All of these elements are required for a valid SMS configuration, except for the storage class ACS routine.

Recommendation: Ensure that a storage class ACS routine is part of your minimal configuration. This prevents users from externally specifying a storage class on their DD statements, causing the data set to be system-managed before you are ready.

The storage class ACS routine ensures that the storage class read/write variable is always set to null. The storage group ACS routine is never run because no data sets are system-managed. So, no data sets are allocated as system-managed by the minimal configuration.

Users become familiar with the device-independent space allocation implemented by SMS facilities supported by the minimal configuration. Specifically, the base configuration contains a default unit that corresponds to a DASD esoteric (such as SYSDA). Default geometry for this unit is specified in bytes/track and tracks/cylinder for the predominant device type in the esoteric. If users specify the esoteric, or do not supply the UNIT parameter for new allocations, the default geometry converts space allocation requests into device-independent units, such as KBs and MBs. This quantity is then converted back into device-dependent tracks based on the default geometry.

Follow these steps to activate the minimal configuration:

1. Allocate SMS control data sets.
2. Define Global Resource Serialization (GRS) resource names for active SMS control data sets.
3. Define the system group.
4. Define a minimal SMS configuration.
5. Define the SMS to z/OS®.
6. Activate the SMS.
7. Control SMS processing
8. Use simplified JCL to allocate data sets.
9. Enforce standards.

To use SMS effectively, use the information in this chapter and in z/OS DFSMSdfp Storage Administrationz/OS DFSMSdfp Storage Administration.