It is important to recognize that virtual memory is a valuable solution to the physical limitations imposed by computer systems. This section of the virtual memory module, looks at how the implementation of virtual memory in a system affects system performance. In order to assess the performance of a system, there must be a systematic way to measure activity in the system. This system of measure is discussed in an overview of the queueing network module. Since there are a number of definitions introduced in this section and referred to thoughout the blue line, a glossary of terms has been included.

Thrashing is a serious problem in multiprogrammed systems. This section of the virtual memory module includes a discussion of the causes of thrashing and preventive measures to keep a system running efficiently.

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