Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!newstop!texsun!digi!kgallagh
From: kgallagh@digi.lonestar.org (Kevin Gallagher)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Formatting MFM drive with RLL controller. Reliable?
Message-ID: <1991Mar14.041558.24419@digi.lonestar.org>
Date: 14 Mar 91 04:15:58 GMT
References: <6830@gdc.portal.com>
Organization: DSC Communications Corp, Plano, TX
Lines: 41

In article <6830@gdc.portal.com> lee@gdc.portal.com (Seng-Poh Lee, Gen
DataComm, +1 203 758-1811) writes:
>
>I know this can be done, I just want to know from people that have done it
>how reliable it is.
>
>I'm talking about formating an MFM drive with a RLL controller. 

I have a MiniScribe 40 Meg, Model 3650.  It is sold as a MFM drive.  I
installed it on 12/9/88.  I attached it to an Adaptec ACB-2072, which is an XT
RRL controller.  (There is also a corresponding AT version of this controller.)
It was my understanding, at the time, that the platters inside this drive were
identical to those MiniScribe used in its RLL certified drives.  So I took a
gamble that the drive would be able to handle RLL.

The specs state that the drive has 6 heads with 809 cylinders, with a park
zone on cylinder 852.  

I used the Adaptec low level format program in the firmware to format the
drive into one large partition, requesting it format 809 cylinders.  When the
low level format and verify completed, it encountered NO track failures, so it
did not use ANY of the spare cylinders above 809.  I decided to re-do the
low-level format and specified 840 cylinders.  This format and verify
completed without a problem.  I then used FDISK from PC DOS 3.3 to partition
the drive into two 32 Meg partitions.  I have about 40 Meg of software and
data installed on the drive, at the present time.

My PC get used just about every day.  I have had over two years of
trouble-free operation.  The only maintenance I do on the drive is to run
Spinrite two or three times a year.

During the past year or so on the net, this topic comes up every now and then.
Some people reported serious problems when they formatted some brands of MFM
drives with RLL.  While others reported no problems with other brands.  

Good Luck!
-- 
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Kevin Gallagher        kgallagh@digi.lonestar.org OR ...!uunet!digi!kgallagh
DSC Communications Corporation   Addr: MS 152, 1000 Coit Rd, Plano, TX 75075
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