> From: Mattis Lind
> Now I am convinced that if I program a new A04A2 PROM the machine
> should behave much better.
Indeed! I have annotated the PROM tables on the Computer History wiki page
with the function of each, and that PROM is the high part of the 'next
microinstruction' field, so if it's bad, the computer will be acting very
strangely indeed! :-)
> The failing chip was yet another NS chip in plastic
Can you see the type? I'd like to add to the page lists of all the alternate
chip types DEC used in place of the Intersil chips specified in the drawings.
>> the 'F' etch rev has one less PROM chip than the 'E' etch rev, but I
>> suspect .. that it's not a micro-program chip, though
My guess was correct; the missing chip is the one I called "Internal
interrupt acknowledge"; it was replaced with a 74154 4->16 demux.
Noel
This one has a failed BCACHE, but I am told it will still boot and run VMS,
albeit slowly. I have not tried this myself, but I have verified that it
boots to the console. It is in a BA42B enclosure (i.e. desktop not
rackmount).
Is there any interest or should I just take out the bits I want from it and
then throw it away?
It is in Manchester, UK. I do occasionally travel to the East Midlands and
to the Reading area though. Not keen on shipping it, but will do so if it
means not throwing it away. The machine is free, any shipping would have to
be paid for of course.
Regards
Rob
I want to read the DROM chip with my programmer, but I can't ID the chip. Does anyone know what kind it is? It is in a PLCC32 package and the label on it is:
369E7
AYOMA
49/95
I am sure at least some of that is DEC stuff, unrelated to the type of chip. However, none of those parts of the label seem to correspond to any EPROM I can find. My programmer's software has an auto detect feature, but that also failed to ID the chip. I don't really want to remove the label if I can avoid it.
The underside is marked
76394-23
Singapore
C4
522 (might be 322)
512X
None of these appear to match anything either.
Any ideas what it might be?
Thanks
Rob
> From: Mattis Lind
> Has anyone dumped the microcode of the PDP-11/05?
> ...
> When tracing the microprogram flow it looks very suspicious. Comparing
> the same sequence with a better working pair reveal a few differences.
> All these can be narrowed down to one single PROM chip.
Josh had an 11/05 that had a uROM fail, and he had to blow a new one (IIRC he
sent in a report, it's in the list archive). I'm not sure if it's the same one
as the one you need, but if his post doesn't give the chip ID, no doubt he can
let us know.
> There are microcode listings in the manual but they need to be treated
> to get into a dump.
Which is exactly what Josh did.
Speaking of which, is there any chance we can get those machine-readable
listings online? I can host them with my other DEC material, and I can also
put them in the Computer History wiki.
Noel
Request for information about a Facit 4070.
Yes, it can be hooked up to a parallel port interface. It takes a single 74LS00 chip to generate the proper signals, and the ACK signals. I did it in a simple jumper wire block (it has a male and female connector along with a jumper field.
At the moment I have lost my documentation, but I have a working unit ready to be dissected to produce the proper diagram (it may take a while). I have connected it to a "real" and a USB parallel port and used direct writes to the parallel port device under Linux with no modification.
Also if you are interested, I have a program that sends out block letters to be punched on the tape (along with leader). The letters are 5x7 and the 8th is the descender for lower case letters.
The various docs for the 4070 are on Bitsavers, and you want to be sure that the "option" board just has jumpers on it (as it comes from the factory).
Al mentioned the 940 so I thought I would fill in the details:
Lichtenberger and Pirtle extended the hardware to include a page map: 14
bits of VA was divided into 3 bits of page # and 11 bits of offset. The 8
pages were held in 2 x 24 bit words divided into a 8 x 6 bit page numbers.
The high order bit of the mapped page number served as the Read Only bit.
This meant that "subsystems" (a.k.a. applications) could be shared between
users.
Additionally, the instruction set was protected against users with specific
prohibition against using the I/O instructions.
This was described in FJCC 1965 with modifications done in 1964.
> From: William Degnan
>> I would need a dump of .. at least A04A2 / E102 on the Control board.
> Can you clarify? Is this a typo?
No, there are two different major versions of the M7261 Control board; see
http://gunkies.org/wiki/PDP-11/05#CPU_board_versions
A04A2 is inded E102 on the later major version of the board; on the earlier
version (prints for that version are in the GT40 prints online, pg. 162 and
on) A04A2 is E92.
Speaking of the two major versions, though, I wonder if the ucode in the two
versions is identical? The uROM chip numbers should give it, (if they are the
same on both versions, albeit in different locations on the board), but I have
yet to check. Does anyone happen to know?
Noel
Before there were books of kids doing thins with computers there was:
The Radio Boys and Girls: Radio,
Telegraph, Telephone and Wireless
Adventures for Juvenile Readers,
1890-1945 - A View Though Literature
By Mike Adams
A Review By Ed Sharpe Director and Lead Archivist for Southwest Museum
of Engineering Communications and Computation
Glendale Daily Planet / KKAT-IPTV
Read At
http://glendaledailyplanet.com/the-radio-boys-and-girls-radio-telegraph-tele
phone-and-wireless-adventu-p570-154.htm
Has anyone dumped the microcode of the PDP-11/05?
I am looking into a CPU board pair that are not behaving that well. The
only switch that does anything is the START switch. The rest is doing
nothing. The CPU clock is stopped.
When tracing the microprogram flow it looks very suspicious. Comparing the
same sequence with a better working pair reveal a few differences. All
these can be narrowed down to one single PROM chip.
It doesn't look like it is something else that is wire-ored onto the micor
address bus since the enable signals for all those are inactive. And one
signal is already low so wire-ORing would not change it.
I would need a dump of the chips or at least A04A2 / E102 on the Control
board. There are microcode listings in the manual but they need to be
treated to get into a dump. So if someone already have a dump that would be
highly appreciated.
/Mattis