Operating System – Meaning, Types and Functions

Operating system is the program, which usually installed into the computer by a boot program. It manages all other programs in computer. Sometimes it also called as “OS”. These programs also called applications. The application uses the operating system by making requests for services through API (Application Program Interface). Sometimes users can directly use the operating system through GUI (Graphical Users Interface) or command language. Operating system is a program that allows you to work with hardware and software on your computer. Basically, there are two ways to use operating system on your computer. The two ways are as follows: 1. for ex., DOS, you type a text commands and computer give respond to you according to your command. This is called command line operating system. 2. With a GUI (Graphical User Interface) operating system (ex., windows). You relate with the computer through graphical user interface with pictures and buttons by using the mouse and keyboard.

An operating system is software that enables the computer hardware to communicate and function with the computer software. Most desktop or laptops come or preloaded with Microsoft windows. Macintosh computers are loaded with Mac OS. Many computers or servers use the Linux or UNIX operating system. The operating system is the first thing loaded on the computer- without operating system (OS) the computer is useless and we can’t do any functions on it. Now at the moment, operating systems have started to use OS in small computers as well. If we mess with electronic devices, we can see the operating system in many of the devices, which we use every day, from mobile phone to wireless access points. The computer use in these little devices is more powerful and they can easily run operating system and applications of it.

The main aim of the operating system is to organize and control the hardware and software so that the device behaves in a flexible way. All computers does not having operating systems, for ex – the computer that controls the microwave oven in your kitchen, does not need operating system to work because it has only one set of job to do. The most common window operating systems developed by Microsoft. There are other hundreds of other operating system available for special-purpose applications, including manufacturing, robotics, and mainframes and so on.

Types of Operating System

Within the family of operating system, there are four types of operating system based on the types of computers. The categories are:

  1. Real-time operating system (RTOS) – Real time operating system used to control machinery, scientific instruments and industrial system. An RTOS hardly have little user-interface capacity, and no end-user utilities. A very important part of an RTOS is managing the property of the computer so that particular operations executes in same amount of time. In a complex machine, having a part move more quickly just because system resources are available may be just as catastrophic as having it may not move at all because the system is busy.
  2. Single-user, single task – As the name implies, this operating system is designed to manage the computer so that one user can do one thing at a time. The Palm OS for Palm handheld computers is good example of modern single user, single task operating system.
  3. Single-user, multi tasking – This is very popular operating system; most people use this operating system on their desktop and laptop today. Microsoft’s Windows and Apple’s Mac OS are both example of single user, multi tasking operating system. It will let a single user have several programs in operation at same time. For example, it is possible in Windows to write a not in Microsoft word while downloading a file from the internet while printing the text on e-mail message.
  4. Multi-user – A multi user operating system allows many users to take advantage of the computer resources simultaneously. The operating system make sure that the requirements of the various users are balanced, and each of the program they are using has sufficient and separate resources so that the problem with one users doesn’t affect the community of the users. UNIX, VMS and main frame operating systems, such as MVS, are the examples of the operating systems. It’s important to differentiate multi user operating system and single user operating system that support networking. Windows 2000 can support hundreds or thousands of networked users.

Functions of the Operating System

The OS plays a vital role when it comes to starting and shutting down the computer which is also known as booting. Six steps take place when a computer is booting: The first step begins as soon as the computer is turned on, the electrical signal reaches to the components in the system unit through the power supply. During the second step, the processor chip is reset due to the electric signal and then it locates the ROM that contains the basic input/output system (BIOS), which is a firmware that contains the startup instructions of the computer. Next, the BIOS launches a series of tests to ensure hardware are working and connected properly, known as the power on self-test (POST), usually when the POST launches, the LED lights of the devices flicker, at times there will be messages displaying on the screen. The forth step takes place when the POST compares the result with the complementary metal-oxide-semiconductor (CMOS) chip data. CMOS uses battery power to preserve the information, data, and memory when the computer shut down. Besides that, it detects new devices and identifies them when these devices are connected to the computer. The “beep” sound usually results when the CMOS detects which later followed by the error messages. The fifth step proceeds when the POST completes without any interference where the BIOS will locate the OS files also known as the system files from any source of drive. The sixth steps occurs when the system file is located, which is then loaded into the RAM from its storage along the kernel of the OS. The system file then launches, and finally, the OS which was stored in memory takes control of the whole computer system. During the final step, the OS loads the information setting. Certain OS may request for user ID and password. After the OS loads, it displays the desktop screen and it starts up background processes.

