| 摘要 |
A computer network is disclosed in which a plurality of computer stations are interconnected by a single bus and wherein access to the bus is controlled by the computer stations themselves through an adapter unit at each station. Each adapter unit is assigned a unique number. When the network is running normally, control of the bus is continually passed from one live adapter unit to another in numerical sequence and the bus is active with messages, control signals or status signals from the particular adapter unit that happens to be in control at the time. If, for any reason, there should be no activity on the bus for a preselected time interval, all adapter units detecting this condition enter an election mode to elect from amongst themselves one adapter unit to assume control and resume activity. In the election mode, each participating adapter unit sends a pulse out over the bus and then monitors the bus for activity for a time period directly proportional to its assigned number. The first adapter unit whose time period expires without detecting activity is the winner and sends another pulse out over the bus causing the other participating adapter units to detect activity before their time periods expire and thus become losers in the election. Each adapter unit includes a line activity indicator for monitoring the bus for activity, a timer for measuring time, a switch which is used in generate pulses and circuitry for interfacing the computer at its associated station to the bus.
|
