TSO Library Concatenation

This page is read from $BENEFIT member of the CatLibs rexx library and reformatted using some ASP scripts for web page viewing, for your convenience.

Benefits of CatLibs

Here are some underlying benefits of using these parmlibs:

• This method is quite efficient for allocating custom libraries. Some methods require that all libs be allocated first, after which they are examined, freed, then reallocated with custom libs ahead of the original. In many cases (depending on how you are reallocating) this can only be done one library at a time, so if you have several libs to be allocated for the same DD, the same free-and-reallocate process must be performed multiple times.
• CATLIBS is much more customizable for each user than many other methods. The number and variety of logon procs can be reduced since we can customize a special environment for each user if necessary.
• If a DSN in an include member is misspelled, accidentally deleted, exclusively enqueued, or otherwise unavailable, this procedure will recover from the condition and reallocate the DD, removing the offending datasets from the concatenation. This will allow you to logon despite problems with individual datasets. Provided the basic datasets are available, you'll still be able to get to the system, which means more availability, and gives you peace of mind in a disaster recovery scenerio.
• Product libraries are grouped into nice packages in separate members of this parmlib. Removing a product from a logon proc is as simple as commenting the include statement in the driver member. Other methods require you to make updates in various areas, and the risk is high that you'll make a mistake causing a JCL error at logon, or leave in a library somewhere that should have been removed.
• It helps to document what libraries correspond to what product. I discovered, for instance, that we had LANRES datasets allocated to our logon procs simply because that's what came with the system and it was difficult to track down what the datasets were for. We don't use LANRES and therefore don't need them allocated. Having product parmlibs helps to self-document all datasets that are in use.
• Only those products you actually use will be allocated to your logon proc. It's senseless for Joe-user to have system programmer libraries allocated! This allows you to assign libraries more easily based on their use.

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