Boolean Number System

Boolean Algebra is an algebra of logic.It is one of the most basic tools to analysis and design logic.It is name after lounge Boolean who developed it in 1854.The original purpose of this algebra was to simply logical statement.And solve logic problems.It had no practical application until 1939 when Shannon applied it to telephone switching circuits.

Logic Gates:
The computer receive store,understand and manipulates information is done by logic operation which are frequently perform in the design of digital system and gate are:AND,OR,NOT,NAND,NOR and X-OR(Exclusive OR).

AND Gate:
AND Gate has two or more inputs but it has only one output.AND input Signal applied to a gate has only two staple eight er 1 or 0.

OR Gate:
An OR Gate is also known as inclusive or gate.It has two or more in pots but only one output of an OR Gate will be high if a Heast anyone of the input is high.The output will be only zero when all inputs are zero.The logical operation will be called OR operation or function.

NOT Gate:
NOT Gate has only one input and only ane output Signal.It is also called inverter.If the input is 1.If the output is 0 then the input is 1.

NAND Gate:
A NAND gates has two or more inputs but only one output.The NAND function is the complement of the AND function.The abbreviation of NAND is a short form of NOT-AND.

NOR Gate:
A NOR gate has two or more inputs but only output.The NOR function is the complement of OR function.OR gate can be combined with an inverter of form a NOR Gate.

X-OR Gate:
The output of X-OR gate is high only when its inputs are different.Its output is low when both inputs A and B are same.

X-NOR Gate:
The X-NOR gate is the complement of X-OR operation.The output of X-Nor is high only when the logic value of both inputs A and B are same.

Element Of Computer System

A.Input Unit:
The Unit is link to the CPU and is used to enter data and program into the Computer memory.For example Keyboard,Mouse etc.

B.Output Unit:
This unit is also link to the CPU and issued to get the information after the processing at data program for example Monitor,Printers.etc

C.Control Unit(CU):
This unit control the operation of all other units it control the check the flow data from input unit to memory to ALU(Arithmetic Logic Unit) for calculation and sent that to memory and to the Output Unit.It has strong hold on all the units with control mechanism.

D.CPU(Central Processing Unit):
It perform operation on data from main memory and written the result of processing to main storage.It is also called the brain of Computer System.Processing is carried out by micro processor which although it serves a very different function.

Software Layer Of Computer Architecture

A.Operating System Layer:
Operating System layer control the way in which all software user the underlying hardware.

B.High Order Software Layer:
It converts all programs in language other than machine language which require translation into machine code before they can be execute.

C.Application Layer:
Application is the end user layer where we can interpret different application.

Hardware Level

A.Physical Device:
Physical Device Layer consists electronic physical components like transistors,resistor,etc.But is largely outside the subject of computer science and more in the province of Computer Technology.

B.Micro Program Layer:
This micro program layer interprets the machine language instruction from machine layer and directly causes the digital lagio elements to perform the require operation the macro logic elements to perform the require operation the macro.It consists micro code and micro program like firm wave.

C.Machine Layer:
The machine layer is the lowest layer at which a program can be written and language are directly interpreted by the hardware.

D.Digital Logic Layer:
Digital logic layer consists the logic gates.All the most basis operation of the machine are provided at this level.The basic element of this layer can be store manipulate and transmit data in the form simple binary representation

Architecture Of Computers

Various Computer Peripheral connected to do some work called System.The stole of Constructing and Organizing many part of Computer is called Architecture Of Computer.

Levels With Computer Architecture:
There are basic two level on the Computer architecture.They are Hardware Level and Software Levels.






Basic Level Of Computer Architecture

Software Level

• Application Layer
• Higher Order Software
• Layer OS Layer

Hardware Level

• Micro Programmed Layer
• Digital Logic Layer
• Physical Device Layer

System Of Number

1.Binary Number System:
It uses two different Symbol 0 and 1 here0 represents off,no,negative,false etc and 1 represent on,yes,positive,true etc.It constant base is 2.The positional weight increase into power of 2 The positional weight increase into power of 2 by unity.for example (0110)2 0,1,10,11,100 etc.

2.Decimal Number System:
It uses 10 different digits.They are 0-9.Its constant base is 10.The positional weight increase into the power of 10 by Unity.

3.Octal Number System:
It uses 8 different digits they are 0 to 7.Its constant base is 8 and the positional weight increase into the power of 8 by unity.For example (2,3,4)8,(421)etc.

