Document revision date: 30 March 2001

## OpenVMS VAX System Dump Analyzer Utility Manual

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## @ (Execute Procedure)

> Causes SDA to execute SDA commands contained in a file. Use this command to execute a set of frequently used SDA commands.

### Format

> @filespec

### Parameter

> #### filespec

> Name of a file that contains the SDA commands to be executed. The default file type is .COM.

### Example

    SDA> @USUAL

> The Execute Procedure command executes the following commands, as contained in a file named USUAL.COM:

>     SET OUTPUT LASTCRASH.LIS
>     SHOW CRASH
>     SHOW PROCESS
>     SHOW STACK
>     SHOW SUMMARY

> This command procedure first makes the file LASTCRASH.LIS the destination for output generated by subsequent SDA commands. Next, the command procedure sends to the file information about the crash and its context, a description of the process executing at the time of the process, the contents of the stack on which the crash occurred, and a list of the processes active on the CPU that crashed.

> An EXIT command within a command procedure terminates the procedure at that point, as would an end-of-file marker.

> You cannot nest command procedures.

## ATTACH

> Switches control of your terminal from your current process to another process in your job.

### Format

> ATTACH [/PARENT] process-name

### Parameter

> #### process-name

> Name of the process to which you want to transfer control.

### Qualifier

> #### /PARENT

> Transfers control of the terminal to the parent process of the current process. When you specify this qualifier, you cannot specify the process-name parameter.

###

#### Examples

#1
    SDA> ATTACH/PARENT

> This ATTACH command attaches the terminal to the parent process of the current process.

#2
    SDA> ATTACH DUMPER

> This ATTACH command attaches the terminal to a process named DUMPER in the same job as the current process.

## COPY

> Copies the contents of the dump file to another file.

### Format

> COPY output-filespec

### Parameter

> #### output-filespec

> Name of the device, directory, and file to which SDA copies the dump file. The default file specification is:

> `SYS$DISK:[default-dir]filename.DMP`

> SYS$DISK and [default-dir] represent the disk and directory specified in your last SET DEFAULT command. You must supply at least the file name.

### Description

> Each time the system fails, it copies the contents of physical memory and the hardware context of the current process (as directed by the DUMPSTYLE parameter) into the file SYS$SYSTEM:SYSDUMP.DMP (or the paging file), overwriting its current contents. If you do not save this crash dump elsewhere, it will be overwritten the next time the system fails.

> The COPY command allows you to preserve a crash dump by copying its contents to another file. It is generally useful to invoke SDA during system initialization (from within SYS$MANAGER:SYSTARTUP_VMS.COM) to execute the COPY command. This ensures that a copy of the dump file is made each time the system fails.

> The COPY command does not affect the contents of SYS$SYSTEM:SYSDUMP.DMP.

> If you are using the paging file (SYS$SYSTEM:PAGEFILE.SYS) as the dump file instead of SYSDUMP.DMP, you can use the COPY command to explicitly release the blocks of the paging file that contain the dump, thus making them available for paging. Although the copy operation succeeds nonetheless, the release operation requires that your process have change-mode-to-kernel (CMKRNL) privilege. Once the dump pages have been released from the paging file, the dump information in those pages might be lost. You need to analyze the copy of the dump created by the COPY command.

### Example

    SDA> COPY SYS$CRASH:SAVEDUMP

> The COPY command copies the dump file into the file SYS$CRASH:SAVEDUMP.DMP.

## DEFINE

> Assigns a value to a symbol or associates an SDA command with a terminal key.

### Format

> DEFINE [symbols-name [=] expression| /KEY key-name command |[/qualifier....]]

### Parameters

> #### symbol-name

> Name, containing from 1 to 31 alphanumeric characters, that identifies the symbol. See Section 7.2.4 for a description of SDA symbol syntax and a list of default symbols.

> #### expression

> Definition of the symbol's value. See Section 7.2 for a discussion of the components of SDA expressions.

> #### key-name

> Name of the key to be defined. You can define the following keys under SDA:

> Key Name | Key Designation
> --- | ---
> PF1 | LK201, VT100, VT52 Red
> PF2 | LK201, VT100, VT52 Blue
> PF3 | LK201, VT100, VT52 Black
> PF4 | LK201, VT100
> KP0...KP9 | Keypad 0--9
> PERIOD | Keypad period
> COMMA | Keypad comma
> MINUS | Keypad minus
> ENTER | Keypad Enter
> UP | Up arrow
> DOWN | Down arrow
> LEFT | Left arrow
> RIGHT | Right arrow
> E1 | LK201 Find
> E2 | LK201 Insert Here
> E3 | LK201 Remove
> E4 | LK201 Select
> E5 | LK201 Prev Screen
> E6 | LK201 Next Screen
> HELP | LK201 Help
> DO | LK201 Do
> F7...F20 | LK201 function keys

> #### command

> SDA command the key is to be defined as. The command must be enclosed in quotation marks (" ").

