Tuesday, November 26, 2013

Operating Systems: Concept and basic features of Windows, Linux with a very brief passing descripti...

इस ब्लॉग्स को सृजन करने में आप सभी से सादर सुझाव आमंत्रित हैं , कृपया अपने सुझाव और प्रविष्टियाँ प्रेषित करे , इसका संपूर्ण कार्य क्षेत्र विश्व ज्ञान समुदाय हैं , जो सभी प्रतियोगियों के कॅरिअर निर्माण महत्त्वपूर्ण योगदान देगा ,आप अपने सुझाव इस मेल पत्ते पर भेज सकते हैं - chandrashekhar.malav@yahoo.com

Operating Systems: Concept and basic features of Windows, Linux with a very brief passing descripti... 



  ICT-

Features of Different Operating systems

Windows 

Windows

Microsoft Windows is an operating system created by Microsoft for PC computers that governs all operations on your computer. An operating system is the software utilized to run and manage programs and functions on the computer. Windows uses a graphical user interface (GUI) consisting of windows, menus, icons, and dialog boxes to help you tell your computer what to do. Windows presents options and commands to you, accepts your responses, and translates them into commands for the computer. Windows eliminates the need for you to remember and type complex commands that require exact syntax.
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To understand how to use a computer, it is important to know several features of the Windows system.

Desktop
The desktop is the area you see when the computer is not running applications. It consists of the icons on top of it, as well as the Start button and other features. The desktop can be used to temporarily store information or to move around documents and windows.
Icon
Icons are little pictures that represent different programs or saved items. Double-clicking on the icon accesses the information icons represent.
Window
Each application opened will appear in its own window, or its own little section of the screen. Windows can be moved and resized so that you can operate many different applications at the same time.
Dialogue Box
When you ask the computer to do certain commands, such as to save your work, the computer will need more information from you, and this will appear in a dialogue box. These boxes contain options and commands for the computer to execute.

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Start Menu
In the lower left-hand corner of the Windows screen is the Start button. When you click on the button a menu will appear, which we will call the Start menu. This menu gives you access to all the different parts and functions of the computer.

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Task Bar
At the very bottom of the screen is a horizontal bar called the task bar. This bar contains (from left to right) the Start button, shortcuts to various programs, minimized programs, and another section of shortcuts that includes sound volume, printers and the time.

Tab Menu
Tab menus, which are often present in dialogue boxes, are menus that represent many different "pages" of information. To access each "page," click on the tab at the top of the dialogue box.
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Once you understand what all the different parts of the computer do, you can begin to use it.
START UP
First of all, you will need to turn the computer on. Do this by pushing the power button on the front of the computer unit. The computer takes a few minutes to start up, so be patient.
SHUT DOWN
To shut down, click with your mouse on the button in the lower left-hand corner of the screen labeled Start. On the menu that pops up, click on Turn off computer. This will bring up a dialogue box with more options in it. Click "Turn Off." It is important to remember that turning off the computer by pressing the power button without going through the shut down process may damage the computer.
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STAND BY
When a computer is left alone for a while, it goes into "sleep" or "stand by" mode to save energy. In stand by mode, the computer slows down its inner processes because they are not being used. The computer also blacks out the monitor. If you wish to use a computer and the monitor is dark, check to see if it is in stand by before you try to start it up. Usually, the computer has a green light on or near the power button that signifies that it is on, but in stand by mode. To "wake it up," move the mouse or hit a key on the keyboard. In about 8-10 seconds the computer will wake up and be fully functional. If you do not realize that the computer is in stand by and you try to turn it on with the power button, the computer will wake up and a dialogue box will appear, but it will not damage the computer.

To open an application you have two options:
1. Open the Start menu and click on the name of the application.
2. Find the icon for the application and either double click it or right click and choose
Open.

To close an application:
1. Most applications can be closed by choosing "File" menu and selecting Quit orExit.
2. If no file menu is available, click the "X" button in the upper right-hand corner of the application's window.

Start menu: In the bottom left-hand corner of the Windows screen is a button labeled "Start." This button displays a menu that gives you access to many of the computer's features. Once the Start menu is opened, all you have to do is highlight what you want and more options will appear. Here we will discuss the many features and uses of the Start menu from top to bottom.

