Imaging DEC uVAX MFM drives - test-drb@ccmp.vtda.org

29 Aug 2006

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Subject: Re: Imaging DEC uVAX MFM drives
   From: "Chuck Guzis" <cclist at sydex.com>
   Date: Tue, 29 Aug 2006 14:04:30 -0700
     To: cctalk at classiccmp.org

On 8/29/2006 at 1:47 PM Zane H. Healy wrote:

>I suspect, but this is only a guess, that the issue is the way the DEC MFM
>drives are formated.  There are only two ways that I'm aware of to format
>an MFM drive for use on a VAX.  One is with a MicroVAX/VAXstation 2000
>(formatter is built into the ROM's), the other is with the Field Service
>Diagnostics (customer diagnostics can't format drives). 
Many ways to format media on DEC systems.  One is a suitable controller and 
(rqdx2/3)on a PDP-11 qbus machine runnig XXDP diags.

The uVAX2000 has formatter in rom (RQDX3 compatable).

uVAX-II with diagnostic/formatter disks (Rx50) and the RQDXn of choice.

The later uVAX-III I think also had more diagnostic capability.

...
 Bingo.  Even back in the old PC XT/AT MFM days, you
couldn't always take an
MFM drive formatted on one manufacturer's controller and use it as-is on
another's. 
Generally you had WDxxxx (compatable), WD RLL mostly compatable, and 
"other" mostly all over the map but may be compatable with WD1003 style.

The S100 market and controllers were a similar problem.  Since controllers
were TTL/CPU and PALS usually the formats were not alike but formatting
was usually not a problem.

SCSI is far easier to live with even older near sasi format (Amprolb).

Allison