Computer Parts – CPU(Central Processing Unit)

Computer Parts – CPU(Central Processing Unit)

Computer Parts – CPU(Central Processing Unit) CPU consists of the following features: CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, More »

Parts of a Computer System Explained

Parts of a Computer System Explained

Information is funny stuff. The information for the web page you are looking at is recorded on a hard disk inside a computer located in New Britain, Connecticut. The information was copied More »

Applications and Uses of Computers

Applications and Uses of Computers

Applications and Uses of Computers or how to use the computer? Getting the right kind of information is a major challenge as is getting information to make sense. College students spend an average More »

Hardware and Software of Computer System

Hardware and Software of Computer System

Computer hardware is any physical device used in or with your machine, whereas software is a collection of code installed onto your computer’s hard drive. For example, the computer monitor you are using to read this More »


Computer Parts – CPU(Central Processing Unit)

CPU part of a computer

Computer Parts – CPU(Central Processing Unit)

CPU consists of the following features:

  • CPU is considered as the brain of the computer.
  • CPU performs all types of data processing operations.
  • It stores data, intermediate results and instructions(program).
  • It controls the operation of all parts of computer.

CPU itself has following three components.

Computer-Cpu- Block-Diagram

Computer-CPU- Block-Diagram


Memory or Storage Unit

This unit can store instructions, data and intermediate results. This unit supplies information to the other units of the computer when needed. It is also known as internal storage unit or main memory or primary storage or Random access memory(RAM).

Its size affects speed, power and capability. Primary memory and secondary memory are two types of memories in the computer. Functions of memory unit are:

  • It stores all the data and the instructions required for processing.
  • It stores intermediate results of processing.
  • It stores final results of processing before these results are released to an output device.
  • All inputs and outputs are transmitted through main memory.

Control Unit

This unit controls the operations of all parts of computer but does not carry out any actual data processing operations.

Functions of this unit are:

  • It is responsible for controlling the transfer of data and instructions among other units of a computer.
  • It manages and coordinates all the units of the computer.
  • It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
  • It communicates with Input/Output devices for transfer of data or results from storage.
  • It does not process or store data.

ALU(Arithmetic Logic Unit)

This unit consists of two subsections namely

  • Arithmetic section
  • Logic Section

Arithmetic Section

Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication and division. All complex operations are done by making repetitive use of above operations.

Logic Section

Function of logic section is to perform logic operations such as comparing, selecting, matching and merging of data.

Parts of a Computer System Explained

Parts of a Computer System Explained

Information is funny stuff. The information for the web page you are looking at is recorded on a hard disk inside a computer located in New Britain, Connecticut. The information was copied from that physical device to other physical devices perhaps hundreds of times before it got to your computer where your web browser is using it to display these words on your monitor. Clearly information is something different from the devices used to store and transmit it.

A computer system consists of both hardware and information stored on hardware. Information stored on computer hardware is often called software.

The hardware components of a computer system are the electronic and mechanical parts.

The software components of a computer system are the data and the computer programs.

Click Here to see the desktop system these notes were originally prepared on. (This was back when anything to do with computers had to be beige. Everything in this picture has since been replaced, except for the gargoyle.)

The major hardware components of a computer system are:

  • Processor
  • Main memory
  • Secondary memory
  • Input devices
  • Output devices

For typical desktop computers, the processor, main memory, secondary memory, power supply, and supporting hardware are housed in a metal case. Many of the components are connected to the main circuit board of the computer, called the motherboard. The power supply supplies power for most of the components. Various input devices (such as the keyboard) and output devices (such as the monitor) are attached through connectors at the rear of the case.

Hardware Components


The terms input and output say if data flow into or out of the computer. The picture shows the major hardware components of a computer system. The arrows show the direction of data flow.

A bus is a group of wires on the main circuit board of the computer. It is a pathway for data flowing between components. Most devices are connected to the bus through a controller which coordinates the activities of the device with the bus.

The processor is an electronic device about a one inch square, covered in plastic. Inside the square is an even smaller square of silicon containing millions of tiny electrical parts. A modern processor may contain billions of transistors. It does the fundamental computing within the system, and directly or indirectly controls all the other components.

The processor is sometimes called the Central Processing Unit or CPU. A particular computer will have a particular type of processor, such as a Pentium processor or a SPARC processor.

Main Memory

Main memory is where programs and data are kept when the processor is actively using them. When programs and data become active, they are copied from secondary memory into main memory where the processor can interact with them. A copy remains in secondary memory.