### Qualifiers

> #### /ECHO

> #### /NOECHO

> Determines whether the equivalence string is displayed on the terminal screen after the defined key has been pressed. The /NOECHO qualifier functions only with the /TERMINATE qualifier. The default is /ECHO.

> #### /IF_STATE=(state-name,...)

> #### /NOIF_STATE

> Specifies a list of one or more states, one of which must be in effect for the key definition to be in effect. States are placed in effect by the /SET_STATE qualifier, which is described in this section.

> The state-name is an alphanumeric string, enclosed in quotation marks (" "). By including several state names, you can define a key to have the same function in all the specified states. If you specify only one state name, you can omit the parentheses.

> If you omit the /IF_STATE qualifier---or use /NOIF_STATE---the current state is used.

> #### /KEY

> Defines a key as an SDA command. You need only to press the defined key and the Return key to issue the command. If you use the /TERMINATE qualifier as well, you do not need to press the Return key.

> When you define some keys as SDA commands, you must press Ctrl/V first before those keys will execute the commands. This is because of the escape sequences the keys generate and the way the terminal driver handles those escape sequences. The following keys, when defined as SDA commands, must be preceded by a Ctrl/V:

> Key Name | Key Designation
> --- | ---
> LEFT | Left arrow
> RIGHT | Right arrow
> F7...F14 | LK201 function keys

> #### /SET_STATE=state-name

> Causes the key being defined to cause a key state change rather than issue an SDA command. When you use the /SET_STATE qualifier, you supply the name of a key state in place of the key-name parameter. In addition, you must define the command parameter as a pair of quotation marks (" ").

> The key state can be any name you think appropriate. For example, you can define the PF1 key to set the state to GOLD and use the /IF_STATE=GOLD qualifier to allow two definitions for other keys, one in the GOLD state and one in the non-GOLD state.

> #### /TERMINATE

> #### /NOTERMINATE

> Causes the key definition to include termination of the command, which causes SDA to execute the command when the defined key is pressed. Therefore, you do not have to press the Return key after you press the defined key if you specify the /TERMINATE qualifier.

### Description

> The DEFINE command causes SDA to evaluate an expression and then assign its value to a symbol. Both the DEFINE and EVALUATE commands perform computations in order to evaluate expressions. DEFINE adds symbols to the SDA symbol table but does not display the results of the computation. EVALUATE displays the results of the computation but does not add symbols to the SDA symbol table.

> The DEFINE/KEY command associates an SDA command with the specified key, in accordance with any specified qualifiers.

> If the symbol or key is already defined, SDA replaces the old definition with the new one. Symbols and keys remain defined until you exit SDA.

###

#### Examples

#1
    SDA>  DEFINE BEGIN = 80058E00
    SDA>  DEFINE END = 80058E60
    SDA>  EXAMINE BEGIN:END

> In this example, DEFINE defines two addresses, called BEGIN and END. These symbols serve as reference points in memory, defining a range of memory locations that the EXAMINE command can inspect.

#2
    SDA>  DEFINE NEXT = @PC
    SDA>  EXAMINE/INSTRUCTION NEXT
    NEXT:   MOVL @00(R6),R0

> Symbol NEXT defines the address contained in the program counter so that you can use the symbol in an EXAMINE/INSTRUCTION command.

#3
    SDA>  DEFINE VEC SCH$GL_PCBVEC
    SDA>  EXAMINE VEC
    VEC: 80B7D31C  ".O.."

> After the value of global symbol SCH$GL_PCBVEC has been assigned to the symbol VEC, VEC is used to examine the memory location or value represented by the global symbol.

#4
    SDA>  DEFINE COUNT = 7
    SDA>  DEFINE RESULT = COUNT * COUNT
    SDA>  EVALUATE RESULT
    Hex = 00000031   Decimal = 49       PR$_SBIS
                                                    RESULT

> The first DEFINE command assigns the value 7 to symbol COUNT. The second DEFINE command defines RESULT to be the result of the evaluation of an arithmetic expression using the symbol COUNT. Evaluation of RESULT shows that system symbol PR$_SBIS has an equivalent value.

