| | | | Sometimes shortened to OS. The software that controls the way the resources and internal tasks of a computer are managed. It is the first program to be loaded on switching on the machine, when the computer boots. The most basic part of the OS, the "Kernel" then remains resident in memory at all times. It interfaces between the hardware and the application programs running on the computer through the Application Program Interface (API), making requests for services, meaning that software developers do not have to account for interacting directly with every possible version of hardware as this is taken care of by the OS. Users interact with the operating system through either a Command Line Interface (CLI) or, more commonly now, a Graphical User Interface (GUI). The former relies on typing commands in directly from the keyboard in a text-only format and has a very basic appearance, whereas the latter uses mouse/stylus input too and the user can be separated from direct interaction at the command level by a variety of more visually appealing interfaces. The most commonly used operating systems today are Microsoft's Windows family, Linux and Unix-based systems and Mac OS X. Services performed by the operating system for application programs include: i) the prioritisation of applications in a multi-tasking environment, ii) management of memory resources, iii) communication with peripheral devices through "Drivers" (a generic or "abstracted" way of controlling each type of device by the operating system is interpreted for the specific device in question by the driver, which is a series of instructions writen for that piece of hardware in particular), iv) management of data storage (on hard disk drives, optical storage media and tape etc), v) networking requirements, including the TCP/IP protocol and others. | | | |
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