Library /sys$common/syshlp/sda.hlb Process Context  *Conan The Librarian (sorry for the slow response - running on an old VAX)

     In a uniprocessor system there are two concepts related to SDA process
     context -- the process that is current on the CPU, and the process in
     whose context process-specific SDA commands will be interpreted.
     Either these two processes are the same, or they are not.  However,
     for a multiprocessor system with more than one active CPU, the notion
     of SDA process context changes to provide a way of displaying
     information relevant to a specific process both when the process
     is current on some processor, and when the process is not.

     The SDA process context will be changed as a result of several
     different SDA commands.  When the "SDA current process" is changed to
     the current process on some CPU, the "SDA current CPU" is changed to
     that CPU in order to keep CPU context and process context in synch.
     When the "SDA current process" is changed to a process which is not
     current on any processor, the "SDA current CPU" is not changed.  When
     the SDA CPU context is changed to a CPU which has no current process,
     the "SDA current process" is undefined, and no process context
     information will be available until SDA process context is set to a
     specific process.  Type HELP CPU_CONTEXT for specific information
     about the "SDA current CPU".

     The following SDA commands will change the "SDA current process":

 	SET PROCESS process_name	! Changes the "SDA current process"
 					! to process_name

 	SET PROCESS /INDEX=n		! Changes the "SDA current process"
 					! to the process with index n

 	SHOW PROCESS process_name	! Changes the "SDA current process"
 					! to process_name

 	SHOW PROCESS /INDEX=n		! Changes the "SDA current process"
 					! to the process with index n

     The following commands will change the SDA process context if the
     "SDA current process" is not the current process on the selected CPU:

 	SET CPU cpu_id		! Changes the "SDA current process" to the
 				! current process on CPU cpu_id

 	SHOW CPU cpu_id		! Changes the "SDA current process" to the
 				! current process on CPU cpu_id

 	SHOW CRASH		! Changes the "SDA current process" to the
 				! current process on the CPU that induced
 				! the system failure

     No other SDA commands will affect the "SDA current process".

     Note:  When analyzing the running system, CPU context is not used
            because all the CPU-specific information may not be available.