Controlling shared DASD

The shared direct access storage device (DASD) option allows multiple systems to access common data on direct access storage devices. This sharing is accomplished through a hardware feature of the DASD control unit together with the reserve/release function of the operating system or through the global resource serialization function of the operating system. (For more information, see z/OS MVS Planning: Global Resource Serialization.)

During system installation, you can choose the shared DASD option. The advantages of using shared DASD include:

Reducing the amount of time your operators have to spend moving volumes from one system to another.
Minimizing the updating of data sets because operators have to update only one instead of two or more duplicates.
Simplifying scheduling. Unless the job has other special requirements, you can run a job needing a specific data set on a shared device on any of the sharing systems.