IBM Mainframe Forum

Hi All,

Can anyone please let me know how many libraries can be coded in a step/JOB ?

The first problem with the query is the term "libraries." This is usually taken to mean "partitioned data sets." There are many other types of data sets that can be mixed with "libraries."

You use DD statements to specify a "library" data set or any other sort of data set to a job step.

The proper way to make this query is to ask, "How many DD statements can I specify for a job step?"

Unfortunately, there is no hard answer to this query, as it depends on the maximum size of a data area in the operating system called a TIOT, and this is set by system administrators when the system is set up. Another complexity is the space required for a DD statement in the TIOT is not fixed.

However, in most systems, you can define approximately 1500 DD statements for one job step. In a few systems it may be lower, and in some systems it may be as high as approximately 3000.

There is a hard limit on the maximum number of job steps in one job: 255.

Terminology is critical in IT, where similar terms may mean very different things. Your question is NOT clear on what you are referring to as "libraries" -- load libraries only? source libraries? all data sets? places a program could be loaded from? Each of these would have different answers.

In other words, as you have stated your question it cannot be definitively answered. People can guess and answer that guess, but someone else could guess differently and answer a different way.