Abstract: In a multiprocessor system, a data transferring port into which data can be written only when no data is stored and from which data can be read only when it is stored is provided, and the port itself is caused to perform an exclusion control, whereby that processor of a plurality of processors which has once acquired a bus mastership is prevented from making another bus use request until the bus use requests of the other processors run out.

Abstract: In a loop bus network system where a plurality of processors are connected to a unidirectional loop bus and each of the processors generates a transmission message with a level number which designates the bus use priority of the message, each of node processors, in which message transmission request is generated, transmits to the loop bus a bus control data including a level number of the message generated therewithin and a data which represents the bus use priority assigned to each node processor for that level number. Each of the node processors compares the bus control data transmitted therefrom to a succeeding node with a control data received from a preceding node and then transmits only the larger data of the compared two data, thereby to ascertain that only one bus control data propagates around the loop and a loop bus use priority is assigned to one of the node processors that has generated the above-mentioned one bus control data.

Abstract: A method of storing articles in a warehouse having a plurality of storage blocks arranged adjacent each other with each of the storage blocks having a plurality of spaced racks for storing articles and linearly extending aisles between the racks. The warehouse also includes article transfer apparatus arranged for movement in respective aisles to transfer articles relative to a given location within a respective storage block and a control arrangement for operating the article transfer apparatus in accordance with a predetermined mode to transfer articles relative to said storage blocks.