Donald Knuth Quotes

Running the test suite like this allows us to catch problems when they are just introduced.

Defect-free software does not exist.

No amount of source-level verification or scrutiny will protect you from using untrusted code.

This will surprise some of your readers, but my primary interest is not with computer security. I am primarily interested in writing software that works as intended.

I used Agitator on some code I had unit-tested, and it made me a better tester. As an Agitar Fellow, I look forward to the leverage of working with an outstanding organization as together we continue to improve the value of developer testing.

Testing can be used to show the presence of bugs, but never to show their absence!

Testing shows the presence, not the absence of bugs.

The real value of tests is not that they detect bugs in the code but that they detect inadequacies in the methods, concentration, and skills of those who design and produce the code.

A program that has not been tested does not work.

The process of software development doesn't feel any better than it did a generation ago.

I think it is inevitable that people program poorly. Training will not substantially help matters. We have to learn to live with it.

There is a strong movement towards increased accountability for software developers and software development organizations.

My reply is: the software has no known bugs, therefore it has not been updated.

When someone builds a bridge, he uses engineers who have been certified as knowing what they are doing. Yet when someone builds you a software program, he has no similar certification, even though your safety may be just as dependent upon that software working as it is upon the bridge supporting your weight.

I found out that most programmers don't like to test their software as intensely as I do.

If I say I've got two versions of Word - that old one from 1982 that's perfect, with zero defects; or the new one that's got all this cool new stuff, but there might be a few bugs in it - people always want the new one. But I wouldn't want them to operate a plane I was on with software that happened to be the latest greatest release!

I think, fundamentally, open source does tend to be more stable software. It's the right way to do things.

I think it's a combination of technical and social factors that leads to all the defects in deployed software.

The fundamental problem with program maintenance is that fixing a defect has a substantial chance of introducing another.

When I write software, I know that it will fail, either due to my own mistake, or due to some other cause.

An individual developer like me cares about writing the new code and making it as interesting and efficient as possible. But very few people want to do the testing.

As a rule, software systems do not work well until they have been used, and have failed repeatedly, in real applications.

Writing software that's safe even in the presence of bugs makes the challenge even more interesting.

All software sucks.

The reality of most software development is that the consequences of failure are simply nonexistent.