OpenVMS VAX System Dump Analyzer Utility Manual

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EXIT

Exits from an SDA display or from the SDA utility.

Format

EXIT

PARAMETERS

None.

QUALIFIERS

None.

DESCRIPTION

If SDA is displaying information about a video display terminal---and if that information extends beyond one screen---SDA displays a screen overflow prompt at the bottom of the screen:⁴
Press RETURN for more. 
SDA> 
If you want to discontinue the current display at this point, enter the EXIT command. If you want SDA to execute another command, enter that command. SDA discontinues the display as if you entered EXIT, and then executes the command you entered.
When the screen overflow prompt does not immediately precede the SDA> prompt, entering EXIT causes your process to cease executing the SDA utility. When you issue EXIT within a command procedure (either the SDA initialization file or a command procedure invoked with the @ command), SDA terminates execution of the procedure and returns to the SDA prompt.

Displays a formatted list of the contents of a block of memory.

Format

FORMAT [/qualifier] location

PARAMETER

location
Location of the beginning of the data block. The location can be given as any valid SDA expression.

QUALIFIER

/TYPE=block-type
Forces SDA to characterize and format a data block at location as the specified type of data structure. The /TYPE qualifier thus overrides the default behavior of the FORMAT command in determining the type of a data block, as described in the Description section. The block-type can be the symbolic prefix of any data structure.

DESCRIPTION

The FORMAT command performs the following actions:

Characterizes a range of locations as a system data block
Assigns, if possible, a symbol to each item of data within the block
Displays all the data within the block
Normally, you use the FORMAT command without the /TYPE qualifier. Used in this manner, it examines the byte in the structure that contains the type of the structure. In most data structures, this byte occurs at an offset of 0A₁₆ into the structure. If this byte does not contain a valid block type, the FORMAT command halts with this message:
%SDA-E-INVBLKTYP, invalid block type in specified block 
However, if this byte does contain a valid block type, SDA checks the next byte (offset 0B₁₆) for a secondary block type. When SDA has determined the type of block, it searches for the symbols that correspond to that type of block.
If SDA cannot find the symbols associated with the block type it has found (or that you specified in the /TYPE qualifier), it issues this message:
No "block-type" symbols found to format this block 
If you receive this message, you might want to read additional symbols into the SDA symbol table and retry the FORMAT command. Most symbols that define data structures are contained within SYS$SYSTEM:SYSDEF.STB. Thus, you would issue the following command:
$ READ SYS$SYSTEM:SYSDEF.STB
Certain data structures do not contain a block type at offset 0A₁₆. If this byte contains information other than a block type---or the byte does not contain a valid block type---SDA displays this message:
%SDA-E-INVBLKTYP, invalid block type in specified block 
To format such a block, you must reissue the FORMAT command, using the /TYPE qualifier to designate a block-type.
The FORMAT command produces a 3-column display:

The first column shows the virtual address of each item within the block.
The second column lists each symbolic name associated with a location within the block.
The third column shows the contents of each item in hexadecimal format.

Example

SDA> READ SYS$SYSTEM:SYSDEF.STB
SDA> FORMAT 800B81F0
800B81F0   UCB$L_FQFL              80000F10
           UCB$L_RQFL
           UCB$W_MB_SEED
           UCB$W_UNIT_SEED
800B81F4   UCB$L_FQBL              800026A8
           UCB$L_RQBL
800B81F8   UCB$W_SIZE                  00E0
800B81FA   UCB$B_TYPE                10
800B81FB   UCB$B_FLCK              07
800B81FC   UCB$L_ASTQFL            800F80E0
           UCB$L_FPC
           UCB$T_PARTNER
800B8200   UCB$L_ASTQBL            8002CF80
           UCB$L_FR3
800B8204   UCB$L_FIRST             8002CA00
           UCB$L_FR4
           UCB$W_MSGMAX
           UCB$W_MSGCNT
   .
   .
   .

From SYS$SYSTEM:SYSDEF.STB, the READ command loads into SDA's symbol table the symbols needed for formatting system data structures. The FORMAT command displays the data structure that begins at 800B81F0₁₆, a unit control block (UCB). If a field has more than one symbolic name, all such names are displayed. Thus, the field that starts at 800B8204₁₆ has three designations: UCB$L_FIRST and UCB$L_FR4, alternative names for the longword; and the two subfields, UCB$W_MSGMAX and UCB$W_MSGCNT.
The contents of each field appear to the right of the symbolic name of the field. Thus, the contents of UCB$L_FIRST are 8002CA00₁₆.

Note

⁴ On hardcopy terminals, SDA does not display such a prompt.

