Z Application Assist Processor
| Company type | Specialized mainframe processor |
|---|---|
| Industry | Computer hardware |
| Founded | June 30, 2004 |
| Products | Mainframe processors for Java and XML workloads |
| Parent | IBM |
The IBM System z Application Assist Processor (zAAP), launched by IBM in 2004, is a specialized mainframe processor designed to execute particular Java and XML workloads on z/OS, thereby improving system efficiency.
zAAP processors are compatible with zSeries 990 and 890 models, as well as subsequent systems through to the z12. From the IBM z13 onward, the zAAP functionality has been merged into the zIIP processors (referred to as zAAP on zIIP).
Although a zAAP engine utilizes the same physical hardware as other mainframe processors, IBM employs microcode restrictions to limit its operations exclusively to Java and XML tasks. Like the Integrated Facility for Linux (IFL) and zIIP, these processors are not specifically engineered to accelerate Java execution. Crucially, IBM does not modify the "software model" or MSU capacity when implementing zAAPs, enabling clients to avoid extra software licensing expenses and thus reduce costs for Java- and XML-based applications. The total count of zAAPs in a system cannot exceed that of central processors (CPs).
IBM officially released the zAAP capability on June 30, 2004, with necessary support for z/OS becoming available on September 24, 2004. The zAAPs are compatible with z/OS V1R6 and later versions, as well as Java 1.4.1 upwards. Enhancements to the z/OS dispatcher and Workload Manager (WLM) allow seamless routing of pure Java workloads to these dedicated engines. Nonetheless, some traditional processor power remains essential for native system service requests initiated by Java applications.
Major software components that benefit from zAAP include WebSphere Application Server, WebSphere Business Integration Server Foundation, WebSphere Process Server, WebSphere Message Broker, Db2, CICS Transaction Server, CICS Transaction Gateway, IMS, along with batch jobs executed through JZOS and UNIX System Services on z/OS. In 2007, IBM expanded zAAP support to encompass XML System Services for z/OS, permitting products such as DB2 9 for z/OS to utilize zAAPs for XML processing tasks.
The inaugural commercial deployment of zAAP occurred on September 1, 2004, at an insurance firm in the U.S. Midwest managing claims processing using Java 1.4.2, WebSphere Application Server Version 5.1, and near-release z/OS V1R6 on a zSeries 990 equipped with two zAAPs—a swift rollout following IBM’s initial design phase in 2003.
Support for zAAPs
Independent software vendors (ISVs) provide support for running their applications on zAAP Specialty Engines by leveraging IBM’s Java or XML Services development toolkit.
For example, GT Software, Inc.’s Ivory Server for z/OS and Ivory Server for CICS take advantage of zAAP for XML parsing via the optional IBM z/OS XML Services feature. Additionally, Ivory Server for Java utilizes zAAP, together with zIIP and the Integrated Facility for Linux (IFL).