Computer Fundamental

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What is a Computer ? A Computer is an electronic device designed to perform Arithmetic operations. It can also perform several nonArithmetic operations on the alphabetic or numeric data used. Computer is a term applied to a group of inter-related electronic devices that automatically :Accept and store input data. Process the inputted data and Output the processed results in the form of reports.

Introduction To Basic Computer Organization The data and instructions entered into the computer system through input units have to be stored inside the computer before the actual processing starts. Similarly, the results produced after processing must be stored to be passed onto the output unit. The Storage Unit is designed to cater to these needs. It provides space for storing the data, instructions, intermediate and final results.

The Central Processing Unit

The CPU provides the fundamental command and instruction environment for the computer. It contains the processor, registers, a control unit, which controls the execution of a program, a clock, and the arithmetic logic unit, which performs mathematical operations and comparisons. A CPU that is contained on a single chip is called a MICROPROCESSOR.

CONTROL UNIT

The Control Unit is able to maintain order and direct the operation of the entire system by selecting, interpreting and seeing to the execution of the program instructions. Although it does not perform any actual processing on the data, the Control Unit provides sequential control over the execution of the program.

ARITHMATIC LOGIC UNIT

The Arithmetic Storage Unit (ALU) of a computer is the place where the actual execution of instructions takes place during the processing operation. All cal-culations are performed and all comparisons are made in the ALU. Date moves from primary storage to the ALU and back again to storage several times before processing is over. All ALU’s are designed to perform four basic arithmetic operations – addition, subtraction, division and multiplication, and logical ope-rations such as less than equal to and greater than.

Storage Unit (Main Memory) The data and instructions entered into the computer system through input units have to be stored inside the computer before the actual processing starts. Similarly, the results produced after processing must be stored to be passed onto the output unit. The Storage Unit is designed to cater to these needs. It provides space for storing the data, instructions, intermediate and final results.

Memory Organization

Memory is a generic term used to describe any data storage area of a computer. A memory is made up of a large number of cells with each cell capable of storing one bit. Memory can be broadly divided into two types – Primary memory that in most cases requires a power source to retain data; and Secondary memory, which does not require any power source once the write operation, is complete.

Storage Devices - Primary Storage The word storage is descriptive of a device or a medium that can accept data, hold it, and deliver it on demand at a later time. Storage may be classified as – Primary Memory and Secondary Memory Primary Storage It is a electronic memory, made up semiconductor chips. This stores: • The instructions waiting to be obeyed • The instructions currently being obeyed • The data awaiting processing • The data currently being processed • The information awaiting output

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Primary Memory : ROM Primary memory is classified as Random Access Memory (RAM) and Read Only Memory (ROM) . A ROM is a storage memory inside the computer that cannot be amended or erased by the processor. ROM is used to hold static information necessary for the computer such as the Basic Input/Output System (BIOS).

Primary Memory : RAM

It is also called as – “the Read-Write Memory”.

Random Access Memory (RAM) is a memory into which the user can enter information and instructions (write) and from which the user can call up data (read). The distinct feature of this kind of memory is that it is volatile; the contents of the memory are lost when power is switch off. It is used only to ‘temporarily’ write or hold the data, instructions or information.

Storage Devices – Secondary Storage The storage capacity of primary storage is not sufficient to store large volume of data. As a result, additional memory called the Auxiliary Memory or Secondary Storage is used with most computer systems. Secondary Storage is characterized by low cost per bit stored, but it generally has an operating speed far slower than that of primary storage. Hard Disk Floppy Disk Compact Disc`

Input Units Data instructions must enter the computer system before any computation can be performed on the supplied data. The input unit that links the external environment with the computer system performs this task. All input devices must provide the computer with data that are transformed into binary codes that the primary memory of the computer is designed to accept. Units called input interfaces accomplish this transformation. Basic input units are Keyboard Mouse Scanners

Hard Disk (Input / Output Device)

It is the largest external memory of the computer system. It is made from magnetic material, which stores data as magnetic fields. Even when the power is off the data in it remains intact. White the read or write operation is going on, a red light on the container of the Hard Disk light up, confirming that some operation is being perform on the Hard Disk.

