Abstract: A system includes a plurality of computers interconnected by a network including one or more switching nodes. The computers transfer messages over virtual circuits established thereamong. A computer, as a source computer for one or more virtual circuit(s), schedules transmission of messages on a round-robin basis as among the virtual circuits for which it is source computer. Each switching node which forms part of a path for respective virtual circuits also forwards messages for virtual circuits in a round-robin manner, and, a computer, as a destination computer for one or more virtual circuit(s), schedules processing of received messages in a round-robin manner. Round-robin transmission, forwarding and processing at the destination provides a degree of fairness in message transmission as among the virtual circuits established over the network.

Abstract: A computer interface system for communicating between computers along designated circuits is provided. An interface unit is provided in each host computer. Each unit includes a memory map that stores a map of physical addresses that correspond to virtual addresses for each application involved in a communication link. Each transfer of data is designated by a circuit that is established using the ATM protocol. The circuit is recognized by each unit involved in the communication and facilitates direct access of each host computer's main memory with minimum intervention from the operating system. A novel dynamic buffer management system is also provided.

Abstract: An integrated earth contouring system uses a postioning system such as a GPS system to track the location of an earthmover on a work site. A display device visible to a driver of the earthmover displays a difference between an existing surface contour and a desired surface contour of the work site. The display device may show a three-dimensional image which rotates or a two-dimensional image having a cursor which rotates to represent the earthmover. A blade sensor tracks the position of the earthmover blade, and the display is updated to show changes in the existing surface contour when the earthmover is moved on the site with the blade height between the height of the existing surface and the height of the desired surface. An orientation sensor on board the earthmover provides the microprocessor with the orientation of the earthmover, and a memory unit is provided to allow storage and retrieval of surface data by the microprocessor.