Multi-processor central control unit of a telephone exchange system and its operation

摘要

A method and apparatus for operating a multiprocessor control computer provides that at least one part of the central processors may be connected through switches to each half of a duplicated central bus system and through switches to each half of duplicated memory banks of a common memory. With the duplication and selectable switching, the multiprocessor control computer may be normally operated while the remainder of the computer may be connected to a special computer for modification of the normal operating program. Data already in one memory bank can also be stored in another memory bank under the same address so that after the special operating time of both memory banks, the memory banks contain the same information at the same addresses. Two specific processors are provided for operating and security functions, while the remainder of the processors carry out exchange functions. One processor controls and is loaded only to a predetermined percentage of its computing capacity while the other always holds open at least that predetermined percent of computing capacity in case it must take over the control function.