I have a MicroVAX 3100 Model 95 (KA51) which seems to be damaging my SIMMs.
It will work for a while and then one or more SIMMs will fail. The failed
SIMMs have always been in SET 0. Sometimes it has been just one SIMM, this
time it seems to have been the whole set of 4.
Is it really possible for the CPU to do this?
Anyone got a KA51 they don't want?
Regards
Rob
Many of you will be familiar with the story of Mel, the Real
Programmer [ http://www.pbm.com/~lindahl/mel.html ]
in which Ed Nather (writing in 1983) relates his experience from 20
years previously in attempting to patch
a BlackJack program written by his ex-colleague (Mel Kaye) for the
ancient RPC-4000 computer, and how the complexity
of the code he had to work through left him so impressed with Mel's
familiarity with the inner workings of the
computer that he abandoned the attempt to patch the code and even 20
years later, he still held Mel as the archetype of a "Real
Programmer".
I first came across the story on a BBS sometime the early 90s, at a
time when I was just starting to become
competent with x86 assembly code, and self-modifying code was a pretty
fascinating idea, as was extreme performance
optimisation.
Then recently I came across the Mel story again, and went looking to
see what (if anything) of the legendary machines and codes
had made their way into the retro-computing archives across the net.
The 'holy grail' would be a copy of the
original BlackJack program with the back-to-front cheat option, and
major bragging rights would come from being
able to make the patch that Ed Nather had given up looking to make.
I'm not there yet.
What I have found so far is:
- What looks to be a dump of a paper tape copy of the BlackJack game
for the LGP-30, the predecessor to the RPC-4000
[ ftp://ftp.informatik.uni-stuttgart.de/pub/cm/lgp30/papertapes/Games/bkjck.tx
]
- A copy of the RPC-4000 reference manual, with description of
registers and opcodes
[ http://www.bitsavers.org/pdf/royalPrecision/RPC-4000/RPC-4000_Programming_M…
]
- Documentation for the RPC-4000 version of BlackJack, written by Mel
Kaye, including what seems to be a writeup
of the feature that Ed was asked to make work correctly ("PLAYING
CONVENTIONS...8:. If SENSE SWITCH 32 is depressed, there
is a better than normal chance of an ace being dealt as the player's
first card").
[ http://www.bitsavers.org/pdf/royalPrecision/RPC-4000/programWriteups/W1-01.…
]
>From looking at the opcodes in the programming manual, I believe that
the loop in question must have been based around
opcode 21 "COMPARE MEMORY GREATER", with the eventual 'overflow' to
opcode 22 (TEST MINUS). I don't know what
sort of work this loop would have been doing, although given the
program documentation clearly states program execution
starts at 00000, and that is also where (in the story) control is
eventually transferred to once the loop exits,
the loop must have been some kind of post-game cleanup, ready to
re-start. So my current theory is
- the data stored in the upper memory locations is the card deck,
(stored initially perhaps as numbers 1..52)
- as cards were "dealt" they were marked as such by (e.g.) setting the sign bit
- the loop without apparant exit is going through the pack removing
the 'dealt' marker, prior to being shuffled at the start of a new
game.
It is apparent that Ed's memory was not completely accurate; not
completely surprising given the 20 year gap from
when the events occurred until when they were documented. He mentions
the clue that helped him understand the
way the loop exited as being the fact that the index register bit was
set even though Mel never used the index register,
and says this index register bit is "between the address and the
operation code in the instruction word".
However reference manual is clear that the index register bit is the
least significant bit, and in fact the opcode
bits (0..4) are adjacent to the data address bits (5..16). I can't see
any way the index bit could have been part
of the loop/overflow.
ard at p850ug1.demon.co.uk (Tony Duell) wrote:
> All the religions that I've come across require oyu to beleive in
> that
> religious system to get to their idea of heaven. As an agnostic, I
> don't
> meet any such criteria. So if there is a hereafter, I am going to end
> up
> in hades...
