Imaging DEC uVAX MFM drives

[Allison]

>
>Subject: Imaging DEC uVAX MFM drives
>   From: J Blaser <oldcpu at rogerwilco.org>
>   Date: Tue, 29 Aug 2006 14:11:25 -0600
>     To: cctalk at classiccmp.org
>
>Since I don't have (at least to my knowledge, yet) a functional VAX that 
>might do the trick, I've removed each drive and attached it to a known 
>working WD1002-WA2 controller [2] running on a 40Mhz 386 box, with 
>Debian Linux.  I'm just using the dd command to image the drive to a 
>file, which I'll burn off to a CD when I've got everything imaged.

This will not work with DEC RDxx drives that have been formatted with
RQDX1/2 or RQDX3 controllers (Qbus 11 or MicroVAX).

>For kicks, if I boot linux and try my dd command, it croaks with this 
>type of message:
>
>hda: read_intr: status=0x59 { DriveReady SeekComplete DataRequest Error }
>hda: read_intr: error=0x10 { SectorIdNotFound }, CHS=0/0/1, sector 0
>
>I get the same type of results when I use dd's seek=n option to other 
>blocks (sectors).
>
>Strangely, it almost appears that there is no low level format on the 
>drives, doesn't it?  I'm not smart enough to make that call though, and 
>it seems strange that *all three* drives show this same result.  Is it 
>possible that the original owner somehow 'bulk erased' the drives?  I 
>did, at least, expect to find formating marks.

There may not be a recognizeable format which is the same as saying no
format using PC hardware.  The drives may be fine and even bootable.

>Is there something I've missed, trying to image these 'DEC' drives?  Did 
>I miss some not-so-obvious jumper somewhere (though I diligently 
>examined all documentation I could find)?  Surely, they're just good-ol' 
>MFM drives, right?


I've tried this it never worked using WD1003/WD1006.  

>[1] I'm imaging three different drive types: RD23-A (71MB Micropolis 
>1325), RD54 (159MB Maxtor XT-2190), and a Rodime RO-202 11MB drive from 
>an AED WINC-08/05 RX01/RL02 emulation system.


71MB Micropolis is RD53 (all full height 5.25 are RD5x).
All half height are RD3x (st225 and St251)

The Rodime is nonDEC, it's likely from a third party.


>[2] Yes, I still have every computer I've ever owned, including two 
>AT-class 286 machines made by Novell in the mid 80's.
>
>[3] Attempting to use the WD1002-WA2 in two different and more modern PC 
>motherboards with onboard IDE interfaces proved a no go.  Even after 
>disabling the IDE controller (both primary and secondary) and the floppy 
>controller in the BIOS there were some general flakiness, and I couldn't 
>ever get the systems to recognize the MFM controller.

The problem is the older controllers will often not work as the newer 
machines are too fast.  You would have to slow down the ISA bus access
(older bioses have a tweek for that.).  Also the 1002 may require a 
driver that is incompatable with newer machines (IDE is closest to 
the wd1003).  

However, PC hard disk cards in general will be incompatable
with DEC controller formatted drives.  Third party controllers like the 
AED you may have a shot but, most of them used proprietory controllers.
Your attempt to image the content of the drives will be unsuccessful
using PC hardware.



Allison