19 Jun
2009
19 Jun
'09
9:38 a.m.
tiggerlasv at aim.com wrote:
Hmm. As far as I can remember, there are no DS jumpers on the drives. If
you have an RQDXE, you have a bunch of jumpers on that in order to set
up which drive is which, and all that.
But the backplane of the BA23 don't have any jumpers, as far as I can
remember.
And in this case, both drives were RD53s. Properly formatted, DEC
branded and everything.
And no, it wasn't me who tried putting this together. I was called in
after the fact, to rescue as much as I could from the trashed drive.
Which is why I suspect it was writing to #1 which trashed #0, since I
believe they were in the process of making a copy of #0, which was their
only copy of the system, and which they booted from.
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
I'm not certain of the mechanics involved, but,
you shouldn't be able to trash the format of either drive,
unless the Drive Select jumpers are set incorrectly.
There are no drive select jumpers. That could, of course, be the
problem. :-)
The only thing that might have an impact on this would
be
if you try it in a BA23 with an un-modified 4-button front panel.
This was definitely in a 4-butten front panel BA23. However, I'm not
sure the front panel is the only place to blame.
*Maybe* the fact that the Ready/Write Protect lines
for the 2nd drive are left floating, is somehow confusing
the RQDXn controller, but that seems doubtful.
The RQDX wasn't confused. It was the drives... When the RQDX started
writing to #0, the write circuitry of #1 also went active. Or if it was
writing to #1 which also activated the circuitry of #0.
Those lines merely report status of the 2nd drive.
The Drive Select and Head Select lines don't go
anywhere near the front panel, and there are
separate signal lines for drives 0, 1, 2, and 3.
Exactly. Which is why I wonder if the front panel really is to blame for
the problem.
From a
modification standpoint, there are NO CHANGES
required to the disk drive
distribution panel; all of the
signal lines are there, and ready to use for 2 drives.
DEC sold the "upgrade" kit for 2 hard drives;
it's called the BA23-UC. It consists only of a 6-button panel.
This is the same 6-button panel that was shipped with
later models of the MicroVax, which clearly supported
2 internal RD-series disk drives.
All the 6-button panels did was to add the extra
ready/write protect buttons. There is no extra logic involved.
The Write Protect LIGHTS for the RX50's were deleted,
as the newer RQDX3 controller doesn't provide any outputs
for the floppy write protect lights.
Most of this information is documented on-line,
in the document "third-party disks.txt".
All that need be done to the 4-button panels is to
solder 2 resistors onto the boards, to pull the 2 signal lines
to their appropriate logic levels. The RQDX3 only uses these
signals to establish that the drive is on-line, and write-enabled.
It has nothing to do which drive is selected when it goes to write.
Have I trashed the format of a drive in a 2-drive BA23 configuration?
Yes, I have. But only because I wasn't paying attention,
and didn't set the Drive Select jumpers to "3" on both drives.
Remember: The distribution panel shifts the signal lines around,
and all hard drives need to be set to "3".
This could easily trip you up if you weren't paying attention,
as some of the drives had DS markings of 0 - 3, and some
were marked 1 - 4 . . .
Thus, depending on what DS settings you have,
you could in theory have 2 drives responding to the
same drive select signal, which could trash your format. 
20 Jun
20 Jun
8:22 a.m.
On 19/06/2009 17:38, Johnny Billquist wrote:
This was definitely in a 4-butten front panel BA23.
However, I'm not
sure the front panel is the only place to blame.
It's not to blame at all. It has nothing to do with the drive selects.
It might stop a drive working reliably, but it definitely cannot cause
two to be selected at the same time. All it can do is tell the RQDX not
to use the drive.
*Maybe* the fact that the Ready/Write Protect
lines
for the 2nd drive are left floating, is somehow confusing
the RQDXn controller, but that seems doubtful.
The RQDX wasn't confused. It was the drives... When the RQDX started
writing to #0, the write circuitry of #1 also went active. Or if it was
writing to #1 which also activated the circuitry of #0.
Those lines merely report status of the 2nd
drive.
The Drive Select and Head Select lines don't go
anywhere near the front panel, and there are
separate signal lines for drives 0, 1, 2, and 3.
Exactly. Which is why I wonder if the front panel really is to blame for
the problem. Hmm. As far as I can remember, there are no DS jumpers
on the drives. If
you have an RQDXE, you have a bunch of jumpers on that in order to set
up which drive is which, and all that.
Not entirely. It's intended to provide sufficient connectors and to
route the some DS lines (etc) to the external unit. That doesn't remove
the need to set the DS jumpers on the drive(s) correctly.
But the backplane of the BA23 don't have any
jumpers, as far as I can
remember.
That's right, the backplane doesn't.
