nOperating System Services :
lUser interface - Almost all operating systems have a user interface (UI)
4Varies between Command-Line (CLI), Graphics User Interface (GUI), Batch
lProgram execution - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error)
lI/O operations - A running program may require I/O, which may involve a file or an I/O device.
lFile-system manipulation - The file system is of particular interest. Obviously, programs need to read and write files and directories, create and delete them, search them, list file Information, permission management.
