Data Set (IBM Mainframe) - Dataset Organization

Dataset Organization

For OS/360, the DCB's DSORG parameter specifies how the dataset is organized. It may be physically sequential ("PS"), indexed sequential ("IS"), partitioned ("PO"), or Direct Access ("DA"). Datasets on tape may only be DSORG=PS. The choice of organization depends on how the data is to be accessed, and in particular, how it is to be updated.

Programmers utilize various access methods (such as QSAM or VSAM) in programs for reading and writing data sets. Access method depends on the given data set organization.