And in this case, both drives were RD53s. Properly
formatted, DEC
branded and everything.
Well, those drives definitely have Drive Select jumpers. Look at the
legend on the PCB by contact numbers 32 to 26 on the 34-way connector.
They're the drive select lines, and you'll see they're labelled, and
they go to a set of jumpers right beside the connector position, next to
the terminator resistor pack. If they were "as supplied by DEC" and the
person who installed them assumed the arrangement for a BA23 should be
the same as for a BA123 and didn't change one, they would both be set to
DS3, and so of course they both were selected at the same time. User
error, pure and simple.
The microPDP-11 Maintenance manual says where they are, and moreover it
says:
Always place the first fixed-disk drive in port 0 (left mass
storage slot of the enclosure containing the RQDX controller.
Set the device select to DS3 on any fixed disk installed in port
0 of the enclosure or expansion unit.
Set the device select to DS4 on any fixed disk installed in port
1 (right mass storage slot) of the enclosure or expansion unit.
This rule also applies to any subsystem installed in a BA23
enclosure.
--
Pete Peter Turnbull
Network Manager
University of York
30 Jun
30 Jun
4:34 p.m.
Sorry for the delay in answering this topic. I finally found the
altered 10-pin cable that was constructed about 20 years ago
(taken out of service about 15 years ago when a BA123 was
substituted for the BA23) to support both a Fixed Disk 0 and
a Fixed Disk 1 with a single BA23 box.
This post discusses the changes to the 10-pin cable which is
plugged into the J4 slot in the BA23 Signal Distribution Panel
which is located just behind the bulkhead at the rear of the two
drive compartment at the front of a BA23 box. These changes
support the use of a (second) Fixed Disk 1.
CRITICAL INFORMATION: The Fixed Disk 0 MUST be
selected as DS3 and the Fixed Disk 1 MUST be selected as DS4.
Failure to do so will almost certainly result in a loss of FORMAT
for both of the Fixed Disk drives. (Been There - Done That!)
I realize that this response is very long and provides a lot of detail.
However, it seems better to provide too much than too little.
I am holding a 4-button front panel for the BA23 in my hands:
P/N 70-20695-01
REV. A2 ECO
MFG. CAN 43/85
After removing the 4 bolts on the back, the PCB board:
BA23 FRONT PANEL
KA 54-15610-00 C1/88
Left-Hand Number which is vertical is 5015609
Right-Hand Number which is vertical is 5415610
The labels for this panel are:
Fixed Disk 0
Write Protect Halt
Removable Run
Disk @ @ o
1 O Ready Restart
DC OK
2 O @ @ o
where: @ is a push-button switch, O is a red LED and o is a green LED
The above front panel (without any alterations in the wiring) supports
ONLY a single Fixed Disk 0 and two floppy disks. However, by altering
the 10-pin cable which is connected to the J4 slot in the BA23 Signal
Distribution Panel, TWO Fixed Disks can be supported PROVIDED
that:
(a) Both Fixed Disks are either READY / NOT READY at the same time
(b) Both Fixed Disks are either WRITE PROTECT / NOT WRITE
PROTECT at the same time
Note that the 10-pin cable which plugs into the J4 slot in the BA23
Signal Distribution Panel is one-half of the other end of the 20-pin
cable which plugs into the Front Panel at the front of the BA23 box.
The two alterations to the 10-pin cable are (lines are numbered from
line 1 to line 10 with the red cable being line 1):
(a) Cut the 5th line just before it enters the J4 slot and splice the
free end to the 1st line (without cutting the 1st line)
(b) Cut the 6th line just before it enters the J4 slot and splice the
free end to the 2nd line (without cutting the 2nd line)
In order to be able to easily remove the above alteration, a short
6" length of 10-pin cable was first attached to a male and female
pair of headers. The female end of the substitute cable was inserted
into the J4 slot and the female end of the standard 10-pin cable
which normally plugs into the J4 slot is plugged in the the male
header on the substitute cable. After normal operation has been
verified, the above two hardware changes are made. A second
Fixed Disk 1 is then cabled to the specified connectors on the
BA23 Signal Distribution Panel AND with the drive select jumper
set as DS4!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
In order to make sure that a little can go wrong as possible, it
is suggested that the XXDP format program be run using ONLY
Fixed Disk 0 set for DS3 when the second disk drive is being
formatted (as well as removing the patched cable). Preliminary
testing to show that this drive is working is also best carried out
in this configuration.
It would be appreciated for feedback to be posted by anyone
who attempts to implement the above changes to the 10-pin
cable.
Also, if Tony Duell can dig up the schematics for the BA23
Signal Distribution Panel to confirm the the reason why the
above changes actually work, that would be very helpful.
