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The System Dump Analyzer, or SDA, is a utility in OpenVMS that allows you to analyze a running system or a system dump after a system failure occurs. With a system failure, the operating system copies the contents of memory to a system dump file or the primary page file. Additionally, it records the hardware context of each processor. With SDA, you can interpret the contents of the dump file, examine the status of each processor at the time of the system failure, and investigate possible causes of failure.


The OpenVMS SDA allows the user to perform the following tasks:

  • Analyze a crash dump
  • Direct (or echo) the output of an SDA session to a file or device (SET OUTPUT or SET LOG).
  • Display the condition of the operating system and the hardware context of each processor in the system at the time of the system failure (SHOW CRASH or CLUE CRASH).
  • Select a specific processor in a multiprocessing system as the subject of analysis (SET CPU).
  • Select the default size of address data manipulated by the EXAMINE and EVALUATE commands (SET FETCH).
  • Enable or disable the sign extension of 32-bit addresses (SET SIGN_EXTEND).
  • Display the contents of a specific process stack (SHOW STACK or CLUE STACK).
  • Format a call frame from a stack location (SHOW CALL_FRAME).
  • Read a set of global symbols into the SDA symbol table (READ).
  • Define symbols to represent values or locations in memory and add them to the SDA symbol table (DEFINE).
  • Delete symbols not required from the SDA symbol table (UNDEFINE).
  • Evaluate an expression in hexadecimal and decimal, interpreting its value as a symbol, a condition value, a page table entry (PTE), a processor status (PS) quadword, or date and time (EVALUATE).
  • Examine the contents of memory locations, optionally interpreting them as assembler instructions, a PTE, a PS, or date and time (EXAMINE).
  • Display device status as reflected in system data structures (SHOW DEVICE).
  • Display the contents of the stored machine check frame (SHOW MACHINE_CHECK or CLUE MCHK) for selected HP computers.
  • Format system data structures (FORMAT).
  • Validate the integrity of the links in a queue (VALIDATE QUEUE).
  • Display a summary of all processes on the system (SHOW SUMMARY).
  • Show the hardware or software context of a process (SHOW PROCESS or CLUE PROCESS).
  • Display the OpenVMS RMS data structures of a process (SHOW PROCESS with the /RMS qualifier).
  • Display memory management data structures (SHOW POOL, SHOW PFN_DATA, SHOW PAGE_TABLE, or CLUE MEMORY).
  • Display lock management data structures (SHOW RESOURCES or SHOW LOCKS).
  • Display OpenVMS Cluster management data structures (SHOW CLUSTER, SHOW CONNECTIONS, SHOW RSPID, or SHOW PORTS).
  • Display multiprocessor synchronization information (SHOW SPINLOCKS).
  • Display the layout of the executive images (SHOW EXECUTIVE).
  • Capture and archive a summary of dump file information in a list file (CLUE HISTORY).
  • Copy the system dump file (COPY).
  • Define keys to invoke SDA commands (DEFINE/KEY).
  • Search memory for a given value (SEARCH).

See also