[comp.sys.ibm.pc.hardware] Installing EDSI and MFM drives in the same system

bartling@dvorak.amd.com (Steve Bartling) (12/10/90)

Hello, 

This probably falls in the category of 'frequently asked questions'
so I am probably going to waste some net bandwidth.

That having been said, here is my question :

How do you install ESDI and MFM drives in the same system ?

I currently own a Western Digital ESDI Dual HD/FD controller
( WD1007A-WA2) and a seagate ST2106E 90 MB ESDI drive 
( equivalent to the CDC Wren III 1/2 height 90 MB ESDI drive ).

I also own a seagate ST4096 80 MB MFM hard disk and a no-name
( MORSE ) Dual HD/FD 1:1 MFM controller.

I would like for these to peacefully coexist in the same system.

My current level of understanding is that I will need to replace
the MORSE controller with a 1:1 MFM HD controller that has the
following features :

1) Relocateable I/O address
2) Selectable IRQ ( IRQ 14 or IRQ 15 )

Are there any other required features ? 

Does anyone have a recommendation for a 1:1 MFM HD controller
that meets the above requirements ?

I have a second question relating to my BIOS :

I have a recent vintage PHOENIX BIOS that I am using on a 386
20 MHZ clone motherboard ( VIP ). Will this bios recognize and
take advantage of a secondary disk drive with a relocated I/O
address ?

How do I get DOS to recognize and use the secondary drive ?

Thanks for your help,

Steve Bartling

email : bartling@dvorak.amd.com

P.S. please reply by email, I don't always have time to read 
     this newsgroup regularly.

dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi) (12/11/90)

>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.
--
Rahul Dhesi <dhesi%cirrusl@oliveb.ATC.olivetti.com>
UUCP:  oliveb!cirrusl!dhesi

kaleb@thyme.jpl.nasa.gov (Kaleb Keithley ) (12/11/90)

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,