Techniques and devices for solving selected problems associated with the use of electronic data-processing equipment;

              Techniques and Devices for Solving Selected Problems Associated with the Use of Electronic Data-Processing Equipment
BY ROBERT G. WRIGHT PRINCIPAL, CHICAGO OFFICE
Presented at Conference on Digital Computers and Data Processors at the University of Michigan, Ann Arbor, Michigan — August, 1955
Problems associated with business applications of electronic data-processing machines are many and varied. Each application has its peculiar requirements, presenting problems which test the ingenuity of the programmer. However, certain problems are common to many business applications. Recognizing this, equipment manufacturers are developing new techniques and devices to facilitate the handling of the more common problems.
Three problems will be discussed: file maintenance, input-output, and sorting. In each case the problem will be defined and selected solu-tions will be explained by reference to techniques and devices of specific makes of electronic data-processing equipment.
FILE MAINTENANCE
Definition
File maintenance, in data-processing terminology, is a procedure whereby a master file, containing a perpetual set of records or data, is "up dated" periodically to include the effect of current transactions or changes. Master files may be maintained on magnetic tape. Or, if stor­age
capacity of a given system is adequate, the files may be maintained in internal memory. Transactions or changes may be introduced through any input medium, but punched cards and magnetic tape represent the most usual method.
Generally, the master file is arranged in a numerical or alpha­betical
sequence. When practicable it is more efficient to arrange the changes in the same sequence before processing against the perpetual records. Frequently, however, it is not practicable to so arrange the transactions because: (1) sorting, in many instances, is a costly opera­tion
on data processing equipment; (2) sorting with standard punched-card equipment involves, under some systems, costly conversion to tapes and may be too time-consuming; or (3) transactions received in
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