Floppy Disk (Input / Output Device)

A Floppy Disk is a flexible plastic disk, coated with magnetic material and enclosed within a plastic sleeve. This is divided into concentric circles called tracks, which are further subdivided into sectors. Data is stored in a floppy disk by encoding bits of data along the tracks of the diskette.

CD/DVD ROM

CDROM stands for Compact Disk Read Only Memory. Information on a CDROM is written by creating pits on the disk surface by shining a laser beam. The CDROM with prerecorded information is read by a CDROM reader, which uses a laser beam for reading. As in a magnetic floppy disk, a CDROM disk is inserted in a slot. A motor at a speed of 360 revolutions per minute rotates it. A laser head moves in and out to the specified position. As the disk rotates, the head senses information by the electronic interface and sent the data to the computer.

DVD ROM Digital Versatile Disk (DVD) is the next generation of Optical storage media. The CD-ROM had one apparent disadvantage - Limited capacity of 650 MB. The DVD packs from 4.7 GB to 17 GB of storage space in the size of the compact disc, This is equal to the storage capacity of 7 CD's! Optical storage devices such as CD-R are suitable for archiving data. Or when you need to distribute large amount data in a Standard acceptable format. The only impediment to widespread acceptance of this new medium is fickle DVD standards, which have not yet been set.

KEYBOARD

The Keyboard is the most common and most versatile of all input devices. The Keyboard is divided into three parts, the Main Keyboard, Function Keys and Numeric Keypad. The Function Keys perform special functions such as loading programs and offering help. The Numeric Keypad is used to enter numeric data or to move the cursor. The NumLock key can be used to switch from numeric data to the cursor.

MOUSE Mouse is used in conjunction with the Keyboard, which use an ElectroMechanical device as pointer to select items from an onscreen menu. The movement of the mouse enables the user to: • Point to icons • Click at Icons to run programs • Choose an item from a list • Draw lines and picture on a screen

Scanners A Scanner converts a printed image in to digital information suitable for input to a computer. A scanner essentially uses the same technology as a fax machine. It reads an image from paper and instead of sending it down the telephone line, converts it to a format that your system can understand. The computer holds the image as a graphic file, which you can print, amend or add to other documents.

Visual Display Unit (Output Device) The Visual Display Unit (VDU) also called as Monitors are standard output devices. The information appears on the screen as and when it is entered from any of the input devices and after it is processed. The Cathode Ray Tube and the display adapter determine features like the number of colors possible and the graphic capabilities. A maximum of 24 to 25 rows and 80 columns per row of information can be display in the Text mode. Apart from text, graphics and pictures can be displayed.

Output Units The Output Unit supplies information and results of computation to the outside world. As computers work with binary codes, the results produced are also in the binary form. Hence before supplying the results to the outside world, it must be converted to human readable form. The Output Units accomplish this task. The basic Output Units are Printers Visual Display Unit (already discussed above).

Printers Printers are the primary output devices used to prepare permanent documents (hard copy), in human readable form. There are several printers that are designed for different types of applications. Printers may be classified as – Impact Printers Non-Impact Printers

Impact Printers Impact Printers create characters by striking a print page with a print hammer (print head). These are further classified depending on the method they adapt to print characters. Some of them can print only one character at a time, while others can assemble an entire output line a time. These can be classified as – Dot Matrix Printer (DMP) Line Printer

Dot Matrix Printers

Dot Matrix Printers are the most commonly used printers with microcomputers. The characters are produced by a series of pins arranged vertically, which strike an inked rib-bon against the paper. Each character is produced within a pre-defined matrix of dots. The speed may vary from 180 characters per second to 380 characters per second. It can also print pictures.

Line Printers Line Printers print complete lines up to 160 characters in width at speeds ranging from 300 to 2000 lines per minute. There are three kinds of Line Printers: Chain, Band and Drum printers.

Non-Impact Printers Non-Impact Printers employ processes other than hammers to form characters on a print page. These are noiseless and more versatile and offer better quality outputs. They cannot produce multiple copies at the same time like their impact counterparts. These can be classified as – Laser Printers Ink Jet Printers

Laser Printers Laser Printers use a laser beam to write characters on a rotating drum that is electro-statically charged. The drum generates a paper copy in a manner similar to a Xerox copier. The speed varies from 6 to 120 pages per minute. They can also print graphics in different colors.

