Computer software is programming code executed on a computer processor. The code can be machine-level code, or code written for an operating system. An operating system is software intended to provide a predictable and dependable layer for other programmers to build other software on, which are known as applications. It also provides a dependable layer for hardware manufacturers. This standardization creates an efficient environment for programmers to create smaller programs, which can be run by millions of computers. Software can also be thought of as an expression that contrasts with hardware. The physical components of a computer are the hardware; the digital programs running on the hardware are the software. Software can also be updated or replaced much easier than hardware. Additionally, software can be distributed to a number of hardware receivers. Basically, software is the computer logic computer users interact with.