HELP

Displays information about the SDA utility, its operation, and the format of its commands.

Format

HELP [command-name]

PARAMETER

command-name
Command for which you need information.
You can also specify the following keywords in place of command-name.

Keyword Function

CPU_CONTEXT Describes the concept of CPU context as it governs the behavior of SDA in uniprocessor and multiprocessor environments

EXECUTE_COMMAND Causes SDA to execute SDA commands contained in a file

EXPRESSIONS Prints a description of SDA expressions

INITIALIZATION Describes the circumstances under which SDA executes an initialization file when first invoked

OPERATION Describes how to operate SDA at your terminal and by means of the site-specific startup procedure

PROCESS_CONTEXT Describes the concept of process context as it governs the behavior of SDA in uniprocessor and multiprocessor environments

SYMBOLS Consists of up to 31 letters and numbers, and can include the dollar sign ($) and underscore (_) characters. When you invoke SDA, it reads in the global symbols from symbols table psect of SYS$BASE_IMAGE.EXE, and from REQSYSDEF.STB, a required subset of the symbols in the file SYSDEF.STB. You can add other symbols to SDA's symbol table by using the DEFINE and READ commands.

Keyword	Function
CPU_CONTEXT	Describes the concept of CPU context as it governs the behavior of SDA in uniprocessor and multiprocessor environments
EXECUTE_COMMAND	Causes SDA to execute SDA commands contained in a file
EXPRESSIONS	Prints a description of SDA expressions
INITIALIZATION	Describes the circumstances under which SDA executes an initialization file when first invoked
OPERATION	Describes how to operate SDA at your terminal and by means of the site-specific startup procedure
PROCESS_CONTEXT	Describes the concept of process context as it governs the behavior of SDA in uniprocessor and multiprocessor environments
SYMBOLS	Consists of up to 31 letters and numbers, and can include the dollar sign ($) and underscore (_) characters. When you invoke SDA, it reads in the global symbols from symbols table psect of SYS$BASE_IMAGE.EXE, and from REQSYSDEF.STB, a required subset of the symbols in the file SYSDEF.STB. You can add other symbols to SDA's symbol table by using the DEFINE and READ commands.

QUALIFIERS

None.

DESCRIPTION

The HELP command displays brief descriptions of SDA commands and concepts on the terminal screen (or sends these descriptions to the file designated in a SET OUTPUT command). You can request additional information by specifying the name of a topic in response to the Topic? prompt.
If you do not specify a parameter in the HELP command, it lists those commands and topics for which you can request help, as follows:
 
  Information available: 
 
  ATTACH     COPY       CPU_Context     DEFINE          EVALUATE   EXAMINE 
  Execute_Command       EXIT       Expressions          FORMAT     HELP 
  Initialization        Operation  Process_Context      READ       REPEAT 
  SEARCH     SET        SHOW       SPAWN      Symbols   VALIDATE QUEUE 
 
Topic? 

READ

Loads the global symbols contained in the specified object module into the SDA symbol table.

Format

READ {/EXECUTIVE directory-spec| [RELOCATE=expression]|filespec}

PARAMETER

filespec
Name of the device, directory, and file that contains the object module from which you want to copy global symbols. The filespec defaults to SYS$DISK:[default-dir]filename.STB, where SYS$DISK and [default-dir] represent the disk and directory specified in your last SET DEFAULT command. You must specify a file name.

QUALIFIERS

/EXECUTIVE directory-spec
Reads into the SDA symbol table all global symbols and global entry points defined within all loadable images that make up the executive. (See Table SDA-13 for a list of those images.)
The directory-spec is the name of the directory containing the loadable images of the executive. This parameter defaults to SYS$LOADABLE_IMAGES.
/RELOCATE=expression
Adds the value of expression to the value of each symbol in the symbol table file to be read. You can use the /RELOCATE qualifier only if you also specify a filespec. The /RELOCATE qualifier is useful for examining images that are position independent and are loaded at a base of zero.

DESCRIPTION

The READ command symbolically identifies locations in memory for which the default symbol table (SYS$SYSTEM:SYS.STB) provides no definition. In other words, the required global symbols are located in modules that have been compiled and linked separately from the executive.⁵
The object module file specified in the READ command can be one of the following:

Output of a compiler or assembler (for example, an .OBJ file)
Output generated by the linker qualifier /SYMBOL_TABLE (for example, an .STB file)

Most often the object module file is a file provided by the operating system in SYS$SYSTEM or SYS$LOADABLE_IMAGES. Many SDA applications, for instance, need to load the definitions of system data structures by issuing a READ command specifying SYS$SYSTEM:SYSDEF.STB. Others require the definitions of specific global entry points within the executive image that are contained within those object modules included in the executive.
Table SDA-12 lists those object module files provided in SYS$SYSTEM. Table SDA-13 lists those loadable images in SYS$LOADABLE_IMAGES that define locations within the executive image.

