Path: utzoo!attcan!uunet!mcvax!hp4nl!dutrun!dutesta!schuur
From: schuur@dutesta.UUCP (Lisp Groep Delft)
Newsgroups: comp.sys.ibm.pc
Subject: Disk Controller Question
Message-ID: <1226@dutesta.UUCP>
Date: 27 Nov 88 16:30:47 GMT
Reply-To: schuur@dutesta.UUCP (Paul E. Schuurmans)
Organization: DELFT UNIVERSITY OF TECHNOLOGY
              Faculty of Electrical Engineering
              Computer architecture and Digital Technique
              Mekelweg 4   -   2628 CD  Delft, The  Netherlands
Lines: 60

I am rather stuck with a problem, I hope someone in Netland can shine
some light on it.
Recently I bought a 30 Meg harddisk (Seagate ST-238R) with controller
(Seagate ST-11R), both using RLL encoding.
My system (XT-clone) already contained a 20 Meg harddisk and a
controller with MFM encoding.
The harddisk is a Microscience HH-725B, the controller is a National
Computer Limited (NCL) NDC5127-50.
Because the first disk is an RLL disk and the other an MFM, I need to have
both controllers in my system.
The RLL controller is configured to have its BIOS at D8000,
the MFM controller has its BIOS at C8000.
Both disks work fine if they are the only disk in the system.
When starting up the system with both controllers plugged in,
the controller at C8000 first reports that it has one disk attached, then the
second controller also reports one disk (it also says that the disk is a
ST-238R).
With a bootable floppy in drive A (because booting from one of the hard disks
does not work), the system starts booting from the floppy drive.
Next the led on the MFM drive blinks (reading the partition table ???) and
a moment later the led on the RLL drive goes on.
This led stays on and nothing happens anymore until I hit Ctrl-Alt-Del.
I have tried using a disk controller of a friend (Western Digital WD-1002
-- the controller, not the friend :-) instead of the NCL controller and
both disks worked fine!!!
So it seems that the NCL controller causes the problem.

Now here are the questions:

  - Does anyone out there know why these controllers
    don't work together?
    Is it possible to make them do so?

  - I don't have any documentation on the Microscience disk
    nor the NCL controller.
    Is there anyone who has?

  - Is it possible to use the Microscience disk (which has a ST-506/ST-412
    interface) on the RLL controller?
    The ST-238R disk also has a ST-412 interface.

                              Thanks in advance,
                                                   Paul.


-------------------------------------------------------------------------------
Paul Schuurmans                    | 
Delft University of Technology     |
Faculty of Electrical Engineering  |        UUCP:  ..!dutesta!schuur
Delft                              |
The Netherlands                    |
-------------------------------------------------------------------------------
-- 
-------------------------------------------------------------------------------
Paul Schuurmans                    | 
Delft University of Technology     |
Faculty of Electrical Engineering  |        UUCP:  ..!dutesta!schuur
Delft                              |
The Netherlands                    |
-------------------------------------------------------------------------------