Monday, March 29, 2010
Recalling a "legendary" mainframe IDMS project: how it took so much to do so little (1991)
This regarded a salary deduction billing system for a life insurance company. The home-written system was called EPIX (P meant payroll) and was written in COBOL with IDMS, but the IDMS ran with the VSAM transparency. The project consisted of taking all the reports that got mailed to client companies, stacking them onto an IDMS database (but actually a VSAM file), and laser printing them in a certain format that made it possible for one clerk to get them all mailed in one business day. A year before we had done something similar with commission systems with just sequential files.
Typically, about 100 bills ran every business day, and what we found was that the IO on the print-image “database” was very slow. One large bill with 26000 print-images would take almost 2 clock hours to run in the print step, while clocking few excp’s. The machine was a Hitachi clone of IBM (3090 something then) . A hardware change made it a bit better in a few months. But the throughput of all the jobs simply improved gradually over the years with technology. When the shop was lifted to Minneapolis after a corporate merger, it got so all 100 bills could run in about an hour in the early morning, including the random-IO VSAM stack. But in the early days there was the practical risk of following seriously behind if there was ever a mishap. So I had to watch things closely. It became compulsive and a kind of "gratification", like a blogger watching his statistics today.
Although the bills could run multi-thread according to the VSAM SHR options, there seem to be occaisonal problems with "unexplained errors", causing the last step to be rerun (part of the database would have to be restored).
In the same shop we had the issue of transmitting bills electronically. In those days there were products like TRACS and Super-TRACS, mainframe system to system. Nobody was thinking about the Internet yet or downloads or anything that resembles the way most consumers today get regular software updates (from Microsoft, Adobe, anti-virus companies, and the like). How times have changed.
Ironically (for me), the acronym “EPIX” would actually get to be the subject of a trademark and domain name fight, totally unrelated to this company or project. See my trademark blog entry April 14, 2008.