© 1981 by British Computer Society
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Change area B-trees: A technique to aid error recovery
Computer Science Department, University of Western Ontario, London, Canada
B-tree structures with the restriction that all data records are stored at the leaves of the tree are investigated from the standpoint of recovery from hardware and software errors. A technique is presented for maintaining the original file inviolatewhich could reside on read only memoryand recording changes in a separate area. Standard algorithms are used for direct access search and hence retrieval time is not affected. Update algorithms are slightly altered to direct all modifications to a separate area. Expressions are developed for storage and time penalties. Due to system overheads, the range of application is limited to files which can tolerate small blocking factors. The technique is contrasted to differential files and a direct point comparison is made to an earlier paper by Severance and Lohman.
Received May 1980. revised August 1980.
* Computer Science Department, University of Western Ontario, London, Ontario, Canada N6A 5B9