General Information

SMS, a component of z/OS, is executed during data set allocation and is used to manage storage space on disk. SMS creates a data set in an appropriate place with appropriate attributes, based upon the data set name. The name, created by the user, should be created using naming conventions and based upon desired data set characteristics. SMS provides interfaces to the user to specify how classes are selected, based upon the data set name.

SMS calls Control-O using DO SMS statements and ACS (CLIST-like routines, that are explained in the following paragraphs) to allocate data sets. SMS calls Automatic Class Selection (ACS) exit routines that control the triggering of ON SMS rules. ON SMS is used to trap SMS information received from the call.

ACS CALL Parameter

When a new data set is allocated, SMS calls one or all of the following ACS exit routines, depending on the value specified in the ACS Call. If you set ACS CALL to ALL, the rule is triggered three times, once for each ACS exit routine.

• Data class selection.
• Management class selection.
• Storage class selection.

Note: Do not set ACS CALL to ALL in combination with DO SMSCLASS, because the rule will assign the same class name to all three classes.