#5
    SDA> DEFINE/KEY PF1 "SHOW STACK"
    SDA> [PF1] SHOW STACK [RETURN]
    Process stacks (on CPU 00)
    -------------------------
    Current operating stack (KERNEL):
                  7FFE8DD4  00001703     SGN$C_MAXPGFL+703
                  7FFE8DD8  80127920
                  7FFE8DDC  00000000
                  7FFE8DE0  00000000
                  7FFE8DE4  00000000
                  7FFE8DE8  00000000
                  7FFE8DEC  7FF743E4
                  7FFE8DF0  7FF743CC
           SP =>  7FFE8DF4  8000E646     EXE$CMODEXEC+1EE
                  7FFE8DF8  7FFEDE96     SYS$CMKRNL+006
                  7FFE8DFC  03C00000

> The DEFINE/KEY command defines PF1 as the SHOW STACK command. When you press the PF1 key, SDA displays the command and waits for you to press the Return key.

#6
    SDA> DEFINE/KEY/TERMINATE PF1 "SHOW STACK"
    SDA> [PF1] SHOW STACK
    Process stacks (on CPU 00)
    -------------------------
    Current operating stack (KERNEL):
       .
       .
       .

> The DEFINE/KEY command defines PF1 as the SHOW STACK command. Also specifying the /TERMINATE qualifier causes SDA to execute the SHOW STACK command without waiting for you to press the Return key.

#7
    SDA> DEFINE/KEY/SET_STATE="GREEN" PF1 ""
    SDA> DEFINE/KEY/TERMINATE/IF_STATE=GREEN PF3 "SHOW STACK"
    SDA> [PF1] [PF3] SHOW STACK
    Process stacks (on CPU 00)
    -------------------------
    Current operating stack (KERNEL):
       .
       .
       .

> The first DEFINE command defines PF1 as a key that sets command state GREEN. The trailing pair of quotation marks is required syntax, indicating that no command is to be executed when you press this key.

> The second DEFINE command defines PF3 as the SHOW STACK command, but using the /IF_STATE qualifier makes the definition valid only when the command state is GREEN. Thus, you must press PF1 before pressing PF3 to issue the SHOW STACK command. The /TERMINATE qualifier causes the command to execute as soon as you press the PF3 key.

## EVALUATE

> Computes and displays the value of the specified expression in both hexadecimal and decimal. Alternative evaluations of the expression are available with the use of the qualifiers defined for this command.

### Format

> EVALUATE {/CONDITION_VALUE|/PSL|/PTE|/SYMBOLS} expression

### Parameter

> #### expression

> SDA expression to be evaluated. Section 7.2 describes the components of SDA expressions.

### Qualifiers

> #### /CONDITION_VALUE

> Displays the message that the $GETMSG system service obtains for the value of the expression.

> #### /PSL

> Evaluates the specified expression in the format of a processor status longword.

> #### /PTE

> Interprets and displays the expression as a page table entry (PTE). The individual fields of the PTE are separated and an overall description of the PTE's type is provided.

> #### /SYMBOLS

> Specifies that all symbols that are known to be equal to the evaluated expression are to be listed in alphabetical order. The default behavior of the EVALUATE command displays only the first several such symbols.

### Description

> If the expression is equal to the value of a symbol in the SDA symbol table, that symbol is displayed. If no symbol with this value is known, the next lower valued symbol is displayed with an appropriate offset if the offset is small enough for the selected symbol to be considered useful.

###

#### Examples

#1
    SDA> EVALUATE -1
    Hex = FFFFFFFF   Decimal = -1           PR$_XSID_N8NNN

> The EVALUATE command evaluates a numeric expression, displays the value of that expression in hexadecimal and decimal notation, and displays a symbol that has been defined to have an equivalent value.

#2
    SDA> EVALUATE 1
    Hex = 00000001   Decimal = 1            ACP$V_SWAPGRP
                                            ACP$V_WRITECHK
                                            EVT$_EVENT

> The EVALUATE command evaluates a numeric expression and displays the value of that expression in hexadecimal and decimal notation. This example also shows the symbols that have the displayed value. A finite number of symbols are displayed by default.

#3
    SDA> DEFINE TEN = A
    SDA> EVALUATE TEN
    Hex = 0000000A   Decimal = 10           EXE$V_FATAL_BUG
                                            SGN$C_MINWSCNT
                                            TEN

> This example shows the definition of a symbol named TEN. The EVALUATE command then shows the value of the symbol.

> Note that A, the value assigned to the symbol by the DEFINE command, could be a symbol. When SDA evaluates a string that can be either a symbol or a hexadecimal numeral, it first searches its symbol table for a definition of the symbol. If SDA finds no definition for the string, it evaluates the string as a hexadecimal number.

#4
    SDA> EVALUATE (((TEN * 6) + (-1/4)) + 6)
    Hex = 00000042   Decimal = 66

> This example shows how SDA evaluates an expression of several terms, including symbols and rational fractions. SDA evaluates the symbol, substitutes its value in the expression, and then evaluates the expression. Note that the fraction --1/4--is truncated to 0.