4.Hexa Decimal Number System:
It uses 16 different digits.They are 0-9.A-F,Here A means 10,B=11,C=12,D=13,E=14 and F=15.Its constant base is 16 and the positional weight increase into power of 16 by unity.

Basic Electronics

Resistor
A resistor is an electrical component that resists the flow of current. The electrical resistance is equal to the voltage drop across the resistor divided by the current that is flowing through the resistor. Resistors are used as part of electrical networks and electronic circuits. In general, a resistor is used to create a known voltage-to-current ratio in an electric circuit. If the current in a circuit is known, then a resistor can be used to create a known potential difference proportional to that current. Conversely, if the potential difference between two points in a circuit is known, a resistor can be used to create a known current proportional to that difference. A resistor has a maximum working voltage and current above which the resistance may change or the resistor may be physically damaged.

Capasitor

A capacitor is an interesting device that is used to store energy and increase the efficiency of circuit systems. Capacitors are usually surrounded by two conductor plates that hold equal but opposite charges. The measure of a capacitor is its capacitance, or the total amount of charge stored on each conductor. As energy is increased on both sides, the capacitor begins to carry a voltage.In modern technology, capacitors have a number of various uses. As mentioned already, a capacitor can be used to store energy temporarily, just like a battery would. More significantly, capacitors are used in power supply and signal processing situations important to the development and running of computer chips. As an example, capicitors can play key roles as the "on/off" switch used to represent binary code. Capacitors can be bought more cheaply in bulk from a major capacitor manufacturer or supplier. Electrical hobbiests may be able to find capacitors at a local electronics store, through mail order, or online.


Diode
The term diode usually implies a small signal device with current typically in the milliamp range. A semiconductor diode consists of a PN junction and has two(2) terminals, an anode(+) and a cathode(-). Current flows from anode to cathode within the diode. An ideal diode is like a light switch in your home. When the switch is closed, the circuit is completed; and the light turns on. When the switch is open, there is no current and the light is off.
However, the diode has an additional property; it is unidirectional; current flows in only one direction(anode to cathode internally). When a forward voltage is applied, the diode conducts; and when a reverse voltage is applied, there is no conduction. In electronics, a diode is a component that restricts the direction of movement of charge carriers. It allows an electric current to flow in one direction, but essentially blocks it in the opposite direction. Thus the diode can be thought of as an electronic version of a check valve.


Transistor
Transistors have revolutionized the electronic industry. Since their introduction devices such as phones, TVs, computers have been made possible. Transistors are solid state semiconductor devices that are used for voltage regulations, amplification and more. Because transistors are used in plethora of different electrical devices, its contribution to technology has been unprecedented. As electrical devices become more complex, transistors will continue to be incorporated into these devices.
In today’s market transistors have a variety of different electrical properties and packaging. Therefore, it is imperative to do the research to find the right packaging and electrical specifications desired. The manufacturing of a transistor is still a delicate process that doesn’t yield good results, therefore it wise to find a reliable transistor manufacturer. Generally there are many transistors within electrical boards, it important that all of them are of the highest quality.


Integrated Circuit
An integrated circuit, or IC, is a small electronic device made out of semiconductor material. Integrated circuits are used for a variety of devices including audio and video equipment, automobiles, and microprocessors. Integrated circuits are often classified according to the number of transistors and other electronic components they contain, including SSI, MSI, LSI, VLSI, ULSI. A basic integrated circuit is often referred to as a microchip or simply a chip. Essentially it is a miniaturized electronic circuit that has been manufactured on a thin wafer of semiconductor.
Types of integrated circuits include analog, digital, and mixed signal chips. The growth of complexity of integrated circuits follows Moore’s Law, which states that the numbers of transistors in an integrated circuit doubles every two years. Integrated circuits are fabricated in a layer process which includes imaging, deposition, and etching.

Types Of Booting

Booting of computer can be done in two ways:
Cold Booting
Warm Booting



Cold Booting
When a computer is turned on, computer reads its RAM space and searches for the DOS system files from the disk drives (Floppy drive A:\ or Hard drive C:\). As soon as it finds the system files, those files will be loaded into computer’s memory from A:\ or C:\ drive, this kind of booting is called as Cold Booting.
So cols booting done when your compute is at OFF state, and you put on the power switch of the computer.



