System-managed buffering (SMB) supports batch application processing and processing of data sets with associated alternate indexes (AIX®). You can use any of the following four SMB processing techniques:

Direct optimized (DO)

Choose this technique for applications that access records in a data set in totally random order.

Sequential optimized (SO)

Choose this technique for backup and for applications that read the entire data set from the first to the last record or read a large percentage of a data set in totally sequential order.

Direct weighted (DW)

Choose this technique for applications that access records in a data set mostly in random order.

Sequential weighted (SW)

Choose this technique for applications that access the entire data set mostly in sequential order.

Related Reading: For more information about Implementation techniques and SMB, see z/OS DFSMS Using Data Sets.