The processor executes the instructions in the order they are provided, unless it is instructed to 'jump' to a different instruction or is interrupted by the operating system. An instruction may also invoke one of many input or output operations, for example, displaying some text on a computer screen, causing state changes that should be visible to the user. For example, an instruction may change the value stored in a particular storage location in the computer-an effect that is not directly observable to the user. Machine language consists of groups of binary values signifying processor instructions that change the state of the computer from its preceding state. This is in contrast to hardware, from which the system is built and which actually performs the work.Īt the lowest programming level, executable code consists of machine language instructions supported by an individual processor-typically a central processing unit (CPU) or a graphics processing unit (GPU). Software is a set of computer programs and associated documentation and data. The application software layer interfaces with the operating system, which in turn communicates with the hardware. A diagram showing how the user interacts with application software on a typical desktop computer.

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