Table SDA-12 Modules Containing Global Symbols Used by SDA
File Contents

CLUSTRLOA.STB Symbols for loadable VAXcluster management code

DCLDEF.STB Symbols for the DCL interpreter

IMGDEF.STB Symbols for the image activator

NETDEF.STB Symbols for DECnet data structures

RMSDEF.STB Symbols that define RMS internal and user data structures and RMS$_ xxx completion codes

SCSDEF.STB Symbols that define data structures for system communications services

SYSDEF.STB Symbols that define system data structures, including the I/O database

Table SDA-13 Modules Defining Global Locations Within the Executive Image
File Contents

CPULOA.EXE Processor-specific data and initialization routines

ERRORLOG.EXE Error logging routines and system services

EVENT_FLAGS_AND_ASTS.EXE Event flag and AST delivery routines and system services

EXCEPTION.EXE Bugcheck and exception handling routines and those system services that declare condition and exit handlers

IMAGE_MANAGEMENT.EXE Image activator and the related system services

IO_ROUTINES.EXE $QIO system service, related system services (for example, SYS$CANCEL and SYS$ASSIGN), and supporting routines

LMF$GROUP_TABLE.EXE Data for valid, licensed product groups

LOCKING.EXE Lock management routines and system services

LOGICAL_NAMES.EXE Logical name routines and system services

MESSAGE_ROUTINES.EXE System message routines and system services (including SYS$SNDJBC and SYS$GETTIM)

PAGE_MANAGEMENT.EXE System pager, its supporting routines, and page management system services (including SYS$CRMPSC, SYS$CREDEL, and SYS$ADJSTK)

PRIMITIVE_IO.EXE Console I/O routines

PROCESS_MANAGEMENT.EXE Scheduler, report system event, and supporting routines and system services

RECOVERY_UNIT_SERVICES.EXE Recovery unit system services

RMS.EXE Global symbols and entry points for RMS

SECURITY.EXE Security management routines and system services

SYSDEVICE.EXE Mailbox driver and null driver

SYSGETSYI.EXE Get System Information system service (SYS$GETSYI)

SYSLICENSE.EXE Licensing system service (SYS$LICENSE)

SYSMSG.EXE System messages

SYSTEM_PRIMITIVES.EXE Miscellaneous basic system routines, including those that allocate system memory, maintain system time, create fork processes, and control mutex acquisition

SYSTEM_SYNCHRONIZATION.EXE Routines that enforce synchronization in a multiprocessing system

WORKING_SET_MANAGEMENT.EXE Swapper, its supporting routines, and working set management system services

**Table SDA-12 Modules Containing Global Symbols Used by SDA**
File	Contents
CLUSTRLOA.STB	Symbols for loadable VAXcluster management code
DCLDEF.STB	Symbols for the DCL interpreter
IMGDEF.STB	Symbols for the image activator
NETDEF.STB	Symbols for DECnet data structures
RMSDEF.STB	Symbols that define RMS internal and user data structures and RMS$_ xxx completion codes
SCSDEF.STB	Symbols that define data structures for system communications services
SYSDEF.STB	Symbols that define system data structures, including the I/O database

**Table SDA-13 Modules Defining Global Locations Within the Executive Image**
File	Contents
CPULOA.EXE	Processor-specific data and initialization routines
ERRORLOG.EXE	Error logging routines and system services
EVENT_FLAGS_AND_ASTS.EXE	Event flag and AST delivery routines and system services
EXCEPTION.EXE	Bugcheck and exception handling routines and those system services that declare condition and exit handlers
IMAGE_MANAGEMENT.EXE	Image activator and the related system services
IO_ROUTINES.EXE	$QIO system service, related system services (for example, SYS$CANCEL and SYS$ASSIGN), and supporting routines
LMF$GROUP_TABLE.EXE	Data for valid, licensed product groups
LOCKING.EXE	Lock management routines and system services
LOGICAL_NAMES.EXE	Logical name routines and system services
MESSAGE_ROUTINES.EXE	System message routines and system services (including SYS$SNDJBC and SYS$GETTIM)
PAGE_MANAGEMENT.EXE	System pager, its supporting routines, and page management system services (including SYS$CRMPSC, SYS$CREDEL, and SYS$ADJSTK)
PRIMITIVE_IO.EXE	Console I/O routines
PROCESS_MANAGEMENT.EXE	Scheduler, report system event, and supporting routines and system services
RECOVERY_UNIT_SERVICES.EXE	Recovery unit system services
RMS.EXE	Global symbols and entry points for RMS
SECURITY.EXE	Security management routines and system services
SYSDEVICE.EXE	Mailbox driver and null driver
SYSGETSYI.EXE	Get System Information system service (SYS$GETSYI)
SYSLICENSE.EXE	Licensing system service (SYS$LICENSE)
SYSMSG.EXE	System messages
SYSTEM_PRIMITIVES.EXE	Miscellaneous basic system routines, including those that allocate system memory, maintain system time, create fork processes, and control mutex acquisition
SYSTEM_SYNCHRONIZATION.EXE	Routines that enforce synchronization in a multiprocessing system
WORKING_SET_MANAGEMENT.EXE	Swapper, its supporting routines, and working set management system services

