Design bugs are often subtle and occur by evolution with early assumptions being forgotten as new features or uses are added to systems.

To our dismay, users who had been enduring several hour waits between jobs run under batch processing were suddenly restless when response times were more than a second.

Regardless of whether one is dealing with assembly language or compiler language, the number of debugged lines of source code per day is about the same!

Because one has to be an optimist to begin an ambitious project, it is not surprising that underestimation of completion time is the norm.

Design bugs are often subtle and occur by evolution with early assumptions being forgotten as new features or uses are added to systems.

The use of the high level language made each programmer a factor of 5 to 10 more productive in a coding sense and more concerned with the semantics than the syntax of modules.

The general problem with ambitious systems is complexity. [...] it is important to emphasize the value of simplicity and elegance, for complexity has a way of compounding difficulties.