Abstract: This disclosure involves the combination of data compression and decompression with a virtual memory system. A number of computer systems are discussed, including so-called embedded systems, in which data is stored in a storage device in a compressed format. In response to a request for data by a central processing unit (CPU), the virtual memory system will first determine if the requested data is present in the portion of main memory that is accessible to the CPU, which also happens to be where decompressed data is stored. If the requested data is not present in the decompressed portion of main memory, but rather is present in a compressed format in the storage device, the data will be transferred into the decompressed portion of main memory through a demand paging operation. During the demand paging operation, the compressed data will be decompressed.

Abstract: A port switching hub consists of a number of local area network ports, a number of internal channels to which these ports may be connected from time to time under program control, and circuitry suitable for causing each channel to function as a local area network repeater. The ports have a variety of control and measurement functions associated with them. An instrumentation, a programmable controller or embedded computer program, for example, estimates the traffic load on each channel based on information available from the port controllers. The control program further predicts the effect of reassigning the ports to different channels based on available data, internal models of network behavior, and other constraints such as address assignment, and changes the port assignment so as to achieve a goal, such as balancing of traffic load or assignment. The reassignment of ports may occur periodically, or in response to an event, and may or may not be forced to occur during a period of channel inactivity.