IBM zAAP
The zAAP ( System z Application Assist Processor ) is a special processor released in 2004 that is available for the IBM mainframe models from z / 990 and z / 890.
A zAAP is able to execute Java applications, so that the other processors of an IBM mainframe system are relieved. The operating system z / OS 1.6 or higher is required as a system requirement for the operation of a zAAP .
The zAAP is not specially optimized for Java applications. Rather, it is a "normal" z / Series CPU that, due to microcode changes, is no longer able to run applications other than the JVM. For this, however, it always runs at maximum speed, while the other CPUs may be "throttled" depending on the computer performance ordered. In addition, a zAAP does not count in the calculation of the machine performance (the so-called MSU rate), which reduces software costs. However, no more zAAPs can be configured as CPs (unrestricted, "normal" processors) in a machine.
The zAAP is also used by the XML parser integrated in the z / OS .
On the current IBM mainframe models (z14, z13 and z13s) zAAP processors are no longer supported, only zIIP processors. With the operating system z / OS v1.11 or higher, suitable zAAP workloads can now be executed on the zIIP processors.