Xref: utzoo comp.sys.ibm.pc:15659 comp.sys.misc:1438
Path: utzoo!attcan!uunet!pilchuck!del
From: del@Data-IO.COM (Erik Lindberg)
Newsgroups: comp.sys.ibm.pc,comp.sys.misc
Subject: Why ST225 can't be formatted MFM after RLL....
Message-ID: <900@pilchuck.Data-IO.COM>
Date: 17 May 88 22:34:05 GMT
References: <1255@kodak.UUCP> <638@mccc.UUCP> <216@octopus.UUCP> <650@mccc.UUCP> <218@octopus.UUCP> <661@mccc.UUCP>
Reply-To: del@pilchuck.Data-IO.COM (Erik Lindberg)
Organization: Data I/O Corporation; Redmond, WA
Lines: 39

In article <661@mccc.UUCP> pjh@mccc.UUCP (Pete Holsberg) writes:
>Misled?  You think that the guys who told me that they were unable to
>MFM-format a plated media drive that they had run under RLL were
>kidding?  Frankly, I didn't initially believe them either, but enough of
>them said the same thing that I got rid of my ST-225 asap.  Maybe it's
>another hummingbird case: theoretically, there's nothing that an RLL
>controller can do to prevent a disk from being reformatted, but in these
>cited cases, it happened.  Probably in conjunction with a powersupply
>problem or some such thing, eh?

No, it's not a hummingbird case. 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.

Notes:
1) People that screw up installation of equipment are quick to blame the
   equipment. When peripheral equipment stops working also, then the new
   gizmo is assumed to have damaged the existing equipment.
2) Those same people will probably not listen to those with the technical
   expertise to explain reality. Reality is what their prior experience
   has shown them, regardless of what science says.
3) Had I not had the technical expertise to reason that RLL encoding could
   not possibly damage the drive, I would have been part of group 1).
   Instead, I tried other approaches until the issue was resolved.
4) Group 1) is the reason Seagate says you will void your warrantee if you
   use the ST225 with RLL. They just don't want to have to hassle with
   the morons out there.

-- 
del (Erik Lindberg) 
uw-beaver!tikal!pilchuck!del