S/390 Partners in Development

VSE/ESA 2.1 and OPTI-CACHE at Pamida, Inc.

In November 1994, Pamida, Inc. (a 186-store discount chain) moved from a 9121-260 (with 64 MB) to a 9672-R21 (with 128 MB) in anticipation of VSE/ESA 2.1 and the new Turbo dispatcher. Soon after the installation of the 9672-R21, the opportunity arose to become an IBM PIP (Product Introduction Program) test site for VSE/ESA 2.1. VSE/ESA 2.1 initially was installed in January 1995 and in June the first attempt was made to move VSE/ESA 2.1 into production. After moving VSE/ESA 2.1 with the new Turbo dispatcher into production, Pamida ran into some real performance problems. Batch processing normally completed during evening shifts was still not finished by the next morning. Batch processing was constantly running 2-4 hours behind, leaving Pamida in a continuous struggle to catch up. The company worked closely with IBM developers in Germany and the only solution seemed to be upgrading to a faster processor.

The Technical Services Manager for Pamida, Inc. (Terry McWilliams) was referred to Jeffrey C. Barnard of Barnard Software, Inc. for technical advice on Pamida's transition to VSE/ESA 2.1.

In order to improve Pamida's I/O subsystem performance, Barnard Software suggested installing its OPTI-CACHE product. OPTI-CACHE is a high speed virtual storage software caching product specifically designed for the VSE/ESA operating system. On one weekend in August 1995, Pamida upgraded the memory on its 9672-R21 from 128MB to 256MB and installed OPTI-CACHE to take advantage of the added memory.

Results were nothing short of amazing. With the installation of OPTI-CACHE, Pamida's nightly batch processing was completed long before the morning shift arrived. Pamida finally was able to catch-up with its processing load and begin to plan for expansion of its business data processing requirements.

Over a recent three day period, OPTI-CACHE processed 33 million I/O requests with an average service time of 1.4 milliseconds. OPTI-CACHE typically reduces the number of I/O operations on Pamida's system by 50%. This savings also reduces the amount of non-parallel work done by the system, resulting in more effective use of the VSE/ESA 2.1 Turbo dispatcher and better utilization of the 9672-R21's multiple CPUs.

Pamida, Inc. is currently running VSE/ESA 2.1, Turbo dispatcher, POWER, VTAM 4.2, CICS 2.3, extensive VSAM, DB2 for VSE 3.5 and Sapiens.