Examples

SDA>  READ SYS$SYSTEM:SYSDEF.STB
%SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYSEXE]SYSDEF.STB;1

The READ command causes SDA to add all the global symbols in SYS$SYSTEM:SYSDEF.STB to the SDA symbol table. Such symbols are useful when you are formatting an I/O data structure, such as a unit control block or an I/O request packet.

SDA>  EXAM/INST EXE$QIO+2;4
EXE$QIO+00002:  CHMK    #001F
EXE$QIO+00006:  RET
SDA>  EXAM/INST V_EXE$QIO
%SDA-E-BADSYM, unknown symbol "V_EXE$QIO"
SDA>  READ/RELOCATE=IO_ROUTINES SYS$LOADABLE_IMAGES:IO_ROUTINES.EXE
%SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]IO_ROUTINES.EXE;1
SDA>  EXAM/INST EXE$QIO+2;4
EXE$QIO+00002:  MOVZBL  04(AP),R3
EXE$QIO+00006:  CMPB    R3,#3F
SDA>  EXAM/INST V_EXE$QIO+2;4
V_EXE$QIO+00002:  CHMK    #001F
V_EXE$QIO+00006:  RET

This SDA session shows that the initial examination of the instructions at EXE$QIO+2 and EXE$QIO+6 produces the vector for the system service, not the system service code itself. The subsequent READ instruction brings into the SDA symbol table the global symbols defined for the system's I/O routines, including one that redefines the entry point of the system service to be the start of the routine EXE$QIO. Thus, the second examination of the same memory locations produces the first two instructions in the routine. The READ command creates a special symbol, V_EXE$QIO, that points to the system service vector.

SDA>  SHOW STACK
Process stacks (on CPU 01)
--------------------------
Current operating stack (KERNEL):
                                 
                7FF8F2B0  806BA870
                7FF8F2B4  7FF8F4C0
                7FF8F2B8  8016F33E     PAGE_MANAGEMENT+0053E
   .
   .
   .
SDA>  READ/RELOCATE=PAGE_MANAGEMENT SYS$LOADABLE_IMAGES:PAGE_MANAGEMENT.EXE
%SDA-I-READSYM, reading symbol table SYS$COMMON:[SYS$LDR]PAGE_MANAGEMENT.EXE;1
SDA>  SHOW STACK
Process stacks (on CPU 01)
--------------------------
Current operating stack (KERNEL):
                                 
                7FF8F2B0  806BA870
                7FF8F2B4  7FF8F4C0
                7FF8F2B8  8016F33E     MMG$LOCK_SYSTEM_PAGES+00188
   .
   .
   .

The initial SHOW STACK command contains an address that SDA resolves into an offset from the PAGE_MANAGEMENT module of the executive. The READ command loads the corresponding symbols into the SDA symbol table such that the reissue of the SHOW STACK command subsequently identifies the same location as an offset within a specific page management routine.

 READ/EXEC

 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]RECOVERY_UNIT_SERVICES.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]RMS.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]CPULOA.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]LMF$GROUP_TABLE.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SYSLICENSE.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SYSGETSYI.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SYSDEVICE.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]MESSAGE_ROUTINES.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]EXCEPTION.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]LOGICAL_NAMES.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SECURITY.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]LOCKING.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]PAGE_MANAGEMENT.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]WORKING_SET_MANAGEMENT.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]IMAGE_MANAGEMENT.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]EVENT_FLAGS_AND_ASTS.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]IO_ROUTINES.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]PROCESS_MANAGEMENT.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]ERRORLOG.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]PRIMITIVE_IO.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SYSTEM_SYNCHRONIZATION.EXE;1 
 %SDA-I-READSYM, reading symbol table  SYS$COMMON:[SYS$LDR]SYSTEM_PRIMITIVES.EXE;1

This READ command brings all global symbols defined in the modules of SYS$SYSTEM:SYS.EXE (as listed in Table SDA-13) into the SDA symbol table. Included in its results is the work performed by the READ commands illustrated in the two previous examples. The READ/EXECUTIVE command, however, does not load those symbols contained in the modules described in Table SDA-12.