Warm Booting
If you are working with your computer and you wish to restart the compute, you simply press CTRL ALT and DEL keys at the same time, and your computer restarts again, searches DOS system files and loads into the computer’s memory. This is termed as Warm Booting. Sometime we press RESET button located nearby POWER button on the compute for warm booting.

Memory Of PC

Many types of memory devices are available for use in modern computer systems. As an embedded software engineer, you must be aware of the differences between them and understand how to use each type effectively. In our discussion, we will approach these devices from the software developer's perspective. Keep in mind that the development of these devices took several decades and that their underlying hardware differs significantly. The names of the memory types frequently reflect the historical nature of the development process and are often more confusing than insightful. Figure 1 classifies the memory devices we'll discuss as RAM, ROM, or a hybrid of the two.

Microsoft Windows

INTRODUCTION


Windows 98 is an operating system which is developed Microsoft Company to overcome the problems of earlier windows programs like windows 3.1, windows 95, windows 98, windows 2000, windows XP, windows ME. It makes our computer easier to use with new and enhanced features. The tools of windows 98 help our computer to run fast with out adding any new hardware. It also makes our computer more entertaining by introducing new features such as enhanced television, video, playback and support for new hardware. It supports many devices like printers, scanners, etc.



What is desktop?
When we power on the computer, after few minutes computer will display some icons like my computer, Recycle Bin, My Document .etc

How to create new folder on desktop?

• Click right mouse button in the blank area of desktop.
• Click on New, click on "Folder".
• Then type the name for folder.
• Click on enter key or click on blank area.

To open the files or Folders

• Select the required files or folders you want to open.
• Click on right mouse click on open.

Or

• Double click the file or Folder, which you want to open.

To create new File in the Folder.

• First open the folder, click on File menu.
• Click on New command
• Then choose the required option. (Word document, excel, worksheet etc)

To open windows explorer.

• Click on start button.
• Click on programs.
• Click on windows explore.

Or

• Right click on the start button.
• Click on explore.

(The left side of the windows explorer window contains a list of your drives and folders and the right side displays the contents of a selected folder)

To copy files or folders

• Click on right mouse button and click on copy.
• Now, open the drive or folder where you want to put the copy.
• Click on Right mouse button again, click on paste.

To delete files or folder

• Open windows explorer.
• Select files or folders you want to delete.
• Press the right button of mouse.
• Click on ok.
• Then a confirm dialog box appears.
• Click on yes button.

To Restore Files or Folders From Recycle Bin.

• Open Recycle bin.
• Select the required Files or Folders.
• Press the Right mouse button.
• Click on Restore.

To make Recycle Bin Empty

• Select the Recycle bin
• Press the Right mouse button.
• Click on Empty Recycle Bin.

To put the shortcuts on desktop.

• Press the right mouse button in the blank area of desktop
• Click on New and click on shortcut.
• Then a dialog box appears.
• Click on Browse button
• Close the required Files or Program name
• Click on open button.
• Click on Next button
• Type the name for shortcuts and click on Finish.

To Find Files or Folders.

• Click on start button and go to find.
• Click on files or folders
• The dialog box appears. Type the name of files, folders or program or type the starting characters with wildcards (*.doc, *.xls, *.jpg, *.bmp, *.tmp, etc)
• Click on find next button.

To Add/Remove programs from start on program menu

• Click on start and click on settings.
• Then click on Taskbar & start menu.
• Click on start menu programs tab.
• Click on Add button and click on browse.
• Locate the program you want to Add, and then click it.
• Click Next and then double click the menu on which you and to program to appear.
• Type the name that you want to see on the menu and the n click on Finish.

To open Notepad.

You can see notepad to create or edit text files that do not require formatting.

• Click on start button
• Click on programs
• Click on Accessories.
• Click on Notepad.

To open WordPad.

WordPad is a text editor for short document, you can format save, print the documents for personal and business use.

• Click on start button
• Click on programs.
• Click on Accessories.
• Click on WordPad.

To Set Date & Time.

• Click on start
• Click on settings.
• Click on Control panel.
• Double click on date & Time.
• Then a dialog box appears.
• Double click the required month, year, date, and time.
• Click on Apply, click on ok.

To Change the Mouse Settings.

• Click on start and click on settings.
• Click on control panel
• Then double click on Mouse.
• Now a dialog box appears.
• Set the required options
• Click apply and click on ok

To check the disk for errors.

