Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!usc!snorkelwacker.mit.edu!bloom-beacon!eru!hagbard!sunic!ugle.unit.no!ugle!thoger From: thoger@solan.unit.no (Terje Th|gersen) Newsgroups: comp.sys.ibm.pc.misc Subject: Re: mfm+ide drive in 1 computer. Message-ID: Date: 13 Jan 91 08:03:40 GMT References: <6833@crash.cts.com> <1928@umriscc.isc.umr.edu> Sender: news@ugle.unit.no Organization: The Norwegian Institute of Technology Lines: 74 In-Reply-To: bkirby@mcs213a.cs.umr.edu's message of 12 Jan 91 19:56:26 GMT In article <1928@umriscc.isc.umr.edu> bkirby@mcs213a.cs.umr.edu (Bill Kirby) writes: In article <6833@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes: >gwoho@nntp-server.caltech.edu (g liu) writes: >> >> [question about ide coexisting with mfm] > >You can't do it easily. ST412/506 MFM and IDE use the same port address and >IRQ. You could try putting the ST412/506 MFM controller at the secondary port >address and a different IRQ, but then your BIOS wouldn't be aware of it. Only >OS'es that support a secondary ST412/506 controller to my knowledge are Unix >based. > >Basically, it's more trouble that it's worth for DOS. > > I'm confused. I've called CompuAdd (i own a compuadd floppy/harddrive > controller), and USA Flex (I was going to buy an IDE drive from them) > and they both claim that the controllers will not interfere with each > other. I specifically told the USA Flex tech. guy that I had heard > of I/O and IRQ conflicts, but he assured me that this wouldn't be a > problem. On AT / 386's there are 2 different type of PC-HD controller interfaces, as far as I've been able to figure out. The first type is known as a WD1003 type interface. Under this system, most of the HD-controlling is done by the host computer. Most ST506/412 and IDE controllers are of this type. The second system is a type where the controller comes with it's own BIOS onboard. In this system, the BIOS takes over most of the 'job' itself. Under this system you do NOT tell your AT that it has a HD installed, as the on-board BIOS does all the initializing etc. that is necessary. Most Hardcards are of this type, as is my Seagate ST02 SCSI-controller. I'm pretty sure that HD-controllers meant to be installed in a XT are of this type, too Now, under DOS, I *know* you can have one of each type installed, as I have done this. I've tried ST506 + Hardcard, ST506 + ST02 SCSI and IDE + ST02. But, having two of the first kind is rather difficult under DOS, as previous posters have noted. (I've never tried two BIOS-equipped ones at the same time.. Hm.. gotta test that someday..) So, what the guy from USA Flex *might* be trying to tell you, is that their IDE controller has onboard BIOS, and therefore can peacefully coexist with a controller using the WD1003-type interface. I say *might*, as I've never heard of a IDE-type controller that is of the second type. > If I decide to get rid of my current drive (ST-225) and go with the > IDE by itself, can I still use my CompuAdd controller to control > my floppy drives? If not, what do I do? Yes, if you get a IDE controller without floppy support. But, at the current prices of USD 40-50 for both FDC-equipped IDE controllers and the ones without floppy-support, you might as well get the one with the FDC, and free up a slot. > Also, does the IDE drive require any special device driver? No, it shouldn't. The only controllers I've heard of that use drivers under DOS are the more advanced SCSI-controllers, that can do up to 7 drives etc. > Thanks, > | Bill Kirby | Internet: bkirby@cs.umr.edu | Just my little USD 0.02 worth etc.. -Terje -- ____________________________________________________________________________ thoger@solan.unit.no | Institute of Physical Chemistry THOGER AT NORUNIT.BITNET | Div. of Computer Assisted Instrumental Analysis | Norwegian Institute of Technology