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Windows Explorer: This program lets you look through all of the files and folders on your computer. You can even open, copy, cut, and paste your files from inside Windows Explorer.
Right-click menu: When you right-click your mouse, a small menu will appear. This is the right-click menu, and it contains a list of the common tasks for whatever program you're currently using. If you use the right-click menu you can leave your cursor in roughly the same spot, which makes resuming your task easier

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Types of O.S

  • Mainframe Systems
–      Batch Systems: In Batch processing same type of jobs batch (BATCH- a set of jobs with similar needs) together and execute at a time. The OS was simple, its major task was to transfer control from one job to the next.The job was submitted to the computer operator in form of punch cards. At some later time the output appeared. The OS was always resident in memory. Common Input devices were card readers and tape drives.
–      Multiprogrammed Systems: Multiprogramming is a technique to execute number of programs simultaneously by a single processor. In Multiprogramming, a number of processes reside in main memory at a time. The OS picks and begins to execute one of the jobs in the main memory. If any I/O wait happened in a process, then CPU switches from that job to another job. Hence CPU in not idle at any time.
–      Time-Sharing Systems: Time sharing, or multitasking, is a logical extension of multiprogramming. Multiple jobs are executed by switching the CPU between them. In this, the CPU time is shared by different processes, so it is called as “Time sharing Systems”. Time slice is defined by the OS, for sharing CPU time between processes. Examples: Multics, Unix, etc.,
  • Desktop Systems: - Computer system dedicated to a single user. The preferences are User convenience and responsiveness. Main OS in use –Windows, UNIX, LINUX, MAC. It can adopt technology developed for larger operating system and often individuals have sole use of computer and do not need advanced CPU utilization of protection features.
  • Multiprocessor Systems: - More than one processor in close communication, sharing the computer bus, the clock and sometimes memory and peripheral devices. Advantages of parallel system are: Increased throughput, Economical, Increased reliability, graceful degradation, fail-soft systems.
  • Distributed Systems: - Distribute the computation among several physical processors. It is a loosely coupled system–each processor has its own local memory; processors communicate with one another through various communications lines, such as high-speed buses or telephone lines. It enables parallelism but speed up is not the goal. Advantages of distributed systems are: Resources Sharing, Computation speed up –load sharing, Reliability, Communications.  Types of Distributed Systems are: Client-Server Systems and Peer-to-Peer Systems
  • Clustered Systems: - Usually performed to provide high availability. In Asymmetric clustering one machine will be in hot stand by mode while other is running the application. In Symmetric clustering 2 or more hosts are running applications and they are monitoring each other. This mode is more efficient. Parallel clusters allow multiple hosts to access the same data on the shared storage.
  • Real-Time Systems: -Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems. Embedded Operating Systems: - OS is embedded on the System itself.  It is fast and application specific. Examples are processor in modern washing machines, cell phones, control systems etc.
  • Handheld Systems: - The major considerations are: Power consumption and weight must be low, memory ranges from 512KB to 8MB. Thus speed of the processor can not be very high because of the power consumption.

Functions of Operating system

a. Process Management
b. Storage Management
c. Memory Management
d. I/O Systems Management
e. Protection and Security.


Introduction

An operating system is a program that manages the computer hardware. It also provides a basis for application programs and acts as an intermediary between a user of a computer and the computer hardware. The purpose of an operating system is to provide an environment in which a user can execute programs in a convenient and efficient manner. 

The operating system must ensure the correct operation of the computer system. To prevent user programs from interfering with the proper operation of the system, the hardware must provide appropriate mechanisms.

The operating system provides certain services to programs and to the users of those programs in order to make their tasks easier. The services differ from one operating system to another, but we identify and explore some common classes of these services.

A computer system can be divided roughly into four components: the hardware, the operating system, the application programs, and the users


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The hardware-the central processing unit (CPU), the memory, and the input/output devices-provides the basic computing resources.
The application programs-such as word processors, spreadsheets, compilers, and web browsers-define the ways in which these resources are used to solve the computing problems of the users.

An operating system performs basic tasks such as,

n  controlling and allocating memory,
n  prioritizing system requests,
n  controlling input and output devices,
n  facilitating networking and
n  Managing file systems.

Internet

To access the Internet from a computer, you need to open a web browser. A web browser is a program such Internet Explorer or Mozilla Firefox that allows you to surf the net.

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Common Applications

Each computer with Windows is preloaded with various applications that you may use.
Although each computer contains different software, most of them contain the same basic applications that you will use frequently. Some of the most widely used applications are.
  • Internet Explorer: Use to access the Internet. Found in Start menu > Programs > Internet Explorer.
  • Windows Media Player: Use to listen to a CD. This program allows you to listen to your favorite CDs while you work. It includes programming features and volume controls. You will need to bring your headphones to listen while you work in the BGSU computer labs. Found in Start menu > Programs > Accessories > Entertainment -> Windows Media Player.
  • Calculator:  Use to do math on the computer. The Windows Calculator can be used by pointing and clicking the calculator on the screen, or by typing in the numbers on the keyboard. Found in Start Menu > Programs > Accessories > Calculator.

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  • Notepad: Used to create text documents. It is an easy and simple editor
  • Paint : - used to draw and paint
  • Sound recorder: simple sound recorder.


