TSS Data Sets

The TSS data set is a fixed-length BDAM data set with equal LRECL and BLKSIZE. There is no required LRECL or BLKSIZE; however, BMC Software recommends a minimum LRECL and BLKSIZE of 4096 bytes. The RECFM for a TSS data set must be FS, and the organization must be PS.

See Batch-Features-and-ETA-Macros for information on using JCL to create TSS data sets.

TSS subroutines that are resident in the IMS control region access the TSS data set. No interregion communication is required.

Consider the following when you are using and maintaining TSS data sets:

  • You can only use one TSS data set at a time within any IMS control region.
  • Use the backup utility in the ETA online interface or IEBGENER to back up the TSS data set.
  • You must protect the TSS data set from unauthorized updates.
  • Because the TSS data set can be updated from any authorized ETA session, you must use GRS or an equivalent utility to protect the TSS data set from multiple concurrent updates.
  • You should not perform data compression on the TSS data set.
  • Because the IMS control region uses the TSS data set, the DASD that you use to store the data set is critical to IMS performance. Treat the TSS data set as you would any other IMS system data set, such as long and short message queue data sets.

 

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