19 Feb
2003
19 Feb
'03
3:29 a.m.
A few weeks ago, I got a rather nice PDP-11/34 (34A, turnkey front panel)
from a scrap yard. They had two identical systems being
used in some sort of
electronic testing devices. I only got one system because the
other one
looked like it had been hit by a forklift a couple times. It wasn't in great
shape, so I salvaged some cards from it (CPU, memory, DELUA, drive
controller, UNIBUS utility stuff...).
My system is in very nice shape though. And along with the CPU, I also got
two RC25 drives, along with controllers and cables. I've never seen these
before. Can anyone tell me anything about them? They look like nice drives,
but I've never really heard much about them.
Anyway, this will be my third 11/34. Of the other two, I still have (and
very much like) one, and one has been passed on to another list member.
Anyway, more questions on recent acquisitions to come shortly, I'm sure.
--
Owen Robertson
19 Feb
19 Feb
4:33 a.m.
--- Owen Robertson <univac2(a)earthlink.net> wrote:
A few weeks ago, I got a rather nice PDP-11/34... I
also got
two RC25 drives, along with controllers and cables. I've never seen these
before. Can anyone tell me anything about them? They look like nice
drives, but I've never really heard much about them.
The controllers should be "KLESI/U" - an intellegent controller that,
I think, should be able to talk to a model TU-80-something (not a
straight TU-80 - that has formatted Pertec I/O over two 50-pin cables,
IIRC) as well as the RC25 drive. Not sure if the controller can talk
to more than one device at a time, though.
You will not be able to spin it up without the removable cartridge.
It has one motor and one positioner, but 50% of the storage is
enclosed in a white disk pack several inches on a side and about 1/2"
thick.
I used to have one, embedded in a VAX-11/725, but it was on loan when
the borrower's company was sold. I heard about the relocation too
late. :-(
I never had a problem with them, but I keep hearing horror stories from
others. They are *not* high performance disks.
The last time I saw one used in a production environment was well over
10 years ago, as the boot node for a small VAXcluster. VMS 5.0
fit on one, barely. Never seen one attached to a PDP-11, but there's
no reason why it shouldn't work. I just don't think people were
buying too many Unibus PDP-11s when the RC-25 came out. If you
were going to spend real $$$, you'd probably have bought a UDA-50 and
a "real" MSCP disk, or replaced the Unibus stuff with a MicroPDP and
some flavor of RD5x drive (or in the case of one of my clients in 1986,
an SMD controller and a Fuji SMD drive, if you didn't have a 100% DEC
requirement).
Probably plenty of room on them for RT-11 or RSTS. Don't know where
you are going to find cartridges these days, though. Perhaps the
usual suspects (Keyways, Continental Computer, Newman, Computer
Clearing House...)
-ethan
3 Mar
3 Mar
3:37 a.m.
Back in the VAX 11/725 days I used to have several such systems. All were
quite reliable, evidently contrary to experience on the list.
At 10:29 AM -0800 2/19/03, Ethan Dicks wrote:
You will not be able to spin it up without the
removable cartridge.
Is this strictly true? My very vague memory recalled that it was possible,
though the removable door had to remain closed while the internal drive was
spun up.
I recently acquired one [and the controller] for my 11/73. I do have one
and only one pack. This pack does have data that I would like to
reacquire, therefore I am unwilling to put it in the drive until I have
some way of proving the drive clean and functional. [Can't accept crashing
the removable.] I have not been able to spin up the disk so far, thus
lending evidence to Ethan's assertion above.
John
4:46 a.m.
--- "John A. Dundas III" <dundas(a)caltech.edu> wrote:
At 10:29 AM -0800 2/19/03, Ethan Dicks wrote:
That was my experience in 1987. I used that fact to get the vendor to
ship me a (free) cartridge so I could spin up the drive and get the 11/725
working.
-ethan
You will not be able to spin it up without the
removable cartridge.
Is this strictly true?
4 Mar
4 Mar
2:42 a.m.
After digging a bit more in the manual, indeed I find the confirming quote:
"NOTE: A disk cartridge must be installed to spin up and operate the disk
drive. The fixed disk does not spin up and run without a removable
cartridge in place. The spin-up cycle takes approximately 1 minute. It
involves spinning the disk platters up to operating speed, cleaning the
internal air system, loading the read/write heads, and performing a
self-test."
Looks like I need to find an additional (possibly sacrificial) cartridge.
Any help?
Thanks,
John
At 10:43 AM -0800 3/3/03, Ethan Dicks wrote:
--- "John A. Dundas III"
<dundas(a)caltech.edu> wrote:
At 10:29 AM -0800 2/19/03, Ethan Dicks wrote:
That was my experience in 1987. I used that fact to get the vendor to
ship me a (free) cartridge so I could spin up the drive and get the 11/725
working.
-ethan You will not be able to spin it up without the
removable cartridge.
Is this strictly true?
7730
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