Abstract: A digital computer which includes a memory refresh system for controlling the generation and sequencing of refresh signals to a memory subsystem comprised of at least one memory unit having a plurality of slots each capable of receiving a dynamic random access memory bank therein. The memory refresh system includes means for generating refresh signals and at least one independent refresh sequence controller for efficiently controlling the sequence in which the memory banks associated with a particular refresh sequence controller receive refresh signals. Each refresh sequence controller controls a combination of multi-stage shift registers for issuing refresh signals to memory banks installed on the corresponding memory unit and multi-stage shift registers for providing wait cycles during which refresh signals are being generated by other independent refresh sequence controllers.

Abstract: A digital computer system has a central processor unit (CPU) and a store queue facility. The store queue facility receives full digital words or segments thereof (bytes) for intermediate storage prior to storage in an addressable unit such as a dynamic random access memory (DRAM). The store queue facility has a plurality of registers for storing digital words and bytes for storage at different, discreet addresses in the addressable unit. The store queue has circuitry for assembling bytes into a digital word or into a plurality of bytes for ultimate storage in the addressable unit. Some combinations of bytes are not valid and will therefore not be entered together in a single digital word.

Abstract: A data stream process pipeline and method of transferring data from a storage device to a central processor unit (CPU) or cache memory includes an input latch arrangement, error correcting circuitry, and an output latch arrangement. In embodiments of the present invention the input and output latch arrangements include two latches and means for multiplexing the outputs of the two latches.

Abstract: A computer system includes an accessible memory controller, an accessible cache controller, and circuitry for accessing the accessible memory controller and the accessible cache controller simultaneously. Certain preferred embodiments of the present invention also include a deassertable miss line, that is, a line which when deasserted indicates that the data was found in the cache and that the memory access should be cancelled.

Abstract: A digital computer having a dual path memory retrieval system for a dynamic RAM memory unit comprised of any number of interleaved memory banks. The system includes means for asserting and deasserting an access signal to specified locations of the interleaved memory banks, a multiplexer having a pair of input channels for each memory bank and a pair of data paths from the output of each memory bank to the corresponding input channels of the multiplexer. The first data path is a direct path between the memory bank and a first one of the pair of input channels and the second data path is a latched path between the memory bank and a second one of the pair of input channels.

Abstract: A bus arbiter for a multi-processor computer provides fair access by dynamically adjusting a base variable of a counter which is determined from a processor number of a previously access-requesting processor having the highest processor number. The counter then varies priority between a minimum processor number, such as zero, and the base variable of the counter. The priority signal from the counter and the current access-requesting processors are then provided to a memory device. The memory device is used to determine which current access-requesting processor is permitted to access the bus.