A computer is a machine for manipulating data or storing data according to a list of instructions. Computers take many forms, from early room-sized complexes to modern personal computers (PCs) and personal digital assistants (PDAs) to tiny embedded systems that add sophisticated capabilities to other devices like toys and appliances.
- On two occasions, I have been asked [by members of Parliament], "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?"...I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
- These machines have no common sense; they have not yet learned to "think," and they do exactly as they are told, no more and no less. This fact is the hardest concept to grasp when one first tries to use a computer.
- Knuth, Donald (1968). "Preface". The Art of Computer Programming, Volume 1: Fundamental Algorithms. Addison-Wesley.
- I have bought this wonderful machine- a computer. Now I am rather an authority on gods, so I identified the machine- it seems to me to be an Old Testament god with a lot of rules and no mercy.
- Trust The Computer. The Computer is your friend.
- "Computer's Credo", Paranoia
- If you don't know anything about computers, just remember that they are machines that do exactly what you tell them but often surprise you in the result.
- The simple fact is that without supporting directives or a mechanism for feedback, security is defined differently by each person and verified by no one. There is no metric for compliance with a "culture", and a "culture of security" is overridden by a culture of "get the job done" every time. If there are rules, write them down. If technology is put in place to implement or monitor the rules, write that down too. If people break the rules, follow up. If the rules prevent legitimate business from getting done, change them. It's that simple.
- "So computers are tools of the devil?" thought Newt. He had no problem believing it. Computers had to be the tools of somebody, and all he knew for certain was that it definitely wasn't him.
- Where a calculator like the ENIAC today is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps weigh only 1½ tons.
- Andrew Hamilton, "Brains that Click", Popular Mechanics 91 (3), March 1949, (pp. 162 et seq.) at p. 258.
- Computers are good at following instructions, but not at reading your mind.
- Donald Knuth (1984) cited in: Jorge Angeles (2011) Dynamic Response of Linear Mechanical Systems. p. 419
- The Analytical Engine has no pretentions whatever to originate anything. It can do whatever we know how to order it to perform.
- Ada Lovelace, An Account of the Analytical Engine, 1842, reprinted in Faster than Thought, ed. B.V. Bowden (Pitman, 1953), cited in Andrew Hodges Alan Turing: The Enigma of Intelligence (Unwin 1985) (probably the first known instance of "Computers can only do what they are programmed to do")
- Dare to be gorgeous and unique. But don't ever be cryptic or otherwise unfathomable. Make it unforgettably great.
- Robert J. Mical, Amiga Intuition Reference Manual, 1986, (ISBN 0201110768), p. 231
- Today’s computers are not even close to a 4-year-old human in their ability to see, talk, move, or use common sense. One reason, of course, is sheer computing power. It has been estimated that the information processing capacity of even the most powerful supercomputer is equal to the nervous system of a snail—a tiny fraction of the power available to the supercomputer inside [our] skull.
- Steven Pinker, How Unique You Are!; Is There a Creator Who Cares About You?, published by Jehovah's Witnesses.
- You, HP, promised me a toxic-free COMPUTER by 2009. Now my friends at Greenpeace tell me that I'll have to wait till 2011. What's up with that?"
- Company wide voice mail to Hewlett Packard 
- Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.
- Andrew S. Tanenbaum, Computer Networks 3rd Ed., 1996, Chapter 2 page 83
- An adversary capable of implanting the right virus or accessing the right terminal can cause massive damage.
- It used to be said of a man who had suffered a catastrophic setback in his line of work that he had been handed his head on a platter. We are being handed our heads with tweezers now.
- The danger of computers becoming like humans is not as great as the danger of humans becoming like computers.
- Konrad Zuse (2005) in: Hersfelder Zeitung. Nr. 212, 12. September 2005.
- What do such machines really do? They increase the number of things we can do without thinking. Things we do without thinking — there's the real danger.
- Anyone who slaps a 'this page is best viewed with Browser X' label on a Web page appears to be yearning for the bad old days, before the Web, when you had very little chance of reading a document written on another computer, another word processor, or another network.
- Tim Berners-Lee (in Technology Review, July 1996)
- Einstein argued that there must be simplified explanations of nature, because God is not capricious or arbitrary. No such faith comforts the software engineer.
- Interviewer: Is studying computer science the best way to prepare to be a programmer? Bill Gates: No. the best way to prepare is to write programs, and to study great programs that other people have written. In my case, I went to the garbage cans at the Computer Science Center and I fished out listings of their operating system. You got to be willing to read other people's code, then write your own, then have other people review your code. You've got to want to be in this incredible feedback loop where you get the world-class people to tell you what you're doing wrong.
- Bill Gates cited in: "Programmers at Work: Interviews With 19 Programmers Who Shaped the Computer Industry", Tempus, by Susan Lammers (Editor)
- Around computers it is difficult to find the correct unit of time to measure progress. Some cathedrals took a century to complete. Can you imagine the grandeur and scope of a program that would take as long?
- SIGPLAN, Association for Computing Machinery (1992) "Epigrams in Programming", September 1982
- A refund for defective software might be nice, except it would bankrupt the entire software industry in the first year.
- Andrew S. Tanenbaum, Computer Networks, 2003, Introduction, page 14
- The primary duty of an exception handler is to get the error out of the lap of the programmer and into the surprised face of the user.
- Verity Stob (11 January 2006). "Catch as catch can: A light-hearted look at exception handling". The Register. Retrieved on 2007-07-04.
- http://quotes.cat-v.org/programming Programming quotations (unsourced)