Main memory is intimately connected to the processor, so moving instructions and data into and out of the processor is very fast.

Main memory is sometimes called RAM. RAM stands for Random Access Memory. “Random” means that the memory cells can be accessed in any order. However, properly speaking, “RAM” means the type of silicon chip used to implement main memory.

When people say that a computer has “512 megabytes of RAM” they are talking about how big its main memory is. One megabyte of memory is enough to hold approximately one million (106) characters of a word processing document. (There will be more about bytes and megabytes later on in these notes.)

Nothing permanent is kept in main memory. Sometimes data are placed in main memory for just a few seconds, only as long as they are needed.

Secondary Memory

Secondary memory is where programs and data are kept on a long-term basis. Common secondary storage devices are the hard disk and optical disks.

  • The hard disk has enormous storage capacity compared to main memory.
  • The hard disk is usually contained inside the case of a computer.
  • The hard disk is used for long-term storage of programs and data.
  • Data and programs on the hard disk are organized into files.
  • A file is a collection of data on the disk that has a name.

A hard disk might have a storage capacity of 500 gigabytes (room for about 500 x 109 characters). This is about 100 times the capacity of main memory. A hard disk is slow compared to main memory. If the disk were the only type of memory the computer system would slow down to a crawl. The reason for having two types of storage is this difference in speed and capacity.

Large blocks of data are copied from disk into main memory. The operation is slow, but lots of data is copied. Then the processor can quickly read and write small sections of that data in main memory. When it is done, a large block of data is written to disk.

Often, while the processor is computing with one block of data in main memory, the next block of data from disk is read into another section of main memory and made ready for the processor. One of the jobs of an operating system is to manage main storage and disks this way.

Primary memory Secondary memory
  • Fast
  • Expensive
  • Low capacity
  • Works directly with the processor
  • Slow
  • Cheap
  • Large capacity
  • Not connected directly to the processor

Input and Output Devices

Input and output devices allow the computer system to interact with the outside world by moving data into and out of the system. An input device is used to bring data into the system. Some input devices are:

  • Keyboard
  • Mouse
  • Microphone
  • Bar code reader
  • Graphics tablet

An output device is used to send data out of the system. Some output devices are:

  • Monitor
  • Printer
  • Speaker

A network interface acts as both input and output. Data flows from the network into the computer, and out of the computer into the network.


Input/output devices are usually called I/O devices. They are directly connected to an electronic module attached to the motherboard called adevice controller. For example, the speakers of a multimedia computer system are directly connected to a device controller called an audio card, which in turn is plugged into a bus on the motherboard.

With many recent computers, the functions of a device controller are integerated with the motherboard. Some motherboards have audio, graphics, and network controllers built in.

Sometimes secondary memory devices like the hard disk are called I/O devices (because they move data in and out of main memory). What counts as an I/O device depends on context. To a user, an I/O device is something outside of the computer case. To a programmer, anything outside of the processor and main memory is an I/O device. To an engineer working on the design of a processor everything outside of the processor is an I/O device.

Embedded Systems

A computer system that is part of a larger machine and which controls how that machine operates is an embedded system. Usually the processor constantly runs a single control program which is permanently kept in ROM (Read Only Memory).

ROM is used to make a section of main memory read-only. Main memory looks the same as before to the processor, except a section of it permanently contains the program the processor is running. This section of memory retains its data even when power is off.

A typical embedded system is a cell phone. This is obvious, but there are many less obvious embedded systems. Your car contains dozens of processors, and even more in its audio system. For instance, each airbag is controlled by its own computer chip. Digital cameras, DVD players, medical equipment, and even home appliances contain dedicated processors.

The overwhelming majority of processor chips are used in embedded systems. Less than 1% of processor chips are used in the familiar desktop computer!

Applications and Uses of Computers

Applications and Uses of Computers

Applications and Uses of Computers or how to use the computer?

Getting the right kind of information is a major challenge as is getting information to make sense. College students spend an average of 5-6 hours a week on the internet.Research shows that computers can significantly enhance performance in learning. Students exposed to the internet say they think the web has helped them improve the quality of their academic research and of their written work. One revolution in education is the advent of distance learning. This offers a variety of internet and video-based online courses.[adsense_inserter id=”%4%”]

Health and Medicine :Computational-Thinking-Critical-for-Students-Looking-for-Computer-Science-Careers-2

Computer technology is radically changing the tools of medicine. All medical information can now be digitized. Software is now able to computer the risk of a disease. Mental health researchers are using computers to screen troubled teenagers in need of psychotherapy. A patient paralyzed by a stroke has received an implant that allows communication between his brain and a computer; as a result, he can move a cursor across a screen by brainpower and convey simple messages.

