Donald Knuth Quotes

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%

Premature optimization is the root of all evil.

Programmers waste enormous amounts of time thinking about, or worrying about, the speed of noncritical parts of their programs, and these attempts at efficiency actually have a strong negative impact when debugging and maintenance are considered. We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%.

There is no doubt that the grail of efficiency leads to abuse. Programmers waste enormous amounts of time thinking about, or worrying about, the speed of noncritical parts of their programs, and these attempts at efficiency actually have a strong negative impact when debugging and maintenance are considered. We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%. A good programmer will not be lulled into complacency by such reasoning, he will be wise to look carefully at the critical code; but only after that code has been identified. It is often a mistake to make a priori judgments about what parts of a program are really critical, since the universal experience of programmers who have been using measurement tools has been that their intuitive guesses fail.

So Chuck and I looked at that and we hacked on em for a while, and eventually we ripped the stuff out of em and put some of it into what was then called en, which was really ed with some em features.

Realize you won't master data structures until you are working on a real-world problem and discover that a hash is the solution to your performance woes.

I love computer programmers. They have a very beautiful definition of complexity as 'the capacity to transmit the maximum information with the minimum data'.

When you program, you want to think you're writing the best possible program for the... for the task you're trying to solve.

As we said in the preface to the first edition, C "wears well as one's experience with it grows." With a decade more experience, we still feel that way.

You can prematurely optimize maintainability, flexibility, security, and robustness just like you can performance.

Efficiency and focus are the keys to success.

Developers, developers, developers, developers.

Covetousness is the greatest of monsters, as well as the root of all evil.

Programming is not a science. Programming is a craft.

Whoever originated the cliche that money is the root of all evil knew hardly anything about the nature of evil and very little about human beings.

Irrationality is the square root of all evil.

The ability to concentrate and to use your time well is everything if you want to succeed in business--or almost anywhere else for that matter.

If it could save a person's life, could you find a way to save ten seconds off the boot time? If there were five million people using the Mac, and it took ten seconds extra to turn it on every day, that added up to three hundred million or so hours per year people would save, which was the equivalent of at least one hundred lifetimes saved per year.

The hardest part of the software task is arriving at a complete and consistent specification, and much of the essence of building a program is in fact the debugging of the specification.

To treat programming scientifically, it must be possible to specify the required properties of programs precisely. Formality is certainly not an end in itself. The importance of formal specifications must ultimately rest in their utility -in whether or not they are used to improve the quality of software or to reduce the cost of producing and maintaining software.

Being dead broke is the Root of all Evil.

Efficiency for me is an obsession..It not only helps me get stronger but makes things simpler.

Good programmers know what to write. Great ones know what to rewrite (and reuse)

There are a thousand hacking at the branches of evil to one who is striking at the root, and it may be that he who bestows the largest amount of time and money on the needy is doing the most by his mode of life to produce that misery which he strives in vain to relieve.

What is the central core of the subject [computer science]? What is it that distinguishes it from the separate subjects with which it is related? What is the linking thread which gathers these disparate branches into a single discipline. My answer to these questions is simple -it is the art of programming a computer. It is the art of designing efficient and elegant methods of getting a computer to solve problems, theoretical or practical, small or large, simple or complex. It is the art of translating this design into an effective and accurate computer program.