27 Feb
2003
27 Feb
'03
1:36 a.m.
Wandering through the local surplus I found a decserver 550 in a full height
rack.
It had the following boards in it.
4 X CXA16-M M3118
1 X DESQA-SA M3127
1 X KDJ11-SD M7554
Bulkheads, power supply, and cables
I read somewhere that it could be converted to a 11/53 with a minimal
effort. How much trouble?
Mike
m m c f a d d e n @ c m h . e d u
27 Feb
27 Feb
1:47 a.m.
On Thu, 27 Feb 2003, McFadden, Mike wrote:
Wandering through the local surplus I found a
decserver 550 in a full height
rack.
It had the following boards in it.
4 X CXA16-M M3118
1 X DESQA-SA M3127
1 X KDJ11-SD M7554
Nice !
I read somewhere that it could be converted to a 11/53
with a minimal
effort. How much trouble?
Rip out the CXA's (16-port serial boards), add a
disk and/or tape
controller, and perhaps some memory. Off you go. The heart of
the DECserver 550 was/is indeed a barebones /53 CPU. Which comes
with 512KB RAM on the CPU card, and its console serial port.
If you need stuff, and would like to trade for one of the CXA's,
contact me off-list...
--f
1:59 a.m.
--- "Fred N. van Kempen" <waltje(a)pdp11.nl> wrote:
Won't you need "real" 11/53 Boot Roms? I got a KDJ-11 board from
Jonathan Engdahl a while back that he had returned to "normal"
status. ISTR there might be a jumper or two that needs to be moved,
but I'm not certain; I didn't mod it.
Nice find. Wish I could grab one like that.
-ethan
On Thu, 27 Feb 2003, McFadden, Mike wrote:
> Wandering through the local surplus I found a decserver 550 in a full
> height rack.
Sweet.
I read
somewhere that it could be converted to a 11/53 with a minimal
effort. How much trouble?
Rip out the CXA's (16-port serial boards), add a
disk and/or tape
controller, and perhaps some memory. 
2:26 a.m.
On 2003.02.27 16:35 "McFadden, Mike" wrote:
[decserver 550]
I read somewhere that it could be converted to a 11/53
with a minimal
effort. How much trouble?
AFAIK all you need to change are the EPROMs on the CPU
board.
And you would need a disk controller of some sort...
pdp11-field-guide.txt says:
M7554-SD KDJ11-SD Q J11 CPU 18MHz, 1.5-Mbyte RAM, LAT ROM
M7554-SD with S-box handle
M7554-SD Refs: EK-KDJ1D-UG
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
7:54 a.m.
Well, it will never be exactly an 11/53, since it's
in the wrong box,
but you can make it effectively equivalent. I'd remove the CXA16-M
serial multiplexers, which I don't think any normal PDP-11 OSs support,
I believe the CXA16s are DHV-like interfaces, RT supports DHVs.
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | email: mbg at world.std.com |
| | |
| "this space | (s/ at /@/) |
| unavoidably left blank" | URL: http://world.std.com/~mbg/ |
| | "pdp-11 programmer - some assembler |
| (DEC '77-'98) | required." - mbg KB1FCA |
+--------------------------------+-------------------------------------+
3:38 p.m.
Here is the webpage where I tell exactly how to mod the DECserver CPU into
an 11/53.
http://users.safeaccess.com/engdahl/KDJ11.htm
In short, you have to reburn the ROMs, and solder in a 1K resistor. On the
old (.5 meg) boards, you also have to cut a jumper.
And here is the best example of the result to date (this is the description
page for the system I just eBayed):
http://users.safeaccess.com/engdahl/ebay/PDP-11_53.htm
Most of the DECserver boards I have found have 1.5 megs of RAM, late
revision CPUs, and 18 MHz cystals. Last week I got one of these for $5 on
eBay. Using a complete rebuild of UNIX as a benchmark, such an 11/53 is only
about 20% slower than an 18 MHz 11/83 with PMI memory. When I "diff -r" two
directory trees, the 11/53 is actually significantly faster.
I drill off the S-box handles, and replace them with a standard latch from
the stock that I got from Ethan. My web page shows how to build the console
cable. I have the user guide for this board. Does someone want to scan this
and put it on the web?
You can drill the handle off a DESQA, install a standard latch, short out
the fuse connector, carefully disassemble the AUI connectors, and replace
the AUI ribbon cable with a longer one. The result is identical to a DELQA.
RQDX3 are cheap and easy to find. The only really difficult part is finding
(large)hard drives. For that, I've figured out how to use other Maxtor
drives (see http://users.safeaccess.com/engdahl/xxdp.htm). But even the
substitutes are hard to find.
--
Jonathan Engdahl
http://users.safeaccess.com/engdahl
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
----- Original Message -----
From: "McFadden, Mike" <mmcfadden(a)cmh.edu>
To: <cctalk(a)classiccmp.org>
Sent: Thursday, February 27, 2003 10:35 AM
Subject: decserver 550 in Kansas City
Wandering through the local surplus I found a
decserver 550 in a full
height
rack.
It had the following boards in it.
4 X CXA16-M M3118
1 X DESQA-SA M3127
1 X KDJ11-SD M7554
Bulkheads, power supply, and cables
I read somewhere that it could be converted to a 11/53 with a minimal
effort. How much trouble?
