5 Things You may not Know about VSAM

VSAM is IBMs virtual storage access method. If we go deep in learning VSAM file we will know many points.

Five Points are as follows:

  1. VSAM has dual role. We can refer it for dataset types, and access method. VSAM primarily used for Applications,and can not be used for Source programs,JCLs and executable modules. We can not edit VSAM datasets with ISPF.
  2. VSAM formats disk records totally different way.
  3. Mostly we use VSAM datasets, for keyed data.
  4. VSAM dataset format by default is VB. In the JCL if we change the RECFM and BLKSIZE, it does not effect on the dataset properties.
  5. RECORDS(1000 500), The maximum allocated size is for 1000 records, it can be incremented of 500 records.RECORDSIZE(250 250), average and maximum size of the records.

Enjoy reading. I welcome your comments.

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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.