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14
Chapter 14: Understanding
How a Probe Uses RAM
How a probe uses RAM
A Windows computer uses Random Access Memory (RAM) as a form of
temporary data storage. Windows separates all available memory into three
sections: protected memory, user memory, and reserved memory. An Observer
probe, depending on how it is configured, uses these types of memory
differently.
The
protected memory is used to load critical operating system files, such as
device drivers. If any of this RAM is dedicated to a driver or some other critical
file, it cannot be used by another program. However, after Windows finishes
loading its drivers, the memory is freed and any program may access the
remaining protected memory.
User memory is all available memory beyond the protected memory. It is available
to any application at any time. The probe uses this memory to temporarily store
statistical information, such as Top Talkers data.
Reserved memory is user memory that you have specifically set aside for use by
the Observer probe. Only the probe may use that portion of RAM. When the RAM
is reserved for the probe not even the operating system may access it—even
when Observer is closed.
By having RAM reserved specifically for the Observer probe, you ensure that the
probe has the memory necessary to capture packets and store these packets for
statistical processing. If Observer runs without any reserved memory, it requests
and uses the operating system’s protected memory for capturing packets. There
is no adverse effect of running an Observer probe without reserved memory, but
it is not the most efficient way to run the probe. By default, the probe uses no
reserved memory. Our recommendation is that you reserve memory for Observer