IBM 990 - Manual (Page 151)

Chapter 6. Software support 139
Figure 6-3 Logical flow of Java code execution on a zAAP
zAAPs do not affect the overall MSU or capacity rating of a system or logical partition, that is,
adding zAAPs to a system or defining to a logical partition does not affect the software license
charges. There is no additional z/OS charge for zAAPs.
Subsystems that exploit zAAPs are:
WebSphere Application Server V5.1
CICS/TS V2.3
DB2 V8
IMS V8
WebSphere WBI for z/OS
The functioning of a zAAP is transparent to all IBM and ISV Java programming on JVM 1.4.1
and above.
Three execution options for Java code execution are available. These options are user
specified in IEAOPTxx and can be dynamically altered by the SET OPT command.
Option 1: Java dispatching by priority (honor_priority=yes)
Option 1 is the default option and specifies that standard CPs execute both Java and
non-Java work in priority order when zAAPs are not configured. When zAAPs are configured,
they only execute Java work in priority order while the CPs execute normal tasks and JVM
tasks in priority order. This option is oriented towards servicing work with the highest priority
first, regardless of the type of work.
Option 2: Java discretionary crossover (crossover=yes)
Standard CPs execute Java work in priority order only if no non-Java (standard) work is
available to be dispatched. This way, Java work may execute on a CP as if it has a lower
priority than non-Java work. This option is oriented towards environments where not enough