Altering Data Set Characteristics

You can change the following Storage Management Subsystem (SMS) attributes of a data set depending on its characteristics:

For SMS-managed generation data sets (GDS), you can change these attributes:
- Alter the expiration date.
- Alter the management class.
- Alter the storage class.
- Roll in deferred generation data set.
For generation data groups, you can change these attributes:
- Alter the expiration date.
- Assign a new generation data group (GDG) limit.
- Uncatalog generation data sets.
- Scratch generation data sets.
For SMS-managed non-generation data sets, you can change these attributes:
- Alter the expiration date.
- Alter the management class.
- Alter the storage class.
For non-SMS-managed non-generation data sets you can change these attributes:
- Alter the expiration date.
- Roll in deferred generation data set (GDS).
For SMS-managed data sets with Data Set Entry Type 'UNKNOWN', you can change these attributes:
- Alter the expiration date.
- Assign a new GDG limit.
- Uncatalog generation data sets.
- Scratch generation data sets.
- Roll in deferred generation data set.
- Alter the management class.
- Alter the storage class.
When Data Set Environment is 'UNKNOWN' and the Data Set Type is also 'UNKNOWN', you can change these attributes:
- Alter the expiration date.
- Assign a new GDG limit.
- Uncatalog generation data sets.
- Scratch generation data sets.
- Roll in deferred generation data set.

You can use the ALTER line operator to perform these tasks. Table 1 summarizes the line operator that ISMF uses to change data set characteristics.

Table 1. Summary of Commands to Alter Data Set Characteristics
Task	Function	Scope	Action
Alter data set characteristics.	ALTER	Single cataloged data set	Invokes a panel that you use to change the Management or Storage Class, GDG limit, and expiration information.

See Using the Data Set ALTER Line Operator for more information. ISMF help panels from each of the ALTER panels describe the attribute fields in detail.