>
> -tony
Assuming that religions actually know or really care about what their
particular deity thinks, says and/or means. IMO religions do not
necessarily represent their deity correctly, they are prone to
(mis)interpreting their own scriptures to suit their own personal
interests. If there is a hereafter, I would expect a lot of people to be
unpleasantly surprised after their deaths. However, we shall all find
out sooner or later :-D
/Jonas
I am passing this info on - I have no connection or further info:
-----------------------
Dave has for sale what looks like a complete IBM System/32 computer system near Omaha, NE.
It's describe as "From January 1975 - a low-end business computer."
Here's the IBM webpage:
http://www-03.ibm.com/ibm/history/exhibits/rochester/rochester_4017.html
See Dave's many fine photos of his system here:
http://picasaweb.google.com/IBMSystem32/
Contact HIM at:
ibmsystem32 at gmail.com
-----------------------
Found those capacitors. Yes, they were indeed the trio that were clustered
together. All the -ve sides clustered together, and the +ve wired to a
motor output connection just as you said.
I spent tonight extracting the IC and the capactors. It went surprisingly
smoothly considering this is probably the smallest circuit board I've worked
on in terms of closeness of tracks.
Now to just wait until the ICs arrive from Hong Kong. I hope it's not by
slow boat. I've ordered and paid for the ICs but have yet to hear any kind
of acknowledgement apart from the standard paypal reciept.
I've also bought an X/Profile emulator. Luckily I've managed to sell one
of my Osborne 1s for $340 NZ (about $255US) to help part-pay for it!
So, here's hoping BOTH Lisas will be up and running 100% soon!. An ominous
sign in the Lisa 2 though. Yesterday it would just suddenly switch off I
was testing this drive. A little jiggling and waiting a while, then a
switch on and it would suddenly go again. Could be something loose, or
could be the PSU starting to give up the ghost. I have a spare working (I
think) PSU, so I might have to call that into service....or attempt a repair
if that's indeed the problem.
Maintence/repair is an ongoing process with this old iron isn't it.
Terry
> Take a look at one of those HP drive schermatics I mentioned. If you are
> working from one of 'my' schematics, oyu want ot look at the sheet
> entitled 'Sony Floppy Drive Spindle Motor Sheet (3)'. You'll see the
> TA7259 chip. Connected to the inputs are the 3 hall devices H1-H3.
> Connected ot the outpus are the 3 motor windings -- notice how the other
> end of these windings are all linked together, but go nowhere else --
> that's the 'star' (or 'wye') configuration I was talking about. And just
> to the left of the widnigns are 3 capacitors C11, C12, C13 wired in
> another star circuit.
>
> I have no idea what the capacitors will be labelled on your PCB. They are
> likely to be a simular value. See if you can find 3 cpaacitors, arounf
> 10uF each, with the +ve side wired to a motor output connection on the
> chip and the 3 -ve sides all linked together. It might be the 3
> capacitors cludered just to the right of the chip in the photo, it might
> not. You cna use the resistance range of your multimeter to check what is
> connected to what, of course.
>
> Alas without the PCB in front of me (and thus being able to trace
> connections) I don;t think I cna be more definite.
>
> -tony
>
>
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1204 / Virus Database: 1435/3442 - Release Date: 02/13/11
>
I have one left, last 2 sold for $150, this one has quite abit of
yellowing and several lab stickers on it, therefore I am only asking $100.
It is fully functional, buyer to pay for actual shipping (or free local
pickup, I am in Chicago)
Feedle I were under the impression that the P112 kits from that last
bit we didn't know existed were sent out in January. An email from
someone wondering where his kit was the first hint that something was
wrong. Here is the email I got from Feedle regarding this problem:
===begin quote===
I'll ship him a kit on Thursday. I don't have the spreadsheet handy: send
me his address directly and I'll generate a label today for tomorrow's
mail run.
We may have a problem, however.
So, I handed the kits to the "[Person] Friday/Executive Assistant" at the
executive office suite I have my office at back in January. About a month
ago, I noted that there is a new person at that desk. I didn't think much
of it, but I remember overhearing a water cooler conversation about how
the previous one was fired.
I sent an E-Mail message yesterday to the EA role account asking if she
could look in the USPS account to see when they were shipped and what the
tracking numbers were.
