IBM System/370 145 Manual page 103

utilization gets higher,
therE~
is less potential for increasing
throughput via increasing the level of multiprogramming.
The information presented in this subsection is designed to enable
the reader to more fully understand the way a system operates in a
virtual storage environment and the factors that influence system
performance. Understanding the environment and knowing the actions that
can be taken to increase system
pE~rformance
will enable each
installation to quantify the amour,~ of effort that is to be devoted to
optimizing the performance of a virtual storage operating system.
A
Guide to the IBM System/310 ModeJl
145
93