Time-tested and Proven—DJC and JEC Compared
When a compelling need arises, companies will try newer solutions. The Dependant Job Control (DJC) solution with Compuware ThruPut Manager is one that IBM is trying to make new again.
Back in the 90s, many companies went through mergers and acquisitions and were forced to try to combine JES2 and JES3 systems into a new composite environment. They weighed the risk and opted to try a then-new solution, Dependent Job Control (DJC). Offered as a component of ThruPut Manager, DJC helped them solve the complex migration from JES3 to JES2 with lower risk and the benefits of overall batch automation.
As part of z/OS R2.2, IBM has included Job Execution Control (JEC), a way to group jobs so you can define dependencies within a group. This concept offers a lot of scheduling flexibility. It sounds new and great, until you realize that ThruPut Manager has already had this feature with DJC for 20 years. Time-tested and proven by many satisfied companies, the capabilities of DJC haven’t changed since 1995. After two decades of ongoing development, DJC works as well as ever.
DJC and JEC by the Numbers
But JEC with z/OS R2.2 is free, sort of. Why would you buy another solution to do the same thing, even it has been proven out? There are a number of differences between the offerings, but here are a few that you might really care about.
- In z/OS, you must define your groups before submitting any of the jobs, which means you have to have it all planned out ahead. ThruPut Manager allows you to define them dynamically until the group is closed (all jobs have completed). In simpler times, static definitions might work, but now everything changes so rapidly that you need the flexibility to make changes in-flight.
- In z/OS, you can define jobs to run BEFORE, AFTER which gives you some scheduling flexibility. ThruPut Manager offers these options as well, but also allows you to use AND and OR type statements to increase your control of the order. IBM supports AND in its logic, but the very valuable OR option isn’t available. Often, this is critical. Imagine having to wait for a job to complete as well as needing it to be after a certain hour. ThruPut Manager also allows you to test for events and set signals. As we all know, your batch ‘plan’ only works well in theory. ThruPut Manager makes it possible to really define what you want to happen so that there are no surprises.
- In z/OS, you can define dependencies within a group. With ThruPut Manager, you can do this, but you can also define dependencies across groups, adding to the flexibility you have in managing your jobs.
- While fewer in number, there are shops still struggling to migrate off JES3, and ThruPut Manager can help you to migrate your JES3 environment.
The JEC in z/OS differs in several other ways from ThruPut Manager, including offering less flexibility in scheduling parameters and the ability to control when each job runs. If you’re already getting all the other benefits of ThruPut Manager, make sure you’ve fully exploited this particular capability. And if you haven’t installed it yet, you might want to take another look.
While you will probably upgrade to z/OS R2.2 anyway, for a variety of reasons, if you want true dependent job control, stick with the proven performer. Choose ThruPut Manager for its DJC capabilities and so much more.
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