Job Control Language is an HP 3000 nuance, a tool embedded in many an application suite under MPE/iX. Making changes to accomodate JCL can be one of the most complex parts of a migration to another platform. Sometimes, though, JCL is there because a more elegant tool wasn't available when the app was designed.
Comp Three, a HP 3000 services provider and software creator, has outlined this kind of migration in a case study up on its Web site. The story in the study covers Raytheon, an HP 3000 site which had been running an in-house project cost and billing system under MPE/iX, but got its migration orders in 2004. Comp Three got called in to help on the migration, which they said was accomplished in three months.
Sound lightning fast? Much of the time might have been saved by passing up the JCL in the application. According to the Comp Three story, better reporting tools from the world of SQL eliminated the need to replace JCL with scripts — the usual substitution on a 3000 migration.
Raytheon picked Oracle as its target platform, along with Windows NT as the operating environment. Comp Three said it got the project completed so quickly with an
“intelligent re-engineering” approach to the migration. Instead of translating function-by-function and screen-by-screen, we inventoried all the HP 3000 functionality, and developed a less redundant system.
Comp Three used its TIPS software to move the IMAGE/SQL data to Oracle, but listed "Eliminating batch reports and JCL files" as its first accomplishment:
In looking at the reports and JCL, we ascertained that almost all of the JCL simply executed various report programs. Most of these programs, in turn, went after a handful of the same datasets.
We replaced all the JCL and reports with a few flexible online reporting screens, each of which allowed for multiple selection criteria, and sorting and summing by any field. These screens allowed for saving to Excel, satisfying the hard copy requirement.
By using cursor-less SQL, the screens all executed many times faster than on the HP 3000 — quickly enough to be run on-line.