Mike
m m c f a d d e n @ c m h . e d u
4:06 p.m.
----- Original Message -----
From: "Jonathan Engdahl" <j.r.engdahl(a)adelphia.net>
To: <cctech(a)classiccmp.org>
Sent: Thursday, February 27, 2003 11:33 PM
Subject: Re: decserver 550 in Kansas City
Here is the webpage where I tell exactly how to mod
the DECserver CPU into
an 11/53.
http://users.safeaccess.com/engdahl/KDJ11.htm
In short, you have to reburn the ROMs, and solder in a 1K resistor. On the
old (.5 meg) boards, you also have to cut a jumper.
<SNIP>
Jonathan, what I want to know is how do you connect the RX50 and
RD(whatever) hard drive to the RQDX3? Did you use standard DEC parts or did
you make something? If you used DEC parts, could you please post a list of
what is needed? I have the RX50, KDJ11, DEQNA, images of the 11/53 ROMS, and
am searching for a suitable hard drive. Anyone reading this with a decent
(size, quality, and price) hard drive for sale feel free to contact me off
list...
Thanks so much for posting the original stuff - seeing that is what got me
back into PDP-11 related systems. My other systems are VAX and Alpha, all
running OpenVMS.
Stuart Johnson
8:03 p.m.
On 2003.02.28 07:00 Stuart Johnson wrote:
Jonathan, what I want to know is how do you connect
the RX50 and
RD(whatever) hard drive to the RQDX3?
There are different distribution panels that
split the 50 pin cable from
the RQDXx. The M9058 dist panel for the BA123 looks like a double QBus
card and sits in "QBus slot 13" in the BA123. The BA23 dist panel is
mounted inside the enclosure on the back of the QBus backplane. I have
the wiring of this panel, I can mail it to you when you want to build
your own dist panel. There is a BA213 dist panel that replaces the front
panel in a BA213 and has some additional switches LEDs to reset the CPU
etc. I think it is not that easy to rebuild this.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
28 Feb
28 Feb
1:36 p.m.
...
Jonathan, what I want to know is how do you connect
the RX50 and
RD(whatever) hard drive to the RQDX3? Did you use standard DEC parts or
did
you make something? If you used DEC parts, could you
please post a list of
what is needed? I have the RX50, KDJ11, DEQNA, images of the 11/53 ROMS,
and
...
Stuart Johnson
See Jochen's reply for the detailed DEC part numbers. See my RQDX3 page for
info on making a hand-built cable that also works.
--
Jonathan Engdahl
http://users.safeaccess.com/engdahl
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
2:40 p.m.
----- Original Message -----
From: "Jonathan Engdahl" <j.r.engdahl(a)adelphia.net>
To: <cctech(a)classiccmp.org>
Sent: Friday, February 28, 2003 9:32 PM
Subject: Re: decserver 550 in Kansas City
<SNIP>
See Jochen's reply for the detailed DEC part
numbers. See my RQDX3 page
for
info on making a hand-built cable that also works.
--
Jonathan Engdahl
http://users.safeaccess.com/engdahl
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
Thanks, got it!
Stuart Johnson
27 Feb
27 Feb
4:04 p.m.
Actually, instead of hacking up the boards, you ought to grab the whole
rack. Do the CPU mods, shove in an RQDX3, figure out how to mount and power
a hard drive, and you're in business.
On my 11/53 that's still in a DECserver chassis, I soldered the disk power
leads to the dummy load board, and the drive rests on the unused card guides
on the left half of the rack. I drilled out the rivets and removed all the
useless superstructure.(unless you have the rack that has a drive bay up
top).
Oh yes, for the RQDX3, you'll either need a distribution board (M9058 or the
thing on the back of a BA23 backplane) or see
http://users.safeaccess.com/engdahl/rqdx3.htm for how to build a cable.
For the console you'll need MMJ cables and adapters which can be bought from
www.l-com.com. Beware, the 9-pin MMJ adapter they sell is probably VAX
compatible, not for the PC COM1: port. I bought the kit version and wired it
up myself. The VT420 is the best terminal to look for. The 11/53 can do up
to 38400 baud.
Did you see the "DECserver" on eBay that is actually a microVAX III
(KA-650)?
--
Jonathan Engdahl
http://users.safeaccess.com/engdahl
"The things which are seen are temporary,
but the things which are not seen are eternal." II Cor. 4:18
----- Original Message -----
From: "McFadden, Mike" <mmcfadden(a)cmh.edu>
To: <cctalk(a)classiccmp.org>
Sent: Thursday, February 27, 2003 10:35 AM
Subject: decserver 550 in Kansas City
Wandering through the local surplus I found a
decserver 550 in a full
height
rack.
It had the following boards in it.
4 X CXA16-M M3118
1 X DESQA-SA M3127
1 X KDJ11-SD M7554
Bulkheads, power supply, and cables
I read somewhere that it could be converted to a 11/53 with a minimal
effort. How much trouble?
Mike
m m c f a d d e n @ c m h . e d u
7968
days inactive
7969
days old
11 comments
8 participants
participants (8)
-
erd_6502＠yahoo.com -
j.r.engdahl＠adelphia.net -
jkunz＠unixag-kl.fh-kl.de -
jwstephens＠cox.net -
mbg＠TheWorld.com -
mmcfadden＠cmh.edu -
ssj152＠charter.net -
waltje＠pdp11.nl