Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!pasteur!agate!eos!labrea!decwrl!pyramid!uccba!ucqais!ggibeau
From: ggibeau@ucqais.uc.edu (George Gibeau)
Newsgroups: comp.sys.amiga
Subject: Re: Harddisk for amiga
Message-ID: <1416@ucqais.uc.edu>
Date: 21 Apr 88 01:43:29 GMT
References: <2653@crash.cts.com> <27253@aero.ARPA> <925@rmi.UUCP> <926@rmi.UUCP> <252@vedge.UUCP>
Organization: Univ of Cincinnati, College of Business Admin.
Lines: 38
Summary: Why use an OMTI controller

In article <252@vedge.UUCP>, lai@vedge.UUCP (David Lai) writes:
> In article <938@unccvax.UUCP>, wdg@unccvax.UUCP (Doug Gullett) writes:
> > I am not familiar with OMTI-controllers.  Could someone fill me in
> > about them.
> 
> I think what they are referring to are SCSI to ST506 adapters manufactured
> by OMTI.  I'm not sure if OMTI is still in business or not but I have the
> following number:
> 
The reason that these kits use an OMTI controller is because the
OMTI controllers write out any bad tracks on the hard drive to the
controller cards ROM.  The OMTI actually has a Zilog Z-80
co-processor on it.  As you probably know, when AmyDos encounters
a bad track on a disk, it throws up all over the place :-).  Since
most hard drives come from the factory with some sort of defect on
them, they (IBM type DRIVES) could not be used with the Amiga

Since the OMTI writes out the bad sectors, it sorta renumbers them so
that it looks like a perfect drive to AmyDos.  (IE. sector 5 is bad, it
then renumbers all the following sectors by one less than the actual
sector number until it encounters another bad sector, and so on.  Then
when you do a checkdisk or verify, it looks like a perfect disk -this
is a very over simplified example, but you get the point.)  There
are two OMTI controllers that are available that will allow IBM drives
to be used with the Amiga, one for MFM format, and one for RLL (RLL gets
you 50% more disk space on RLL type drives, ie. 40 meg + RLL = 60 megs)
  
Hope this helps a bit.

George Gibeau

Walking the fence between Amiga and IBM (hope the wind doesn't shift)


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