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Native VSAM Considerations › Native VSAM Data Set Structures

Native VSAM Data Set Structures

You can structure a native VSAM data set as a key-sequenced data set (KSDS), an entry-sequenced data set (ESDS), or a relative record data set (RRDS). The following table lists the characteristics of each data set structure.

Native VSAM Data Set Structures

VSAM Structure 1

Access method

Record Format

 

KSDS
  • Prime index
  • Alternate indexes

Fixed or variable

Spanned or nonspanned

ESDS
  • Relative byte address (RBA)
  • Alternate indexes

Fixed or variable

Spanned or nonspanned

RRDS

Relative record number

Fixed

Nonspanned

1 KSDS = key-sequenced data set

ESDS = entry-sequenced data set

RRDS = relative record data set