[comp.sys.ibm.pc.misc] please tell me how to co-install RLL & MFM hard drives....PLEASE!

v087mxgb@ubvmsa.cc.buffalo.edu (Shawn E Thompson) (05/14/91)

Thank you for reading............





I have a type 2 - 20 Mb MFM hard drive installed (works fine)

I received a 30 Mb RLL drive FREE!!! and want to use both


Ive heard that I can, but how do I do this....both have a
controller card for my 286 machine, how do I partition them
and set one as drive 0 and one as drive 1, etc....



TIA


ST

chchoi@eng.auburn.edu (Cheong Hyeon Choi) (05/15/91)

In article <76334@eerie.acsu.Buffalo.EDU> v087mxgb@ubvmsa.cc.buffalo.edu writes:
>I have a type 2 - 20 Mb MFM hard drive installed (works fine)
>
>I received a 30 Mb RLL drive FREE!!! and want to use both
>
>Ive heard that I can, but how do I do this....both have a
>controller card for my 286 machine, how do I partition them
>and set one as drive 0 and one as drive 1, etc....
>
 Hi. Yes, I had the same experience. In this case, you try to format
MFM drives as RLL if your two MFM drive is products of Seagate.
After that, you are getting more disk capacities. With my experience,
there had been no problem. But I don't know exactly why it works but
very fine. As I know, the capacity of the MFM drive is going to increase
by 50%. Do it.

Choi`

oneel@heawk1.gsfc.nasa.gov ( Bruce Oneel ) (05/15/91)

In article <chchoi.910514223205@banana.eng.auburn.edu> chchoi@eng.auburn.edu (Cheong Hyeon Choi) writes:


   In article <76334@eerie.acsu.Buffalo.EDU> v087mxgb@ubvmsa.cc.buffalo.edu writes:
   >I have a type 2 - 20 Mb MFM hard drive installed (works fine)
   >
   >I received a 30 Mb RLL drive FREE!!! and want to use both
   >
   >Ive heard that I can, but how do I do this....both have a
   >controller card for my 286 machine, how do I partition them
   >and set one as drive 0 and one as drive 1, etc....
   >
    Hi. Yes, I had the same experience. In this case, you try to format
   MFM drives as RLL if your two MFM drive is products of Seagate.
   After that, you are getting more disk capacities. With my experience,
   there had been no problem. But I don't know exactly why it works but
   very fine. As I know, the capacity of the MFM drive is going to increase
   by 50%. Do it.

   Choi`

Well, you can reformat your MFM drive as RLL,  but, it might not work
as well as you want it to.  Most newer MFM drives really aren't
"certified" to run RLL.  As an example, a ST238 (30 or so meg,
seagate RLL drive) is the same as a ST225 (20 or so meg, seagate MFM
drive).  (I may have the numbers wrong, but the idea is right).
They're the same things, but, the st238 has passed tests showing that
it will work with the higher densities of RLL.  Sure, the 225 will low
level format to 30 or so meg with an rll controller, but you may get
errors later (or sooner).  It's up to you.  The reason why there is
about a 50 % increase in the disk space is that MFM is 17? sectors per
track and RLL is 26? sectors per track.

bruce
--
Bruce O'Neel              oneel@heasfs.gsfc.nasa.gov
NASA/GSFC/STX/Code 664

richard@ariel.ucs.unimelb.edu.au (Richard Begg) (05/16/91)

In article <chchoi.910514223205@banana.eng.auburn.edu>, chchoi@eng.auburn.edu (Cheong Hyeon Choi) writes:
|> In article <76334@eerie.acsu.Buffalo.EDU> v087mxgb@ubvmsa.cc.buffalo.edu writes:
|> >I have a type 2 - 20 Mb MFM hard drive installed (works fine)
|> >
|> >I received a 30 Mb RLL drive FREE!!! and want to use both
|> >
|> >Ive heard that I can, but how do I do this....both have a
|> >controller card for my 286 machine, how do I partition them
|> >and set one as drive 0 and one as drive 1, etc....
|> >
|>  Hi. Yes, I had the same experience. In this case, you try to format
|> MFM drives as RLL if your two MFM drive is products of Seagate.
|> After that, you are getting more disk capacities. With my experience,
|> there had been no problem. But I don't know exactly why it works but
|> very fine. As I know, the capacity of the MFM drive is going to increase
|> by 50%. Do it.
|> 
|> Choi`

You can TRY to format your 20MB as RLL, but if you value your data,
I wouldn't recommend it.  I seem to remember an argument about this
earlier this year.  Maybe it will work for you, but from personal 
experience, the problems aren't worth it.  If you wan't to try it,
at least get a program like spinrite to have a look at the disk
and check it for potential problems.  

Another idea if you have both MFM and RLL controllers is to install them
both. You will need to change the jumpers on one of them to change the
IO address and interrupts (I hope you have the manuals!).

-- 
Richard Begg (richard@asis.unimelb.edu.au)
Programmer ASIS/ITS - University of Melbourne

mstr@vipunen.hut.fi (Markus Strand) (05/17/91)

>I have a type 2 - 20 Mb MFM hard drive installed (works fine)
>
>I received a 30 Mb RLL drive FREE!!! and want to use both

If you can install both controllers, MFM for the MFM drive and
RLL for the RLL drive, if you can change the I/O to do this.
 OR
Use the RLL drive with a MFM controller. You lose some diskspace
but you won't have any problems.


Markus Strand
mstr@vipunen.hut.fi