Subject: Re: Curt Vendel needs RK05 drive on east coast

From: Al Kossow <[email-masked]>
Date: Mon Jun 2 07:58:38 2003

RM05 packs are 300mb cake platters... Quite different from 2.5mb RK05's

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From: Vintage Computer Festival <[email-masked]>
Date: Mon Jun 2 07:58:46 2003

> RM05 packs are 300mb cake platters... Quite different from 2.5mb RK05's

Ok, my ignorance.

What drive is required to read them?

-- 

Sellam Ismail                                        Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger                http://www.vintage.org

 * Old computing resources for business and academia at www.VintageTech.com *

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From: Philip Pemberton <[email-masked]>
Date: Tue Jun 3 08:15:01 2003

In message <[email-masked]>

> What drive is required to read them?
Google revealed http://www.proximity.com.au/~brian/comp/vax750.html. I'm
guessing the disk packs belonged to a DEC VAX system of some type or other.
The URL I mentioned gives specs for someone's VAX 11/750 BTW. The RM05 is
supposedly a 250MB "Massbus" disk, if that means anything to any DEC experts
around here...
Disclaimer: I've never even seen a Digital (DEC) machine, much less used one.
I just plugged "DEC Digital RM05" into Google and had a look through the
results...

Later.
-- 
Phil.
[email-masked]
http://www.philpem.dsl.pipex.com/

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From: "John Allain" <[email-masked]>
Date: Tue Jun 3 08:18:47 2003

>> Ok, my ignorance.

I don't know of a better resource than this,
though it doesn't have everything, like RL02's and the RK.

http://www.netbsd.org/Documentation/Hardware/Machines/DEC/vax/storage.html#s
torage:rm05

"RM05
 Capacity: 256MB Size: 14" removable, ~200Kg
 Power: 220/240V @ 14A start, 10A run
 Notes: 12 platters, based on CDC 9766"

>>> needs RK05 drive on east coast

The RetroComputing Society of Rhode Island is
a good place to try on the east coast for DEC:
http://www.osfn.org/rcs

John A.

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From: Jochen Kunz <[email-masked]>
Date: Tue Jun 3 08:20:12 2003

> What drive is required to read them?
A RM05 drive or a RK05 drive. ;-) 
The more important question is what machine and OS was used to write 
the disk packs? The RK05 needs a UNIBUS or OMNIBUS controller, so at 
least PDP-8, PDP-11 or a VAX comes in question. The RM05 is a MASSBUS 
drive. MASSBUS (e.g. via a UNIBUS - MASSBUS controller) can be found 
on larger PDP-11s, VAXen and PDP-10 / DECSYSTEM 10 / 20 machines. 
-- 

tschüß,
         Jochen

Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/

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From: Ethan Dicks <[email-masked]>
Date: Tue Jun 3 08:25:40 2003

--- Philip Pemberton <[email-masked]> wrote:
> supposedly a 250MB "Massbus" disk, if that means anything to any DEC
> experts around here...

Quite a bit.

The RM05 was the largest in a particular line of MASSBUS drives based
on CDC internals.  I have not personally laid hands on an RM05, but
I have worked on the innards of a number of CDC drives and of several
DEC RM03s.  The RM02 and RM03 are repackaged CDC 9762 drives.  The
difference being rotation speed (the RM02 was sold with RH11 controllers,
while the faster RM03 went to VAXen and perhaps PDP-11/70s).  The RM05
is a repackaged CDC 9766.

I don't have the capacity figures right here, but ISTR that a raw 9762
drive (on an SMD controller) was around 80MB, but as DEC used it in the
RM02/RM03 it was an effective 67MB.  I know that the 160MB SMD Fuji drive
I have emulates two RM03s, at 67B each.  There may be a similar thing
going on with the 9766 vs the RM05.

You can use an RM05 with an 11/750, but it's possible that the packs
in question were also used with a PDP-11.  Knowing a little about the
source might help extraction (although sticking an RM05/9766 on a
suitably equipped VAX under UNIX and using 'dd' could get you a disk
image file).

-ethan

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From: "Fred N. van Kempen" <[email-masked]>
Date: Tue Jun 3 08:33:22 2003

On Mon, 2 Jun 2003, Ethan Dicks wrote:

> on CDC internals.
Correct.

> is a repackaged CDC 9766.
Afaik, just relabeled... unlike the RM02/3, they didnt change the
05 [much].

> in question were also used with a PDP-11.
I doubt the RH11 is fast enough to handle the RM05 blasting its data
onto the bus.  Wasnt the RM03 the largest one to be runnable off the
RH11 controller?

Anyway... yeah, if you can find a VAX with Massbus controller and an
RM05 drive, you only need to grab a straight image off the packs, and
do any "smart" work on simulators such as SimH or Charon-VAX.

