User Operating-Systems Interface | Readstall

User Operating-Systems Interface

04-02-19 Afreen Shaik 0 comment

We mentioned earlier that there are several ways for users to interface with the operating system. Here we discuss two fundamental opproaches. one provides a command-line interface, or command interpreter, that allows users to directly enter commands to be performed by the operating system. The other allows users to interface with the operating system via a graphical user interface, or GUI.

  • COMMAND INTERPRETERS

Some operating systems include the command interpreter in the kernel. Others such as Windows and UNIX, treat the command interpreter as a special program that is running when a job is initiated or when a user first logs on. On systems with multiple command interpreters to choose from, the interpreters are known as shells. For example, on UNIX and LINUX systems, a user may use choose among several different shells, including the Bourne shell, C  shell, Bourne – Again shell,  Korn  shell, and others. Third party  shells and free user-written shells are also available.

            The main function of the command interpreter is to get and execute the next user-specified command. Many of the commands given at the level manipulate files: create, delete, list, print, copy, execute, and so on.

            In one approach, the command interpreter itself contains the code to execute the command. An alternative approach – used by UNIX, among other operating systems – implements most commands through system programs. In this case, the command interpreter does not understand the command in any way; it merely uses the command to identify a file to be loaded into memory and executed. Thus, the UNIX common to delete a file.

  • GRAPHICAL USER INTERFACES

A second strategy for interfacing with the operating system is through a user-friendly graphical user interface, or GUI. Here , rather than entering commands directly via a command – line interface, users employ a mouse-based window-and-menu systems characterized by a DESKTOP metaphor. The user moves the mouse to position its pointer on images, or icons, on the screen that represents programs, files, directories, and system functions.

Graphical user interfaces first appeared due in part to research taking place in the early 1970s at Xerox PARC research facility.

             Traditionally, UNIX systems have been dominated by command-line interfaces. These includes the common Desktop Environment(CDE) and X-Windows systems, which are common on commercial versions of UNIX, such as Solaris and IBM’S AIX systems. In addition, there has been significant development in GUI designs from various open-source projects, such as K Desktop Environment (or KDE) and the GNOME desktop by the GNU project.Both the desktops runs on Linux and various UNIX systems and are available under open-source licenses.

  • CHOICE OF INTERFACES

The choice of whether to use a command-line or GUI interface is mostly one of personal preferences. System administrators who manage computers and power users. The command-line interfaces usually make repetitive tasks easier, in part because they have their own program. The program is not compiled into executable code but rather is interpreted by the command-line interface. These shell scripts are very common on systems that are command-line oriented, such as UNIX and Linux.

The user interface can vary from system to system and even from user to user within a system. It typically is substantially removed from the actual system structure. The design of a useful and friendly user interface is therefore not a direct function of the operating system.



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