FAILSOFT PERIPHERAL EXCHANGE

In a computer system, use of two or more I/O exchanges between peripheral controllers and serial peripheral units, such as disk files, disk packs and tape drives, provides redundant communication paths that can be made available for communication between the N controllers and the M peripheral units. All peripheral controllers and units are connected to each exchange. Each controller and unit may be manually assigned to a certain exchange. In the case of two exchanges, if a certain one fails due to loss of power, all peripheral units are automatically assigned to the other exchange.