• Click on start button and click on programs.
• Click on Accessories, and click on system tools.
• Click on scandisk.
• Then a dialog box appears.
• Select the drive (c: a:,d: etc)
• Choose the type of test.
• Click on Automatically Fix errors.
• Click on start button.

To Change the Background of Desktop

• Click on right mouse button in the blank area of desktop.
• Click properties, then a dialog box will Appears.
• Click on background tab.
• Choose any picture or web document.
• Choose any display option (stretch, tile, center)
• Click on Apply and click on ok

To Apply Screen Saver

• Press the opposite mouse button in the blank area of desktop.
• Choose properties.
• Then a dialog box wills Appears.
• Click on screen saver.
• To Apply text as screen saver, choose 3d Text
• Click on settings and type the required text or your name.
• Choose the required size, resolution, speed, spins style, font etc.
• Click on ok.
• Choose the required timing from wait option.
• Click on apply.
• Click on ok.

To Change the Appearance of windows

• Press the opposite mouse button in the blank area of desktop.
• Choose properties and then a dialog box appearance.
• Click on Appearance tab.
• Choose any time and scheme.
• Click on Apply, Click on OK.

Calculator.

- Input the non-calculation items by tab setting.

- Load calculator with the following procedure.

Process:

• Click on start
• Click on Program
• Click on Accessories
• Click on Calculator.

In the absence of short cut, run the program as below.

Process:

• Click on Start
• Click on Run
• Calculate the item using calculator and copy it.

v Click on Ms WordPad to the right destination and paste it. Repeat the same steps till all the items are calculated.

MULTI-MEDIA:

The multiple mediums of communication are known as multi-media in computer terminology. We use different types of mediums in communication. That may be textual information video clips, audio or video. It is found one of the fastest and casualty ways of communication in modern technology. In this chapter, we will learn how to play the audio and video.

A multimedia computer should have the following peripheral devices: Pentium I having 100MHz(Minimum)

AGP Display.

1GB of Hard disk

Sound card

Modem (modulator and Demodulator)

64MB RAM (Random Access Memory)

CD-Drive:

Playing Audio CD:

Insert the audio CD into the CD ROM Drive.

Load the program in the given path.

• Click on Start
• Click on Program
• Click on Accessories
• Click on Entertainment
• Click on CD-Player

After detecting the drive and music tracks, the main window will be active. Click on the control button such as play, rewind, and forward stop and eject as usual in our cassette player.

Playing Videos:

Repeat the same steps as usual with the given steps.

Process:

• Click on Start.
• Click on Program.
• Click on Accessories.
• Click on Entertainment.
• Click on Media Player.
• Choose file then open. Now locate the drive that may be either D:\> or E:\> according to the partition of the disk.
• Double click on Mpgav main folder and locate the fill to be played.

Control Panel

It is the main controlling unit that coordinates and controls the peripheral devices. In other words, it's the main controlling section form where the system settings and options are changed. It's a way of creating a favorable working environment as per the user's interest. Installing and removing program, hardware components and their drivers, new font, changing the screen display setting of mouse, multimedia, keyboard and sound all are performed using control panel. Once the settings are changed form control panel the effect can be obtained from any of the windows associated program.

Loading Control Panel:

• Click on Start
• Click on Settings
• Click on Control Panel
• In the absence of the short cut, run the program as below.
• Click on Start Bottom.
• Click on Run and display the dialogue box

After having displayed the icons of control panel, double click the respective one and change the settings accordingly.

MICROSOFT WORD PAD

It is a word processing application program, which developed by the Microsoft Corporation. It's the simple but common word processing application that lads us create simple documents such as a letter, application and report. After having the good concept of WordPad. We can easily run the advanced applications. It's the preliminary platform of word-processing, which is available as the window has been installed or it is a small processing of Microsoft word.

Loading word pad.

• Click on Start.
• Click on Program
• Click on Accessories
• Click on Word-Pad

In the absence of the shortcut, run the program as below,

• Click on Start
• Click on Run

Immediate after that a standard word processing screen is appeared.

Title Bar

Menu Bar

Tools Bar

Format Bar

Ruler

Status Bar

What is Cursor?

It's the vertical blinking line, which can be defined as the tip of the pen. It's the main indicator that should be before data insertion and manipulation. It can be easily moved from one place to another with the help of the following key combination.

Editing Text:

An editing is the process of changing the physical values either adding or removing the text.

