Performance Guidelines
Determine the maximum size of the virtual=real area for a real machine
with 768K of storage that executes a VM/370 system that requires 244K to 1PL. r r, r " I 1768K I 1768K - 256KII ARS = 768K - 1244K + 4KI----1 + 12K + 4KI-----------1 I I 256K I I 64K i I L L.J L .J.J ARS = 768K -[244K + 12K + 12K + 32K] ARS = 768K - 300K ARS = 468K r r , I 1768K - 256K - 468KI VRS = 768K - 1244K + 12K + 12K + 4KI------------------I I I L L
r r, , I 144K, I VRS = 768K - 1268K + 4KI---1 + 16K I I 164K I I L L .J VRS = 768K -[268K + 4K[O] + 16K] VRS = 484K
.J
Note that the fraction (44/64) resulting from the RM - 256K - ARS 64K
calculation in Formula 2 is truncated to zero.
64K
14 IBM VM/370 Planning and System Generation Guide , .J
, I + 16K I I .J

Performance Guidelines
Determine the maximum size of the virtual=real area for a real machine
with 384K of real storage. The VM/370 system requires 244K to IPL. r r, r " I I 384K , 1384K - 256K" ARS 384K - 1244K + 4KI----1 + 12K + 4KI-----------I' , I 256K I I 64K , t
L L .J ARS = 384K -[244K + 4K[2] + 12K + 8K] ARS = 384K -[272K] ARS 112K
L .J.J Note that the fraction 384/256 in the trace table calculation is rounded
to the next higher integer, two.
r r "
! 1384K - 256K -112KI I VRS = 384K - 1244K + 8K + 12K + 4KI-----------------1 + 16K I , I 64K I , L L .J .J r r , , I I 16, I VRS = 384K - 1264K + 4KI--1 + 16K I I 1641 I L L L .J VRS = 384K -[28 OK] VRS = 104K
Note that the calculation RM - 256K - ARS 64K
results in a fraction that is then replaced by zero. Part 1. Planning for System Generation 15