Initialization

The first step in using Control-M/Tape is to initialize Control-M/Tape in each CPU. This is done by starting procedure CTTINIT, and is usually performed as part of the IPL process. The initialization process establishes the Control-M/Tape Real-Time environment, by

1. creating the main Control-M/Tape Control Table (TCT) in Extended Common Storage Access (ECSA)
2. creating a Control-M/Tape subsystem if dynamic subsystem installation was requested

   Note: The subsystem is named CTTD, and cannot be renamed.

3. loading and defining the Control-M/Tape SVC, if dynamic SVC installation was requested by setting the DYNSVC installation parameter to Y in the CTTPARM member

   The SVC number can be specified as an installation parameter.

4. establishing the Write to Operator (WTO) intercept so that mount messages can be modified.
5. establishing the VOLSTAT intercept, so that I/O errors on tapes can be tracked by Control-M/Tape
6. establishing interfaces between Control-M/Tape and the operating system, if dynamic interface installation was requested by setting the DYNINTR parameter to Y in the CTTPARM member

   This is accomplished by setting intervention points in the operating system where Control-M/Tape obtains control. These interfaces remain until a termination process is run

7. opening the files necessary for the Real-Time environment: Media Database, Trace file and Stacking Database
8. loading modules into ECSA and setting their entry point in the TCT
9. loading rule tables, pool definitions, vault definitions, and view definitions into ECSA, and setting their address in the TCT
10. activating the Control-M/Tape subsystem

    The block of information in common storage containing key control data and pointers is called the Control-M/Tape Control Table (TCT). Its common storage address is used by all real-time components (that is, the Control-M/Tape SVC and the subsystem). All activity starts from this block, which contains pointers to all Control-M/Tape tables and modules in storage. The control block, along with its related routines, remains in common storage until Control-M/Tape is shut down.

Upon completion of the initialization process, the Control-M/Tape Real-Time environment is established and Control-M/Tape takes control of removable media processing.

After initialization, no address space is needed for the Control-M/Tape environment, even though Control-M/Tape is active in the system.