You execute the System Dump Analyzer program by means of commands. SDA reads these commands from SYS$INPUT, which can be your terminal or a command file. You can send the output to a file or to your terminal. Any of the following commands invoke SDA: $ ANALYZE/CRASH_DUMP dump_file $ ANALYZE/SYSTEM $ RUN SYS$SYSTEM:SDA When a fatal BUGCHECK error causes the system to fail, the system writes the current state of the hardware registers and all physical memory to a directory file called SYSDUMP.DMP in the SYSEXE directory on the system disk. Alternatively, the system's paging file may be specified as the destination of the dump information instead of SYSDUMP.DMP. This is useful on systems that have constrained disk space. If there is insufficient space on the system disk, the file SYSDUMP.DMP may be created on a separate disk (dump off system disk, DOSD). Note that pages currently in the paging file (paged out) are not saved because the paging file is too large. Although these pages are lost from the crash dump, the effect on debugging will be minimal because most pages relating to the system failure are still in physical memory when the failure occurs, and are thus saved in the dump file. Of course, if the paging file is used as a dump file, the pages that are there are wiped out. SDA is always run during system startup. When executed at this time, SDA first checks to see if the system has just failed. If so, SDA executes the CLUE HISTORY command to record information from the system dump. If the system has not just failed, SDA exits. HP recommends that the system manager set up the system-startup file so that SDA collects additional information during system startup. The required SDA commands should be included in a command procedure referenced by the CLUE$SITE_PROC logical name in the system logical name table. The following example shows the SDA commands typically invoked via CLUE$SITE_PROC during system startup. The most important of these is the COPY command, which copies the dump file to another file. This operation is recommended because the system always overwrites this file in the event of a system failure, and the record of the previous failure is lost unless another copy exists. Furthermore, if the paging file was used as the dump file, the pages that contain the dump information are not available for paging until they are explicitly released by the COPY command. ! ! SYS$MANAGER:SAVEDUMP.COM ! ! Print dump listing and save dump if system just failed ! ! Add the following command to SYS$MANAGER:SYLOGICALS.COM ! to invoke these SDA commands automatically on reboot ! after a system failure: ! ! $ DEFINE /SYSTEM CLUE$SITE_PROC SYS$MANAGER:SAVEDUMP.COM ! SET OUTPUT DISK1:SYSDUMP.LIS ! Create listing file READ/EXEC ! Read symbols into the SDA symbol table SHOW CRASH ! Display crash information SHOW STACK ! Show current stack SHOW SUMMARY ! List all active ! processes SHOW PROCESS/PCB/PHD/REG ! Display current process COPY SYS$SYSTEM:SAVEDUMP.DMP ! Save dump file (always last) EXIT If you need more information on the system failure, you can execute SDA interactively or add SDA commands to this startup file.