26 Apr
2020
26 Apr
'20
1:33 p.m.
So I've had a boat anchor pdt11/150 here for awhile. It's probably one
of the weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports,
ish, and a pair of RX01 drives.
Ish.
The trick is the system is very closed in: There are 4 boards inside
with a lot of early microprocessors to do the IO instead of a real Q
bus. The bottom board is a controller that is sort of like an RX01 but
instead of using the DX: driver it uses a special PD: driver. The CPU
connects to this with a 14 pin DIP ribbon cable, and on the back of the
CPU module is a 64kb memory module and a serial module that has a
console, printer, modem and three additional serial ports that are their
own thing.
Problem with this one was that it would not come up. Serial tests seemed
to fail using an error code of waiting for input which didn't make a lot
of sense. So today I decided to pull the serial board and see if I could
swap the UARTs.
I quickly figured out the problem: The serial board "connects" to the
main board by two sets of bars with three screws each that hold the
board to an interconnecting header that sends the signals. As soon as I
loosened the screws I realized that the header isn't connecting to pins
on either board, it literally presses against pads on the boards that
complete the circuit. Nothing but pressure and springiness holds it
together. No screw, pin and socket, anything.
With that I cleaned off the headers and wiped down the pads on the
boards till they shined like the top of the chrystler building. I then
reassembled and torqued the screws down evenly, finishing with the
center screw first followed by the outside screws. It is to note that
the hinges that hold the CPU and memory/serial boards to the body of
this thing attach to the bottom of those screws so when you open it up
you are flexing the assembly and probably stretching the screws a bit.
Which results in bad contact...
Plugged it in and all is well.
RT-11SJ (S) V05.01C
.DIR SY:
SPCINV.SAV 10 21-Mar-1989 OTHELO.SAV 45 21-Mar-1989
SPCINV.DAT 1 21-Mar-1989 TODAY .SAV 20 22-Feb-1988
DECMAN.SAV 14 21-Mar-1989 SPACWR.SAV 13 21-Mar-1989
STRTRK.SAV 54 21-Mar-1989 SWAP .SYS 26P 27-Jul-1984
RT11SJ.SYS 64P 19-Jun-1988 TT .SYS 2P 19-Jun-1988
PD .SYS 3P 19-Jun-1988 DX .SYS 4P 21-Jan-2000
PIP .SAV 30P 21-Jan-2000 DUP .SAV 52P 21-Jan-2000
DIR .SAV 20P 21-Jan-2000
15 Files, 358 Blocks
128 Free blocks
Another little DEC mystery solved. One odd thing about these: There are
only four chip slots for the CPU and microcode, but one of the carriers
has two dies on it so the system *does* have EIS and FIS instructions.
Why not...
Chris
26 Apr
26 Apr
1:42 p.m.
Somehow I like the term ?Boat Anchor? to describe the PDT-11/150. I?ve had one for well
over 20 years. At a bare minimum, it needs the on/off switched replaced, as it?s broken
off. Is that the disk that came with yours? I like how it?s all games. :-)
I can?t remember, are these disks formatted strange?
Zane
On Apr 26, 2020, at 1:33 PM, Chris Zach via cctalk
<cctalk at classiccmp.org> wrote:
So I've had a boat anchor pdt11/150 here for awhile. It's probably one of the
weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports, ish, and a pair of RX01
drives.
Ish.
The trick is the system is very closed in: There are 4 boards inside with a lot of early
microprocessors to do the IO instead of a real Q bus. The bottom board is a controller
that is sort of like an RX01 but instead of using the DX: driver it uses a special PD:
driver. The CPU connects to this with a 14 pin DIP ribbon cable, and on the back of the
CPU module is a 64kb memory module and a serial module that has a console, printer, modem
and three additional serial ports that are their own thing.
Problem with this one was that it would not come up. Serial tests seemed to fail using an
error code of waiting for input which didn't make a lot of sense. So today I decided
to pull the serial board and see if I could swap the UARTs.
I quickly figured out the problem: The serial board "connects" to the main
board by two sets of bars with three screws each that hold the board to an interconnecting
header that sends the signals. As soon as I loosened the screws I realized that the header
isn't connecting to pins on either board, it literally presses against pads on the
boards that complete the circuit. Nothing but pressure and springiness holds it together.
No screw, pin and socket, anything.
With that I cleaned off the headers and wiped down the pads on the boards till they
shined like the top of the chrystler building. I then reassembled and torqued the screws
down evenly, finishing with the center screw first followed by the outside screws. It is
to note that the hinges that hold the CPU and memory/serial boards to the body of this
thing attach to the bottom of those screws so when you open it up you are flexing the
assembly and probably stretching the screws a bit. Which results in bad contact...
