| 摘要 |
A data processing and transmission network includes plural information processing systems and shared sub-systems remote from the information processing systems. Each shared sub-system includes an I/O bus (36) and a plurality of I/O bus interface logic circuits (38, 40, 42) coupled to the bus. Each interface logic circuit is coupled to one of the system processing devices (P1) via a bidirectional fiber optic link (18, 24, 30), and thereby couples its associated processing device to the I/O bus. Further fiber optic links couple each system processing device to the I/O bus of each remaining sub-system through an associated I/O bus interface logic circuit. Each sub-system further includes multiple I/O devices (90, 92), each device coupled to a device controller (86, 88) which in turn is coupled to the I/O bus. The bus interface logic circuits and device controllers incorporate arbitration circuitry (44, 46, 48, ... 94, 96) and communicate with one another via their associated I/O bus to resolve contentions for control of the bus at the sub-system level rather than at the system processor level. These features provide a network with a high degree of redundancy, substantially reduced data access times, and flexibility in network configurations. Regardless of network size, each sub-system I/O device is equally available to all system processing devices, and each system processing device is transparent to the other system processors. <IMAGE> |
