19 Jun
2009
19 Jun
'09
12:27 p.m.
Pete Turnbull <pete at dunnington.plus.com> wrote:
The note that I read didn't say anything about power requirements, as
far as I can remember. But maybe I should check the note I read again.
This was about six years ago... (And as far as I know, the site is still
running that machine, but they now have a couple of SCSI disks on it
instead.)
It could be that there are two revisions of the backplane? (Was it you
who said that?)
I know for a fact that a steel plant in Sweden stood still for five days
because of this, six years ago. (Well, one part of it anyway.)
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
On 17/06/2009 16:34, Johnny Billquist wrote:
Ok. I haven't checked all the details here, so it's part my research,
and part information I've recevied from others. The only reason I even
know about it is because I had to recover the data from a disk that they
"destroyed" by doing this.
> It's actually worse. The write enable
signal apparently always gets to
> both drives no matter what else you are doing. So when you write to one
> drive, the other will also start writing, even if the head is moving
> right at that time. I've had to recover an RD53 which was destroyed that
> way. (Salvage as much data as I could, and then reformat the drive.)
That won't happen unless both drives are also selected. Having the
write enable signal go to both drives at the same time is normal in
ST412 systems, and indeed all the signals go to all the drives at the
same time in such systems. > The funny
thing is that DEC actually do write in the documentation that
> it is not permissible to have two hard drives in a BA23, but that note
> is not so easy to find, and if you don't have the documentation, it even
> easier to assume that you can, since you do have connectors for two drives.
The DEC information actually says that it's because of the power
requirements. > I believe
it's a hardware "bug", which can't be fixed without cutting
> wires, and adding new ones. But maybe someone knows better here?
Mine works, and I've not cut any wires. 
20 Jun
20 Jun
10:40 a.m.
On 19/06/2009 17:27, Johnny Billquist wrote:
Mine works, and I've not cut any wires.
It could be that there are two revisions of the backplane? (Was it you
who said that?)
It wasn't me, but it's possible. However, the earliest manuals I have
suggest you can use both positions, and I've never seen a unit where it
mattered.
--
Pete Peter Turnbull
Network Manager
University of York
Pete Turnbull <pete at dunnington.plus.com>
wrote:
I believe
it's a hardware "bug", which can't be fixed without
cutting >
wires, and adding new ones. But maybe someone knows better
here? 
12:15 p.m.
New subject: DEC KM11 Question
I recently acquired two complete original DEC KM11 maintenance panel
board sets (the board with the four toggle switches and bank of
incandescent lamps) and the other "extender" board with the
transistorized drivers for the lamps.
From what I've been able to tell, these boards can
be used for
diagnosing things at the microcode level on (at least) the first
generation microcoded Unibus PDP 11's (11/35, 11/45, 11/05) as well as
diagnosis of the RK11 disk controllers (with an appropriate plastic
overlay for the indicator lights). The question I have is can this be
used on an 11/34a to step through the microcode?
The 11/34a runs fine so I don't need them for actual diagnostic work,
but it'd be at least cool to try out the KM11s (I understand that two
are needed) and watch the lights if they in fact will work on the
11/34a. I've dug around in the usual places to try to find the answer
myself, and have come up empty. Also, if the KM11 can be used on the
11/34a, does anyone know of documentation that explains how to use it in
this context?
1:01 p.m.
New subject: DEC KM11 Question
On Jun 20, 2009, at 12:15 PM, Rick Bensene wrote:
I recently acquired two complete original DEC KM11
maintenance panel
board sets (the board with the four toggle switches and bank of
incandescent lamps) and the other "extender" board with the
transistorized drivers for the lamps.
From what I've been able to tell, these boards can be used for
diagnosing things at the microcode level on (at least) the first
generation microcoded Unibus PDP 11's (11/35, 11/45, 11/05) as well as
diagnosis of the RK11 disk controllers (with an appropriate plastic
overlay for the indicator lights). The question I have is can this be
used on an 11/34a to step through the microcode?
The 11/34a runs fine so I don't need them for actual diagnostic work,
but it'd be at least cool to try out the KM11s (I understand that two
are needed) and watch the lights if they in fact will work on the
11/34a. I've dug around in the usual places to try to find the answer
myself, and have come up empty. Also, if the KM11 can be used on the
11/34a, does anyone know of documentation that explains how to use
it in
this context?
The KM11 predates the 11/34 by a few years...I wonder if it can be
used in that machine at all, I kinda doubt it. The KY11-LB front
panel, if properly equipped with the two additional (10-pin I think)
"maintenance" cables, can be used to single-step microcode in the
11/34 CPU.
-Dave
--
Dave McGuire
Port Charlotte, FL
3:33 p.m.
New subject: DEC KM11 Question
From what I've been able to tell, these boards
can be used for
diagnosing things at the microcode level on (at least) the first
generation microcoded Unibus PDP 11's (11/35, 11/45, 11/05) as well as
diagnosis of the RK11 disk controllers (with an appropriate plastic overlay for the indicator lights). The question I
have is can this be
used on an 11/34a to step through the microcode?
AFAIK it can't be used on an 11/34. There is a way of single-stepping the
microocde on an 11/34 -- IIRC you link a couple of special cables between
the frontpanel control board and one of the CPU boards (10 wire ribbon
cables?) There's then some odd key combination on the panel that lets
you single-step the mircocode.
The 11/34a runs fine so I don't need them for
actual diagnostic work,
but it'd be at least cool to try out the KM11s (I understand that two
are needed) and watch the lights if they in fact will work on the
Not all devices need 2 KM11s. The 11/45 can use two, but one is for the
main CPU, the other for the FPU. You cna use one at a time. The RK11-C
really needs two, the RK11-D and RX01 just have one KM11 connector. I
can't remember the 11/40.
-tony
7:29 p.m.
New subject: DEC KM11 Question
Rick,
I'm not an expert on either the KM11 or the /34a, though I too have a
working /34a. AFAIK, the KM11 is not compatible with the /34a. However,
in addition to the processors mentioned above, I believe the /70 can take
advantage of two (one for the CPU, one for the FP11?), and the RK05 can
take one [both of which I also have]. Fairly certain there are a good
number of other peripherals that can use the KM as well.
Wish I could come across a pair. Someday when I'm wealthy I'll buy the
kit from Guy.
John
From what
I've been able to tell, these boards can be used for
diagnosing things at the
microcode level on (at least) the first
generation microcoded Unibus PDP 11's (11/35, 11/45, 11/05) as well as
diagnosis of the RK11 disk controllers (with an appropriate plastic
overlay for the indicator lights). The question I have is can this be
used on an 11/34a to step through the microcode?
5488
days inactive
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days old
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participants (6)
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ard＠p850ug1.demon.co.uk -
bqt＠softjar.se -
dundas＠caltech.edu -
mcguire＠neurotica.com -
pete＠dunnington.plus.com -
rickb＠bensene.com