Path: utzoo!attcan!uunet!tektronix!sequent!mntgfx!mikes
From: mikes@mntgfx.mentor.com (Mike Stanbro)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Hard drive / controller problems
Message-ID: <1988Jul19.101402.774@mntgfx.mentor.com>
Date: 19 Jul 88 17:13:59 GMT
References: <16800327@clio>
Organization: Mentor Graphics Corporation, Beaverton Oregon
Lines: 56

From article <16800327@clio>, by berger@clio.las.uiuc.edu:
> 
> I didn't translate all the alphabet soup you listed, but you mentioned
> using a "twisted" 34 pin cable.  That's what IBM supplies for their
> floppy disk drives, but it should not be used with the hard disk.  Use
> a straight cable, and set the disk address select jumper on the
> drive appropriately.
> 
> If you didn't find any ROM at c800:0000, then you may have one of the
> very old dump XT controllers.  I don't know what you have to do to
> get that to recognize a second drive.
> 
> 			Mike Berger
> 			Department of Statistics 
> 			Science, Technology, and Society
> 			University of Illinois 
> 
> 			berger@clio.las.uiuc.edu
> 			{ihnp4 | convex | pur-ee}!uiucuxc!clio!berger


I experienced a similar problem the other night while trying to configure an HD
for a friend.  I was trying to get two identical HDs to run off of one controller 
so that I could do an XCOPY of all the data from drive C to drive D.  

I expected everything to plug together and be up and running in a matter of 
minutes ... two hours later (like you) I had tried every combination and could
only get one drive at a time to operate.  What really made it frustrating was
that I had done this before and had things work just fine ... I was ready to 
spit fire!!!

Then it dawned on me ... I was using a different 34 pin cable.  I dug up the
previous cable and compared it to the one I had been trying to use; they
were different!  There is a difference between the signals that are twisted for a 
floppy cable and an HD cable.  I suspect that you are using a "twisted" type cable
and that it is the floppy type instead of the HD type. Try to locate an HD type 
twisted cable and configure both drives as "DS1" or, better yet, use a non-twisted
cable and configure the first drive as "DS1" and the second drive as "DS2".
Either way, the terminator should be at the second drive (the end of the cable).

I too recommend the non-twisted type of cable because it eliminates the confusion and
it is the "normal" way of connecting two drives together.  Some smart guy at IBM
apparently conceived the idea of twisting the cable so that all the drives could 
be setup as DS1 and they didn't have to reconfigure the drives during manufacturing
when there were two drives connected to one controller.

By the way, you can get away with a non-twisted cable for two HDs but you are
forced to use a twisted cable for two floppies; the floppy controller is 
specifically designed to work with the twisted cable.  

Good luck ... let me know if it works.
-- 
Mike Stanbro, Research Engineer                     (503) 626-1437
Mentor Graphics Corp., 8500 SW Creekside Place, Beaverton OR 97005
...!{sequent,tessi,apollo}!mntgfx!mikes   OR  mikes@pdx.MENTOR.COM
These are my opinions, & not necessarily those of Mentor Graphics.