"Oh, you didn't hear?" is never a good thing when starting this sort of
conversation. Apparently, the previous EA was fired in early February,
precisely because she was so bad at her job that .. well, she wasn't doing
it.
So, the short of it is, there's no tracking numbers for the packages sent,
if they were even sent at all. The only evidence that they have that the
packages I gave them even existed is the fact that when I dropped them off
she put them in the log for billing purposes (it's worth noting that my
internal account was charged for the flat-rate postage). There is no
record in either the Click N Ship account they use, nor in the paper logs
they keep for packages that are hand-handled and metered with the
conventional postage meter. Where the packages actually are is, at the
moment, an exercise left to the reader.
I'm now really worried: because according to my notes, that makes two out
of the eight (?) people who ordered kits from you who haven't received
them. In looking at the notes: I _DID_ ship Steve Hirsch a kit in that
January shipment.
I'm obviously not happy about this from the "services I'm paying for as a
tenant in a fairly pricey executive office center" perspective. The
Management has already assured me that they will compensate me somehow for
the lost materials... but I stressed upon them that the worst part is the
"one-of-a-kind" nature of the kits: that this was the tail end of a
production run, and I don't have enough parts to just make more. Plus,
there's the lost goodwill: you personally depended upon me to get those
kits shipped out, and I probably let you down.
Anyway, I'm going to meet with the office manager in a couple of hours to
have a more in-depth conversation about what can be done about this.
I'll keep you posted.
===end quote===
Since the email was sent, I had a phone conversation with Feedle about
this. The kits were found stashed in a cupboard along with some seventy
other packages this now ex office assistant never posted. So, you WILL
get your kits.
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
I read an AP article that says that Ebay will start charging as the Ebay
fee charge, not 10% of the selling fee or $50, whichever is less, but
rather 10% plus the shipping charges.
I would encourage everyone here who is selling a 300# printer for $50 to
take a close look at whether to sell anything on ebay anymore if this is
accurate.
I sort of sympathize with Ebay in trying to clamp down on the crop of
people who now have low prices (buy it for a buck) but $30 shipping costs.
However this move pretty much makes me want to pull everything I have,
as there will be a negative outflow on my account by my calculation for
my Wyse terminals ($40) etc. by the time I sell them. I'm not
interested in paying people to take my stuff.
Jim
A couple of months ago I asked about diagnosing problems with the
TOuchscreen board in an HP150.
Well, I took some time off that project [1] but finally got back to it. I
decided in the end to make a text unit that would plug into the
touchscreen PCB, produce the clock signal, accept the sync and data
signals and display the status of the 35 beams on LEDs.
[1] Sort-of classic computer related. I've been writing a set of articles
for HPCC on how to fix HP9800 machines.
Being me, I built it from TTL (actually HC and HCT parts). It only took
me a couple of afternoons do design and build it. It starts with a 4MHz
master clock, divided down with a couple of '393 counters. A '30 adn '138
produce a paair of spaced clcok pulses from this, a '02 combines one
ofthes with the sync signal from the tocuhscreen. These are all latched
in a '175 to procude 3 clocks -- the clock to the touchscreen PCB, a
clock to sample the data from the touchscreen PCB and an end-of-scan
pulse to latch the received data and send it to the LEDs. The data is
shifted into '4094 shift registers/latches whihc feed a couple of rows of
LEDs. The powrr supply stats as 12V from my bench supply. That feedsthe
+ve input of the touchscreen. A 7805 powes the logic and LEds inthe test
box. And a 7660A provides the -12V supply for the tocuhscreen PCB.
Anyway, after connecting it to the defective tocuhscreen PCB, I found
that one of the beams appeared to be blocked all the time. Blocking other
beams got the appropriate response from the test box, so I was pretty
sure the logic was all working properly.
Since I knew which beam was malfunctioning, I tested its IR LED in-circuit
with an ohmmeter (system powered down, of course, It read differnetly
>from the others either side of it, so I desoldered it and tested it out
of circuit. It's open.
So the guy who told me that the emitter (LED) was the most likely failure
was right.
Now all I need to do is find a replacement.
-tony
