A fast cache flush mechanism includes, associated with the cache, an auxiliary portion (termed a flush count memory) that references a flush counter during the addressing of the cache. This flush counter preferably has a count capacity of the same size as the number of memory locations in the cache. Whenever the cache is updated, the current value of the flush counter is written into the location in the flush count memory associated with the memory location in the cache pointed to by an accessin...

An information processing unit and storage system comprising at least one low speed, high capacity main memory having relatively long access time and including a plurality of data pages stored therein and at least one high speed, low capacity Cache memory means having a relatively short access time and adapted to store a predetermined plurality of subsets of the information stored in said main memory data pages. Instruction decoding means are located in the communication channel between the main...

A cache memory wherein data words identified by odd address numbers are stored separately from data words identified by even address numbers. A group of diagnostic control registers supply signals for controlling the testing of the cache within the cache memory to determine the operability of the individual elements included in the cache memory.

One or more storage control units (SCUs) interface one or more channels with a plurality of disk drives. One or more host processors are connected to the channels. Associated with the SCUs are one or more cache storage units (CSUs) having a relatively short access time as compared to direct accessing of the disk drives. The CSUs are transparent to the user who programs the hosts as though he were addressing the disk drives directly. An SCU converts the disk address (starting address and number o...

A system and method are provided for bypassing cache memory when reading data from system memory particularly when the primary memory could include memory types where the read operation mixes non-data with data. A system and method are provided for bypassing and invalidating cache memory when writing data to system memory particularly when the primary memory could include memory types where the write operation mixes non-data with data.

A cache hit logic for determining whether data required by a processor is stored in a cache memory includes a dummy cell string that operates the same as a sense amplifier for sensing a tag address stored in a tag memory cell array and a comparison logic for determining whether the sensed tag address coincides with an input tag address, a dummy sense amplifier, and a dummy comparison logic. The cache hit logic improves the reliability of a hit signal and operation speed is not limited.

A cache memory and method for operating a cache memory are provided which comprise a tag RAM, tag RAM sense amplifier circuitry, data RAM sense amplifier circuitry and decision circuitry. Timing difficulties exist in determining whether or not a hit has occurred and in outputting the data from the data RAM upon occurrence of a hit. Upon addressing a tag entry and the corresponding data entry, the tag information is output from the tag RAM and is compared with input address information. A decisio...

A system and method for distributed cache. Cache tag storage and cache data storage are maintained in separate pipeline stages. Cache tag storage is operated by a data producer. Cache data storage is operated by a data consumer. Cache hits and misses are determined by the data producer prior to any operations being performed by the processor. In the event of a cache miss, produced data is sent to the processor to be processed. In the event of a cache hit, the cache address of the corresponding p...

An integrated cache memory circuit is provided comprising a tag RAM, a comparator and a data RAM. Each of the tag RAM and the date RAM have an array of memory cells and plural sense amplifiers. Each memory cell of the RAMs is connected via a respective bit line to one of the plural sense amplifiers. The sense amplifiers of the tag RAM have respective outputs coupled to a first input of the comparator. The comparator having a second input for address information and an output for selectively enab...

A cache controller stores pre-set variables for pre-fetch block size and stride value. A cache controller receives an access request for the main memory from the processor, and generates a pre-fetch request based an the access request and the variables. The cache controller reads data from main memory based on the generated pre-fetch request and writes this data to the cache memory.