ABCs of z/OS System Programming Volume 3 - IBM Redbooks

5.31 Planning and defining data classes
DATA CLASS ATTRIBUTES
DATA SET TYPE
RECORD LENGTH
BLOCKSIZE
SPACE REQUIREMENTS
EXPIRATION DATE
VSAM ATTRIBUTES
What does it look like?
Figure 5-31 Planning and defining data class
DC A
DC B
DC C
Sources of Data Class:
User Data Class defined (DD)
ACS DC routine (*)
RACF default
Planning and defining data classes
After you establish your installation’s standards, use your service level agreement (SLA) for
reference when planning your data classes. SLAs identify users’ current allocation practices
and their requirements. For example:
► Based on user requirements, create a data class to allocate standard control libraries.
► Create a data class to supply the default value of a parameter, so that users do not have to
specify a value for that parameter in the JCL or dynamic allocation.
Have data class names indicate the type of data to which they are assigned, which makes it
easier for users to identify the template they need to use for allocation.
You define data classes using the ISMF data class application. Users can access the Data
Class List panel to determine which data classes are available and the allocation values that
each data class contains.
Figure 5-32 on page 294 contains information that can help in this task. For more information
about planning and defining data classes, see z/OS DFSMSdfp Storage Administration
Reference, SC26-7402.
Chapter 5. System-managed storage 293