Abstract: A method of providing access to a multiplexed data bus having a plurality of data processing units coupled thereto. Each unit self-assigns sequence numbers thereto for identification purposes. The unit having the lowest sequence number obtains immediate access to the bus and may relinquish the bus by transmitting a control word, or token, with an incremented sequence number. All units receive the token but only the unit having the incremented sequence number gains access to the bus. The token passing continues through the series of sequence numbers and then recycles when no unit accepts the token (bus timeout). A newly added unit self-assigns a sequence number equal to the one transmitted prior to the bus timeout and thus acquires bus access on the next cycle. If a unit in the cycle fails, a bus timeout occurs mid-cycle and the access loop recycles. The units not gaining access to the bus during the cycle decrement their sequence numbers to close the gap, and hence gain access on the next cycle.

Abstract: A method for use with a computer which directly transfers incoming data into the computer memory. A functional address contained in a received message is used to index a pointer in a vector table. The indexed pointer addresses an input control block associated with the functional address. The input control block is used to control the flow of data into the computer memory. The input control block also controls access to the computer memory for subsequent messages having the same functional address.