Some pitfalls in computer design

It is common knowledge that a commercial machine rarely comes up to the hopes of its original designer. Computing machines are often as much as three times slower than originally intended. The paper looks at one section of a computing machine and deduces the reason as inattention to `side effects? at a sufficiently early stage in the design process, and to `add-on? extras that have a greater effect than expected. The study illustrates the need for more attention to be given to these problems by researchers and the need for more willing co-operation between designer and user.