The second function of the OS is by providing a user interface. The two types of user interface are the graphical user interface (GUI) and the command-line interface. The GUI basically provides user with an easy way to perform a command or task by having the menus with buttons or other pictures to allow user to click it with ease. Instead of having simple buttons to click on, advance users work with command-line interface to configure, manage and troubleshoot devices and other software. The command-line interface works only with commands by using the keyboard. To perform such command, one must type in the commands accurately with the exact spellings and punctuations.

OS also manages programs. It depends on certain OS, some OS can only run one program at a time, while some can run up to thousands of programs at the same time with one or multiple users. There are the single user/single tasking OS, single user/multitasking OS, multiuser OS, and the multiprocessing OS. When one multitasks, the program that is actively used by the user is said to be in the foreground, while the other programs are known to be in the background.

The OS’s fourth function is memory management. The OS does so by transferring the data and program instructions from the RAM to the hard disk when they are not needed at the moment because at times there is only limited space for the RAM when it has to perform other functions, when the same data and program instructions is needed again, the OS then transfer them from the hard disk to the RAM.

The fifth function of the OS is coordinating tasks. As the phrase implies, the OS determines the order of the tasks which are processed. User can adjust or set the priority of certain tasks, in which result the other tasks to queue up until the preceding task is performed.

Every hardware has a driver which acts like a manual. The sixth function in this case, allows the computer to identify and install it without having the computer to thoroughly “learn” all the details of the hardware. With the Plug and Play technology today, the OS can automatically configure the new devices as the devices are installed on the computer.

The OS is also very important by providing a consistent way for software to deal with hardware without having the computer to thoroughly learn all the details of hardware. The OS interacts with the hardware via drivers. An easy example would be installing a printer to many computers.

The seventh function allows user to easily connect to the internet instead of having to configure the tedious broadband service. OS can automatically configure the internet connection.

The OS also function as a performance monitor, which in this case identify and reports information about the software or the devices of the computer.

File management allows user to easily access their files and documents by allowing users to organize it. It also allows user to search or locate their files at ease and install new programs or software. The ninth function is important because without it, the computer will be a mess where all the files and programs are not well organized and randomly wonders in the computer. The OS also provides other utility such as cleaning up, defragmenting, diagnosing, and backing up the files and disks.

With internet access, the OS is able to notify the user or update software automatically when an update is available. Many OS today comes with the automatic update feature. These updates are useful when it comes to fixing program bugs and errors. Sometimes, these updates can enhance the performance of the driver.

Last but not least, the OS is also meant for controlling the network and administering security by providing an administrator account. A typical account usually consist of the user ID and password.

Examples of Operating System

Microsoft Windows

The Microsoft Windows is an operating system for personal computers made by Microsoft that was released in November 1985. It is used a graphical user interface instead. Input from the user usually comes from using a computer mouse and the commands are run by clicking on the icon representing the virtual cursor controlled by a mouse. There was a small learning curve required to use the Windows properly, but it was more easier to interact with graphical representations than commands and text lines, and there is no special programming language needed to be learned.

The strengths of Microsoft Windows is its ease of use because the user is already familiar with the look of windows and familiar graphical user interface. So, the users can more comfortable in front of a screen. In addition, it also has many office application that are compatible with windows such as Microsoft Office. Microsoft Office is the best office suite around, and Microsoft are make sure that Windows has the best support for it. This is one of the main reasons why Windows users are often reluctant to switch operating systems.