A second post describing the 6-button front panel for the
BA23 which correctly supports both a Fixed Disk 0 and
a Fixed Disk 1 along with 2 floppy disk drives will be posted
separately immediately after this post. This post describing
the 6-button BA23 front panel should put to rest the question
of whether or not a BA23 can support 2 fixed disk drives.
Sincerely yours,
Jerome Fine
Pete Turnbull wrote:
On 19/06/2009 17:38, Johnny Billquist wrote:
This was definitely in a 4-butten front panel
BA23. However, I'm not
sure the front panel is the only place to blame.
It's not to blame at all. It has nothing to do with the drive selects.
It might stop a drive working reliably, but it definitely cannot cause
two to be selected at the same time. All it can do is tell the RQDX not
to use the drive.
*Maybe* the fact that the Ready/Write Protect
lines
for the 2nd drive are left floating, is somehow confusing
the RQDXn controller, but that seems doubtful.
The RQDX wasn't confused. It was the drives... When the RQDX started
writing to #0, the write circuitry of #1 also went active. Or if it
was writing to #1 which also activated the circuitry of #0.
Those lines merely report status of the 2nd
drive.
The Drive Select and Head Select lines don't go
anywhere near the front panel, and there are
separate signal lines for drives 0, 1, 2, and 3.
Exactly. Which is why I wonder if the front panel really is to blame
for the problem. Hmm. As far as I can remember, there are no DS
jumpers on the drives.
If you have an RQDXE, you have a bunch of jumpers on that in order to
set up which drive is which, and all that.
Not entirely. It's intended to provide sufficient connectors and to
route the some DS lines (etc) to the external unit. That doesn't
remove the need to set the DS jumpers on the drive(s) correctly.
But the backplane of the BA23 don't have any
jumpers, as far as I can
remember.
That's right, the backplane doesn't.
And in this case, both drives were RD53s.
Properly formatted, DEC
branded and everything.
Well, those drives definitely have Drive Select jumpers. Look at the
legend on the PCB by contact numbers 32 to 26 on the 34-way connector.
They're the drive select lines, and you'll see they're labelled, and
they go to a set of jumpers right beside the connector position, next to
the terminator resistor pack. If they were "as supplied by DEC" and the
person who installed them assumed the arrangement for a BA23 should be
the same as for a BA123 and didn't change one, they would both be set to
DS3, and so of course they both were selected at the same time. User
error, pure and simple.
The microPDP-11 Maintenance manual says where they are, and moreover
it says:
Always place the first fixed-disk drive in port 0 (left mass
storage slot of the enclosure containing the RQDX controller.
Set the device select to DS3 on any fixed disk installed in port
0 of the enclosure or expansion unit.
Set the device select to DS4 on any fixed disk installed in port
1 (right mass storage slot) of the enclosure or expansion unit.
This rule also applies to any subsystem installed in a BA23
enclosure. 
1 Jul
1 Jul
11:34 a.m.
Also, if Tony Duell can dig up the schematics for the
BA23
Signal Distribution Panel to confirm the the reason why the
above changes actually work, that would be very helpful.
Sorry, I don't think I have them. I never did much with DEC hardware that
modern (I am more of an Omnibus/Unibus person). I do have a BA23, and I
guess I could pull the switch PCB and see what's going on.
If the scrematics are on the web anywhere, I'd be happy to take a look
and see what's going on.
-tony
30 Jun
30 Jun
4:35 p.m.
New subject: 6-Button Fron Panel for BA23 (Was: PDP-11 Controller needed to use a couple of RX33 drive)
I am NOW holding a 6-button front panel for the BA23 in my hands:
P/N 70-22007-02
REV. B1 ECO
MFG. KAO 49/87
Right-Hand Number which is vertical is 90-09255-04
After removing the 4 bolts on the back, the PCB board:
BA23 FRONT PANEL
KA 54-16458-02 8150/87 (last 4 characters hand written in ink)
Left-Hand Number which is vertical is 5016457
The labels for this panel are:
Fixed Disk 1 Fixed Disk 0
Write Protect Write Protect Halt
Run
@ @ @ o
Ready Ready Restart
DC OK
@ @ @ o
where: @ is a push-button switch and o is a green LED
NOTE: I have never tested this 6-button front panel with a BA23
box, so I do not know if it functions correctly as would be expected
from the labels. In addition, since DEC manufactured
an RQDXE
board which specifically provided for Fixed Disk 1 to be supported
by an RQDXn, it seems reasonable to assume that the 6-button
front panel could handle TWO hard drives and that DEC supported
this configuration with the Fixed Disk 1 being held in an expansion
BA23 box. This would allow 2 additional 5 1/4" drive bays, one
in the first BA23 box and the second in the expansion BA23 box,
to hold other drives such as an RX50 floppy drive and a TK50 tape
drive. What I do NOT know is which connectors should be used
on the BA23 Signal Distribution Panel in the BA23 expansion box,
i.e. the Fixed Disk 0 pair of connectors or the Fixed Disk 1 pair of
connectors. If anyone has ever placed a Fixed Disk 1 in a BA23
box or knows of any documentation which provides the answer,
please HELP!!!!!!!!!!!!!!!
