| 摘要 |
Storage or retrieval of a record from computer storage or memory is generally accomplished by scanning, or direct addressing. Scanning a file of records to retrieve one particular record requires comparing its key with the key of one record after another until a match is found. Direct addressing involves assigning each record to a specific location usually on the basis of a record key. Direct addressing provides the most rapid means of accessing a single record in a file, but the process of transforming a record key, to a corresponding address or location where the record can be found, is subject to certain disadvantages. Neither complete randomization nor a completely uniform distribution results when keys are converted to addresses even by random conversion transformations or hashing techniques. A transformation or hashing process is provided herein which not only leads to a greater degree of randomness, but is so general that it is effective for both static and volatile files.
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