Design and Implementation of a Real Time Information Storage and Retrieval System

Presented here is a paper on the “Design and Implementation of a Real Time (On Line) Information Storage and Retrieval System”. Guidance is given into the design and testing of a hashing function for a volatile set of alphanumeric keys. The interrelationship between the hashing function and the Information Storage and Retrieval (IS&R) System is examined with respect to design criteria. Finally the design of the IS&R System itself is presented in terms of an attempt to optimize the Input/Output (I/O) time versus disk and memory storage for a volatile set of records. Built into the IS&R System design is the flexibility to optimize the systems performance under both the ideal and worst case hashing function design or performance. Emphasis, in the design, is placed on the I/O time required in updating, or inquiring, the file for a matched record retrieval. The following techniques were combined to form the original IS&R System: data structures, directory (dictionary) concept, bit directories, link listing (chaining), hashing function, and minimization of disk head movement. The theory of the IS&R System is derived in general and is applicable to a variety of applications as long as the application possess the following requirements: a highly volatile set of records, a real time (or on line) retrieval requirement, difficulty in designing (or choosing) a hashing function due to the volatile set of keys, and heavy activity on updating, or inquiring, the file. Detailed algorithms of the system design are presented for this purpose.