#5
    SDA> EVALUATE/CONDITION 80000018
    %SYSTEM-W-EXQUOTA, exceeded quota

> This example shows the output of an EVALUATE/CONDITION command.

#6
    SDA> EVALUATE/PSL 04080009
            CMP TP FPD IS CURMOD PRVMOD IPL DV FU IV T N Z V C
             0   0  0   1  KERN   KERN   08  0  0  0 0 1 0 0 1

> SDA interprets the entered value 04080009 as though it were a processor status longword (PSL) and displays the resulting field values of that longword.

#7
    SDA> EVALUATE/PTE ABCDFFEE

>       |31       28|27       24|23       20|19       16|15       12|11        8|7
>       |           |           |           |           |           |           |
>       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-->
>       |1 |  0 1 0 1  |0 |--| 1 1 |--| 0|                          0DFFEE
>       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-->
>       Vld  Prot= EW   M     Own=U     W                      Page Frame Number

>                  Page is Active and Valid

> The EVALUATE/PTE command displays the expression ABCDFFEE as a page table entry (PTE) and labels the fields. It also describes the status of the page.

## EXAMINE

> Displays either the contents of a location or range of locations in physical memory, or the contents of a register. You can use location parameters to display specific locations or use qualifiers to display entire process and system regions of memory.

### Format

> EXAMINE [/qualifier[,...]] [location]

### Parameter

> #### location

> Location in memory to be examined. You can represent a location by any valid SDA expression (see Section 7.2). To examine a range of locations, use the following format:

> m:n | Range of locations to be examined, from m to n
> m;n | Range of locations to be examined, starting at m and continuing for n bytes

> The default location that SDA uses is initially 0 in the program region (P0) of either of the following:

> - The process that was executing at the time the system failed (if you are examining a crash dump)
> - Your process (if you are examining the running system)

> Subsequent uses of the EXAMINE command with no parameter specified increase the last address examined by 4. Use of the /INSTRUCTION qualifier increases the default address as appropriate to the translation of the instruction. To examine memory locations of other processes, you must use the SET PROCESS command.

### Qualifiers

> #### /ALL

> Examines all the locations in the program and control regions and parts of the writable system region, displaying the contents of memory in hexadecimal longwords. Do not specify parameters when you use this qualifier.

> #### /CONDITION_VALUE

> Examines the specified longword, displaying the message the $GETMSG system service obtains for the value in the longword.

> #### /INSTRUCTION

> Translates the contents of the specified range of memory locations into MACRO instruction format. If more than 16 bytes are specified in the range, /INSTRUCTION processing might skip some bytes at the beginning of the range to ensure that SDA is properly synchronized with the start of each instruction. You can override this synchronization by specifying the /NOSKIP qualifier.

> The length of the instruction displayed varies according to the opcode and addressing mode. If SDA cannot decode a memory location, it issues the following message:

>     %SDA-E-NOINSTRAN, cannot translate instruction

> When you use this qualifier with the EXAMINE command, SDA calculates subsequent default addresses by adding the length of the last instruction, including all operands, to the last address examined.

> #### /NOSKIP

> Causes the EXAMINE command not to skip any bytes in the range when translating the contents of memory into MACRO instructions. The /NOSKIP qualifier causes the execution of the /INSTRUCTION qualifier by default.

> #### /NOSUPPRESS

> Inhibits the suppression of zeros when displaying memory with one of the following qualifiers: /ALL, /P0, /P1, /SYSTEM.

> #### /P0

> Displays the entire program region for the default process. Do not specify parameters when you use this qualifier.

> #### /P1

> Displays the entire control region for the default process. Do not specify parameters when you use this qualifier.

> #### /PSL

> Examines the specified longword, displaying its contents in the format of a processor status longword. This qualifier must precede any parameters used in the command line.

> #### /PTE

> Interprets and displays the specified longword as a page table entry (PTE). The display separates individual fields of the PTE and provides an overall description of the PTE's type.

> #### /SYSTEM

> Displays portions of the writable system region. Do not specify parameters when you use this qualifier.

> #### /TIME

> Examines the specified quadword, displaying its contents in the format of a system-date-and-time quadword.

### Description

> The following sections describe how to use the EXAMINE command.

> Examining Locations

> When you use the EXAMINE command to look at a location, SDA displays the location in symbolic notation (symbolic name plus offset), if possible, and its contents in hexadecimal and ASCII formats:

>     SDA> EXAMINE G6605C0
>     806605C0:  80002119  ".!.."

> If the ASCII character that corresponds to the value contained in a byte is not printable, SDA displays a period (.). If the specified location does not exist in memory, SDA displays this message:

>     %SDA-E-NOTINPHYS, address : not in physical memory

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