An operating system is a set of program files and routines that controls a computer's resources and provides access to a computer's services. More specifically, an operating system allows a computer's hardware components, including processors and drives, to communicate with its software components, such as applications and data instruction sets. In modern personal computers, workstations and other computing devices, operating systems are essential components, which computers cannot function without.
Overcoming Idle Time
Engineers originally developed operating systems as a means for overcoming the idle time of central processing units. CPUs are responsible for executing computer commands; and even the slowest CPUs can process data in microseconds, or millionths of a seconds. In comparison, other computer components, such as hard disks, are considerably slower. To prevent CPUs from idling, or remaining inactive until other components have a chance to respond, engineers created operating systems. These systems overcome idle time by automatically ordering or sequencing CPUs to complete successive tasks while awaiting the completion of previous tasks. The process that operating systems use for sequencing tasks is known as multiprogramming.
Without an operating system, a user would be unable to provide a modern computer with instruction sets or commands. Before the adoption of operating systems, engineers communicated instructions to computers by physically pushing buttons, flicking switches or connecting cards and other hardware components. Using an operating system simplifies the instruction process, as a user can give virtual, software-based commands through a keyboard, mouse or other input device. For personal computing, users commonly rely on graphical user interface or GUI operating systems. These operating systems provide interfaces with selectable, interactive icons and other graphics that appear within menu selection screens. Older operating systems had text-based interfaces, which required users to type in responses to prompts to initiate operations.
A process refers to an active program or a program that a computer is currently executing. In addition to consisting of programming code, a process contains temporary data and variables. For a computer to execute processes, it needs to utilize an abundance of resources, including memory, program files, CPU time and input/output devices. An operating system serves as a computer's process manager and is responsible for conglomerating, and organizing those resources. Other process-managing tasks of an operating system include creating and deleting processes, scheduling processes and synchronizing processes.
Without an operating system, interacting with peripherals or secondary, non-essential input/output devices on a computer would be much more complicated. This is because operating systems interpret the data that peripherals provide and present it to users in standardized formats. For example, regardless of whether a user loads an image file to a computer via a CD-ROM or a USB storage device, an operating system will present that image file to the user in the same way.