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-------- Original message --------
From: "Ian S. King" <isking at uw.edu>
Date: 2016-11-29 7:19 PM (GMT-08:00)
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: Thinking about acquiring PDP stuff
On Tue, Nov 29, 2016 at 5:17 PM, Brad H <vintagecomputer at bettercomputing.net
> wrote:
>
>
> That sounds interesting.? I imagine they'd be worth even more than an 8/E?
>
>
> Keep in mind that the 8/I is a fairly substantial investment in space and
weight.? Also, if you want to add something, it's not as easy as plugging a
card into a backplane.? The 8/I requires wirewrap work.
--
Ian S. King, MSIS, MSCS, Ph.D. Candidate
The Information School <http://ischool.uw.edu>
Dissertation: "Why the Conversation Mattered: Constructing a Sociotechnical
Narrative Through a Design Lens
Archivist, Voices From the Rwanda Tribunal <http://tribunalvoices.org>
Value Sensitive Design Research Lab <http://vsdesign.org>
University of Washington
>There is an old Vulcan saying: "Only Nixon >could go to China."
I'm curious.. what do people do with these things? ?I've seen videos of some in large racks being used to play music, etc. ?The rack ones seem like a a pretty substantial investment in space for something that doesnt (or does it?) have much practical use today.
> From: Peter Coghlan
> Can anyone suggest an existing, simple QBUS device that I could study
> the documentation of to figure out what a basic QBUS device needs to
> have and to give me some ideas on how to implement one?
Depends. Do you want to be able to do interrupts? Do you want to be able to
do DMA? Each is a significant increment in complexity.
Later DEC QBUS devices may not be the best things to look at, since they tend
to use special DEC QBUS control chips (I'm _not_ talking about bus
transceiver chips here) which are of course no longer available.
If all you want is master/slave (i.e. the ability to read/write registers),
try this:
http://ana-3.lcs.mit.edu/~jnc/tech/QSIC/test.pdf
It implements a single 16-bit register. (Changing it to support a single
block of registers would of course be trivial.)
The switches (and associated comparators) in the lower left allow one to set
the bus address it responds to; the 3 latches on the right hold the register
contents; the drivers/buffers below them drive LEDs to display the register
contents. The control logic is about as simple as it can be; one latch, and a
couple of gates.
You should probably read the QBUS description in any QBUS PDP-11 manual
before attempting to understand it, but having done that, it should be pretty
self-explanatory - the signal names should clue you in to what they mean.
> From: Glen Slick
> I have an M9405-PA. It has one male and one female 3-row 50-pin
> D-shell connector.
That's on the metal plate, right? The board itself should have a 2x25
Berg header.
Noel
> From: Brad H
> I was thinking about trying to acquire something early 70s...
Anything DEC early 70's is going to be fairly expensive, alas. Only once one
gets to QBUS -11's does the price come down.
> if it is feasible to buy in pieces .. but is dependent on parts
> availability
I would not recommend this route. Those machines are a lot of bits and
pieces, and if you buy a few, unless you're incredibly lucky, it will take
forever for the rest of them to show up. There will be a few things that just
never show. (Even when buying a 'complete' system, one will often find that
it has been robbed of a few critical components, probably cannabilized to
keep another machine running BITD.)
There might be a rare exception (I see the guys in Mahwah selling a PDP-8
chassis, and also a front panel with switches, and it _might_ be possible to
round up all the boards - but that's more like the exception than the rule.)
Noel
Did you end up trying anything yet? Isn't there some requirement for a working battery for it to power on or was that just the power routing through the battery so a corroded one isn't a simple run without it fix?
-------- Original message --------From: Chris Pye <pye at mactec.com.au> Date: 11/26/16 12:26 AM (GMT-06:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Macintosh Portable
Does anyone know off hand what polarity that Mac Portable requires? I know that the original was 7.5V @ 1.5A, but not sure of the polarity.
