Operating Systems
>>Types of OS
>>Interface to the world

Examples of Operating Systems


DOS (Disk Operating System) was the first widely-installed operating system for personal computers. It is a master control program that is automatically run when you start your PC. DOS stays in the computer all the time letting you run a program and manage files. It is a single-user operating system from Microsoft for the PC. It was the first OS for the PC and is the underlying control program for Windows 3.1, 95, 98 and ME. Windows NT, 2000 and XP emulate DOS in order to support existing DOS applications. To use DOS, you must know where your programs and data are stored and how to talk to DOS.


UNIX operating systems are used in widely-sold workstation products from Sun Microsystems, Silicon Graphics, IBM, and a number of other companies. The UNIX environment and the client/server program model were important elements in the development of the Internet and the reshaping of computing as centered in networks rather than in individual computers. Linux, a UNIX derivative available in both "free software" and commercial versions, is increasing in popularity as an alternative to proprietary operating systems.

UNIX is written in C. Both UNIX and C were developed by AT&T and freely distributed to government and academic institutions, causing it to be ported to a wider variety of machine families than any other operating system. As a result, UNIX became synonymous with "open systems."

UNIX is made up of the kernel, file system and shell (command line interface). The major shells are the Bourne shell (original), C shell and Korn shell. The UNIX vocabulary is exhaustive with more than 600 commands that manipulate data and text in every way conceivable. Many commands are cryptic, but just as Windows hid the DOS prompt, the Motif GUI presents a friendlier image to UNIX users. Even with its many versions, UNIX is widely used in mission critical applications for client/server and transaction processing systems. The UNIX versions that are widely used are Sun's Solaris, Digital's UNIX, HP's HP-UX, IBM's AIX and SCO's UnixWare. A large number of IBM mainframes also run UNIX applications, because the UNIX interfaces were added to MVS and OS/390, which have obtained UNIX branding. Linux, another variant of UNIX, is also gaining enormous popularity.


Windows is a personal computer operating system from Microsoft that, together with some commonly used business applications such as Microsoft Word and Excel, has become a de facto "standard" for individual users in most corporations as well as in most homes. Windows contains built-in networking, which allows users to share files and applications with each other if their PCs are connected to a network. In large enterprises, Windows clients are often connected to a network of UNIX and NetWare servers. The server versions of Windows NT and 2000> are gaining market share, providing a Windows-only solution for both the client and server. Windows is supported by Microsoft, the largest software company in the world, as well as the Windows industry at large, which includes tens of thousands of software developers.

This network effect is the reason Windows became successful in the first place. However, Windows 95, 98, ME, NT, 2000 and XP are complicated operating environments. Certain combinations of hardware and software running together can cause problems, and troubleshooting can be daunting. Each new version of Windows has interface changes that constantly confuse users and keep support people busy, and Installing Windows applications is problematic too. Microsoft has worked hard to make Windows 2000 and Windows XP more resilient to installation problems and crashes in general.


The Macintosh (often called "the Mac"), introduced in 1984 by Apple Computer, was the first widely-sold personal computer with a graphical user interface (GUI). The Mac was designed to provide users with a natural, intuitively understandable, and, in general, "user-friendly" computer interface. This includes the mouse, the use of icons or small visual images to represent objects or actions, the point-and-click and click-and-drag actions, and a number of window operation ideas. Microsoft was successful in adapting user interface concepts first made popular by the Mac in its first Windows operating system. The primary disadvantage of the Mac is that there are fewer Mac applications on the market than for Windows. However, all the fundamental applications are available, and the Macintosh is a perfectly useful machine for almost everybody. Data compatibility between Windows and Mac is an issue, although it is often overblown and readily solved.

The Macintosh has its own operating system, Mac OS which, in its latest version is called Mac OS X. Originally built on Motorola's 68000 series microprocessors, Mac versions today are powered by the PowerPC microprocessor, which was developed jointly by Apple, Motorola, and IBM. While Mac users represent only about 5% of the total numbers of personal computer users, Macs are highly popular and almost a cultural necessity among graphic designers and online visual artists and the companies they work for. In general, Mac users tend to be enthusiasts.

Navigation Tip
To navigate through the website, click on the coloured circles at the top of the screen.

Click here to download the detailed version in '.doc' format.

Popular Operating Systems



Microsoft Windows

Go to: Home | Processor Management | Memory and Storage Management | Device Management | Interface to the world | User Interface - The Future | Types of Operating Systems | Examples of operating Systems | Links
top top