# Perfect Computer Notes

Super Easy Short Computer Notes To Improve Computer Literacy and Your IT Skills

# Explain Parts of CPU and its Working

## CENTRAL PROCESSING UNIT / CPU / Microprocessor / Processor

Central processing unit is the brain of computer. It is also called CPU or processor. Processor is used to process data according to given instructions. It performs arithmetic and logical operations on data.

 Parts / Components of CPU / Processor on computergap.com

It controls all activities of different parts of a computer. As brain in human body controls all other parts of body and takes decisions, CPU controls all other parts of the computer and their working. A CPU has three basic parts: Arithmetic Logic unit, Control unit and Registers.
 Microprocessor or Processor or CPU or Central Processing Unit computergap.com

## 1.    ARITHMETIC LOGIC UNIT (ALU)

ALU performs data processing according to given instructions. All computations are done in this unit. ALU is the real place in computer where actual execution of instructions takes place. ALU may be further categorized into two sections according to their function:
ARITHMETIC SECTION of ALU performs arithmetic operations like addition, subtraction, multiplication and division on data.
LOGIC SECTION of ALU performs logical operations like comparison between two values. For example, 10>5 will give TRUE answer. And 5<1 will give FALSE answer. Control unit sends data and instruction to perform calculation on the data to the ALU. ALU then performs this calculation.

## 2.    CONTROL UNIT

Control unit controls all over operations of different parts of computer. For example it takes data and instructions from input unit and stores it into memory. It sends data to ALU for processing. It takes results from ALU and sends it to output device. It can also store results in memory. Control unit performs all these functions by giving commands to relevant part of the computer.
Control unit performs following four functions for executing instructions of a computer program.

1.  Fetching: obtaining instruction from memory
2.  Decoding: understanding this instruction
3.  Data Fetching: If needed, obtaining data from memory
4.  Executing: Control unit sends the instruction and data to ALU for taking suitable action on the instruction

## 3.    REGISTERS

A register is a very small and temporary memory area in ALU. It holds instruction and data as long as it is being processed by CPU. When instruction and data is fetched from memory then it is stored in a register. ALU contains a number of registers for example AX, BX, CX, DX etc. A Register may be of 8 bits, 16 bits, 32 bits or more.

# Explain Different Types Of Output Devices

Output devices

Out put devices are used to display results of processing to the user. They perform the following functions:
2.  Convert data into human readable form
3.  Display results to the user

Examples include: Monitor, printer, plotter, speaker, and multimedia projector.

### Different Types of Output Devices

1.    Monitor
 LCD Monitor

 CTR Monitor

Monitor is the most commonly used output device used to display results of processing. It has a TV like shape. Pictures on monitor are formed with picture elements called PIXEL. Monitors may be Monochrome that will display results in Black & White. Color Monitors are also available. They display results in multi colors. Monitor produces soft copy output.

2.    Printers

Printers are used to produce hard copy out put. They print processing results on paper. Printers are divided into two main categories:
·    Impact Printers
·    Non Impact printers

Impact Printers.

These printers print with striking of hammers or pins on ribbon. For example Dot Matrix printer and daisy wheel printers are impact printers.

Non-Impact Printers.

These printers do not use striking mechanism for printing. They use electrostatic and laser technology. Quality and speed of these printers is better than Impact printers. For example Laser printer and Inkjet printers are non-impact printers.

 Speakers for Desktop computer

Speakers and head sets produce sound output. We can listen recorded voices, sounds or music with the help of speaker or headset. Speaker produces sound output with the help of sound card.
 Headsets - used to produce audio output

4.    Plotter

A plotter is an output device used to produce image-quality graphics in a variety of colors. Plotters are used to print large maps, architectural drawings, graphs and charts. Plotters are used to draw different designs of buildings or internal structure of machines. Plotters offer the fastest way to efficiently produce very large drawings or color high-resolution graphics. Engineers and Architects use plotters.

5.    Multimedia Projector.
 Multimedia Projector

Multimedia projector is used to produce computer output on a big screen. These are used in meeting rooms or in classrooms of educational institutes. Since the output produced by multimedia projector is displayed on a large screen, it can be viewed by a large number of people in a hall, meeting / conference room or a class room. Mostly teachers use data projectors in class rooms for delivering lectures ( a use of audio visual aids technology)

# What are Different Types of Input Devices

### INPUT DEVICES

Input devices are used to enter data and instructions into computer memory from external world. The examples of input devices include: Keyboard, Mouse, Track ball, Track Pad, Joy stick, Touch Screen, Light pen,  Scanner, Digital Camera, Microphone, Graphics tablet etc. They perform three main functions.
 Different Types of input devices for computer

### Three Functions of Input Devices

1. Receive data from user. For example,  user enters data from keyboard by typing numeric number 5
2. Convert data into binary form [the language of 0 and 1 also called the machine language. Machine language   is the only language, a computer can understand directly.]

