Access to Records in a VSAM Data Set

You can use addressed-sequential and addressed-direct access for the following types of data sets:

Entry-sequenced data sets
Key-sequenced data sets

You can use keyed-sequential, keyed-direct, and skip-sequential access for the following types of data sets:

Key-sequenced data sets
Fixed-length RRDSs
Variable-length RRDS

All types of VSAM data sets, including linear, can be accessed by control interval access, but this is used only for very specific applications. CI mode processing is not permitted when accessing a compressed data set. The data set can be opened for CI mode processing to permit VERIFY and VERIFY REFRESH processing only. Control interval access is described in Processing Control Intervals.