Semi-Operational Evaluation of File Modeling Techniques. Volume I.

摘要

In the report,significant new steps have been made toward the establishment of a systematic and comprehensive methodology for file system design. In the area of system description a structure embodying three important interlocking levels of abstraction has been introduced. These abstractions include the user's predicate set description level,the access-path level,and the physical organization level. This structure provides a natural environment for the use of the flexible quantitative FOREM file organization modeling systems. The issues of design and the corresponding parameters at each level are delineated by means of illustrative examples. Five more files,consisting of a military intelligence application, a business administrative application,and three management information applications,have been surveyed. Two application descriptions extracted from this survey are used in this report as test vehicles to verify the design methodology and the quantitative evaluation tools. Included in this report are also extensions of the earlier formulation of the optimization problem for the selection of secondary indexes and the FOREM models. These latter extensions,including a preprocessor for FOREM I and a secondary index facility for the PHASE II (FOREM II) model,are documented in revised versions of the user's guides for both models. (Author)