Repeats execution of the last command issued. On terminal devices, the KP0 key performs the same function as the REPEAT command.

Format

REPEAT

PARAMETERS

None.

QUALIFIERS

None.

DESCRIPTION

The REPEAT command is useful for stepping through a linked list of data structures or for examining a sequence of memory locations.

Examples

SDA>  FORMAT @IOC$GL_DEVLIST
8000B540   DDB$L_LINK              8000B898
8000B544   DDB$L_UCB               8000B5E0
8000B548   DDB$W_SIZE                  0044
   .
   .
   .
8000B554   DDB$B_NAME_LEN                03
           DDB$T_NAME              "OPA"   
   .
   .
   .
SDA>  FORMAT @.
8000B898   DDB$L_LINK              8000BBE0
8000B89C   DDB$L_UCB               8000B9E0
8000B8A0   DDB$W_SIZE                  0044
   .
   .
   .
8000B8AC   DDB$B_NAME_LEN                03
           DDB$T_NAME              "MBA"   
SDA>  [KP0]
8000BBE0   DDB$L_LINK              807F85C0
8000BBE4   DDB$L_UCB               8000BC80
8000BBE8   DDB$W_SIZE                  0044
   .
   .
   .
8000BBF4   DDB$B_NAME_LEN                03
           DDB$T_NAME              "NLA"

This series of FORMAT commands pursues the chain of device data blocks (DDBs) from the system global symbol IOC$GL_DEVLIST. The second FORMAT command is constructed so that it refers to the contents of the address at the current location (see Section 8.2.4 for a discussion of SDA symbols). Subsequently, pressing the KP0 key---or issuing the REPEAT command---is sufficient to display each DDB in the device list.

SDA> SHOW CALL_FRAME
Call Frame Information
----------------------
        Call Frame Generated by CALLG Instruction
    
Condition Handler       7FFE7D78  00000000
SP Align Bits = 00      7FFE7D7C  00000000
   Saved AP             7FFE7D80  7FFE7DC0      CTL$GL_KSTKBAS+005C0
   Saved FP             7FFE7D84  7FFE7D94      CTL$GL_KSTKBAS+00594
   .
   .
   .
SDA> SHOW CALL_FRAME/NEXT_FP
Call Frame Information
----------------------
        Call Frame Generated by CALLS Instruction
    
Condition Handler       7FFE7D94  00000000
SP Align Bits = 00      7FFE7D98  20FC0000
   Saved AP             7FFE7D9C  7FFED024      CTL$GL_KSTKBAS+005E4
   Saved FP             7FFE7DA0  7FFE7DE4      SYSTEM_PRIMITIVES+020AA
   .
   .
   .
SDA> REPEAT
Call Frame Information
----------------------
        Call Frame Generated by CALLG Instruction
    
Condition Handler       7FFE7DE4  00000000
   .
   .
   .

The first SHOW CALL_FRAME displays the call frame indicated by the current FP value. Because the /NEXT_FP qualifier to the instruction displays the call frame indicated by the saved FP in the current call frame, you can use the REPEAT command to repeat the SHOW CALL_FRAME/NEXT_FP command and follow a chain of call frames.

Note

⁵ SDA extracts no local symbols from the object module.

  4556P005.HTM
  OSSG Documentation
  22-NOV-1996 14:13:09.32

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OpenVMS VAX System Dump Analyzer Utility Manual

EXIT

Format

EXIT

PARAMETERS

QUALIFIERS

DESCRIPTION

Format

FORMAT [/qualifier] location

PARAMETER

location

QUALIFIER

/TYPE=block-type

DESCRIPTION

Example

Note

4 On hardcopy terminals, SDA does not display such a prompt.

HELP

Format

HELP [command-name]

PARAMETER

command-name

QUALIFIERS

DESCRIPTION

READ

Format

READ {/EXECUTIVE directory-spec| [RELOCATE=expression]|filespec}

PARAMETER

filespec

QUALIFIERS

/EXECUTIVE directory-spec

/RELOCATE=expression

DESCRIPTION

Examples

Format

REPEAT

PARAMETERS

QUALIFIERS

DESCRIPTION

Examples

Note

5 SDA extracts no local symbols from the object module.

⁴ On hardcopy terminals, SDA does not display such a prompt.

⁵ SDA extracts no local symbols from the object module.