Performance Guidelines
Calculate the maximum size of the virtual=real area for a particular
real machine sizeby recalculating the amount of real storage required
by CP and subtracting that value from the real machine size..When you calculate the amount of real storage required by CP this time, you do
not permanently allocate free storage for the portion of storage that is
available for the virtual=real area (according to Formula1). The
result of Formula 2 is the maximum size virtual=real area(VRS) you can
specify for a particular real machine size. Formula 2 is:
r r
, ,I IRft - 256K - ARS I I VRS = RM - I I + T + 12K + 4KI---------------1 + 16KI I I 64K I I L L .J .J Use the same value for RM, I, and T as you used in Formula 1. ARS (the
available real storage) is the result calculated from Formula1. If the
calculationRM - 256K - ARS 64K
results in a negative value, replace it with zero. If thesaae calculation results in a fractional number, disregard the fraction (see Examples 1 and 2). 16K is the amount of storage needed at IPL time for
the dynamic paging area. AfterVM/370 is loaded (via IPL), the size of
the dynamic paging area is the number of pages fromDKKCPE to DKKSAV plus 16K.
The following table shows the maximum size virtual=real area you can
specify for some real machine sizes. h 384K
512K
768KHI 2M 104K 232K 484K 732K 1744K Note that in this table it is assumed the value of I is equivalent to
244Kl.lSince the amount of storage required to IPL VM/370 varies with the
inclusion of optional features and the number of devices inDBKRIO, this figure is used in the following example for illustrative purposes
only.Part 1. Planning for System Generation 13
Calculate the maximum size of the virtual=real area for a particular
real machine size
by CP and subtracting that value from the real machine size..
not permanently allocate free storage for the portion of storage that is
available for the virtual=real area (according to Formula
result of Formula 2 is the maximum size virtual=real area
specify for a particular real machine size. Formula 2 is:
r r
, ,
available real storage) is the result calculated from Formula
calculation
results in a negative value, replace it with zero. If the
the dynamic paging area. After
the dynamic paging area is the number of pages from
The following table shows the maximum size virtual=real area you can
specify for some real machine sizes.
512K
768K
244Kl.
inclusion of optional features and the number of devices in
only.