Searching a string:

The process of finding a particular term that has been repeated many times on the document is etymologically said to be searching a string. Especially to note down the position and order of execution, such items are sleeked.

• Position the cursor at the beginning of the document.
• Choose find on the edit main menu and specify the string as below.
• Type the finding word or letter in find what criteria.
• Click on find next many times till the entire terms are sleeked.

Replacing a String:

After the particular term has been sleeked successfully may be replaced by a new term, which is performed through replace in global correction and manipulation. After we specify the both of searching and replacing strings, one by one will be replaced conditionally.

• Choose replace on the edit main menu and specify the both of searching and replacing strings as below:
• Click on replace for individual while replace all, global replacements.

Paste Special:

With the use of simple paste, the whole attributes can be copied with no options. By using paste special we can highlight only the selected attribute. It has the following common attributes.

• Highlight the preformatted item and copy it.
• Position the cursor and choose paste special then any of the following attributes.

Inserting Date and Time:

If the system date is correct, it shows the current date in different styles. From which where the right one we can select accordingly.

• Locate the cursor and choose date and time on the insert main menu.
• Choose any of the following date and time format.

Inserting an object:

No program in software industry is self-executable and independent from all aspects. The feature available in one program may not be other. In this respect, the new feature has to be added as an object. The object may be a picture, freehand, interactive image, chart and diagram, metafiles or simply a document extracted form the relative sources.

• Click on Insert Menu.
• Choose the Object, then a dialogue box will display.
• Choose the Microsoft Clip Art Gallery
• Then Picture dialogue box will display
• Choose the any one picture
• Click on ok.

Posses a head by following necessary steps then choose exit or return to Ms-WordPad on the file main menu after a complete object has been created.

Formatting Letters:

The process of changing the physical attributes and appearance of the selected text in terms of the letter type, size, style and other initials is called formatting letters in computer terminology. If all the information is uniform, then we can't distinguish between them.

v Highlight the part of document and choose fonts on the format main menu. Now specify the letter type, style and necessary initials as below:

Formatting a Paragraph:

Naturally, to be a complete document, there may be different paragraphs. If all of them are uniform, we can't locate the selected one more easily. The paragraph may constitute the alignment and indentation form left, right and first line.

v Locate the paragraph and choose paragraph on the format main menu. Now specify the alignment and indents as below:

Note: To format two or more paragraphs, all of them should be highlighted first.

Tab Setting:

When we press the tab key, initially the cursor moves 4 characters right wards with left alignment. By using tab setting, we can specify the tab stop position especially for tabular tasks. Position the cursor and choose tabs on the format main menu and specify the value for the tab stop in the interval by clicking on set button as below.

• Click on ok and input the values by pressing the tab key. Input the following information and find out the amount and grand total with the help of calculator.

Limitations of MS-DOS

Limitations of MS-DOS
1. It is a command line user interface (CUI) operating system. You must type commands from the keyboard for each and every action.
2. It is a single user Interface operating system and It doesn't support multitasking. You must close first file to open next file in MS-DOS.
3. It accepts only 8 characters as filename and 3 characters as extension.
4. It doesn't support some symbols as file name and extensions like \,/, . , ! , , , , etc.
MS-DOS accepts two types of commands which are Internal DOS commands and External DOS Commands.

Types of Operating System

1. Command line User Interface(CUI):

In command line user interface the command must be typed for each and every action. MS DOS is the popular CUI operating system. In CUI The user must close the running file to open next new file, user could not work with multiple application at the same time. In CUI Operating system user could not use any pointing device like mouse, touch pad, track ball etc.

2. Graphical User Interface:
In Graphical User interface the user can apply any command or action by the help of pointing devices. Windows, Mac OS are the popular graphical operating systems. In graphical operating system the user can work with multiple applications at the same time, which is known as multi tasking.

MS-DOS ( Microsoft Disk Operating System): Microsoft DOS (Disk Operating System) is a command line user interface. MS-DOS 1.0 was released in 1981 for IBM computers and the latest version of MS-DOS is MS-DOS 6.22, which was released in 1994. While MS-DOS is not commonly used by itself today, it still can be accessed from every version of Microsoft Windows by clicking Start / Run and typing "command" or by typing "CMD" in Windows NT, Windows 2000 or Windows XP. Some points before MS-DOS

Drive Prompt: The drive prompt defines the drive in which you are working.
A: First Floppy Disk Drive B: Second Floppy Drive C: First Partition of the hard disk drive.
D: Second Partition of the hard disk drive.
The last drive (Generally E: or F: ) : CD ROM Drive

2. Directory: Directory defines the root or path where you are creating files or directories. You can store sub-directories and files in a directory. In windows operating system It appears as a folder.

