Shared Tape Allocation Manager (STAM) Facility › Components

Components

The STAM facility includes the following components:

• STAM control file—A file residing on a DASD volume accessible by all systems that participate in tape drive sharing. The control file contains the status of each device as viewed by each system sharing the device. When a tape drive is allocated by STAM to one of the CPUs in the complex, the device’s entry in the control file is updated to reflect the allocation and to prevent other systems from allocating the drive.
• STAM parameter file—A file common to all systems, used to describe the tape drives and systems controlled by STAM.
• Two configuration file records—The STAM record to specify the location of the STAM control file and the STAM option; and the STAMPARM record to identify the filename of the STAM parameter file.
• A utility program, VMTSTF—Used to initialize the control file when sharing drives among multiple VM systems. The VMTSTF utility reads the STAM parameter file and builds a framework for the locks that STAM uses to allocate drives. Each system has a reserved area on the STAM control file disk which is used to hold locking and control information for that system. The control information includes a list of devices defined to that system.
• A CA VM:Tape operator command, STAM—Used to control the tape drive manager, display the status of tape drives, and change the status of tape drives. It allows the operator to determine the status of the tape drive manager and any device in the STAM complex.
• Extensions to the CA VM:Tape START and DRAIN operator commands to facilitate control of tape drives across systems.