VSAM Vs Non-VSAM (for Experienced)

The differences are written by considering VSAM and Non-VSAM file are as below -

  • VSAM files can be ESDS, KSDS, LDS, or RRDS.
  • Non-VSAM files can be flat files, BSAM files, QSAM files, PS, GDG, or sequential files.
High-speed data retrieval because of its organized index. Slow data retrieval because of no organized index.
Supports all types of data retrieval (sequential, random, dynamic, linear). Supports only sequential retrieval.
Records can be deleted physically, and the space used by deleted records can be reused for storing newly inserting records without reorganization. This helps for faster retrieving. Records can be deleted logically but not physically.
Supports in batch and online systems. Supports in the batch system only.
Records are in sorted order by default. Records should get sorted manually before use if required.
VSAM files require the utility to create, edit and delete the file. Non-VSAM files can be created, edited, and deleted using the ISPF facility.
Only works with data stored on disk and can't handle data stored on other devices like tapes. Files can store on both disks and tapes.
VSAM uses its own access method to process the data from files. Non-VSAM files use either use BSAM, QSAM, or BPAM.
Supports index and alternate index. Doesn't support any index.
Datasets can be shared across systems and regions. Datasets stores locally.

The identical thing is, both VSAM and Non-VSAM files are used in mainframe environment only.

To conclude this, VSAM is a more effective and far better option than non-VSAM files. VSAM files replace the traditional Non-VSAM files everywhere except in report programming.