Definitions for "VSAM"
Keywords:  mvs, mainframe, sequential, ibm, legacy
Virtual Storage Access Method. VSAM data sets may be accessed sequentially and randomly.
Virtual Storage Access Method. A file-oriented access method which provides for the definition and read/write usage of keyed, sequential and relative record files.
Virtual Sequential Access Method - A data access method used with IBM Mainframes running MVS, OS/390, z/OS and VSE/ESA operating systems. VSAM has been in use for over 30 years. The original VSAM had a 4-gigabyte limit for the size of data sets. IBM has enhanced VSAM to support record-level sharing and file sizes larger than 4 gigabytes. The current architectural limit varies according to the size of the data control intervals (CI's). For a 512-byte CI size, the maximum size is 2 terabytes; for a KSDS with a CI size of 32 kilobytes, the maximum size is 128 terabytes. For additional information about VSAM refer to