Packet pre-processing unit which checks received packet validity and redundancy

    公开(公告)号:GB2509977A

    公开(公告)日:2014-07-23

    申请号:GB201301063

    申请日:2013-01-22

    Applicant: IBM

    Abstract: A packet pre-processing unit receives a data packet containing header information and application data, checks the validity of the packet by reference to stored subscription data using header data for the IP destination address, destination port and VLAN tag, checks whether the application data has already been received, and only outputs the packet for further processing if the packet is valid and doesnt contain redundant application data, thereby reducing the load of the memory, bus, and CPU of the computer system.

    Hardware compression method finding backward references with multi-level hashes

    公开(公告)号:GB2524516A

    公开(公告)日:2015-09-30

    申请号:GB201405315

    申请日:2014-03-25

    Applicant: IBM

    Abstract: A system for data compression has a multi-stage pipeline structure 113 and a distributed memory comprising a main hash table 101 and at least one victim hash table 103. The system concurrently writes an uncompressed data element 105 in the main hash table using a first address 115 generated by a first hash function 107 on the data element, and reads a first data element 109 from the main hash table using the first address, so as to avoid a collision. The system then concurrently writes the first data element to the victim hash table using a second address 117 generated by a second hash function 111 on the first data element, and reads a second data 120 element from the victim hash table using a third address 121generated by the second hash function on the uncompressed data element. The first or second data element is selected depending on which has the longest match to the uncompressed data element, and is used for providing a compressed format with backward reference to the longest match.

    Method to improve compression ratio for a compression engine

    公开(公告)号:GB2524515A

    公开(公告)日:2015-09-30

    申请号:GB201405314

    申请日:2014-03-25

    Applicant: IBM

    Abstract: An output sequence of data elements 203 representing a sequence of input data elements 201 in compressed format, each output data element comprising a backward reference 207 to matched strings, is further processed by an extended matcher to improve the compression ratio. The extended matcher identifies a backward reference in a selected output data element, selects the string to which it refers and then combines it with strings of one or more subsequent output data elements to form one or more combined strings. The extended matcher then looks for a sequence in the stored input data elements matching at least part of the one or more the combined strings, and selects a combined string having the longest matching sequence. The backward reference of the output data element is then redefined 217 by the extended matcher to indicate the new longest matching sequence. The compression system may have a multi-stage pipeline structure. The compression may be LZ77.

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