The size of control intervals can vary from one VSAM data set to another, but all the control intervals within the data portion of a particular data set must be the same length. Use the access method services DEFINE command and let VSAM select the size of a control interval for a data set, or request a particular control interval size. For information about selecting the best control interval size, see Optimizing Control Interval Size.

In a linear data set all of the control interval bytes are data bytes. There is no imbedded control information.