PDP-11 info needed.

From: Christian Fandt <cfandt_at_servtech.com>
Date: Wed Jul 8 16:43:23 1998

At 00:26 08-07-98 +0100, ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
>> >Please tell me about this disk I/F. Any FAQ on it somewhere?
>>
>> RA60 is a removable disk, part of the RA series of MSCP (mas storage
>> communications protocol) disks... MSCP is a Digital proprietary
>
>Eh? While the command set of the UDA50 is MSCP, I wasn't aware that MSCP
>command packets were sent to RA drives. I don't see why it would be
>impossible to make an SDI controller that used some other command set.
>
>> >Also, I would like to find the same tech info or descriptions on the MSCP
>> >interface which I understand the RL01s and RL02s have.
>>
>> MSCP was used for many disks put out by Digital, but not the RL01 or
>> RL02... these disks are smarter than an RK05, but still required
>
>IMHO the RL11 is dumber than the RK11. For one thing the RK11 supports
>spiral reads/writes. And to move heads you load the disk address register
>with the cylinder you want to go to, not the number of cylinders you want
>to move. With the RL11 you've got to remember where you are.
>

In a msg sent to the list by me a short while ago, I mentioned a five-board
set which was designated RK611 according to text on the foil of side 2 of
three of the boards. How is the RK611 interface different from the others?

On another subject, in several of the PDP machines here there's an M7856
module (the DL11-W option) designated as "SLU and realtime clock". What
exactly does SLU mean in this case? Serial Line Unit?

BTW, two M7856 modules are in the 11/34A I'm keeping. One has a
hand-written label saying "CONSOLE" and the other is several
incomprehensible letters also hand-written. I assume the Operator's
Console, such as an LA120 or VT-something is attached to the module labeled
"CONSOLE". It does have a cable running from the module connector out to a
25pin "D" connector bolted to the back of the cabinet which in turn has a
ten or 15-foot cable attached.

There are a group of 16 D25 connectors on the back panel of the machine
(cabled to the two M7819's) obviously for the user terminals. Unlike the
IBM 9370 and HP 250/30 machines I have, on which the operator's console is
attached to one of the corresponding group of user terminal connectors, it
seems there typically is a separate serial console connector for the DEC
world just for the system operator. Is my thinking correct here?

The second M7856, what could that be for? The cable attached to that other
M7856 has a connector on the other end with, IIRC, 6 or 7 pins inside a
flat, white nylon shell. Length of the cable is about three or four feet.
The nylon shell end connects to nothing that I can see anywhere.

Another BTW: it seems I have a fairly nice 11/34A that I'm keeping out of
that truckload. It has an M8267 FP processor (FP11-A) attached to the
KD11-EA processor board pair (M8265 & M8266) along with the M8268 11/34
cache module (KK11-A), etc.

I will ask the list more questions about the 11/34A soon as I want to fire
her up and check her out. Those questions would be something on the order
of "What do I do first, second, next, etc." (told ya I would ask
'newbie-like' questions!) I already see some notes attached to the machine
as to bootup sequence but I'm sure I'll have to check with you folks a
little first. There are likely disk packs buried in that heap of packs
which are called for in that note. There are maybe 75 to 80 packs to
rummage through. Just hope they're labeled in some manner!!

It was said to run RSX-11M and I gotta crack the manuals on that OS before
I get too close to the power switch. Anything I should know or do first
before I apply power?

Thanks for your help!
--Chris
-- --

Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA
Member of Antique Wireless Association
        URL: http://www.ggw.org/freenet/a/awa/
Received on Wed Jul 08 1998 - 16:43:23 BST

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