Computer – Operating System
An operating system is the most important software that runs on a computer. It manages the computer’s memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer’s language. Without an operating system, a computer is useless.
It is a program with following features:
- An operating system is a program that acts as an interface between the software and the computer hardware.
- It is an integrated set of specialized programs that are used to manage overall resources and operations of the computer.
- It is specialized software that controls and monitors the execution of all other programs that reside in the computer, including application programs and other system software.
Objectives of Operating System
- To make a computer system convenient to use in an efficient manner
- To hide the details of the hardware resources from the users
- To provide users a convenient interface to use the computer system
- To act as an intermediary between the hardware and its users and making it easier for the users to access and use other resources
- To manage the resources of a computer system
- To keep track of who is using which resource, granting resource requests, according for resource using and mediating conflicting requests from different programs and users
- To provide efficient and fair sharing of resources among users and programs
Characteristics of Operating System
- Memory Management — keeps tracks of primary memory i.e. what part of it is in use by whom, what part is not in use etc. and allocates the memory when a process or program requests it.
- Processor Management — allocates the processor(CPU) to a process and deallocates processor when it is no longer required.
- Device Management — keeps track of all devices. This is also called I/O controller that decides which process gets the device, when, and for how much time.
- File Management — allocates and de-allocates the resources and decides who gets the resources.
- Security — prevents unauthorized access to programs and data by means of passwords and similar other techniques.
- Job accounting — keeps track of time and resources used by various jobs and/or users.
- Control over system performance — records delays between request for a service and from the system.
- Interaction with the operators — The interaction may take place via the console of the computer in the form of instructions. Operating System acknowledges the same, does the corresponding action and informs the operation by a display screen.
- Error-detecting aids — Production of dumps, traces, error messages and other debugging and error-detecting methods.
- Coordination between other software and users — Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems.
Operating systems usually come pre-loaded on any computer you buy. Most people use the operating system that comes with their computer, but it’s possible to upgrade or even change operating systems. The three most common operating systems for personal computers are Microsoft Windows, Mac OS X, and Linux.
Modern operating systems use a graphical user interface, or GUI (pronounced gooey). A GUI lets you use your mouse to click icons, buttons, and menus, and everything is clearly displayed on the screen using a combination of graphics and text.
Each operating system’s GUI has a different look and feel, so if you switch to a different operating system it may seem unfamiliar at first. However, modern operating systems are designed to be easy to use, and most of the basic principles are the same.
Microsoft created the Windows operating system in the mid-1980s. Over the years, there have been many different versions of Windows, but the most recent ones are Windows 10 (released in 2015), Windows 8 (2012), Windows 7 (2009), and Windows Vista (2007). Windows comes pre-loaded on most new PCs, which helps to make it the most popular operating system in the world.
Mac OS X
Mac OS is a line of operating systems created by Apple. It comes preloaded on all new Macintosh computers, or Macs. All of the recent versions are known as OS X (pronounced O-S Ten), and the specific versions include El Capitan (released in 2015), Yosemite (2014), Mavericks (2013), Mountain Lion (2012), and Lion (2011).
Linux (pronounced LINN-ux) is a family of open-source operating systems, which means they can be modified and distributed by anyone around the world. This is different from proprietary software like Windows, which can only be modified by the company that owns it. The advantages of Linux are that it is free, and there are many different distributions—or versions—you can choose from.