5. Maintenance › 5.16 SAS Configuration Options Used by CA MICS › 5.17.1 Overview of PDSEs

5.17.1 Overview of PDSEs

Historically, CA MICS has been installed as a collection of
primarily partitioned data sets along with several SAS data
libraries, and a few physical sequential data sets.

We recognize the benefits of migrating from partitioned data
sets to partition data set extended format data sets.
Following are the advantages of using PDSE data libraries:

o  A PDSE can automatically reuse space within the data set
   without having to periodically run a utility to reorganize
   it.  It can use noncontiguous space, reclaimed from deleted
   members.

o  The size of a PDSE directory is flexible and expands to
   fit the members stored in it.

o  The system reclaims space automatically whenever a member
   is deleted or replaces, and returns it to the pool of
   space available for allocation to other members of the
   same PDSE.  The space is reused without having to do an
   IEBCOPY compress.

o  PDSE members can be shared.  This allows modification of
   separate members of the same PDSE, at the same time.

o  Reduced directory search time.  The PDSE directory, which
   is indexed, is searched using that index.

o  Allows creation of multiple members simultaneously.

o  PDSEs can reside in up to 123 extents.

o  When written to DASD, logical records are extracted from
   the user's blocks and reblocked.