Article ID: 168105
Article Last Modified on 11/1/2006
APPLIES TO
- Microsoft Windows NT Workstation 3.51
- Microsoft Windows NT Workstation 4.0 Developer Edition
- Microsoft Windows NT Server 3.51
- Microsoft Windows NT Server 4.0 Standard Edition
This article was previously published under Q168105
SYMPTOMS
When you start Windows NT from a different SCSI logical unit number (LUN) other than LUN 0, a memory dump file (memory.dmp) file will not be created.
CAUSE
The Diskdump.sys file in Windows NT does not check for any other LUN besides LUN 0. If the Windows NT computer is started from any other LUN than 0, this driver will not load, disabling the ability to write a dump file if the computer traps (displays a blue screen error message).
MORE INFORMATION
Small Computer System Interface (SCSI) SCSI is a hardware interface that allows for the connection of up to 15 peripheral devices to a single expansion board that plugs into the computer called a SCSI host adapter or SCSI controller.
SCSI devices are daisy chained together. Each device has two ports, one for the incoming cable and another for the outgoing cable to the next device. Each device must be set to a unique ID number (SCSI ID), which is normally done by manually flipping a rotary switch on the device itself. The highest number has the highest priority. Thus, the host adapter usually defaults to ID 7 in the case of an 8-device SCSI system.
Each SCSI device can be further broken up into eight logical units, identified by logical unit numbers (LUNs) 0 to 7. Although most SCSI disks contain only one disk inside and are addressed as LUN 0, CD-ROM and optical disk jukeboxes contain multiple units. Each disk in these devices can be addressed independently via LUN numbers; for example, a four-disk jukebox could be assigned LUN 0 to 3. RAID systems are beginning to use multiple LUN addressing in their fault tolerant disk systems as well.
On most computers you will not need to worry about LUN addressing since, by default, most SCSI controllers and devices are set to LUN 0. However, many of the newer SCSI controllers have the ability to start from LUNs other than zero (adaptec 2940 allows starting from LUN 0 or 1). You should be able to detect LUN addressing through the SCSI boot process or by entering the BIOS of SCSI controller installed on the system.
Obtaining SCSI Standards reference manuals:
American National Standard (ANSI) for Small Computer System Interface (SCSI), X3.131-1986. This approved standard is available from:
American National Standards Institute
11 West 42nd Street 13th Floor
New York, NY 10036
Sales Department: (212) 642-4900
The Small Computer System Interface - 2 (SCSI-2) was approved by ANSI on August 31, 1990. Since then, the X3T9.2 committee has asked ANSI to return SCSI-2 for further editing. Revision 10d is in the works, but it is not finished yet. Revision 10c can be purchased from:
Global Engineering Documents
2805 McGaw
Irvine, CA 92714
(800) 854-7179
Outside USA and Canada: (714) 261-1455
Global has identified this document as X3.131-199x. (The latest revision is Rev 10c with a date of 3/9/90.)
If you are looking for an introduction to SCSI, try:
SCSI: Understanding the Small Computer System Interface
Written by NCR Corporation
Available from: Prentice Hall, Englewood Cliffs, NJ, 07632
Phone: (201) 767-5937
ISBN 0-13-796855-8
If you want an easy-to-read reference book on SCSI-2 that includes timing diagrams (but omits all command sets other than for disks, tapes, and processor devices), try:
The SCSI Bench Reference
ENDL Publications
14426 Black Walnut Court
Saratoga CA, 95070
(408) 867-6642
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