That sounds interesting. ?I imagine they'd be worth even more than an 8/E?
Sent from my Samsung device
-------- Original message --------
From: william degnan <billdegnan at gmail.com>
Date: 2016-11-29 5:13 PM (GMT-08:00)
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: Thinking about acquiring PDP stuff
On Tue, Nov 29, 2016 at 7:28 PM, jim stephens <jwsmail at jwsss.com> wrote:
>
>
> On 11/29/2016 3:51 PM, Noel Chiappa wrote:
>
>> There might be a rare exception (I see the guys in Mahwah selling a PDP-8
>> chassis, and also a front panel with switches, and it_might_? be possible
>> to
>> round up all the boards - but that's more like the exception than the
>> rule.)
>>
>>???????? Noel
>>
> He sold the boardset first, now has broken up part of the rest. parts of
> the backplane were sold earlier as well.
>
> I've watched this vendor for a while and bought some things, which were
> clean.? He also sold a complete 8/E
> recently and as noel said, went for $$$
>
> thanks
> Jim
>
I am working on liberating 10 PDP 8i's...but the guy has fallen off comms.
I plan to make a trip to the location, see what I can do.? I don't want
these, just want to help find a good home for them.
b
I saw one in a thrift shop years ago... I seem to remember Woz a
stenciled on or printed on
In a message dated 11/29/2016 6:40:43 P.M. US Mountain Standard Time,
ian.finder at gmail.com writes:
I believe the "Woz" edition was actually produced in greater quantities
than the normal one.
Either way, even if it were a real signature- Woz is known to have low
enough standards with a sharpie that his autograph may in fact devalue
an item!
- Ian
On Tuesday, November 29, 2016, Electronics Plus <sales at elecplus.com> wrote:
> http://dallas.craigslist.org/ndf/sys/5890446928.html
>
>
>
>
>
>
--
Ian Finder
(206) 395-MIPS
ian.finder at gmail.com
> From: Peter Coghlan
> Interrupts would be great to have
If you decide you need interrupts, the DLV11 (MP-00055) has a simpile
interrupt circuit built out of flops and gates.
> However, I am puzzled by the BPOK and BINIT signals being connected to
> U7 even though they do not seem to get used ... I wonder is this just
> because two tranceivers were left over and they might as well have
> something connected to them that might come in handy later or is it
> because I am failing to understand something properly?
Neither, but your first one is close! :-)
Actually, that design started as a CAD file (for KiCAD) that I got from Dave
B; I munged on it until it was what I wanted. Those two signals were
connected to that transceiver in Dave's original circuit; my design doesn't
(as you discovered) actually use BPOK or BINIT, so they just stayed connected
up, but unused.
> there are rather more than 50 QBUS signals listed on the top right of
> the circuit diagram.
As Glen indicated, it actually takes 2 50-pin connectors.
> I suppose the power rails and those labeled "spare" are likely
> candidates for omission.
I don't think they'd have carried power through that connector. The spare lines
might well be connected through.
I haven't checked the pinout of the 50-pin Berg headers (which were the
original, the 'D' connectors came later), but if they followed UNIBUS
precedent, every other wire in the flat cable will be a ground, to help
minimize cross-talk between lines with signals on them.
> I was hoping that there would be lots of signal pairs like SCSI
Well, the QBUS wasn't designed to go through a cable, originally it was
backplane only; so it doesn't have differential pairs, or anything like that.
Noel
Might already be gone, located in Longmont near Denver. Give him a call!
$25 - Epson DXF5000 ( Longmont ) near denver
We have some wide carriage dot matrix printers. They work and they are worth
next to nothing.
Come and get them intact or search the dumpster for parts
If I have to throw these IBM, Epson and OKI dot matrix printers in the trash
- they will be in pieces no larger than a candy bar. I promise to break them
up so that no one can ever use them.
I might give them away for free, but our dumpster will contain tiny bits if
you think waiting is the better plan
303-651-7919
634 Main Longmont
