us have irreplaceable items as most
likely Don did. Again, Sellam did the right thing, and I am reasonably
sure it was also what Don would have wanted.
> On 19/09/2004 Sellam Ismail wrote:
> >I made an initial phone call to Don's number and got an answering machine
> >(presumably Don's voice is still on the OGM). I chose not to leave a
> >message. I'll try again later today.
>
> Sellam, I'm shocked by your lack of tact and respect. No matter how
> important Don's collection might be in your eyes, you shouldn't lose
> sight of the fact that his wife and family have just lost him. They
> probably couldn't care less about what happens to his stuff in the
> garage at this point.
>
> I've asked my wife for her opinion on this and she said that she
> would instantly scrap and toss my stuff if she ever found herself in
> a similar situation. I can't blame her.
>
> What do others think of this ?
>
> Greetings, Jos
Hi there
I saw your posting. I think I know where I can pick up these
Regulators. Do you have the datasheets / pinouts so that I can test them?
Venkat VU2KV
A short update on the collector's list which I maintain here :
http://www.geocities.com/computercollectors/
(Paul and Jerome, if you read this, I need your current email address
as the ones I have keep getting bounced.)
If other collectors want to be on this list, check it out to see if it
is in a format you wish to be associated with, and email me here :
antiquecomputers(a)hotmail.com
Don't reply to the list or to this address (I'll miss it)
with a complete listing of your address, email, phone number (if you
want) and list of interests in the computer collecting area.
Thanks.
We now return you to our regularly scheduled programming.
BM
At 22:50 23/09/2004, you wrote:
>On Wed, 2004-09-22 at 11:17 -0700, Vintage Computer Festival wrote:
> > On Wed, 22 Sep 2004, Jules Richardson wrote:
> >
> > > Apologies if someone's mentioned this one before. Quite possibly the
> > > coolest gadget I've seen in a long time, though:
> > >
> > > http://www.cyberniklas.de/pongmechanik/indexen.html
> >
> > Awesome. It would be great to get stuff like this exhibited at the VCF.
> >
> > The web page is pretty smart also. What terrific technical and design
> > work.
>
>Amazing, huh? If I read that right, it's 52 relays though (I don't know
>any German) which makes it sound rather like a 'simple' relay control
>system rather than an actual relay computer. I fired off an email to
>them to see if they'll let me have a nose at the wiring diagrams.
I did some back-of-a-fag-packet calculations (i.e. they might be completely
& utterly wrong, in which case I'd appreciate corrections) on a relay
computer...
Assume you want a Z80-type CPU. This has ~8k gates. Typically, it seems to
take 1 relay per input to implement any given gate. Now, I don't know how
many "x-input" gates there are in a Z80, so I'll assume that - on average -
it will require 3 relays/gate. Thus, we need ~24,000 relays to implement
the Z80.
If each relay needs, say, 25mA @ 6v to operate, then the peak current draw
of our R80 (as I shall call it) could be around 600A (I think). And that's
before we've added memory, i/o, etc.
As for the heat/noise - well, IMHO it's worth building it just to
experience that! Mind you, you'll need a lot of room: If you use 30mm by
13mm relays, then the board space you need is at least 9.36 square
metres... Still, if you assume that each board needs approx 40mm of space
incl. airflow room, then you should be able to fit the R80 into 2 400mm by
400mm by 2000mm cabinets (internal w/d/h)...
The relays I've been looking at typically quote around 25ms to operate
(either way), so I don't see how you could clock the R80 at anything faster
than around 40Hz; and you'd probably want to drop to 20Hz to be on the safe
side. The same relays quote a typical lifetime of 10e7 operations; so at
20Hz, your R80 should last a little under 139 continuous hours of operation
before relays started failing...
Creating a screen driver should be interesting....
Question: Wouldn't it be easier to implement an OR gate with no relays at
all (just two wires joining together)? Or would you need to use the relays
to keep the output voltage/amperage regulated?
Additional: Hunting around for a suitable CPU to implement in relays, I
came across the P8 CPU design (http://www.rexfisher.com/P8/P8_TOC.htm).
This uses a 74LS181 4-bit ALU, which I reckon would require 149 relays to
replicate. The only thing that confuzzles me is: what use, exactly, is a
1-input AND? Several of these appear on the 74LS181 schematic...
Cheers,
Ade.
This looks neat. This guy also has a 1920's "addometer" and a 1890
Stephenson adder.
http://cgi.ebay.com/ws/eBayISAPI.dll?
ViewItem&category=1247&item=2272912817&rd=1
I'm not affiliated with seller.
Mike
Still on my Pong trip, here.. :-)
Can anyone tell me how the original Atari arcade Pong (and probably the
home version too) interacted between the bat and the ball? (Anyone got
one they can hook up and try?)
I've found one reference that says the bats were split into 8 segments;
but when the ball hit the bat, was the resulting direction of travel
influenced *only* by the bat segment hit, or also by the direction of
travel at the collision point?
Presumably if the ball hits the bat at the nearmost end, then the ball
is returned in the exact opposite direction (i.e. reflected back along
its path by a simple reverse of direction). But what about the other 7
positions?
cheers,
Jules