5 Jan
2014
5 Jan
'14
9:20 a.m.
On 01/04/2014 09:32 PM, Jerome H. Fine wrote:
Since I am not very handy with a soldering iron, I soldered a
post into each of the holes where the zero ohm R7 "resister"
should go, then wire wrapped to produce a jumper. Otherwise,
the DEC controllers will not recognize the drive.
My experience with the PDP-11 XXDP diagnostics is that they
will also format the above RD5n and RD3n drives. Note that
the RD53 only needs an RQDX2 while the RD54 requires an
RQDX3, as does (if I remember correctly) the RD31 and RD32.
RQDX2 depending on the REV level would know RD53 and RD54.
Early revs didn't.
Michael
Thompson wrote:
From:
Glen Slick <glen.slick at gmail.com>
Date: Sat, 4 Jan 2014 12:02:32 -0800
Subject: Re: MFM Control Signals and RD disk size
On Sat, Jan 4, 2014 at 11:16 AM, emanuel stiebler <emu at e-bbes.com>
wrote:
This was posted years ago for the RD53 - Micropolis 1325 or 1335:
Unscrew the two screws holding the circuit board to the bottom of the
drive
and carefully lift it up. Along one edge of the circuit board you
will find
a place where it would appear that a resistor should be -- this place is
marked
R7. Solder a jumper into that spot to make this drive into an RD53.
Set
the
drive select jumper to DS2 and you should be in business.
On 2014-01-04 11:59, Robert Jarratt wrote:
> So how does it do this when the disk is yet to be formatted? In other
> words,
> when it formats the disk how does it know what size the disk is?
>
DEC drives have this information in a special area of the drive.
If for exmaple, the MV2000 finds this blocks, it formats to exactly
this
specs. You see this, if you go into the MV2000 diagnostics.
All other drives, you have to enter the specs manually ...
How does that match with this information, if it is correct, that the
MicroVAX 2000 disk recognizer works for the set of known disk drives
even if the disk came from a different system and has no DEC specific
information or formatting on it currently?
http://home.iae.nl/users/pb0aia/vax/fmtbob.html
"The standard DEC drives that are supported in the VS2000 and their
industry equivalents are:
RD54 - Maxtor XT-2190
RD53 - Micropolis 1325 or 1335
RD31 - Seagate ST-225
RD32 - Seagate ST-251-1
If you have any of these standard drives you can simply plug it into
your 2000 and the ROM formatter will automatically recognize the drive
types. I've never seen this fail, even if the drive has never seen a
DEC machine before, or even if the drive was previously formatted in
a PC."
As for the drive select jumper, perhaps the VS2000
uses DS2.
VS2000 does not use something odd compared to the rest.
BUT for the PDP-11 in a BA123 box which uses the
special
distribution board, ALL hard drives are set to DS3!!!!!!!!!!!
Same board for the uVAXII
For the PDP-11 in a BA23 box, normally ONLY one MFM
drive is supported with a 4 button front panel using DS3. If
you have a 6 button front panel, drive 0 (in the left most drive
bay) uses DS3. Drive 1 (in the right most drive bay) uses DS4.
As long as both drives are in WRITE PROTECT mode, you
will be safe if both drives are set to DS3. If you do not have
the WRITE PROTECT mode selected for either drive and
you use DS3 for both drives, be prepared to lose all files on
both drives!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
(I still remember that situation after 25 years!!!!!!!!!!!!!!!!!!)
I made a 6 button years ago out of a 4 button. You could also
jumper the second drive differently and that worked. I have a uVAXII
in a BA23 with two RD53s.
Allison