Technical data

SDA Description
Using PAGEFILE.SYS
If you are using the SYS$SYSTEM:PAGEFILE.SYS as the crash dump file, you
must include SDA commands in SYS$MANAGER:SYSTARTUP_VMS.COM that
free the space occupied by the dump so that the pager can use it. For instance:
$ ANALYZE/CRASH_DUMP SYS$SYSTEM:PAGEFILE.SYS
.
.
.
COPY dump_filespec
EXIT
2 Analyzing a System Dump
SDA performs certain tasks prior to bringing a dump into memory, presenting its
initial displays, and accepting command input. This section describes those tasks,
which include the following:
• Verifying that the process invoking it has privileges to read the dump file
• Using RMS to read in pages upon request
• Reading the system symbol tables (SYS$SYSTEM:SYS.STB and
SYS$SYSTEM:REQSYSDEF.STB)
• Executing the commands in the SDA initialization file
For detailed information about the investigation of a system failure, see
Section 8.
Requirements
To be able to analyze a dump file, your process must have the following:
• Read access to the file that contains the dump and to copies of the following
symbol tables, which SDA reads by default:
SYS$SYSTEM:SYS.STB (the system symbol table)
SYS$SYSTEM:REQSYSDEF.STB (the required subset of the symbols in
the file SYSDEF.STB)
• A system UIC or SYSPRV privilege for a process to read the dump file.
As included in the distribution kit, SYS$SYSTEM:SYSDUMP.DMP,
SYS$SYSTEM:SYS.STB, and SYS$SYSTEM:REQSYSDEF.STB are protected
against world access.
• Sufficient virtual address space for SDA to access the entire dump and any
required symbol tables.
To ensure that SDA has the correct amount of virtual address space, a value
of 16,000 of the system parameter VIRTUALPAGECNT should be sufficient to
analyze any dump, unless there is an exceptionally large number of symbols.
You might need to increase the size if your particular installation places
heavy demands on the virtual address space of the process.
SDA–8