Other parameters of the DD statement identify the data set, give volume and unit information and volume disposition, and describe the data set's physical attributes. You can use a data class to specify all of your data set's attributes such as record length and record format but not data set name and disposition. Specify the name of the data class using the JCL keyword DATACLAS. If you do not specify a data class, the automatic class selection (ACS) routines assign a data class based on the defaults defined by your storage administrator. See z/OS DFSMSdfp Storage Administration for more information on data class.