Review of "Computer Security Handbook, by Computer Security Research Group." Macmillan Information, New York, 1973

Liu discussed the close relationship of structured programming to other information systems technol-ogy/methodology. He pointed out that maintainability of systems-especially of data base systems-is one of the chief advantages of using structured programming. In conclusion Liu said: "As effective as structured programming is in reducing the cost of producing programs and increasing the lines of debugged code per man-day, it is not going to resolve the problems of data base (or any other business information system) that was designed by systems analysts who have little understanding of the company operation and the company attitude. Systems designers must be responsive to the users. Users-contrary to what many systems design people think-know their own field and know what they need. Also, the more flexible the designed system is, the better and longer life it will have-though more difficult to implement it." The third speaker, Paul Richey, a computer process designer and in-house intructor of Structured Programming and Program Design, also of P.G.&E., then got down to the essence of structured programming. He concurred that the basic control logic elements in structured programming (with the top-down approach) were: SEQUENCE, IFTHENELSE, and DO-WHILE. "However," Richey said, "to extend the power of COBOL, And to make COBOL both readable and maintainable, three more logic elements have to be added: CASE, DOUNTIL, nd GOTO." Richey defined SEWUENCE as nothing more than concatenation of two COBOL primatives, a COBOL primative with a control logic element and two control logic elements. IFTHENELSE was explained as "the basic control logic element that allows the program to select the proper action from two actions." "In some instances," Richey stated, "one of the actions can be null. The important consequence of executing an IFTHENELSE is that no matter which action is selected, on completion, the control is passed to the same point. "Often, one of the selected actions is itself an IFTH-ENELSE. This is called a nested IF About which there is still a lot of controversy. Because of certain properties of COBOL, nested IFs can become cumbersome, both to read and to maintain. When this happens the GOTO will be used to de-nest the IF. However, all branches willgo downward. One final point: uniform indentation of IF statements is a must to maintain readability." Then DOWHILE "allows the program to repeat an action more than once, depending on the condition. This, of course, is looping. But since DOWHILE checks the …