Structural way of thinking for attaining reliable software

This paper describes quantitative relations of software errors from the view point of human errors, and gives a design planning method for attaining high reliability software. The software design process is a huge chain of human mental processing, during which inevitable human errors occur. By separating built-in and check-out errors, clear characteristics may be obtained, and quantitative measurements are possible. Checks and tests are another part of design also suffering from human errors. Various data are shown to establish quantitative relationships. The quantitative quality design of the software development process is introduced