Science :

Scientists have long been users of it. A new adventure among scientists is the idea of a “collaboratory”, an internet based collaborative laboratory, in which researchers all over the world can work easily together even at a distance. An example is space physics where space physicists are allowed to band together to measure the earth’s ionosphere from instruments on four parts of the world.

Business :

Business clearly see the interest as a way to enhance productivity and competitiveness. Some areas of business that are undergoing rapid changes are sales and marketing, retailing, banking, stock trading, etc. Sales representatives not only need to be better educated and more knowledgeable about their customer’s businesses, but also must be comfortable with computer technology. The internet has become a popular marketing tool. The world of cybercash has come to banking – not only smart cards but internet banking, electronic deposit, bill paying, online stock and bond trading, etc.

Recreation and Entertainment:

Our entertainment and pleasure-time have also been affected by computerization. For example:

i) In movies, computer generated graphics give freedom to designers so that special effects and even imaginary characters can play a part in making movies, videos, and commercials.

ii) In sports, computers compile statistics, sell tickets, create training programs and diets for athletes, and suggest game plan strategies based on the competitor’s past performance.

iii) In restaurants, almost every one has eaten food where the clerk enters an order by indicating choices on a rather unusual looking cash register; the device directly enters the actual data into a computer, and calculates the cost and then prints a receipt.


Various departments of the Government use computer for their planning, control and law enforcement activities. To name a few – Traffic, Tourism, Information & Broadcasting, Education, Aviation and many others.


There are many uses computers in Defence such as:

1) Controlling UAV or unmanned air-crafts an example is Predator. If you have cable I would recommend watching the shows “Future Weapons” and “Modern Marvels”. The show future weapon gives an entire hour to the predator.

2) They are also used on Intercontinental Ballistic Missiles (ICBMs) that uses GPS and Computers to help the missile get to the target.

3) Computers are used to track incoming missiles and help slew weapons systems onto the incoming target to destroy them.

4) Computers are used in helping the military find out where all their assets are (Situational Awareness) and in Communications/Battle Management Systems.

5) Computers are used in the logistic and ordering functions of getting equipments to and around the battlefield.

6) Computers are used in tanks and planes and ships to target enemy forces, help run the platform and more recently to help diagnose any problems with the platforms.

7) Computers help design and test new systems.


In today’s technologically growing society, computers are being used in nearly every activity.

Recording Information

Official statistics keepers and some scouts use computers to record statistics, take notes and chat online while attending and working at a sports event.

Analyzing Movements

The best athletes pay close attention to detail. Computers can slow recorded video and allow people to study their specific movements to try to improve their tendencies and repair poor habits.


Many sportswriters attend several sporting events a week, and they take their computers with them to write during the game or shortly after while their thoughts are fresh in their mind.


While some scoreboards are manually updated, most professional sports venues have very modern scoreboards that are programmed to update statistics and information immediately after the information is entered into the computer.


Computers have aided in the design of safety equipment in sports such as football helmets to shoes to mouth guards

Computer Hardware Fundamentals

Computer Hardware Fundamentals

Hardware represents the physical and tangible components of a computer i.e. the components that can be seen and touched.

Examples of Hardware are following:Computer Hardware

  • Input devices — keyboard, mouse etc.
  • Output device
    s —
    printer, monitor etc.
  • Secondary storage devices — Hard disk, CD, DVD etc.
  • Internal components — CPU, motherboard, RAM etc.

Relationship between Hardware and Software

  • Hardware and software are mutually dependent on each other. Both of them must work together to make a computer produce a useful output.
  • Software cannot be utilized without supporting hardware.
  • Hardware without set of programs to operate upon cannot be utilized and is useless.
  • To get a particular job done on the computer, relevant software should be loaded into the hardware
  • Hardware is a one-time expense.
  • Software development is very expensive and is a continuing expense.
  • Different software applications can be loaded on a hardware to run different jobs.
  • A software acts as an interface between the user and the hardware.
  • If hardware is the ‘heart’ of a computer system, then software is its ‘soul’. Both are complimentary to each other.

Hardware: this is the physical components contained in a computer system. For example; printers, monitor and speaker.

Peripheral Device: any hardware device connected to and controlled by the central processing unit. Examples of peripherals are modems, disk drives, printers, scanners and keyboard.