Alternatively, if the first (perhaps only) BA23 box is used to hold both
Fixed Disks, the Signal Distribution Panel at the rear of the compartment
can be used to connect the Fixed Disks to the RQDXn controller.
The metal bulkhead is clearly marked with the connectors to be
used for Fixed Disk 0 and Fixed Disk 1.
If an RX50 floppy drive is also required and a second BA23 box
is not present, then it would be possible to run the required cables
from a BA23 box out to an external location to an RX50
floppy
drive. While not the best solution, I would deem it to be acceptable
since the RX50 is an enclosed box.
CRITICAL INFORMATION: The Fixed Disk 0 MUST be
selected as DS3 and the Fixed Disk 1 MUST be selected as DS4.
Failure to do so will almost certainly result in a loss of FORMAT
for both of the Fixed Disk drives.
Finally, while there are no LEDs to provide information about the
WRITE PROTECT status of the media in a floppy drive, I am
confident that an RX50 drive could be connected in addition to
a Fixed Disk 0 and a Fixed Disk 1. However, the unit numbers
for the floppy media will (if both Fixed Disks are present) be set
as 2 and 3.
I realize that the above information is not a specific response to
the discussion below, however, it does pertain to the use of TWO
Fixed Disks along with the facts of what is probably needed to
operate Fixed Disk 0 and Fixed Disk 1 using either a single BA23
box or 2 BA23 boxes.
In my previous e-mail, I discussed my experience in using TWO
Fixed Disks with a 4-button front panel in a single BA23 box.
I also added my expectation of what would likely be the usage
when 2 BA23 boxes are used with TWO Fixed Disks.
Sincerely yours,
Jerome Fine
Pete Turnbull wrote:
On 19/06/2009 17:38, Johnny Billquist wrote:
This was definitely in a 4-butten front panel
BA23. However, I'm not
sure the front panel is the only place to blame.
It's not to blame at all. It has nothing to do with the drive selects.
It might stop a drive working reliably, but it definitely cannot cause
two to be selected at the same time. All it can do is tell the RQDX not
to use the drive.
*Maybe* the fact that the Ready/Write Protect
lines
for the 2nd drive are left floating, is somehow confusing
the RQDXn controller, but that seems doubtful.
The RQDX wasn't confused. It was the drives... When the RQDX started
writing to #0, the write circuitry of #1 also went active. Or if it
was writing to #1 which also activated the circuitry of #0.
Those lines merely report status of the 2nd
drive.
The Drive Select and Head Select lines don't go
anywhere near the front panel, and there are
separate signal lines for drives 0, 1, 2, and 3.
Exactly. Which is why I wonder if the front panel really is to blame
for the problem. Hmm. As far as I can remember, there are no DS
jumpers on the drives.
If you have an RQDXE, you have a bunch of jumpers on that in order to
set up which drive is which, and all that.
Not entirely. It's intended to provide sufficient connectors and to
route the some DS lines (etc) to the external unit. That doesn't
remove the need to set the DS jumpers on the drive(s) correctly.
But the backplane of the BA23 don't have any
jumpers, as far as I can
remember.
That's right, the backplane doesn't.
And in this case, both drives were RD53s.
Properly formatted, DEC
branded and everything.
Well, those drives definitely have Drive Select jumpers. Look at the
legend on the PCB by contact numbers 32 to 26 on the 34-way connector.
They're the drive select lines, and you'll see they're labelled, and
they go to a set of jumpers right beside the connector position, next to
the terminator resistor pack. If they were "as supplied by DEC" and the
person who installed them assumed the arrangement for a BA23 should be
the same as for a BA123 and didn't change one, they would both be set to
DS3, and so of course they both were selected at the same time. User
error, pure and simple.
The microPDP-11 Maintenance manual says where they are, and moreover
it says:
Always place the first fixed-disk drive in port 0 (left mass
storage slot of the enclosure containing the RQDX controller.
Set the device select to DS3 on any fixed disk installed in port
0 of the enclosure or expansion unit.
Set the device select to DS4 on any fixed disk installed in port
1 (right mass storage slot) of the enclosure or expansion unit.
This rule also applies to any subsystem installed in a BA23
enclosure.
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ard＠p850ug1.demon.co.uk -
bqt＠softjar.se -
jhfinedp3k＠compsys.to -
pete＠dunnington.plus.com