Updated: 07 June 2001

OpenVMS VAX System Dump Analyzer Utility Manual

Order Number: AA--PV6TB--TE

This manual explains how to use the System Dump Analyzer (SDA) to investigate system failures and examine a running system.

Revision/Update Information: This manual supersedes the VMS System Dump Analyzer Utility Manual, Version 6.0.

Software Version: OpenVMS VAX Version 7.1

Digital Equipment Corporation Maynard, Massachusetts

Digital Equipment Corporation makes no representations that the use of its products in the manner described in this publication will not infringe on existing or future patent rights, nor do the descriptions contained in this publication imply the granting of licenses to make, use, or sell equipment or software in accordance with the description.

Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written license from Digital or an authorized sublicensor.

Digital conducts its business in a manner that conserves the environment and protects the safety and health of its employees, customers, and the community.

© Digital Equipment Corporation 1996. All rights reserved.

The following are trademarks of Digital Equipment Corporation: Bookreader, DECdtm, DECnet, DECUS, DECwindows, Digital, IAS, MASSBUS, OpenVMS, OpenVMS Cluster TMSCP, VAX, VAX DOCUMENT, VAXcluster, VMS, VMScluster, and the DIGITAL logo.

The following is a third-party trademark:

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All other trademarks and registered trademarks are the property of their respective holders.

ZK4556

The OpenVMS documentation set is available on CD-ROM.

This document was prepared using VAX DOCUMENT, Version V3.2m.

Contents

Index

Intended Audience

The OpenVMS VAX System Dump Analyzer Utility Manual is primarily intended for the system programmer who must investigate the causes of system failures and debug kernel-mode code, such as a device driver. This programmer should have some knowledge of OpenVMS data structures to properly interpret the results of System Dump Analyzer (SDA) commands.

This manual also includes information required by the system manager in order to maintain the system resources necessary to capture and store system crash dumps. Those who need to determine the cause of a hung process or improve system performance can refer to this manual for instructions for using SDA to analyze a running system.

Document Structure

The OpenVMS VAX System Dump Analyzer Utility Manual contains the following sections:

Section	Description of Contents
SDA Description	Includes the following information: An introduction to the functions of the System Dump Analyzer (SDA) A description of SDA features A discussion of key concepts of SDA An illustration of the use of SDA This section also includes instructions for maintaining the optimal environment for the analysis of system failures and notes the requirements for processes invoking SDA.
SDA Usage Summary	Summarizes how to use SDA, including invoking SDA, exiting from SDA, and recording the output of an SDA session. It also describes required privileges.
SDA Qualifiers	Describes ANALYZE command qualifiers that govern the behavior of SDA: /CRASH_DUMP, /RELEASE, /SYMBOL, and /SYSTEM.
SDA Commands	Describes each SDA command; descriptions include the following information about each command: Function Format Parameters This section also provides examples of situations in which specific commands are useful.

Related Documents

For additional information, refer to the following documents:

• OpenVMS System Manager's Manual: Essentials
• OpenVMS System Manager's Manual: Tuning, Monitoring, and Complex Systems
• OpenVMS System Management Utilities Reference Manual
• Guide to Creating OpenVMS Modular Procedures
• Guide to OpenVMS Performance Management
• OpenVMS VAX Device Support Manual¹
• OpenVMS DCL Dictionary
• OpenVMS System Services Reference Manual

Investigators of VMScluster failures will find the discussion in OpenVMS Cluster Systems and the discussion of the Show Cluster utility in the OpenVMS System Management Utilities Reference Manual helpful in understanding the output of several SDA commands.

For additional information on the Open Systems Software Group (OSSG) products and services, access the Digital OpenVMS World Wide Web site. Use the following URL:

http://www.openvms.digital.com

Reader's Comments

Digital welcomes your comments on this manual.

Print or edit the online form SYS$HELP:OPENVMSDOC_COMMENTS.TXT and send us your comments by:

Internet	openvmsdoc@zko.mts.dec.com
Fax	603 881-0120, Attention: OSSG Documentation, ZKO3-4/U08
Mail	OSSG Documentation Group, ZKO3-4/U08 110 Spit Brook Rd. Nashua, NH 03062-2698

How To Order Additional Documentation

Use the following table to order additional documentation or information. If you need help deciding which documentation best meets your needs, call 800-DIGITAL (800-344-4825).

