Turing complete

A computer is Turing complete if it can do anything that any Turing machine can do, if it had all the time, memory, and software that it needs. If it can do anything that any Turing machine can do, that proves that it can do anything that any computer can do. It does not mean the computer can let you type something in the same way, or that it will show the same graphics. It means that it can change one set of numbers to another set of numbers in the same way.

For instance, a computer from Dell can do anything that a computer from Hewlett-Packard can do, and the Hewlett-Packard can do anything the Dell can do. One computer might need more time, memory, and software (including the operating system) to do what another computer can do, and it might need a different keyboard, monitor or other input/output, but you would not need a new CPU chip. Any well-known computer is Turing complete. But the simplest calculators are not Turing complete. All they can do is add, subtract, multiply, and divide. They cannot play chess for instance, no matter how you try to combine their four functions.