Date: Tue, 2 Nov 2010 14:22:48 -0400
From: Dan Roganti <ragooman at gmail.com>
Subject: Re: TTL HEX LED driver chip
On Tue, Nov 2, 2010 at 2:06 PM, Chuck Guzis <cclist at sydex.com> wrote:
> On 2 Nov 2010 at 13:33, MikeS wrote:
>
>> There's that ubiquitous string instrument again (I guess if it were a
>> girl's name it'd be in caps?), mysteriously in reference to a
>> hexadecimal display this time...
>
> I've long wondered if the Germans exclaim "Bratsche!"
>
> --Chuck
> (not giving in to repeating a very long list of viola jokes)
>
isn't this attributed to deep seeded oppression of diodes versus just a typo
;)
++++++++++++++++++++++++++++++++++++++++++++++++
Aw come on now, that's not fair!
I think I can speak for Chuck as well when I say unequivocally that although
we may have inadvertently stepped on and crushed (or exceeded the PIV of)
one or two we have never oppressed a single diode in our entire lives,
whether deep seededly (sic) or not; as a matter of fact I love the little
buggers, silicon or germanium, Schottky or not, high power or low power and
all powers in between, equally and without prejudice, and have assembled
many little teams of them in matrices on the outputs of a demux chip to
solve problems like this in a simple, straightforward, low power (and cheap)
way.
mike
In particular, the MRA42P solder cup 42 pin "winchester" plug for
Diablo 31 disk drives.
parts scalpers are asking $75 ea, and have made web searching useless
looks like on-line surplus store catalogs have all but disappeared
Date: Tue, 02 Nov 2010 06:36:07 -0700
From: "Chuck Guzis" <cclist at sydex.com>
Subject: Re: Amstrad 3in drive spares
>A word of caution here--observe that the 4-pin power connector looks
exactly like a standard 3.5" conector, but the +12 and +5 leads are
interchanged. If you try to use a power connector wired for a 3.5"
drive, you'll make magic smoke.
+++++++++++++++++++++++++++++
WHOA! Now that's a pretty harsh way of making sure folks only use your
proprietary drive...
Date: Tue, 2 Nov 2010 09:03:41 -0400
From: Dan Roganti <ragooman at gmail.com>
Subject: Re: TTL HEX LED driver chip
<snip>
>But I like the last solution even more, 2 chips, 74247, 74138, transistor
>inverter, a few diodes, viola !
++++++++++++++++++++++++++++++++++++++++++++
There's that ubiquitous string instrument again (I guess if it were a girl's
name it'd be in caps?), mysteriously in reference to a hexadecimal display
this time...
;-)
Haven't tried looking for this in a while, maybe one has shown up somewhere
AMS 315 14" 300mb winchester service manual (circa 1982) preferably with Trident
interface (SMD was more common)
I'll be putting up the product manual and brochure for it on bitsavers today
>So I have these 2 PDP-8/L core stacks I am trying to recover:
> Is there any realistic way of getting one fully functional stack out of
> these ?
>
I assume the 8/L core stack is the same as the 8/I. Its made up of 3 core
plane boards and the 2 diode boards. If you can figure out if one of
the planes in the really bad stack seems good you could swap it with the
other stack.
>One would be perfect, if bit 3 @ adr 0 would be alive...
>
If you haven't you may want to check memory current and strobe timing to see
if its totally dead or can be adjusted back to working.
On 2010-10-27 06:20, William Donzelli<wdonzelli at gmail.com> wrote:
>> > 1.> The PDP-11 was in architectural ways more important than the VAX, if
>> > ?> nothing else than just because the VAX was basically just extending the
>> > ?> PDP-11.
> Just to throw another question into the fire:
>
> Just how important was the PDP-11 or VAX-11/780 hardware architecture
> in the grand scheme of things? Did either machine really bring
> anything new to the table?
I honestly don't know.
The PDP-11 have been attributed with the common I/O and memory bus
(Unibus), with memory mapped I/O as well as the concept of condition
codes. Also the general registers with a nice set of addressing modes to
use on them. And we should probably not forget having the PC as just a
general register (although few, if any, picked that one up). So the
PDP-11 can be used as a accumulator-based machine, a memory-memory based
machine, or a stack based machine. It's possible to implement all
concepts found in architectures at that time easily on the PDP-11.
The basic PDP-11 architecture was deigned so that if an instruction took
an argument, any kind of argument was equally valid.
But as usual, the question is: was really the PDP-11 first with these
things, or can you find earlier examples?
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
Date: Sun, 31 Oct 2010 14:22:35 -0400 (EDT)
From: "O. Sharp" <ohh at panix.com>
Subject: Re: Repairing core memories....
On Sun, 31 Oct 2010, Jos Dreesen wrote:
> So I have these 2 PDP-8/L core stacks I am trying to recover:
>
> One would be perfect, if bit 3 @ adr 0 would be alive...
> Although this is 99.99% OK, it is of course not good enough.
<snip>
I suspect I'm not the only one on the list who:
-thinks opening up a core-stack and repairing it is
theoretically possible;
-also thinks it would be a hell of a daunting project;
-is somewhat amazed at the dexterity and patience of the people
who originally hand-wired them at manufacture; and
-thinks pulling off a repair of a core-plane by rewiring it by
hand would give significant bragging rights. :)
-O.-
+++++++++++++++++++++++++++
Agreed ;-)
But if anybody does want to, I've got a small (220x16) MDS (Fabri-Tek) core
plane with an already damaged section, cut-off edge connectors etc. to
practice on; for even more fun I could even throw in a few of two different
sizes of raw cores...
mike
Trying to get back into the scanning groove - got shelves of manuals
that need to become bits instead of paper. These two aren't going to
burn up the Internets but they're now merged with the digital
infinite:
Land Innovation Site Computation and Design for HP 86/87:
http://chiclassiccomp.org/docs/index.php?dir=%2Fcomputing/LandInnovation
An unknown, unsourced disassembler dump of the SOL20 boot ROM:
http://chiclassiccomp.org/docs/index.php?dir=%2Fcomputing/ProcessorTechnolo…
Neither of these were original documents and were in somewhat bad
shape, so the originals are out the door. Other stuff I'm scanning I
will keep as relics, but most will be offered up (most for free) after
they're scanned.
-j
--
silent700.blogspot.com
Retrocomputing and collecting in the Chicago area:
http://chiclassiccomp.org