For example decimal number 5 will be converted to binary number 101.
5/2     quotient =2  remainder =1
2/2     quotient =1  remainder =0
1/2     quotient =0  remainder =1
so we write remainders from bottom to top (101) which is binary equivalent of decimal 5.
1. Provide converted data in binary form (101) to computer memory for processing.
Following are the introduction to some popular types of input devices:

1.    Key board

 different types of input devices of computer - keyboard

Keyboard is the most familiar input device. It is most widely used input device to enter data and instructions into the computer. Keyboard has a set of keys like a typewriter. It has alphabetic keys for A,B,C…Z or a,b,c,…z. It has numeric keys like 0,1,2,3,…9. It has function keys F1,F2,…F12 used to perform specific tasks.
It has other keys used for editing like Delete, Backspace, Home, End, etc.

### 2.    Mouse

 Mouse -  input device
Mouse is an input device used to control motion of pointer on screen. A mouse has two or three buttons called Left, Right and Middle button. Buttons are used to perform different functions. It has a rubber or metal ball inside its body. Mouse is rolled over a flat surface called mouse pad. The movement of ball is detected by internal circuits of mouse. These circuits convert this movement into digital signals, which are sent to computer. Mouse is used in graphical applications. It is also used for playing video games on computer.

### 3.    Track Ball

 Track ball
Track Ball is an input device like a mouse. It is used in Lap top computers to control motion of pointer on screen. It is a pointing device like upside down mouse. It has a ball on its upper side. This ball is moved by fingers or thumb and the pointer moves accordingly on screen.

Track pad is a pointing input device. It is used in Lap top computers to control motion of pointer on screen. Track pad is a stationary input device. It has a flat surface of 1.5 to 2 square inch. Finger is moved on this surface to move pointer on screen.

### 5.    Joy stick

 Joy stick

Joystick is an input device used to play games on computer. It is used to control motion of an object quickly in game with the help of a hand held stick. This stick can be moved forward, backward or side ways. This stick is mounted on a ball. When stick is moved then ball is moved and signals are sent to the computer.

### 6.    Light Pen

 Light pen use

Light pen is an input device consisting of a special pen that is connected to a computer's monitor. The user points at the screen with the pen and selects items or chooses commands either by pressing a clip on the side of the light pen or by pressing the light pen against the surface of the screen (the equivalent of performing a mouse click).

### 7.    Microphone

 Microphone

Microphone is an input device used to enter sounds into the computer. We can record sounds in computer with the help of microphone and sound card.

### 8.    Scanner

 Scanner

Scanner is an input device. It is used to save pictures or text on paper into computer memory. It converts picture or text on paper in to binary form and saves it in computer memory. With the help of scanner we may save our time to type a lot of text. For example, if we have a book and wish to enter the whole text of book in to computer. It will be a long, tedious and time consuming job. But if we use a scanner, we can do this with in less time. We can scan each page of book. Editing of the scanned text is also possible. So our job will become very easy with the help of a scanner.

### 9.    Graphics tablet / digitizer

 Graphic Tablet

A graphics tablet consists of a special pen called stylus and a flat pad. The image is created on the monitor screen as the user draws it on the pad with the help of stylus (special pen). Graphics tablet is also called a digitizer.

### 10. Touch Screen

 Touch Screen

In ATM and in latest smart phones, touch screen is used to receive input from the user. The user enters data by the touch of his finger on different menu options or icons present on touch screen. Actually touch screen is both input / output device. It performs both functions.

### 11. Digital Camera

 Digital camera

A digital camera is one of the latest input devices. We can take pictures with he help of digital camera. These pictures are saved on digital camera's internal memory. There is no need of a film role as used in traditional cameras. Later on we can easily input these pictures with the help of a data cable into computer's memory. Latest digital cameras can take still snapshots and can record video as well. This is all about Different Types of Input Devices for Computer with pictures.

# What are Different Types of Computer Hardware

What is Hardware?
The physical parts of a computer are called hardware. Hardware can be touched or seen by us. For example, hard disk, mouse, keyboard, CD, CD-ROM Drive, Floppy Disk, Speakers, Modem and Printers - all are computer hardware.
 Explain different types of computer hardware

### Different types of hardware components on the basis of the functionality

they provide are as follows:

1.    Input devices

Input devices are used to enter data and instructions into computer. Examples of input devices are:
Keyboard, mouse, scanner, digital camera etc.
 Microphone

 Mouse

 Keyboard

2.    The Central Processing unit
Central processing unit is the brain of the computer. It is also called CPU or Processor. Intel is the leading manufacturer of microprocessors. For example, Intel Pentium IV 3.2 MHz is an example of a cpu.
 CPU or Microprocessor or simply Processor

3.    Output devices
Output devices are used to show the results of processing to the user. For example monitor, printer, plotter, speaker and data projector are out put devices.
 Speakers

