Abstract: A method for storing data in a memory, including compressing fixed-sized pages of data, and storing the compressed pages into available smaller memory spaces on a medium if the compressed page will fit into such space, or storing the compressed pages onto available larger memory spaces on the medium, if the compressed page will not fit into the smaller space.

Abstract: A method and system for detecting and correcting all single bit errors in a data word, for detecting all 2-bit errors regardless of whether the two bits in error are consecutive, and for detecting all consecutive 3-bit and 4-bit errors regardless of whether the three bits or four bits are in a single byte. In a preferred embodiment, a set of check bits are established for the data word by exclusively ORing a set of data bits that are unique to each check bit, storing the data bits and check bits, retrieving the data bits, generating a new set of check bits from the retrieved data bits, and comparing the new set of check bits against the old set to establish a syndrome pattern which may be expressed as a hexadecimal for comparison with hexadecimals previously assigned to the data bits.

Abstract: A computer using virtual memory management employs a random-access type storage device such as a semiconductor memory for page swapping. The semiconductor memory is formatted to provide multiple partitions of varying block size, e.g., two block sizes, for compressed pages, and another block size for uncompressed original-sized pages. The data to be stored is in pages of fixed size, and these pages are compressed for storage if the compressed size fits in the block size of one of the small-block partitions in the memory. If a data page is not compressible to one of the small block sizes, it is stored uncompressed in the other full-size partition. The operating system maintains a table storing the locations of the pages in the partitions, so upon recall the page (if compressed) is retrieved from its location found using the table, decompressed and sent to the CPU. The relative number of blocks in the partitioned memory (e.g.

Abstract: A data compression and decompression method and apparatus utilizing a sliding window dictionary in combination with an adaptive dictionary. Incoming data moves through a buffer and is compared against both the sliding window dictionary and the adaptive dictionary, and matched data is replaced with a pointer to the dictionary entry. All incoming data is entered into the sliding window dictionary, but only data which satisfies certain criteria is entered into the adaptive dictionary.

Abstract: A high speed direct memory access (DMA) sub-system of a microprocessor system provides data interfaces between a high speed peripheral bus, such as a small computer system interface (SCSI) bus, and a DMA random access memory (RAM) to provide the data bandwidth necessary to prevent a bottleneck to transfers through the high speed peripheral bus. To his end, the invention has a separate DMA bus and a separate DMA RAM over which high speed data transactions may be made at a very high speed using one or more DMA cycles. The DMA transactions are controlled by a high speed data controller. Primary control of the DMA subsystem is assigned to the DMA sub-system, but the microprocessor may arbitrate for control of the sub-system. The microprocessor has the highest priority so it wins all arbitrations unless a DMA cycle is in progress, and in that event, the DMA cycle is temporarily given highest priority.

Abstract: A random-access type storage device such as a hard disk or semiconductor memory is formatted to provide multiple partitions of varying block size. The data to be stored is in blocks of fixed size, and these blocks are compressed if the compressed size fits in the block size of a small-block partition in the storage device. If a data block is not compressible to the small block size, it is stored uncompressed in another of the partitions. The memory device also contains a table storing the locations of the blocks in the partitions, so upon recall the block is retrieved from location, decompressed (if it had been compressed), and sent to the CPU. For example, there may be two partitions, one using the block size of the original (uncompressed) data, and the other having a block size corresponding to the typical compressed size of the blocks of data (perhaps one-half the size of the original data blocks). The relative number of blocks in each partition (e.g.