Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!samsung!emory!hubcap!ncrcae!ncr-sd!iss-rb!booboo!davel
From: davel@booboo.SanDiego.NCR.COM (David Lord)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: 2 hard drives in 1 machine...HOW?
Message-ID: <1991Feb14.174151.27512@SanDiego.NCR.COM>
Date: 14 Feb 91 17:41:51 GMT
References: <1122@applix.com> <1991Feb13.180633@hammer.Prime.COM>
Sender: @SanDiego.NCR.COM
Reply-To: davel@booboo.SanDiego.NCR.COM (David Lord)
Organization: NCR Corporation, Rancho Bernardo
Lines: 68


  I couldn't find the original article, but having just gone through this
  I'd like to add a few comments. First of all, in retrospective I think
  that it would have been well worth the cost of paying someone to install
  the drive. The process should be fairly straight forward but when something
  goes wrong it's a real pain to solve. If you are going to install a second
  drive yourself you really should have the documentation for the controller
  and BOTH drives. You will need to Know how to set the Disk Select switches
  and how to remove the termination resistor from one drive (usually done
  with a bank of switches). These drives come from the factory set to
  Disk Select 1 and with the resistor installed.

In article <1991Feb13.180633@hammer.Prime.COM| cummings@hammer.Prime.COM (Kevin Cummings) writes:
|In article <1122@applix.com>, jimr@applix.com (Jim Rouleau [ext 256]) writes:

|OK, these are both ST506/ST412 interface drives.  (MFM to some.)

||>      The controller cable I'm using has the card connector, some straight
||> cable, connector '1', a twisted section, and finally connector '2'.

|Hmm, I replaced the twisted cable with a straight through cable.  I then
|strapped each drive so that it worked.  Remember to hook up the data cables
|too.  B^)  And since you can boot either drive independently, I'll assume
|you're getting the cables plugged in right.  Are your edge card connectors
|keyed?  Especially '2'?

  This is the daisy chain cable. The drive at the end will be C:, the
  one in the middle will be D:. Remove the termination resistor from D:.
  If you're using twisted cable than BOTH drives must be Disk Select 2.
  If you're using straight through cable than C: is Disk Select 1 and
  D: is Disk Select 2.

||>    What makes a drive first or second and how does the machine
||> distinguish them?  Is is just the data cable or does the controller
||> cable play too? (Does anyone know 'why the twist'? I,ve heard
||> "hard drive cables are different than floppy cables", but isn't 
||> the twist the only difference?) What about the terminating resistors?
||> Do I want the first physical drive on connector '1' or '2'?

  Used to be that straight through cables were used on hard drives,
  now twist cables are commonly used on both. For the data cables (the
  two narrow ribbon cables) connector 1 goes to C:, 2 goes to D:. Make
  sure the colored edge of the cables goes to pin 1 on all connectors
  (the connectors on the controller may not be keyed to prevent them
  from being put in the wrong way).

||>    Another thing, what about the partitions?  Right now I've got a
||> bootable partition on each drive.  Will DOS be nice and allow me
||> to change the logical drive of the second physical drive so that
||> if the last logical drive of the Micropolis if E> and I cd to
||> F> then I will be accessing the Miniscribe? Or do I have to change
||> something first, while I can still access each drive as the first?

  I don't know, I run DOS 4.01 so I only have one partition on each disk.

|Here is where I think you are getting into trouble.  I had some problems
|partitioning my second hard drive.  What works is:  Create only an EXTENDED
|DOS PARTITION on the second drive.  Don't create a PRIMARY (bootable) DOS
|PARTITION.  I found out the hard way that you can't access any bootable
|partitions except the one you booted from!  Actually, because my second

  I didn't have this problem with DOS 4.01. Both my drive have a primary
  partition. Dos does complain about the disk at boot time until I got
  it partitioned. And of course you have to low-level format it before
  you partition it.


  Good Luck.