Advanced Micro Devices Corporation

Quantum Corporation

Hang Diem Nguyen

Clifford M Gold

Trinh C Bui

Bryan John Mee

Hoa V Luong

Minnie Uppuluri

George Li

Steve Paul

A method of coordinating access to a data buffer including a plurality of data blocks, using a buffer list with a plurality of entries corresponding to the data blocks. Each buffer list entry includes: (i) a status code for indicating the status of data in the corresponding data block, and (ii) a partial address common to both the next buffer list entry and a data block corresponding to said next buffer list entry. A status code is selected from a cyclical set of sequential status codes having a period of N, the status codes sequentially, and alternately, representing the most recent history of a data block, including: (i) full status, indicating data in the data block has been retrieved from the storage device or is to be stored to the storage device, or (ii) empty status, indicating data transferred out of the data block to a host or to the storage device. A store flag maintains a status code representing empty status, and a retrieve flag maintains a status code representing full status. When storing data into the data buffer, locating a desired buffer list entry list with an empty status code by traversing the buffer list, calculating the address of each entry using the partial address in the previous entry, until the desired entry is found. The address of the data block corresponding to the found entry is calculated and data is stored in the data block when the status code of the entry matches the store flag status code. The found entry status code is advanced once, and if the entry is last in the buffer list the store flag status code is advanced twice. Similarly, when retrieving data from the data buffer, locating a desired entry in the buffer list with a full status code by traversing the buffer list, calculating the address of each entry using the partial address in the previous entry, until the desired entry is found. The address of the data block corresponding to the found entry is calculated and data is retrieved from the data block when the status code of the entry matches the retrieve flag status code. The found entry status code is advanced once, and if the entry is last in the buffer list the retrieve flag status code is advanced twice.

Buffer management and system coordination method

A method is provided for use in a Token ring network including a plurality of stations serially connected by a transmission medium so as to form a closed loop on which packets of data are circulated, wherein each respective station includes a media access controller and a buffer memory, the method including the steps of transferring data of a respective packet from a media access controller to a buffer memory; storing the data in a sequence of contiguous memory locations in the buffer memory; in the course of the step of transferring the data, generating status information for the data; after said step of storing the data, storing the status information in the buffer memory contiguously with the stored data at the beginning of the sequence of memory locations in which the data are stored.

Method for transfer of data between a media access controller and buffer

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Fremont, CA, United States of America

Hang Diem Nguyen