Conventions

The name of the OpenVMS AXP operating system has been changed to the OpenVMS Alpha operating system. Any references to OpenVMS AXP or AXP are synonym ous with OpenVMS Alpha or Alpha.

VMScluster systems are now referred to as OpenVMS Cluster systems. Unless otherwise specified, references to OpenVMS Clusters or clusters in this document are synonymous with VMSclusters.

In this manual, every use of DECwindows and DECwindows Motif refers to DECwindows Motif for OpenVMS software.

The following conventions are also used in this manual:

Ctrl/ x	A sequence such as Ctrl/ x indicates that you must hold down the key labeled Ctrl while you press another key or a pointing device button.
PF1 x or GOLD x	A sequence such as PF1 x or GOLD x indicates that you must first press and release the key labeled PF1 or GOLD and then press and release another key or a pointing device button. GOLD key sequences can also have a slash (/), dash (--), or underscore (_) as a delimiter in EVE commands.
[Return]	In examples, a key name enclosed in a box indicates that you press a key on the keyboard. (In text, a key name is not enclosed in a box.)
...	Horizontal ellipsis points in examples indicate one of the following possibilities: Additional optional arguments in a statement have been omitted. The preceding item or items can be repeated one or more times. Additional parameters, values, or other information can be entered.
. . .	Vertical ellipsis points indicate the omission of items from a code example or command format; the items are omitted because they are not important to the topic being discussed.
( )	In command format descriptions, parentheses indicate that, if you choose more than one option, you must enclose the choices in parentheses.
[ ]	In command format descriptions, brackets indicate optional elements. You can choose one, none, or all of the options. (Brackets are not optional, however, in the syntax of a directory name in an OpenVMS file specification or in the syntax of a substring specification in an assignment statement.)
[|]	In command format descriptions, vertical bars separating items inside brackets indicate that you choose one, none, or all of the options.
{ }	In command format descriptions, braces indicate a required choice of options; you must choose one of the options listed.
{|}	In command format descriptions, vertical bars separating items inside braces indicate that you choose one item from among those listed.
text style	This text style represents the introduction of a new term or the name of an argument, an attribute, or a reason. This style is also used to show user input in Bookreader versions of the manual.
italic text	Italic text indicates important information, complete titles of manuals, or variables. Variables include information that varies in system output (Internal error number), in command lines (/PRODUCER= name), and in command parameters in text (where device-name contains up to five alphanumeric characters).
UPPERCASE TEXT	Uppercase text indicates a command, the name of a routine, the name of a file, or the abbreviation for a system privilege.
Monospace type	Monospace type indicates code examples and interactive screen displays. In the C programming language, monospace type in text identifies the following elements: keywords, the names of independently compiled external functions and files, syntax summaries, and references to variables or identifiers introduced in an example.
-	A hyphen at the end of a command format description, command line, or code line indicates that the command or statement continues on the following line.
numbers	All numbers in text are assumed to be decimal unless otherwise noted. Nondecimal radixes---binary, octal, or hexadecimal---are explicitly indicated.

SDA Description

When a fatal error causes the system to fail, the operating system copies the contents of memory to a system dump file; the system also records the hardware context of each processor in the system.

The System Dump Analyzer (SDA) provides a means of interpreting the contents of the system dump file, thus enabling you to examine the status of each processor at the time of the failure and to investigate the probable causes of the crash.

To examine the system dump file, you invoke SDA by using the DCL command ANALYZE/CRASH_DUMP. You can also invoke SDA to analyze a running system, using the DCL command ANALYZE/SYSTEM. Most SDA commands generate useful output in this mode of operation.

Following are brief explanations of SDA qualifiers. Details about these qualifiers are in the SDA Qualifiers section.

Qualifier	Description
/CRASH_DUMP	Invokes SDA to analyze a specified dump file
/RELEASE	Invokes SDA to release those blocks that are occupied by a crash dump in a specified system paging file
/SYMBOL	Specifies a system symbol table for SDA to use in place of the system symbol table it uses by default (SYS$SYSTEM:SYS.STB)
/SYSTEM	Invokes SDA to analyze a running system

The following tables show the SDA commands that you can use to perform operations within the SDA utility. These commands are in groups of related information. Details about SDA commands are in the SDA Commands section.

Table SDA-1 describes information that you can select and display about processes.

