Virtual Sequential Access Method is a data storage methodology used on OS/390 mainframes. When VSAM was new, it was considered to be complex, but with a little bit of effort, it is easy to work with and tune. VSAM is the underlying method for most database files. VSAM is explained in the following pages
Understanding VSAM file types
Getting information about VSAM files
VSAM performance tuning
IAM, a VSAM alternative
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