LINUX

Introduction

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Linux is a UNIX-based operating system originally developed as for Intel-compatible PC's. It is now available for most types of hardware platforms, ranging from PDAs  to mainframes. Linux is a "modern operating system", meaning it has such features as virtual memory, memory protection, and preemptive multitasking.
Linux is built and supported by a large international community of developers and users dedicated to free, open-source software. This community sees Linux as an alternative to such proprietary systems as Windows and Solaris, and as a platform for alternatives to such proprietary applications as MS Office, Internet Explorer, and Outlook.
As a result of this community, there is a very large collection of free software available for Linux. There are graphical environments (GUIs), office applications, developers' tools, system utilities, business applications, document publishing tools, network client and server applications -- the list goes on.
The best part of this community is that all code is open. Linux is free. This means more than just costing nothing. This means that you are allowed to do whatever you want to with the software. This is why Redhat, Mandrake, and Suse are all allowed to sell their own distributions of Linux. The only restriction placed on Linux is that, if you distribute Linux, you must grant all the privileges to the code that you had, including providing the source. This prevents a corporation from using the Linux kernel as the basis for their proprietary operating system.
Linux specifically refers to the Linux kernel. However, the kernel is useless without a set of tools and applications to run on the kernel. Linux is most commonly distributed with this toolset and a collection of applications in what is called a "distribution". The most common are Redhat, Mandrake, Suse, and Debian. Distributions differ in three basic ways: the process for installing the distribution, the applications available, and process for installing and managing these applications.
Linux looks and feels much like any other UNIX system. Its development began in 1991, when a Finnish student, Linus Torvalds, wrote Linux, a small but self-contained kernel.

How Linux is Different

Linux is distinguished from many popular operating systems in three important ways.
  • Linux is a cross-platform operating system that runs on many computer models. Only Unix, an ancestor of Linux, rivals Linux in this respect. In comparison, Windows 95 and Windows 98 run only on CPUs having the Intel architecture. Windows NT runs only on CPUs having the Intel architecture or the DEC Alpha.
  • Linux is free, in two senses. First, you may pay nothing to obtain and use Linux. So, Linux is free in an economic sense. Second, Linux and many Linux applications are distributed in source form. This makes it possible others to modify or improve them. This not possible with most operating systems, which are distributed in binary form.
  • Linux has attractive features and performance. Free access to Linux source code lets programmers around the world implement new features, and tweak Linux to improve its performance and reliability. The best of these features and tweaks are incorporated in the standard Linux kernel or made available as kernel patches or applications. Not even Microsoft can mobilize and support a software development team as large and dedicated as the volunteer Linux software development team, which numbers in the hundreds of thousands, including programmers, code reviewers, and testers.


Linux Features

  • Free software 

  • Copyleft:  FSF protects software freedom by copylefting its software. If the FSF placed its software in the public domain, others would be free to transform it into a proprietary product, denying users the freedom intended by the original author of the software

  • The Linux kernel: Linus Torvalds writes Linux kernel for the first time. GNU software integrated with Linux kernel, producing a fully functional operating system. Since the initial production release, the pace of development has accelerated as Linux has been adapted to include support for non-Intel processors and even multiple processors, sophisticated TCP/IP networking facilities such as IP masquerading, and more.

  • The X Window System: X is a unique graphical user interface in two major respects. First, X integrates with a computer network, letting users access local and remote applications. Second, X lets you configure its look and feel to an amazing degree.

Linux distributions


 Popular Linux Distributions and Their Web Home Pages
Distribution
Home Page
Caldera OpenLinux
Debian Linux
Slackware Linux
Red Hat Linux
SuSE. Linux

MS-DOS


MS-DOS, acronym for Microsoft Disk Operating System is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems. It was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s. But it was gradually superseded by operating systems offering a graphical user interface (GUI), in particular by various generations of the Microsoft Windows operating system.
The first edition, MS-DOS 1.0, was launched in 1982.
Features of MS-DOS:
  • Single user.
  • single tasking
  • not supports networking
  • Supports only character line interface (CLI).
  • Simplicity and transparency.
OS commands are the commands available in MS-DOS that are used to interact with the operating system. Unlike in Windows, DOS commands are the primary way in which you use the MS-DOS operating system. Some of the popular commands are
  • dir - The dir command is used to display a list of files and folders contained inside the folder that you are currently working in.
  • chdir/cd - The chdir command is used to display the drive letter and folder that you are currently in. Chdir can also be used to change the drive and/or directory that you want to work in.
  • mkdir - The mkdir command is used to create a new folder.
  • del - The del command is used to delete one or more files.
  • copy - The copy command does exactly that - it copies one or more files from one location to another.
  • date - The date command is used to show or change the current date.
  • rename - The rename command is used to change the name of the individual file that you specify.

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