Software: also called a program is a series of instructions that tells the hardware how to perform tasks. Without software most hardware are useless.

Backing Store: Storage external to the computer used for large quantities of data or large programs. Backing store is also known as secondary store, auxiliary store or external store.

User: a user is someone who communicates with the computer or uses information it generates.

Fundamentals of Computer Software

Fundamentals of Computer Software

Fundamentals of Computer Software is a Collection of programs or bunch of programs called as software. Softwares are of two types:


This is that software, which serves specific purposes and allow the user to create applications which are for a given purpose like financial accounting, payroll, examinations, human resources management etc. These software can be further classified, depending upon the source of development as well the users.


These are those software packages, which are developed by group of people or an individual to used by others. The most commonly available pre-

written application software are:220px-Operating_system_placement.svg

a). Word Processing Software: These are those software, which usually automate the day to day documentation work of an organization. t helps in creating texts, manipulating, formatting and printing of the text, so that the drafting, redrafting, typing again and again manually now becomes easy and less paper wastage as well the time taken also is reduced a lot. Wordstar, wordperfect, microsoft word etc. are some of the available wordprocessors.

b). Electronic Spread Sheets: Electronic spread sheets are like sheets of paper with rows and columns. ESS allow numbers, characters, formulae and all other types of data which has to be entered in tabular form into rows or columns. Usage of ESS gives significant advantages and benefits over using paper spread sheets. Some of the most commonly available and used spread sheets are lotus 1-2-3, MS-Excel, supercalc etc.

c). Data Base Management System: Data base is an organized collection of data, which is logically related. The data has to be managed so that the retrieval of information is effective and easy. Managing data involves creating, deleting, updating, adding, modifying data in databases. Along with these querying are printing reports also comes as DBM. DBMS is a software package that allows a user to perform above functions. It also allows multiple computers sharing the data files. Some of the DBMS Packages commonly used by people are Dbase, FoxPro, Clipper, Paradox etc.

This DBMS technology has been subjected to many improvements and advanced DBM software has been evolved which are called RDBMS (Relational Data Base Management Systems), ORDBMS (Object-oriented RDBMS) etc. Oracle, Ingress, Sql server, Informix, Sybase, Db2 etc. are the some examples.


This is that software which is used for developing or running a computer system. This software controls all processing activities and makes sure that the resources and the power of the computer are used in most efficient manner. Systems software consists of following softwares.

a). Operating Systems: Operating system is set of programs that control and support hardware and provide various services which are used for better operating performance of the computer. The major functions of any operating system are:

  1. It assigns processors to tasks
  2. It manages memory and other storage areas.
  3. It act as a command interpreter.
  4. File management.
  5. Input – Output management.
  6. Establishing data security & integrity.
  7. Maintains account of processor time for billing purposes.
  8. Provides data and time services etc.

The operating system can be classified as single user and multy user depending on the number of users working on it at a given point of time.

DOS is a good example of single user operating system and UNIX, Windows -NT, LINUX etc. are some of the common multy user operating system.

b). Language Processors: As a digital computer accepts digits and characters as input, however this input is not understandable;e by the computer. To make the computer understand it, the input has to be conversed into machine language. The software which makes this conversion and increases the productivity of the programmer are called language processors or translators. There are two basic types of translators.

  1. Compiler and Online Compilers: Compiler is a software that will accept the totalprogram code as input and then converts it into machine code, that means converts source code into object code.Ex: COBOL, C.
  2. Interpreters: Interpreter also does the same task of compilerbut it does in a different manner. The interpreter takes the program code (source code) line by line and converts it into machine (object code).

c).Utility Tools : These utilities are those software programs are provided by the manufacturer of various hardwares to perform specific tasks commonly used to all data processing installations. Device drivers, directory and file management utilities are the some examples.

Hardware and Software of Computer System

Hardware and Software of Computer System

Computer hardware is any physical device used in or with your machine, whereas software is a collection of code installed onto your computer’s hard drive. For example, the computer monitor you are using to read this text and the mouse you are using to navigate this web page is computer hardware. The Internet browser that allowed you to visit this page and the operating system that the browser is running on is considered software.

hardwar and software

hardwar and software

All software utilizes at least one hardware device to operate. For example, a video game, which is software, uses the computer processor (CPU), memory (RAM), hard drive, and video card to run. Word processing software uses the computer processor, memory, and hard drive to create and save documents.

