GPA Manual

Guardian Performance Analyzer (GPA) Manual—135081
Glossary-1
Glossary
#OUT. The GPA output file.
blocked request. A request that cannot be processed because another application has blocked
access to a record or file.
cache. A portion of memory used to store frequently accessed information in order to save
the time otherwise required for disk I/O operations.
cache call. A request for disk data expected to be found in cache.
cache fault. An event that occurs when a disk process expects to find a data block in cache
and discovers that the memory manager has removed it.
cache hit. A successful retrieval of data from cache.
disk queue time. Average amount of time spent waiting for a disk process to service a
request.
disk volume queuing. A buildup of disk I/O requests waiting to be completed.
dispatch. An event representing the allocation of CPU cycles to a process.
dynamic process control block. A Process Control Block (PCB
) used for a process whose
execution life is shorter than the measurement period analyzed by GPA.
GPA. The program module that performs the system analysis.
index level. In a key-sequenced file, the B-tree structure for minimizing access time consists
of one or more index levels.
MEASCOM. The command interface used to access Measure
.
MEASFH. A Measure
file handler process that builds counter records from the data in the
measurement data file.
Measure. The Tandem system performance monitoring product.
message. Information sent by one process to another process. This may be a request for
service or data.
net messages. A measure of the effective workload for a disk subprocess. Messages that do
not constitute “work” from a performance point of view are subtracted from the total
messages to obtain a meaningful number. For example, messages associated with queue
management are not considered to be performing work and are subtracted from the net
message value.