Table SDA-1 Selecting and Displaying Information About Processes

Operation	SDA Command
Display the condition of the operating system and the hardware context of each processor in the system at the time of a crash	SHOW CRASH
Display a summary of all processes on the system	SHOW SUMMARY
Select a process to become the SDA current process	SET PROCESS
Examine the memory of any process	SHOW PROCESS
Select a specific processor in a multiprocessing system as the subject of analysis	SET CPU
Display information about the state of a processor at the time of the system failure	SHOW CPU
Display multiprocessor synchronization information	SHOW SPINLOCKS
Display the contents of a specific process stack or the interrupt stack of a specific processor	SHOW STACK
Display the layout of the loadable executive images	SHOW EXECUTIVE

Table SDA-2 describes information that you can display about data structures.

Table SDA-2 Displaying Information about Data Structures

Operation	SDA Command
Display memory management data structures	SHOW POOL, SHOW PFN_DATA, SHOW PAGE_TABLE
Display device status, as reflected in system data structures	SHOW DEVICE
Display OpenVMS RMS data structures of a process	SHOW PROCESS/RMS
Display lock management data structures	SHOW RESOURCE, SHOW LOCK
Display information contained in various local area network (LAN) data structures	SHOW LAN
Display VAXcluster management data structures	SHOW CLUSTER, SHOW CONNECTIONS, SHOW RSPID, SHOW PORTS

Table SDA-3 describes SDA commands that you can use to examine, evaluate, and validate information.

Table SDA-3 Examining, Evaluating, and Validating Information

Operation	SDA Command
Evaluate an expression in hexadecimal and decimal, interpreting its value as a symbol, a condition value, a page table entry (PTE), or a processor status longword (PSL)	EVALUATE
Examine the contents of memory locations, optionally interpreting them as MACRO instructions, a PTE, or a PSL	EXAMINE
Validate the integrity of the links in a queue	VALIDATE QUEUE

Table SDA-4 describes the SDA commands that you can use to search for, format, and copy information.

Table SDA-4 Searching for, Formatting, and Copying Information

Operation	SDA Command
Search memory for a given value	SEARCH
Format system data structures	FORMAT
Format a call frame from a stack location	SHOW CALL_FRAME
Copy the system dump file	COPY

Table SDA-5 describes the operations you can perform to manage the SDA utility and the SDA symbol table.

Table SDA-5 Managing the SDA Utility and the SDA Symbol Table

Operation	SDA Command
Define keys to invoke SDA commands	DEFINE/KEY
Switch control of your terminal from your current process to another process in your job	ATTACH
Direct (or echo) the output of an SDA session to a file or device	SET OUTPUT or SET LOG
Repeat execution of the last command issued	REPEAT
Create a subprocess of the process currently running SDA	SPAWN
Change the options shown by the SHOW PROCESS/RMS command	SET RMS
Define symbols to represent values or locations in memory and add them to the SDA symbol table	DEFINE
Read a set of global symbols into the SDA symbol table	READ
Display the hexadecimal value of a symbol and, if the value is equal to an address location, the contents of that location	SHOW SYMBOL
Exit from the SDA display or from the SDA utility	EXIT

Table SDA-6 describes the commands that you can use to display information produced by DECdtm.

Table SDA-6 Displaying Information Produced by DECdtm

Operation	SDA Command
Display information about all transactions on the node or about a specified transaction	SHOW TRANSACTIONS
Display information about transaction logs currently open for the node	SHOW LOGS

Although SDA provides a great deal of information, it does not analyze all the control blocks and data contained in memory. For this reason, in the event of system failure it is extremely important that you send Digital Equipment Corporation a Software Performance Report (SPR) and a copy of the system dump file written at the time of the failure.

1 System Management and SDA

The system manager must perform the following operations in regard to the system dump file:

• Ensure that the system writes a dump file whenever the system fails.
• Ensure that the dump file is large enough to contain all the information to be saved.
• Ensure that the dump file is saved for analysis.

The following sections describe these tasks.

1.1 Understanding the System Dump File

The operating system attempts to write information into the system dump file only if the system parameter DUMPBUG is set. ¹ If DUMPBUG is set and the operating system fails, the system writes the contents of the error log buffers, processor registers, and physical memory into the system dump file, overwriting its previous contents.

If the system dump file is too small, it cannot contain all of memory when a system failure occurs. For most systems, this means that the system's page table (SPT) is not included in the dump. SDA cannot analyze a dump unless the entire SPT is included in the dump.

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