What is VSAM?
VSAM stands for Virtual Storage Access Method. It’s a Data Management method used to organize, store, catalog, retrieve and delete the datasets in mainframe system (VSAM and Non-VSAM). This access method makes it easier for an application to execute an I/O operation (moving data between an I/O device and memory). In fact VSAM is the first access method designed for Virtual Storage Environment.
VSAM supports fixed as well as variable length records. These records are placed in blocks of Control Intervals and these control intervals are further placed as Control Area (CA consists of multiple CIs).