OS, Types of OS, Functions of OS and Utility Software

Operating System Concept

What is an operating system?
A number of definitions of operating system abound. A basic definition could be that it’s a program that lets you run other programs.The other programs are called applications or application programs. The application programs make use of the operating system by making requests for services through a defined application program interface (API). In addition, users can interact directly with the operating system through a user interface such as a command line or a graphical user interface (GUI).
An operating system is basically a intermediary agent between the user and the computer’s resources (CPU (process scheduling), memory (memory management), display, keyboard, mouse (device drivers), persistent storage (file systems), and the network). 

• Manages the computer’s resources (hardware, abstract resources, software)
• It’s a resource allocator.
• It is also used to control programs to prevent errors and improper computer use.
• It is interrupt driven

Types of Operating System (OS)

There are Many Operating Systems those have be developed for performing the operations those are requested by the user. There are many OS which have the capability to perform the requests those are received from the system. The OS can perform a single operation and also multiple operations at a time. There are generally four types, categorized based on the types of computers they control and the sort of applications they support. The categories are:

1. Real-time operating system (RTOS) - Real-time operating systems are used to control machinery, scientific instruments and industrial systems. An RTOS typically has very little user-interface capability, and no end-user utilities, since the system will be a "sealed box" when delivered for use.
2. Single-user, single task - As the name implies, this operating system is designed to manage the computer so that one user can effectively do one thing at a time. The Palm OS for Palm handheld computers is a good example of a modern single-user, single-task operating system.
3. Single-user, multi-tasking - This is the type of operating system most people use on their desktop and laptop computers today. Microsoft's Windows and Apple's Mac OS platforms are both examples of operating systems that will let a single user have several programs in operation at the same time. For example, it's entirely possible for a Windows user to be writing a note in a word processor while downloading a file from the Internet while printing the text of an e-mail message.
4. Multi-user - A multi-user operating system allows many different users to take advantage of the computer's resources simultaneously. The operating system must make sure that the requirements of the various users are balanced, and that each of the programs they are using has sufficient and separate resources so that a problem with one user doesn't affect the entire community of users. Unix is a good example of multi-user operating systems.

Functions of Operating Systems

1. Booting: Booting is a process of starting the computer operating system starts the computer to work. It checks the computer and makes it ready to work.
2. Memory Management: It is also an important function of operating system. The memory cannot be managed without operating system. Different programs and data execute in memory at one time. if there is no operating system, the programs may mix with each other. The system will not work properly.
3. Loading and Execution: A program is loaded in the memory before it can be executed. Operating system provides the facility to load programs in memory easily and then execute it.
4. Data security: Data is an important part of computer system. The operating system protects the data stored on the computer from illegal use, modification or deletion.
5. Disk Management: Operating system manages the disk space. It manages the stored files and folders in a proper way.
6. Process Management: CPU can perform one task at one time. if there are many tasks, operating system decides which task should get the CPU.
7. Device Controlling: Operating system also controls all devices attached to computer. The hardware devices are controlled with the help of small software called device drivers.
8. Printing controlling: Operating system also controls printing function. It a user issues two print commands at a time, it does not mix data of these files and prints them separately.
9. Providing interface: It is used in order that user interface acts with a computer mutually. User interface controls how you input data and instruction and how information is displayed on screen. The operating system offers two types of the interface to the user;

• Graphical-line interface: It interacts with of visual environment to communicate with the computer. It uses windows, icons, menus and other graphical objects to issues commands.
• Command-line interface: it provides an interface to communicate with the computer by typing commands.

Utility Software

A program that performs a very specific task, usually related to managing system resources. Operating systems contain a number of utilities for managing disk drives, printers, and other devices. Quite often, a utility software (program) is built right in to the operating system. Examples of utility software (programs) are : 

• Anti-virus software - As the name suggests, helps to protect a computer system from viruses and other harmful programs by checking files before opening for viruses. Performs scans of system, example Window defender.
• Disk tools -  Include a range of different tools to manage hard disk drives and other storage devices. Disk tools are important because a failure of a hard disk drive can have disastrous consequences. Keeping disks running efficiently is an important part of overall computer maintenance. This includes utilities to scan the hard disks for any potential problems,
• Disk cleaners to remove any unnecessary files.
• Disk management to create and format hard disk preparing the disk to store files.
• Disk defragmenters to re-organize file fragments on a hard disk drive to increase performance.
• System information -  A free tool included with Microsoft Windows that allows users to view information about the computer, its hardware, drivers, and software related data
• Device manager - It is used to manage the hardware devices installed in a computer like hard disk drives, keyboards, sound cards, USB devices, and more.
• Event Viewer - Is a component of Microsoft's Windows NT line of operating systems that lets administrators and users view the event logs on a local or remote machine.