![Fernando Corbató](images/avatarlar/pexels-riccardo-bresciani-307.png)
![Fernando Corbató](images/avatarlar/pexels-riccardo-bresciani-307.png)
Design bugs are often subtle and occur by evolution with early assumptions being forgotten as new features or uses are added to systems.
![Fernando Corbató](images/avatarlar/pexels-riccardo-bresciani-307.png)
The computer field is intoxicated with change. We have seen galloping growth over a period of four decades and it still does not seem to be slowing down. The field is not mature yet and already it accounts for a significant percentage of the Gross National Product.
![Fernando Corbató](images/avatarlar/pexels-marius-venter-165.png)
Systems with unknown behavioral properties require the implementation of iterations which are intrinsic to the design process but which are normally hidden from view. Certainly when a solution to a well-understood problem is synthesized, weak designs are mentally rejected by a competent designer in a matter of moments. On larger or more complicated efforts, alternative designs must be explicitly
and iteratively implemented. The designers perhaps out of vanity, often are at pains to hide the many versions which were abandoned and if absolute failure occurs, of course one hears nothing. Thus the topic of design iteration is rarely discussed. Perhaps we should not be surprised to see this phenomenon with software, for it is a rare author indeed who publicizes the amount of editing or the
number of drafts he took to produce a manuscript.
![Fernando Corbató](images/avatarlar/pexels-marius-venter-165.png)
Clearly, one can obfuscate one's ideas with a compiler language but it's harder. To some extent one is talking about what one wants rather than how one wants to do it. The trouble with machine code, of course, is that when you look at a random section of machine code you don't know what properties of the instructions the programmer really wanted to exploit.
![Fernando Corbató](images/avatarlar/pexels-simon-migaj-747.png)
The value of metaphors should not be underestimated. Metaphors have the virtue of an expected behavior that is understood by all. Unnecessary communication and misunderstandings are reduced. Learning and education are quicker. In effect metaphors are a way of internalizing and abstracting concepts allowing one's thinking to be on a higher plane and low-level mistakes to be avoided.
![Fernando Corbató](images/avatarlar/pexels-riccardo-bresciani-307.png)
It is important to emphasize the value of simplicity and elegance, for complexity has a way of compounding difficulties and as we have seen, creating mistakes. My definition of elegance is the achievement of a given functionality with a minimum of mechanism and a maximum of clarity.