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Path: utzoo!attcan!uunet!lll-winken!lll-tis!mordor!lll-lcc!unisoft!hoptoad!dasys1!pechter
From: pechter@dasys1.UUCP (Bill Pechter)
Newsgroups: comp.sys.ibm.pc,comp.sys.misc
Subject: Re: Why ST225 can't be formatted MFM after RLL....
Summary: long story about reformatting
Keywords: RLL WD low-level format
Message-ID: <4553@dasys1.UUCP>
Date: 21 May 88 13:04:33 GMT
References: <1255@kodak.UUCP> <638@mccc.UUCP> <216@octopus.UUCP> <650@mccc.UUCP> <218@octopus.UUCP> <661@mccc.UUCP> <900@pilchuck.Data-IO.COM>
Reply-To: pechter@dasys1.UUCP (Bill Pechter)
Organization: Datamerica Systems, NYC
Lines: 45

This is rather long so if you'd like to skip it go ahead, I won't tell.

In article <900@pilchuck.Data-IO.COM> del@pilchuck.Data-IO.COM (Erik Lindberg) writes:

> It's a case of brain damaged disk controller firmware.
>I saw this case once. After formatting a drive on an OMTI RLL
>controller, and finding that the drive would not hold the format reliably,
>I tried to reformat the drive MFM again on the original Western Digital
>XT controller. It would not take a format, just returned errors.
>
>I was able to force a low level format to the drive using a Datamac MFM
>controller card that I had, and it is working to this day as an MFM drive
>with only a single bad sector on it. The obvious conclusion is that the
>controller firmware (at least for the Western Digital controller) saw
>something on the disk that it simply couldn't deal with.

I had the same problem.  I picked up a Lapine 20 meg drive which I was unable 
to format on  a number of different WD-1002-WX1 controllers.  I put the 
darned thing on an BAD (would low level format but not read/write) Adaptec 
non RLL controller, low leveled it twice and then put it back on the WD where
I then re-low leveled it and got me a 20 meg with 0 bad sectors for $30. 
(Thank you Trenton State Computer Festival :->)

How about it WD.  Anyone have any good explanation as to what's going on on
the controller.  I'd love to know what I did right and how this actually
worked.  I got the idea to switch controllers after I fixed my DEC Pro350's
ST412 by low level format on my WD after the DEC controller came up with
fatal errors initializing the drive.  I work with SMD 300 meg and up disks
every day and understand controllers -- but I can't figure out what's wrong
here.  The WD came up with errors like 22 or 25 and the manual said to check
the connections between disk and controller.  That obviously was not the 
problem. 

Here's my best guess as to what happens.
  
I think the drive'd been RLL'd and the low level format was checking
the header to check if it was on track (there'd be no header on the first time
out for a new drive (right) and somehow it thought the RLL info was it's
header and when I went to a different make controller the header was way off
so it was ignored.) 

Anyone else have any info that can explain this to me?
-- 
Bill Pechter          {sun!hoptoad,cmcl2!phri}!dasys1!pechter
 USnail 103 Governors Road, Lakewood, NJ 08701
 AT&T 201-370-0709 Evenings