什麼是作業系統

控制電腦的許多不同操作及管理、協調電腦程式執行的軟體。作業系統是調度由電腦執行的工作順序，並把這些工作分配給電腦的各種硬體系統，例如中央處理器、主記憶體和周邊設備。在載入、儲存和執行程式時，以及在執行諸如存取檔案、運行軟體應用程式、控制顯示器與儲存裝置和直譯鍵盤命令等個別工作時，中央處理器都在作業系統管理下進行。當電腦同時執行幾個工作時，作業系統便以最有效的方式分配電腦時間和各種資源，以分時系統來決定處理工作的優先次序，作業系統還管理電腦同網路中其他電腦的互動。現代電腦作業系統變得愈來愈與機器無關，能在任何一種硬體平台運作，目前最廣泛使用的一種不拘平台的作業系統是UNIX。大部分個人電腦的作業系統是微軟公司的Windows作業系統。

operating system (OS)

Software that controls the operation of a computer, directs the input and output of data, keeps track of files, and controls the processing of computer program. Its roles include managing the functioning of the computer hardware, running the applications programs, serving as an interface between the computer and the user, and allocating computer resources to various functions. When several jobs reside in the computer simultaneously and share resources (multitasking), the OS allocates fixed amounts of CPU time and memory in turn, or allows one job to read data while another writes to a printer and still another performs computations. Through a process called time-sharing, a large computer can handle interaction with hundreds of users simultaneously, giving each the perception of being the sole user. Modern computer operating systems are becoming increasingly machine-independent, capable of running on any hardware platform; a widely used platform-independent operating system in use today is UNIX. Most personal computers run on Microsoft's Windows operating system, which grew out of and eventually replaced MS-DOS. See also Linux.