Plugged it in and all is well.
RT-11SJ (S) V05.01C
.DIR SY:
SPCINV.SAV 10 21-Mar-1989 OTHELO.SAV 45 21-Mar-1989
SPCINV.DAT 1 21-Mar-1989 TODAY .SAV 20 22-Feb-1988
DECMAN.SAV 14 21-Mar-1989 SPACWR.SAV 13 21-Mar-1989
STRTRK.SAV 54 21-Mar-1989 SWAP .SYS 26P 27-Jul-1984
RT11SJ.SYS 64P 19-Jun-1988 TT .SYS 2P 19-Jun-1988
PD .SYS 3P 19-Jun-1988 DX .SYS 4P 21-Jan-2000
PIP .SAV 30P 21-Jan-2000 DUP .SAV 52P 21-Jan-2000
DIR .SAV 20P 21-Jan-2000
15 Files, 358 Blocks
128 Free blocks
Another little DEC mystery solved. One odd thing about these: There are only four chip
slots for the CPU and microcode, but one of the carriers has two dies on it so the system
*does* have EIS and FIS instructions. Why not...
Chris
1:53 p.m.
No I put together an RX02 with an RX01 controller on my bigger computer
to format a special disk. It can only use RX01 formatted disks, and to
make a boot disk you need the PD.SYS driver and to copy/boot the PD
driver to the boot block.
And yes, the switch on the back is broken. How did you guess :-) For
awhile I used it in the 80's as a mini BBS with MUBasic and a little
program I ran on top of that. Technically it did... work.. ish.
C
On 4/26/2020 4:42 PM, Zane Healy wrote:
Somehow I like the term ?Boat Anchor? to describe the
PDT-11/150. I?ve had one for well over 20 years. At a bare minimum, it needs the on/off
switched replaced, as it?s broken off. Is that the disk that came with yours? I like how
it?s all games. :-)
I can?t remember, are these disks formatted strange?
Zane
On Apr 26, 2020, at 1:33 PM, Chris Zach via
cctalk <cctalk at classiccmp.org> wrote:
So I've had a boat anchor pdt11/150 here for awhile. It's probably one of the
weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports, ish, and a pair of RX01
drives.
Ish.
The trick is the system is very closed in: There are 4 boards inside with a lot of early
microprocessors to do the IO instead of a real Q bus. The bottom board is a controller
that is sort of like an RX01 but instead of using the DX: driver it uses a special PD:
driver. The CPU connects to this with a 14 pin DIP ribbon cable, and on the back of the
CPU module is a 64kb memory module and a serial module that has a console, printer, modem
and three additional serial ports that are their own thing.
Problem with this one was that it would not come up. Serial tests seemed to fail using an
error code of waiting for input which didn't make a lot of sense. So today I decided
to pull the serial board and see if I could swap the UARTs.
I quickly figured out the problem: The serial board "connects" to the main
board by two sets of bars with three screws each that hold the board to an interconnecting
header that sends the signals. As soon as I loosened the screws I realized that the header
isn't connecting to pins on either board, it literally presses against pads on the
boards that complete the circuit. Nothing but pressure and springiness holds it together.
No screw, pin and socket, anything.
With that I cleaned off the headers and wiped down the pads on the boards till they
shined like the top of the chrystler building. I then reassembled and torqued the screws
down evenly, finishing with the center screw first followed by the outside screws. It is
to note that the hinges that hold the CPU and memory/serial boards to the body of this
thing attach to the bottom of those screws so when you open it up you are flexing the
assembly and probably stretching the screws a bit. Which results in bad contact...
Plugged it in and all is well.
RT-11SJ (S) V05.01C
.DIR SY:
SPCINV.SAV 10 21-Mar-1989 OTHELO.SAV 45 21-Mar-1989
SPCINV.DAT 1 21-Mar-1989 TODAY .SAV 20 22-Feb-1988
DECMAN.SAV 14 21-Mar-1989 SPACWR.SAV 13 21-Mar-1989
STRTRK.SAV 54 21-Mar-1989 SWAP .SYS 26P 27-Jul-1984
RT11SJ.SYS 64P 19-Jun-1988 TT .SYS 2P 19-Jun-1988
PD .SYS 3P 19-Jun-1988 DX .SYS 4P 21-Jan-2000
PIP .SAV 30P 21-Jan-2000 DUP .SAV 52P 21-Jan-2000
DIR .SAV 20P 21-Jan-2000
15 Files, 358 Blocks
128 Free blocks
Another little DEC mystery solved. One odd thing about these: There are only four chip
slots for the CPU and microcode, but one of the carriers has two dies on it so the system
*does* have EIS and FIS instructions. Why not...
Chris
1:58 p.m.
