System software includes a number of applications, such as utilities, operating systems, compilers and debuggers, that lie at a level of functionality just above the actual computer hardware. This software is designed to operate the computer hardware and provide a platform for running application software.
Software is generally categorized into systems software and applications software, with the former providing low-level operating functionality and the latter providing tools for the end user, such as word processing, database programming and web browsing tools. Primary system software includes utility software and the operating system software.
A computer's operating system is perhaps one of the most important pieces of software because it allows the different components of the computer, such as its memory, disk storage devices and display output, to work together while allowing the user to run applications. Popular operating systems include Apple OS X and iOS, Microsoft Windows, Linux and z/OS. These operating systems provide unique graphical user interfaces and built-in command line functionality. Currently, many operating systems are built for specific types hardware, such as the Apple iOS. However, other operating systems, such as Android, provide more flexibility in terms of the types of computers or devices with which they are compatible.