JZOS is a technology for enabling java on z/OS to access and leverage traditional z/OS facilities. This technology is composed of two components: first is a launcher, whose job is to efficiently initialize a J2SE runtime from JCL; second are the programming interfaces available to applications for accessing traditional z/OS resources such as datasets.
The JZOS launcher technology initializes a J2SE runtime; a runtime that lacks features such as: transaction, security, and connection management; checkpoint and/or recoverability facilities for batch jobs; inherent high availability and other WebSphere qualities of service provided by enterprise middleware such as WebSphere. Furthermore, for each step executed, JZOS will initialize a Java virtual machine (JVM). For a few batch steps this may not be an issue, but when executing 10’s, 100’s, 1000’s of steps within a batch window, the overhead of JVM initialization and destruction will both dramatically decrease the overall performance of the system as well as significantly increase the CPU instructions executed which, on z/OS, directly impacts the monetary cost of the system.
The JZOS programming interfaces (API’s) serve a different purpose than the launcher. With the JZOS programming interfaces, programs can access traditional z/OS resources like HFS/ZFS files, VSAM files, etc.
Since Compute Grid is hosted within an application server, there is no need to initialize the batch runtime; therefore the JZOS launcher isn't used within the Compute Grid environment. The JZOS programming interfaces however can be leveraged by Compute Grid applications, enabling these applications to access traditional z/OS artifacts such as ZFS, HFS, VSAM, and others. The JZOS programming interfaces coupled with Compute Grid delivers a strong integration point for enterprise java batch applications and traditional z/OS.
Message was edited by: Snehal Antani
