z/OS data set definitions

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Every data set that a build process references must correspond to a data set definition. These topics describe data set definitions and how to create them.

A data set definition contains all of the information related to a given z/OS® data set. Every data set that a build process references must correspond to a data set definition, including:
  • Temporary, working data sets used by compilers, such as the SYSUT files that a COBOL compiler uses
  • Permanent data sets that will represent project artifacts
  • Unmanaged data sets, like language environment partitioned data sets, that are included in a SYSLIB concatenation
A data set definition contains the following information:
  • The name of the data set definition
  • A usage type that indicates whether the data set definition is for a zFolder data set, an output data set, an existing data set, or a temporary data set
  • The physical attributes that are required to create a data set.
  • The name of the data set
  • An optional member name
Remember: A data set definition makes no statement about the actual existence of a data set on a particular build system. It is only a container for information about a data set. When the data set definition is combined with information from a build request, such as the target system and a high-level qualifier (HLQ), you can allocate a new data set with the characteristics you specify in that data set definition.
A build process uses a data set definition four ways:
  1. As a reference to a data set and, optionally, to a member that already exists; for example, data sets containing system libraries supplied by CICS® or COBOL language environment (LE) system libraries
  2. As a new, permanent data set, wherein you specify the data set characteristics required to create a data set
  3. As a temporary data set, wherein you specify the data set characteristics required to create a data set. In the Translator portion of the Data set definition allocations table, set the temporary flag in the Keep column to indicate that this data set should be deleted before job processing ends.
    Note: You can improve system performance by eliminating much of the overhead and time required to move data physically between main storage and an I/O device if you use Virtual Input Output (VIO) devices for temporary data set allocation. To use this option, specify VIO as the Generic Unit parameter in the temporary data set definition.
  4. As a reference to a data set extended by a zFolder. When you create a new zFolder in a zComponent Project, you associate a data set definition with that zFolder. When the build process references this container, the data set is allocated based on the attributes you set in the data set definition.