That switch is obviously a design flaw! I sort of picked up on it as a design flaw when I
got mine. :-)
Zane
On Apr 26, 2020, at 1:53 PM, Chris Zach <cz at
alembic.crystel.com> wrote:
No I put together an RX02 with an RX01 controller on my bigger computer to format a
special disk. It can only use RX01 formatted disks, and to make a boot disk you need the
PD.SYS driver and to copy/boot the PD driver to the boot block.
And yes, the switch on the back is broken. How did you guess :-) For awhile I used it in
the 80's as a mini BBS with MUBasic and a little program I ran on top of that.
Technically it did... work.. ish.
C
On 4/26/2020 4:42 PM, Zane Healy wrote:
> Somehow I like the term ?Boat Anchor? to describe the PDT-11/150. I?ve had one for
well over 20 years. At a bare minimum, it needs the on/off switched replaced, as it?s
broken off. Is that the disk that came with yours? I like how it?s all games. :-)
> I can?t remember, are these disks formatted strange?
> Zane
1:52 p.m.
On April 26, 2020 at 3:33 PM Chris Zach via cctalk
<cctalk at classiccmp.org> wrote:
So I've had a boat anchor pdt11/150 here for awhile. It's probably oneof the
weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports,ish, and a pair of RX01
drives.
Plugged it in and all is well.
...
Chris
Alas. Where were you and this list 32 years ago when I was given one of these with no
clue what to do to make it work? I had it for a long time, but it's gone now. The
only DEC machine I ever had. A sad story I won't bore you with.
Congratulations on getting it working!
Will
"A designer knows he has achieved perfection not when there is nothing left to add,
but when there is nothing left to take away." -- Antoine de Saint-Exupery
"The names of global variables should start with // " -- https://isocpp.org
3:31 p.m.
At 03:33 PM 4/26/2020, Chris Zach via cctalk wrote:
So I've had a boat anchor pdt11/150 here for
awhile. It's probably one of the weirdest pdp11s ever built: An 11/03 CPU ish, six
serial ports, ish, and a pair of RX01 drives.
I remember using one for a while in the early 80s. I kind of liked it.
I think the local DEC rep gave it to us for a song for some reason.
- John
4:36 p.m.
They were interesting little devices. Apparently someone ported
Multiplan or Visicalc to one but Dec shot the project down. They were
essentially a turnkey personal computer in the late 1970's but DEC was
afraid they would cut into the sales of their minicomputers.
So it was sold as a branch office terminal connector. You could boot
RT11 and poll 4 terminals and a printer, sending the data over a sync
serial modem port to the home office. Sad.
Fortunately Dec wouldn't make the same mistake with the Professional
systems. Oh wait, they did, no wonder they went out of business....
C
On 4/26/2020 6:31 PM, John Foust via cctalk wrote:
At 03:33 PM 4/26/2020, Chris Zach via cctalk wrote:
So I've had a boat anchor pdt11/150 here for
awhile. It's probably one of the weirdest pdp11s ever built: An 11/03 CPU ish, six
serial ports, ish, and a pair of RX01 drives.
I remember using one for a while in the early 80s. I kind of liked it.
I think the local DEC rep gave it to us for a song for some reason.
- John
5:54 p.m.
On Sun, Apr 26, 2020, 5:36 PM Chris Zach via cctalk <cctalk at classiccmp.org>
wrote:
They were interesting little devices. Apparently
someone ported
Multiplan or Visicalc to one but Dec shot the project down. They were
essentially a turnkey personal computer in the late 1970's but DEC was
afraid they would cut into the sales of their minicomputers.
So it was sold as a branch office terminal connector. You could boot
RT11 and poll 4 terminals and a printer, sending the data over a sync
serial modem port to the home office. Sad.
Fortunately Dec wouldn't make the same mistake with the Professional
systems. Oh wait, they did, no wonder they went out of business....
They made all new kinds of mistakes you never thought possible with the
pro, decmate and rainbow.
Warner
C
On 4/26/2020 6:31 PM, John Foust via cctalk wrote:
At 03:33 PM 4/26/2020, Chris Zach via cctalk
wrote:
> So I've had a boat anchor pdt11/150 here for awhile. It's probably one
of the weirdest pdp11s ever built: An 11/03 CPU ish, six serial ports, ish,
and a pair of RX01 drives.
I remember using one for a while in the early 80s. I kind of liked it.
I think the local DEC rep gave it to us for a song for some reason.
- John
1700
days inactive
1701
days old
7 comments
5 participants
participants (5)
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cz＠alembic.crystel.com -
healyzh＠avanthar.com -
imp＠bsdimp.com -
jfoust＠threedee.com -
wrcooke＠wrcooke.net