| 摘要 |
A data processing unit includes a number of tightly coupled central subsystems, a number of peripheral subsystems, a main memory and a system management facility all coupled in common to a system bus. The system management unit has top priority on the system bus and includes centralized resources which provide apparatus for indicating the status of power and temperature, booting the subsystems, testing the subsystems, timing central subsystem functions, and allowing local and remote maintenance access to the subsystems. The system management facility receives commands from the central subystem to read from and write into the timers as well as to read the status of the overall system. The system management facility generates special commands to the central subsystem to indicate when the timers have decremented to ZERO as well as special commands to aid in hardware and software debugging. |