In a computer, hardware is what makes a computer work. A CPU processes information and that information can be stored in RAM or on a hard drive. A sound card can provide sound to speakers and a video card can provide an image to a monitor. All of this is hardware.

On that same computer, software can be installed and allow a person to interact with the hardware. An operating system, like Windows or Mac OS, is software. It provides a graphical interface for people to use the computer and other software on the computer. A person can create documents and pictures using software.

Can a computer run without software?

In most situations, yes, a computer can run without software being installed. However, if an operating system or interpreter is not found on the computer, it either generates an error or doesn’t output any information. Installing programs onto the computer in addition to an operating system gives the computer additional capabilities. For example, a word processor is not required, but it allows you to create documents and letters.soft-had

Can a computer run without hardware?

This depends on the hardware. Most computers require at least a display,hard drive, keyboard, memory,motherboard, processor, power supply, and video card to function properly. If any of these devices are missing or malfunctioning, an error is encountered, or the computer will not start. Adding hardware such as a disc drive (e.g. CD-ROM or DVD), modem,mouse, network card, printer, sound card, or speakers are not required, but give the computer additional functionality.

Computer Fundamentals for Beginners

Computer Fundamentals for Beginners

Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of set of instructions (called program), gives the result (output), and saves it for the future use.

Computer device desktop

Computer device desktop

This Computer Fundamentals for Beginners tutorial covers a foundational understanding of computer hardware and parts of the computer hardware, computer software applications, operating systems, peripherals etc. along with how to get the most value and impact from computer technology. You can read th

Computer Fundamentals tutorial has been prepared for the beginners as well as advanced learners who want to deal with computers. This tutorial is also very useful for the undergraduate students of computer science, engineering, business administration, management, science, commerce and arts where an introductory course on computers is a part of curriculum. After completing this tutorial you will find yourself at a moderate level of expertise in knowledge of computer basics from where you can take yourself to next levels

Knowledge of computers is not a prerequisite to follow the contents of this tutorial. This tutorial assumes no background in computers or computer programming.

Today’s world is an information-rich world and it has become a necessity for everyone to know about computers. Purpose of this tutorial is to introduce you about computer and its fundamentals.

Functionalities of a computer
Any digital computer carries out five functions in gross terms:

  • Takes data as input.
  • Stores the data/instructions in its memory and use them when required.
  • Processes the data and converts it into useful information.
  • Generates the output
  • Controls all the above four steps.

Computer Definition
Computer is an electronic data processing device which accepts and stores data input,
processes the data input, and generates the output in a required format.
Following list demonstrates the advantages of computers in today’s arena.

High Speed

  1. Computer is a very fast device.
  2. It is capable of performing calculation of very large amount of data.
  3. The computer has units of speed in microsecond, nanosecond, and even the picosecond.
  4. It can perform millions of calculations in a few seconds as compared to man who will spend many months for doing the same task.

In addition to being very fast, computers are very accurate. The calculations are 100% error free. Computers perform all jobs with 100% accuracy provided that correct input has been given.

Storage Capability
Memory is a very important characteristic of computers. A computer has much more storage capacity than human beings. It can store large amount of data. It can store any type of data such as images, videos, text, audio and many others.

Unlike human beings, a computer is free from monotony, tiredness and lack of concentration. It can work continuously without any error and boredom. It can do repeated work with same speed and accuracy.

A computer is a very versatile machine. A computer is very flexible in performing the jobs to be done. This machine can be used to solve the problems related to various fields. At one instance, it may be solving a complex scientific problem and the very next moment it may be playing a card game.

A computer is a reliable machine. Modern electronic components have long lives. Computers are designed to make maintenance easy.

Computer is an automatic machine. Automation means ability to perform the given task automatically. Once a program is given to computer i.e., stored in computer memory, the program and instruction can control the program execution without human interaction.

Reduction in Paper Work 
The use of computers for data processing in an organization leads to reduction in paper work and results in speeding up a process. As data in electronic files can be retrieved as and when required, the problem of maintenance of large number of paper files gets reduced.

Reduction in Cost
Though the initial investment for installing a computer is high but it substantially reduces the cost of each of its transaction.

Following list demonstrates the disadvantages of computers in today’s arena

No I.Q
A computer is a machine that has no intelligence to perform any task.

Each instruction has to be given to computer.

A computer cannot take any decision on its own.

It functions as per a user’s instruction, so it is fully dependent on human being

The operating environment of computer should be dust free and suitable.

No Feeling
Computers have no feelings or emotions.

It cannot make judgement based on feeling, taste, experience, and knowledge unlike a human being.