3. Path: path also defines the root where you are creating directory or file. It begins with drive prompt and displays all root directories name to reach to the current directory.

4. Wild Cards: In MS-DOS you can use some characters for special purpose, which are known as wild cards. * (Astrik sign) : Which defines group of character.
? (Question mark) : Which defines individual character.
# You can use these wild cards if you need to copy, cut or delete files or directories having same filename or extension.

5. Filename : It defines the name of the file. You could not create more than two files having same name with in a same directory. It supports only 8 characters as filename.

6. Extension: It defines the nature of the file. As people has different cast same as computer files has different extensions for different applications, files.
.sys : System files
.bat : Batch files
.exe : Executable file
.dll : Dynamic link library files.
.doc : Document file (Microsoft Word)
.xls : Worksheet file (Microsoft Excel)
.ppt : Presentation file (Microsoft Powerpoint)
.gif : Graphics Interchange Format (Image file)
.jpg : Joint photographic expert group (Image file)
.png : Portable Network Graphics (Image file)
.htm/.html: Hyper text markup Language (Webpage format file)

7. System file : Those file having extension .sys, which are required to boot the computer are known as system files. In MS-DOS Three files are required to boot the computer
IO.SYS
MSDOS.SYS
COMMANDCOM.SYS

Based On Software

The computer software is a set of instructions which makes the hardware parts workable. Generally we can compare the software with oxygen for the human body. As the oxygen needed for human body the software instruction needed the computer hardware to run properly. The computer software can be divided in three main parts.

Types of software

1.Application Software

Those softwares which has particular task are the application software like documentation, presentation, publication etc. Microsoft word, Excel, PowerPoint, Adobe PageMaker, Photoshop etc are the application software's.

2.System Software

A.Language Processor

The language processor is also a powerful part of the system software which translates different programming codes as required. The language processors can be defined as follows

1.Interprietor

The interpreter is a program that translates user’s programming language to high lever languages into machine language code and fetches them to the computer to execute. Interpreter translate one statement at a time.

2.Assembler

The assembler is the software which translates programs written in assembly language into machine code, which the computer understands. One assembly instruction is converted into machine instruction.

3.Compiler

The compiler is a program that translates use’s programming languages or high level languages into machine language code and fetches them to the computer to execute just like the interpreter. Unlike interpreters, compilers translate the whole program instead of the one program instruction.

B.Utility Software

The software which checks the system and manages file to make the system up to date is the utility software. It works as the doctor of the computer. It any error occurs on the computer it automatically fixes it. All the antivirus programs, System tools etc. are the utility software.

3.Operating System

The operating system is the master controller of the computer system. The operating system creates link between hardware and the application software of the computer. It controls entire system and creates environment for different application software.

Based On Hardware

The computer display is divided into many types. Some of the main display types of are listed below:

1. CRT(Cathode Ray Tube) Display:
Video display terminals are the most popular I/O devices used today in direct-access processing applications. Cathode ray tube message and the processed output from the computer. The information regarding bits are displayed on the monitor in character form which we see as alphanumeric characters. Only the characters can be seen on the screen the higher is the resolution or better is the character display or graphics display. The CRT has the 24 lines rows and 80 screen that can be turned on or off to help create an image)

2. LCD (Liquid Crystal Display):
The display in which liquid crystals and polarizer can manipulate light to charge the liquid crystal cells that provide the display. Such type of display is used in the portable computers, like laptop computer.

3. Resolutions:
The number of pixels produces the resolution in the screens. The resolution depends on the monitor and the display adapter installed on the computer. In the screen, the high resolution increases the area of the desktop but decreases the size of the items but the lower resolution increases the size of the items and decreases the size of the desktop.
Some of the resolutions are listed below
• 640 by 486 pixels
• 720 by 480 pixels
• 720 by 576 pixels
• 800 by 600 pixels
• 1024 by 768 pixels
• 1152 by 864 pixels
• 1280 by 1024 pixels
• 1600 by 1200 pixels
The above resolutions are applied according to the size of the monitor
Computer Hardware:
All the physical components of the computer which can be see and touch are the hardware parts of the computer. All the peripheral parts attached with the computer are known as the hardware parts of the computer like Monitor, Mouse, Keyboard, CPU, Speaker etc. (See Input devices, Output devices, Storage devices)
Computer Software: The computer software is a set of instructions which makes the hardware parts workable. Generally we can compare the software with oxygen for the human body. As the oxygen needed for human body the software instruction needed the computer hardware to run properly. The computer software can be divided in three main parts.

