🚀 go-pugleaf

mlm@cs.brown.edu (Moises Lejter) writes:
>	Is it possible to use a MFM hard disk drive with an RLL
>	controller? Are there particular MFM drives that will do it?
>	How would I tell?
 
Possible, but not a good idea, especially with Seagate hard drives.  If you do
not format an ST412/506 drive as it is specified then the warranty is
invalidated.  I personally wouldn't risk it.  The moment of truth is right
after you format the drive RLL.  If you come up with a significant number of
bad tracks then it probably is a good idea to reformat it MFM, but again,
please don't do this to a Seagate drive, you will void the warranty.  If it's
out of warranty and you don't care if the drive might up and die, go ahead and
do it.

>	I have a PC-XT at home with what I believe is an MFM drive and
>	controller.  I'm considering buying a second hard-disk, and
>	was wondering whether I could just buy an RLL controller and
>	disk, and connect my existing hard disk to it as a second
>	drive.

I have yet to see an MFM and RLL controller that will play nice together on an
ISA bus.  Either you get two MFM drives or two RLL drives.

>	Alternatively, is there any reason not to have both an MFM and
>	an RLL controller on the same machine?

I don't see any reason why not, but then again, I don't manufacture the
controllers.  The problem deals with the guts of how hard drive interfaces
have evolved.  Fortunately when SCSI becomes the de facto standard for the IBM
compatable environment, all of this will disappear.
 
     // JCA

 /*
 **--------------------------------------------------------------------------*
 ** Flames  : /dev/null                     | My opinions are exactly that,
 ** ARPANET : crash!pnet01!jca@nosc.mil     | mine.  Bill Gates couldn't buy
 ** INTERNET: jca@pnet01.cts.com            | it, but he could rent it.  :)
 ** UUCP    : {nsoc ucsd hplabs!hd-sdd}!crash!pnet01!jca
 **--------------------------------------------------------------------------*
 */