Runtime Considerations › Specifying File Characteristics › Specifying Characteristics of a Concatenated Data Set

Specifying Characteristics of a Concatenated Data Set

You define a concatenated data set (z/OS) by coding multiple DD statements in your JCL for a single ddname. For CA ADS Batch, characteristics that you specify for the file at the IDD level are enforced for every data set.

Rules for Concatenated Data Sets

Concatenated data sets must conform to the following rules:

• Data sets can be of different device types; for example, disk, tape, or scheduler (SYSIN).
• The data set with the largest block size must appear first in the concatenation.
• The record formats must be equivalent; that is:
  • All fixed or fixed blocked, or a mixture of the two
  • All variable or variable blocked, or a mixture of the two
  • All undefined
• The record lengths must correspond to the record format:
  • If the record format is fixed or fixed blocked, the logical record lengths must be equal.
  • If the record format is variable or variable blocked, the logical record lengths must be less than or equal to the first logical record length.
  • If the record format is undefined, the logical record length is not applicable.

In addition, the data sets must conform to standard z/OS rules for concatenated data sets; for example, the maximum number of data sets allowed in a concatenation is 255.