Path: utzoo!attcan!uunet!wuarchive!usc!elroy.jpl.nasa.gov!thyme!kaleb
From: kaleb@thyme.jpl.nasa.gov (Kaleb Keithley	)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Installing EDSI and MFM drives in the same system
Message-ID: <1990Dec10.191146.17945@thyme.jpl.nasa.gov>
Date: 10 Dec 90 19:11:46 GMT
References: <1990Dec10.152501.12543@mozart.amd.com> <2794@cirrusl.UUCP>
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 23

In article <2794@cirrusl.UUCP> dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi) writes:
>>How do you install ESDI and MFM drives in the same system ?
>
>Couldn't you just buy an ESDI drive and controller combination that
>uses MFM encoding?  Then you would have both ESDI and MFM in the same
>system.

Most (all) MFM and RLL drive/controllers actually use the ST506 protocol.
ESDI, and SCSI are alternative protocols.  With ESDI and SCSI the data
encoding scheme (MFM, RLL, ARLL, etc.) is transparent to the protocol.

I think the original question meant how do you install a mixture of
ST506 (MFM) and ESDI controller/hard disks into the same system.  Since
I haven't tried it personally, I'm reluctant to say it can or can't
be done.  But since many ST506 controllers have a jumper to set it as
the secondary controller, I think that it may be possible to do it in
this manner.  Caveat Emptor.

-- 
Kaleb Keithley                      Jet Propulsion Labs
kaleb@thyme.jpl.nasa.gov

You can please all of the people some of the time,