DATACLAS parameter

Parameter type

Keyword, optional

This parameter is useful only if SMS is running. Without SMS, use the DCB parameter (described on section DCB parameter) or the AMP parameter (described on section AMP parameter). If you use a data class for your new data set, SMS must be running but your data set does not have to be SMS-managed.

Purpose

Use the DATACLAS parameter to specify a data class for a new data set. The storage administrator at your installation defines the names of the data classes you can code on the DATACLAS parameter.

If SMS is not installed or is not active, the system syntax checks and then ignores the DATACLAS parameter.

SMS ignores the DATACLAS parameter if you specify it for (1) an existing data set or (2) a data set that SMS does not support.

You can use the DATACLAS parameter for both VSAM data sets and physical sequential (PS) or partitioned (PO) data sets.

A data class defines the following data set allocation attributes:
  • Data set organization
    • Record organization (RECORG) or
    • Record format (RECFM)
  • Record length (LRECL)
  • Key length (KEYLEN)
  • Key offset (KEYOFF)
  • Type, PDS, PDSE, basic format, extended format, large format, or HFS (DSNTYPE)
  • Space allocation (AVGREC and SPACE)
  • Retention period (RETPD) or expiration date (EXPDT)
  • Volume-count (VOLUME)
  • Compaction
  • Media interchange type
  • Space constraint relief
  • Block size limit
  • For VSAM data sets (IMBED or REPLICATE, CISIZE, FREESPACE, SHAREOPTIONS, REUSE, INITIAL LOAD, SPANNED/NONSPANNED, BWO (backup while open), and LOGGING OPTIONS)

Note

The volume-count on the VOLUME parameter in the data class specifies the maximum number of SMS-managed volumes that a data set can span. The maximum volume-count allowed by data class is 255. For SMS-managed DASD data set, the maximum volumes that a data set can span is 59, a greater than 59 volume-count in data class will be overridden with 59. The volume-count is ignored for data sets to which no storage class is assigned.

For tape data sets, only the following attributes apply:
  • EXPDT
  • LRECL
  • RECFM
  • RETPD
  • VOLUME COUNT

References

See z/OS DFSMS Using the Interactive Storage Management Facility for information on how to use ISMF to view your installation-defined data classes.

Parent topic: DD statement