Abstract: An efficient request-reply protocol for a client-server communication and data processing model. Under the novel protocol, a client sends a Request to a server and awaits a Reply. If the Reply is not sent before expiration of a timeout period in the client, the client sends a second Request. The server provides a conditional Acknowledge if a second Request is received from the client. Thereafter, the client waits for the server to transmit a Reply without the client sending additional Requests. Under normal conditions, the inventive protocol performs as well as the best prior art protocol (the optimistic model), while under abnormal conditions, the inventive protocol performs better than the optimistic protocol and only slightly worse than the prior art pessimistic protocol. Since normal conditions should prevail for a substantially longer amount of time than abnormal conditions, the present invention provides better average performance than either prior art client-server protocol.

Abstract: A method and apparatus for analyzing each microinstruction in a microinstruction-based electronic circuit having a plurality of registers to determine which registers in a processing cycle are not involved in the processing cycle, and preventing those registers from being clocked during such processing cycle. Hence, inactive registers during a processing cycle do not consume power at the level of active registers, thus lowering overall power usage by any system employing such gated-clock registers.

Abstract: A method and apparatus for using multiple code rates for forward error correction in a cellular digital data radio communication system. Each base station broadcasts a quantity called the power product (PP), which is equal to the base station transmit power, P.sub.BT, multiplied by the power level received at the base station, P.sub.BR. For a mobile unit to determine its appropriate transmit power, P.sub.MT, requires measuring the power received, P.sub.MR, at the mobile unit and performing the following calculation: P.sub.MT ==PP/P.sub.MR. When channel path loss is large, it is possible that the power control calculation will return a value greater than the maximum transmit power capability of the mobile unit. In such a case, the mobile unit selects a lower code rate. Base station receiver sensitivity improves as the code rate decreases, so the result is similar to increasing the transmitter power. In the preferred embodiment, the invention uses 3 different code rates.

Abstract: A fault-tolerant storage device array using a copyback cache storage unit for temporary storage. When a Write occurs to the RAID system, the data is immediately written to the first available location in the copyback cache storage unit. Upon completion of the Write to the copyback cache storage unit, the host CPU is immediately informed that the Write was successful. Thereafter, further storage unit accesses by the CPU can continue without waiting for an error-correction block update for the data just written. In a first embodiment of the invention, Read-Modify-Write operations are performed during idle time. In a second embodiment of the invention, normal Read-Modify-Write operation by the RAID system controller continue use Write data in the controller's buffer memory. In a third embodiment, at least two controllers, each associated with one copyback cache storage unit, copy Write data from controller buffers to the associated copyback cache storage unit.

Abstract: A redundant array storage system that can be configured as a RAID 1, 3, 4, or 5 system, or any combination of these configurations. The invention includes a configuration data structure for addressing a redundant array storage system, and a method for configuring a redundant array storage system during an initialization process. The redundant array storage system includes a set of physical storage units which are accessible in terms of block numbers. The physical storage units are each configured as one or more logical storage units. Each logical storage unit is addressed in terms of a channel number, storage unit number, starting block number, offset number, and number of blocks to be transferred. Once logical storage units are defined, logical volumes are defined as one or more logical storage units, each logical volume having a depth characteristic. After the logical volumes are defined, redundancy groups are defined as one or more logical volumes. A redundancy level is specified for each redundancy group.

Abstract: An environment sensing/control circuit for use in conjunction with an electronic subsystem. The invention is capable of sensing and controlling conditions of the environment of the subsystem. The invention is capable of being implemented as a stand-alone device or replicated numerous times in an integrated circuit. The invention identifies changes including intermittent changes, in the environment of the subsystem from a reference state, the reference state being dynamically determined by a processor. Upon detecting such a change, the invention signals the processor. The invention can also serve as a flexible interface for control signals from the processor to the subsystem.