--f

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From: "Zane H. Healy" <[email-masked]>
Date: Tue Jun 3 08:37:33 2003

>going on with the 9766 vs the RM05.

I recommend the excellent document on DEC disks at Phil Budne's site:
http://www.ultimate.com/phil/pdp10/

From that document:
Old interfaces (removable unless noted)
=======================================

disk	cap.	sec/trk	trk/cyl	cyl	notes
================ via PDP-11 RK-11, PDP-8 RK8

RK02	1.2M	12	2	203	Diablo model 30 low density (256B sect)
					avg seek: 70ms (15ms min)
					1500 rpm; avg rot delay: 20ms
					xfer: 22.2us/word
					1100 BPI max
RK03	2.5M	12	2	203	Diablo model 30 high density (512B sect)
					avg seek: 70ms (15ms min)
					1500 rpm; avg rot delay: 20ms
					xfer: 11.1us/word
					2200 BPI max
RK05(J)	2.5M	12	2	203	1500rpm; RK03 cartridge;
					RK8 max xfer 1.44Mb/s (8.32us/wd 1.1??)
					seek: 50ms/10ms/85ms
RK05F	5M	12	2	203	1500rpm; fixed rk05; 2xRK05 to s/w

================

RK06	13M	22	3	411	2400rpm; dec built
RK07	27M	22	3	823	2400rpm; dec built;
					xfer 538KB/s; lat=12.5ms
					seek: 36.5ms avg, 8.5ms min
					avg access 49ms

Massbus
=======
disk	cap.	sec/trk	trk/cyl	cyl	notes
RM02	67M	32	5	823	pack; CDC 9762; 2400 rpm
					xfer=6.4Mb/s (806KB/s); avg acc 42.5ms
					seek 30ms (avg), 6ms (min)
					avg latency 12.5ms
RM03	67M	32	5	823	pack; CDC 9762; 3600 rpm
					xfer=9.6Mb/s (1.2MB/s); avg acc 38.3ms
					seek 30ms (avg), 6ms (min)
					avg latency 8.3ms

RM05	256M	32	19	823	pack; CDC 9766
RM06	?

>suitably equipped VAX under UNIX and using 'dd' could get you a disk

BUT, can you use it if the RM05 was written on a 36-bit PDP-10 system?  On a positive note, after doing some looking it seems most likely that the data was written on either a PDP-11/70 or a VAX.

The idea of getting a disk image of the disks is probably the best, and it can be done with more than just a VAX running UNIX, it can also be done using VMS, and can also be done on a PDP-11.  It looks like SIMH supports RM05's, so it would be a simple matter of booting the right OS in SIMH, and reading the data that way.  Getting data out of SIMH would be tricky, but not impossible.

				Zane

-- 
--
| Zane H. Healy                    | UNIX Systems Administrator |
| [email-masked] (primary)    | OpenVMS Enthusiast         |
|                                  | Classic Computer Collector |
+----------------------------------+----------------------------+
|     Empire of the Petal Throne and Traveller Role Playing,    |
|          PDP-10 Emulation and Zane's Computer Museum.         |
|                http://www.aracnet.com/~healyzh/               |

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From: Brian Chase <[email-masked]>
Date: Tue Jun 3 08:45:45 2003

> suitably equipped VAX under UNIX and using 'dd' could get you a disk

I seem to recall there being some folklore about Atari running at least
part of their business on one or more VAXen, and at some point bartering
some VAX equipment in exchange for services.

There's some history on Atari's VAX systems here:
  <http://www.jmargolin.com/vmail/vmail.htm>

-brian.

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From: Ethan Dicks <[email-masked]>
Date: Tue Jun 3 08:56:37 2003

--- Brian Chase <[email-masked]> wrote:
> > Knowing a little about the source might help extraction...
> 

Commodore, too, used VAXen, (though probably because of their commercial
prominence at the time, rather than because of any sort of cross-
pollinization of personnel).  Remember "cbmvax"?

-ethan

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From: Vintage Computer Festival <[email-masked]>
Date: Tue Jun 3 09:22:45 2003

> on larger PDP-11s, VAXen and PDP-10 / DECSYSTEM 10 / 20 machines.

Knowing Atari, there tapes were most definitely written on a PDP-11
system.

--

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From: Brian Chase <[email-masked]>
Date: Tue Jun 3 09:30:58 2003

> Knowing Atari, there tapes were most definitely written on a PDP-11

Or a VAX, since there are numerous mentions of the VAX systems being
used by Atari.  Of course, we're not talking about /tapes/, we're
talking about RM05 disk packs!

I just hope whoever ends up trying to read the disk packs knows what
they're doing.  It'd be a real shame if they managed to crash the drives
and ruin the disk packs.

-brian.