Ink Jet Printers

The print head of an Ink Jet Printer, form characters by spraying a very fine jet of magnetically or electrically charged ink through a nozzle and over horizontal and vertical deflectors. The deflectors enable the printer to vary the direction of the ink spray. The work at speeds of 1-2 pages per minute.

Introduction To Software

What is a Software? Software is a program or a collection of programs written to enable the computer to perform useful tasks. A program is made up of special commands and statements that are obeyed and executed by the computer.

Types of Software Computer software may be classified into two broad categories: Application Software and System Software

Application Software Application Software is a set of programs necessary to carry out operations for a specified application. For example, programs to solve a set of equations, process an examination result, would constitute application software.

System Software System Software is a general program written for the system. They provide the environment to facilitate the writing of application software. Programming language translators are examples of system software.

Introduction to Operating System An Operating System is an integrated set of programs that is used to manage the various resources and overall operations of a computer system. It is designed to support the activities of a computer installation. Its prime objective is to improve the performance and efficiency of a computer system and increase facility, the ease with which the system can be used.

Functions of Operating System It provides the necessary instructions and data to the CPU by loading them into the memory. The Operating system is loaded into the memory when the computer is switched on. The CPU with the help of the Operating System, which then processes data to get information, reads these instructions. The Operating System displays this information to the user.

Introduction to Windows Research in windows was started in early 1980 at the XEROX Corporation, US. Basic concept of today’s windows systems was first introduced at XEROX PARC. Next APPLE Computers adopted this technology on its MACINTOSH computer models. And then MICROSOFT. At XEROX PARC the GUI (Graphic User Interface) interface took shape and the mouse was born.

What is Windows Windows is a software system that offers a variety of facilities to develop applications, manages computer resources and eases to use the computer efficiently.

A window is a highly user to work with ‘picture’ or view. Windows owes its name to the fact that it runs and exhibits each program in a separate window on the screen. There may be several windows on the screen at the same time, each belonging to a different program.

Introduction to Windows 98

Windows 98 includes tools that help your computer run faster than Windows 95 without adding new hardware. Windows 98 includes a suite of programs designed to optimize your computer’s efficiency, especially when used together.p

Introduction to Windows 98 Features of Windows 98 Windows 98 makes your computer easier to use, with new and enhanced features. True Web integration - Improved Web features - Internet Connection wizard - Internet Connection Sharing - Active Desktop - E-mail - NetMeeting - FrontPage Express Multiple display support

Introduction to Windows 98 Features of Windows 98 Power management Universal Serial Bus Accessibility wizard Help Improved reliability Windows Update

Maintenance wizard Drive Converter Backup Disk Defragmenter More entertaining New hardware and graphics

System File Checker ScanDisk

WebTV for Windows

Registry Checker Registry Checker Backup

Desktop themes

DirectX

Introduction to Windows 98 The Windows 98 Desktop

Introduction to Windows 98 The Start Button

The Start button provides a launch point for all applications on the system.

Introduction to Windows 98 The Taskbar

The Taskbar (normally positioned at the bottom of the screen) provides a constant view of which applications are running on the system and an easy way to switch between them. The Taskbar also provides constant additional information such as the system time, power consumption information on laptop computers, and volume control if you have a sound card fitted, all of which can be further tailored by the user.

Introduction to Windows 98 The Recycle Bin re ov on e cati ot r a li n l p l t a ap w i h t n ame in. s a e Fil to filen le B c ! e y e t g in du lica Rec n ar en dup the W itt a o t r g w in ed v s u sa be

When files or system icons are deleted they are first moved to the Recycle Bin. As long as files are in the Recycle Bin they can easily be recovered if they have been accidentally deleted.

Windows 98 will preserve files until the system actually truly runs out of free disk space. When this happens Windows 98 will purge the contents of the Recycle Bin.

Introduction to Windows 98 The My Computer All of the main aspects concerning configuration and access to the system’s local resources, such as the hard and floppy disk drives, are contained within the My Computer Desktop group. This allows the user to view local resources as objects. Double clicking on any drive will expand an additional window allowing the user to view the next level.

Introduction to Windows 98 The Network Neighborhood

Network Neighborhood provides an easy mechanism for browsing any network systems and resources that you may be able to connect to. Windows 98 is capable of

displaying a common view of your entire network