Operating System

Definition

·        An Operating System, or OS, is low-level software that enables a user and higher-level application software to interact with a computer’s hardware and the data and other programs stored on the computer.

·        An OS performs basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as printers.

Operating Systems

•                     The operating system is the most important program that runs on a computer.

•                     Operating system is an interface between computer and user.

•                     It is responsible for the management and coordination of activities and the sharing of the resources of the computer.

•                     Operating systems provide a software platform on top of which other programs, called application programs, can run.

•                     There are instances where processes need to communicate with each other to exchange information. It may be between processes running on the same computer or running on different computers. The OS provides these services to application programs, making inter-process communication possible, and relieving the user of having to worry about how this accomplished.

Operating System types

As computers have progressed and developed, so have the operating systems. Below is a basic list of the types of operating systems and a few examples of operating systems that fall into each of the types. Many computer operating systems will fall into more than one of the below types.

CUI- CUI means you have to take help of a keyboard to type commands to interact with the computer. You can only type text to give commands to the computer as in MS DOS or command prompt. There are no images or graphics on the screen and it is a primitive type of interface. In the beginning, computers had to be operated through this interface and users who have seen it say that they had to contend with a black screen with white text only. In those days, there was no need of a mouse as CUI did not support the use of pointer devices. CUI’s have gradually become outdated with the more advanced GUI taking their place. However, even the most modern computers have a modified version of CUI called CLI (Command Line Interface).

CUI operating systems are:

MSDOS & UNIX

GUI -  Graphical User Interface, a GUI operating system contains graphics and icons and is commonly navigated by using a computer mouse. See the GUI definition for a complete definition. Examples of GUI operating systems are:

Macintosh, Windows 98 & Windows CE

Multi-user - A multi-user operating system allows for multiple users to use the same computer at the same time and different times. See the multi-user definition for a complete definition. Examples of operating systems that would fall into this category are:

Linux, UNIX , Windows 2000 & Macintosh

Multiprocessing - An operating system capable of supporting and utilizing more than one computer processor. Examples of operating systems that would fall into this category are:

Linux, Unix, Windows XP &  Macintosh

Multitasking - An operating system that is capable of allowing multiple software processes to run at the same time. Examples of operating systems that would fall into this category are:

Linux, UNIX, Windows 8 & Macintosh

Multithreading - Operating systems that allow different parts of software program to run concurrently. Examples of operating systems that would fall into this category are:

Linux, Unix, Windows XP & Macintosh

Examples of Operating Systems

UNIX

·        UNIX was one of the first operating systems to be written, in 1971.

·        Advantages of UNIX are…

ƒ           Multitasking – multiple programs can run at one time.

ƒ           Multi-user – allows more than a single user to work at any given time. This is accomplished by sharing processing time between each user.

ƒ           Safe – prevents one program from accessing memory or storage space allocated to another program, and enables file protection, requiring users to have permission to perform certain functions, such as accessing a directory, file, or disk drive. 

Linux

Linux (lee'nuhks/ or /li'nuks/,_not_/li:'nuhks) is a free and open-source operating system first developed by Linus Torvalds and friends that was first announced August 25, 1991. The Linux kernelruns on numerous different platforms including the Intel and Alpha platform and is available under theGNU General Public License.The system can be distributed, used, and expanded free of charge. In this way, developers have access to all the source codes, thus being able to integrate new functions or to find and eliminate programming bugs quickly. Thereby drivers for new adapters (SCSI controller, graphics cards, etc.) can be integrated very rapidly.