Based On Size/Speed

Super Computer
Super computers are the most powerful and faster of all computer system. Supercomputer are even faster then the mainframes. The supercomputers are being used in the complex scientific calculations and research project. The supercomputers are important innovation in history of computer. They may be employed in massive data processing, solving very complex problems. Supercomputers are used in weather forecasting, rock launching, seismology, nuclear physics, weapon research and so on. The cost of these computers are very high (more than 15 million dollars). CRAY I, CRAY X-MP, HITAC S-300 etc. are the popular super computers.






Mainframe computer
Mainframe computer is larger than mini computer and smaller than supercomputer. It is very popular in database field. It is also applied as web server. It can support more than 1000 processors at the same time.





Micro Computer

A computer which is based on the microprocessor, is called a microcomputer. It is small, low cost digital computer. Microcomputer has a microprocessor on a single chip, which is its Central Processing Unit(CPU). It also has other units like input devices memory unit. It is also called personal computer. IBM PC, Apple macintosh etc. are the microcomputers.

Introduction Of Computer

The computer comes from the word "COMPUTE",which means,"TO CALCULATE".Thereby,a computer is an electronic device that can perform arithmetic operations at high speed. A computer is also called a data processor because it can store,process,and retrieve data whenever desired.



HISTORY OF COMPUTER



ABACUS
The ABACUS was the first calculating device of the world, which was first introduced in middle Asia (China) nearly 3000 BC. The ABACUS is a portable device that consists of beds strung on wires or wooden rods.The ABACUS has two parts divided by middle bar. The above part is known as heaven and the lower part is known as Earth. Each ball of the heaven part takes value 1 and each ball of earth part takes value 5 in calculating.

Napier’s Bone

The Napier’s Bone was developed by Scottish mathematician John Napier in 1614 AD. It is very helpful to calculate long number mathematical calculations. It has 11 rods with sequenced numbers.

Slide RuleThe Slide Rule was invented by William Oughtred in 1617 AD. The device was made on the principle of logarithms. This device consists of tow graduated scales. One of the scales passes over the other. The scales are devised in such a way that suitable alignment of one scale against the other makes it possible to obtain products, quotients or their function by inspection. The slide rule was used by the engineers till 1970s. This was replaced by calculator.

Pascaline

The pascaline was developed by French mathematician Blaise Pascal in 1642 AD. This machine had a capacity of adding or subtracting 8 column numbers up to 999999999. This machine could add and subtract only.

Leibniz’s Calculating Machine

The leibniz’s calculator was developed by German philosopher Gottfried von Leibniz in 1671 AD. This machine is also known as stepped calculator. It can calculate addition, subtraction, multiplication, division and square root etc.

Difference Engine

The Difference Engine was developed by English Mathematician Charles Babbage in 1823. The difference engine was with mechanical memory. Later he design a bigger machine which could compute up to 20 decimal places, called analytical Engine in 1830s. This machine was made to solve differential equations. Since Charles Babbage contributed to develop actual calculating device, he is considered as the Father of Computer.

8.Howard Akein

Next important event was added in the History of computer in 1930. MARK I the first elecromechanical compute was designed by Haward Aiken in 1944 which has the power to support 23 digits. It was build by combining more then 7 lakh separate parts and nearly 500 million wires. It has the power to perform 3 calculations per second. 9

9.ENIAC
The ENIAC is the acronym of Electronic Numerical Integrator And Calculator. Which was designed by John mauchly and presper Eckert in 1947. It was formed by combining more than 18000 vacuum tubes, more than 70000 resistors, more than 10000 condensers and more than 6000 switches.

10.EDVAC

The EDVAC is the acronym of Electronic Discrete Variable Automatic Computer, which was developed by John Mauchley and John Presper Eckert with the help of Goldstine Neumann in 1949. This machine was used to store the data and information as well as theinstruction.

11.UNIVAC
The UNIVAC is the acronym of Universal Automatic Computer which was developed by the company founded by mauchley and Eckert in 1951. It became the first commercially used electronic computer of the world.