Overview of Computing Resources
The following resources are used to run a SAS program:
|
Resource
|
Description
|
|---|---|
|
CPU time
 |
the amount of time that
the central processing unit (CPU) uses to perform requested tasks
such as calculations, reading and writing data, conditional logic,
and iterative logic.
|
|
real time
|
the clock time (elapsed
time) it takes to execute a job or step. Real time is heavily dependent
on the capacity of the system and on the load (the number of users
who are sharing the system's resources).
Because you cannot always
control the capacity demand and the load demand on your system, real
time is sometimes a less useful measure of program efficiency than
CPU time. However, excessive use of real time often motivates programmers
to improve a program's efficiency. Some procedures enable you
to use threaded processing to reduce real time. Threaded processing
can increase CPU time. Therefore, it is recommended that you track
both CPU time and real time.
|
|
memory
 |
the size of the work
area in volatile memory that is required for holding executable program
modules, data, and buffers.
|
|
data storage space
 |
the amount of space
on a disk or tape that is required for storing data. Data storage
space is measured in a variety of units, some of which are used only
in certain operating environments, as described below:
|
|
I/O
 |
a measurement of the
Read and Write operations that are performed as data and programs
are copied from a storage device to memory (input) or from memory
to a storage or display device (output).
|
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