●●● ●●●● 2.1 Operating System Services ●●●● ●●● ●●● ●●●● o Generally operating-system should provide one set of common services( that are helpful to the user o User interface(Ul) Almost all operating systems have a user interface Command-Line interface(CLI) o Graphics User Interface(GUI Batch Interface Commands and directives are entered into files, and those files are executed4 2.1 Operating System Services ⚫ Generally operating-system should provide one set of common services （that are helpful to the user） ⚫ User interface (UI) Almost all operating systems have a user interface ⚫ Command-Line interface (CLI) ⚫ Graphics User Interface (GUI) ⚫ Batch Interface ▪ Commands and directives are entered into files, and those files are executed