Why We Specialize in I/O Subsystem Tuning

WHY WE SPECIALIZE IN I/O SUBSYSTEM TUNING

We are a performance tuning company who has developed a very sophisticated, mathematical/statistical engine. We analyze a very specific area of a data center - the I/O - VSAM subsystem, which drives a companies VSAM, DB2, CICS, IMS, Catalogs, Operating Systems files, ISPF/TSO, most third party application packages and most new mainframe software.

VSAM usage increased tremendously with the evolution of database technology systems, transaction-processing systems, application development tools and application products. Since DASD and CPU costs remained relatively high, VSAM design and tuning skills remained a high-priority skill for most companies to maintain within their IT departments. An individual with VSAM tuning skills could minimize the I/O, DASD and CPU resources required to support major IT systems by selecting the optimum VSAM parameters and reorganizing the VSAM file structure at the appropriate times.

With the advent of relational database technology, a new type of VSAM data organization scheme has emerged: Linear Data Sets. In an IBM mainframe relational environment, that application is DB2 UDB (Universal Database) for z/OS.

Therefore, the skills required to maintain high-quality performing VSAM systems were eliminated by the combination of the growth of relational systems with Linear Data Systems and the reduction in the cost of DASD and CPU.

This was a major mistake, because all of the underlying system files, which drive and control the performance of IMS, DB2, User Catalogs and CICS to name just a few, are all still pure vanilla VSAM data sets.

Needless to say, many non-relational legacy systems still remain in production today, (millions of lines of code) and even with the current costs of DASD and CPU, the financial benefits of tuning these systems can be significant. It's important to make wasted CPU cycles available to install newer versions of strategic software products and make more CPU resources available to higher-priority tasks.

We have taken up the slack in this highly visible processing area but invisible to the technicians who must analyze the files.

Critical Path Software, Inc.