ABSTRACT
In his acceptance of the Turing Award, Ken Thompson
reminded us that unless one writes a program oneself, one
cannot completely trust it. Most people realize that
although writing a program may be useful, even necessary,
for trust, it is not sufficient. That is to say, even the most
skilled and motivated programmers make errors. On the
other hand, if one had to write every program that one uses,
computers would not be very useful. It is important to learn
both to write and recognize reliable code.
