Programs

The defining feature of modern computers which distinguishes them from all other machines is that they may be programmed . That is to say that some type of instructions (theprogram ) can be given to the computer, and it will process them. Modern computers based on the von Neumann architecture often have machine code in the form of animperative programming language .
With practical terms, a computer program may be just a few instructions or extend to many millions of instructions, as do the programs for word processors and web browsers for example. A typical modern computer can execute billions of instructions per second (gigaflops ) and rarely makes an error in judgment over many years of operation. Large computer programs consisting of several million instructions may take teams of programmers years to write, and due to the complexity of the task almost certainly contain errors.