User View of Operating Systems

User Interface: Help the user use the computer system productively, Provide consistent user interface services to application programs to lower learning curves and increase productivity, Choice of user interface depends on the kind of user.

User Functions: Program execution, File commands, Mount and unmount devices, Printer spooling, Security, Inter-user communication, System Status, Program Services.

Interface Design: CLI - Command Line Interface, Batch System Commands, Menu-Driven Interfaces, GUI - Graphical User Interface.

Command Languages: Provide a mechanism to combine sequences of commands together. These pseudo-programs are known as scripts or batch files. Startup files – OS configuration, user preferences.
Features of Command Languages: Can accept input from the user and can output messages to I/O devices, Provide ability to create and manipulate variables, Include the ability to branch and loop, Ability to specify arguments to the program command and to transfer those arguments to variables within the program, Provide error detection and recovery.

Menu-Driven Interface: No need to memorize commands, All available commands are listed, Menus can be nested, Low data requirements.

Duocentric Interface: Focus on the document rather than the application being executed, Expand role of OS by moving capabilities from the application to system services. Example: click on document to run program, Effort to assure that every application program responds in similar ways to user actions.

(source: John Wiley & Sons - Wilson Wong, Linda Senne, Bentley College)