The weakness of Microsoft Windows is its installation is more difficult than the Linux operating system because its need a high resource requirements of hardware such as a faster processor, more internal memory and a larger hard disk. In addition, the other weakness of windows is its price. Microsoft Windows can run between $50.00 – $150.00 US dollars per each license copy. Although Windows does have software programs, utilities, and games for free, the majority of the programs will cost anywhere between $20.00 – $200.00+ US dollars per copy.


The MS-DOS is an operating system for personal computers made by Microsoft that was first released in August 1980. It is remembered as the first standard operating system to be adopted by many manufacturers of personal computing machines. It uses a completely text-based programming language to allow users to work with, or interface with, their PC. The Commands are typed into computers at a specific command prompt location on the computer screen using a standard keyboard. Commands must be very precise and correct.The user must specify which commands they want, how they want it to run, and what program or system they want to use on your computer. This requires the user to learn a specific language and syntax rules to use of their computers.

The strengths of MS-Dos is its very lightweight and very stable operating system. It does not have the overhead of a multitasking operating system. It is a contraction for Disk Operating System and it is very fast and stable even on a relatively slow machine. It starts up fairly quickly on most hardware, uses little memory, and allows direct access to hardware, unlike most protected mode operating systems today.

The weakness of MS-Dos was its single-user or single-test system design that couldn’t support multitasking, networking and other sophisticated application required of computer of every size. It is 16-bit and limited to 640k of RAM. In addition, it runs in real mode, so a buggy or malicious program can cause corruption. Today, it is a relic of times past, but its simple structure and user interface make it an accessible learning tool for operating system students.


Linux is a cross-platform operating system based on Unix. It is the software on a computer that enables applications and the computer operator to access the devices on the computer to perform desired functions. It can be installed on PCs, laptops, netbooks, mobile and tablet devices, video game consoles, servers, supercomputers and more. It enjoys unparalleled popularity among programmers, who contribute enhancements and improvements to the standard code set. The operating system (OS) relays instructions from an application to, for instance, the computer’s processor. The processor performs the instructed task, then sends the results back to the application via the operating system.

The strengths of Linux is characterized by its power, flexibility, and constant maintenance by legions of programmers worldwide while maintaining careful adherence to industry standards. The most appealing aspect of Linux distributions is their cost or available for free. You can download and use a distribution on as many computers as you want. Once installed, updates and patches are also available for free, and updated regularly. In addition, Linux computers tend to be more secure than their Windows counterparts, with less susceptibility to viruses and malware.

The weakness of Linux is many windows programs will not run in Linux such as iTunes, Microsoft Office, Internet Explorer and many other Windows programs. The good news is that there are decent ways around most of these problems. For example, music libraries can be managed with an iPod using programs such asAmarok, Banshee, or Rhythmbox in Linux. In addition, Mozilla Firefox and Google Chrome are outstanding Internet browsers which can be used in the place of Internet Explorer. It is also possible to run iTunes in Linux using Wine, VirtualBox, or Parallels, though it is difficult to have good results.


The Mac OS is a series of Unix-based graphical interface operating systems for Mac computers developed and marketed by Apple Inc that was introduced in January 24, 1984. The first version “Mac OS X Server 1.0” are released in year 1999, and a desktop version “Mac OS X v10.0” followed on March 24, 2001. Mac OS is a development platform that supports multiple development technologies including UNIX, Java, the proprietary Cocoa and Carbon runtime environments, and a host of open source, Web, scripting, database and development technologies.

The strengths of Mac OS is its has a good security that protect the computer. Mac OS has a two-layered system to protect the computer. The attractive GUI sits atop a Unix core, and Unix is best-known for its security features. It’s simply impossible to install a destructive trojan or virus unless the user explicity allows it root access via typing in the admin password. Mac OS’s built-in firewall is set up to work unobtrusively out of the box as well as being highly configurable.

The weakness of Mac OS is its price. All that flashy secure reliable power comes at a price. Macs cost more than machines that run other operating systems. Highly specialized software can be difficult to source for Mac OS, such as industry-specific applications, and businesses you work with may provide files in one of the few non-Mac OS formats left in the computer world, such as Microsoft Publisher.

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