 LCD Monitor

 Printer

4.    Memory chips
Memory is a component of a computer to store data and instructions. RAM is an example of memory chip. It stands for Random Access Memory. Every program to be executed is loaded in RAM from hard disk. CPU executes the programs loaded in RAM.RAM is a temporary memory, all data and programs are lost from RAM, when computer is turned off. ROM stands for Read Only Memory. ROM is permanent memory chip; we cannot change or delete its contents. It is a non-volatile memory.
 ROM shape 1

 RAM

 ROM shape 2

5.    Storage devices
Storage Devices are used to store large amounts of data permanently. For example: hard disk, CD, DVD etc. are storage devices. Moreover, Zip Disk and Floppy disk is also considered as storage devices.
 Hard Disk

 DVD ROM

 Floppy Disk

 ZIP Disk

 CD ROM
6.    Communication devices
Communication devices are used to send and receive data from one computer to another. For example Modem, Network Interface Card, Hub, switches, routers, gateways and even networking cables are included in communication devices
 Wireless PCI NIC Card

 External Modem

# Differentiate between Analog and Digital Computers

The differences between analog and digital computers are as follows:

 Digital Computers 1 Analog Computers Work on continuous values. Digital computers Work on discrete values. 2 Analog Computers have low memory. Digital computers have a very large memory 3 Analog computers have Slow speed. Digital computers have fast speed. 4 Analog computers are less reliable. Digital computers are more reliable. 5 Analog computers used in engineering and science and medical fields. Digital computers are used in all fields of life. 6 Analog computers are used to calculate / measure analog quantities like speed and temperature. Digital computers are used to calculate mathematical and logical operations. It can solve addition, subtraction, division, multiplication and other mathematical and statistical operations. 7 Analog computers provide less accurate results. Digital computers provide 100% accurate results. 8 Normally Analog Computers are specific purpose Digital Computers are general purpose 9 Analog computers are difficult to use Digital computers are easy to use 10 Examples of Analog computers are: thermometer, analog clock, speedometer etc. Examples of digital computers are: Personal Computer, laptops, smart phones etc.

# Uses Of Computer In Industry

Computers are used in industry in different types of systems.

### Computer-Controlled Robots are Used in Industry

Computer-controlled robots are used to perform many complicated jobs in industry. Robots are computer controlled programmable machines. They can perform mechanical jobs, too, like pick and place different parts, welding or painting cars etc.
 Different Uses of Computers in Industry

### Automated Production Systems

Today, computer-controlled robots are used to assemble cars. No doubt, these systems work faster than human beings. Another popular and efficient use for computer controlled robots is in the field of spray painting. The consistency and repeatability of a robot's motion have enabled near perfect quality painting while at the same time wasting no paint and leaving no place without paint.
 Uses of computers in industry area

Perhaps the most popular applications of robots are in industrial welding. The repeat-ability, uniformity in quality, and speed of robotic welding is unmatched.
Computer controlled Robots can be found in the manufacturing industry, the military, space exploration, transportation, and medical applications.

### Computer-aided manufacturing

Computer-aided manufacturing is the manufacturing technique that uses computers or computerized automated machines and robots to control the manufacturing of all parts of a product. Therefore, all manufacturing process is managed by computer systems with the help of specially designed software and hardware. The main advantages of using Computer aided manufacturing technique is:

1. Product is manufactured up to the standards with great accuracy.
2. The product quality is high and consistent.
3. The CAM reduces the cost of the production.

### Design Systems - Computer Aided Design

There exist many computer programs used to design the model of a product on the computer system. This process is called Computer Aided Design or CAD. This is due to Computer Aided Design techniques that we can test the designed product with the help of computer. When the design is completed successfully, the actual product is manufactured. This will reduce the cost and risk of failure.

# Uses Of Computer in Medical Field

Today Computers are an essential part of an hospital. Doctors and administration staff uses computers to manage patient history and medicine stocks etc. Computers play a key role in the medical field.  Their uses include storing patient related data, housing knowledge bases, providing the logic and circuitry for medical equipment, scanning and imaging the body, and facilitating speedy communications. Computers can be used in medical field in the following ways:

We can computerize the accounting, payroll and stock system of the hospital. We can keep the record of different medicines.
•  Recording Medical History Of Patients
Computer can be used to store the medical history of the patients. Medical history is very important for patients as well as doctors. Doctors may better prescribe the medicines on the basis of the medicines used in past for a particular patient and the results obtained. Database Management System software is used to store Patient records efficiently. are stored on computer databases in the medical field.  The medical history of a patient includes physical symptoms, diagnoses, treatments, and even family medical history.  Details of the medications prescribed are stored together with details of any that can not be prescribed, such as an allergy to penicillin.  Appointments are scheduled using a computer database.  Billing information is also stored.  Hospitals and surgeries depend on computers for administrative and financial functions.
•  Monitoring Systems
Many computerized devices are used to monitor the blood pressure, heartbeat and brain of the patients. Computers guide in some surgical operations, too. For example in laparoscopic surgery, the surgeon inserts the medical tools and a small camera, and conducts the operation with the help of computers and monitors.  Computers also monitor heart rates, pulse rates and brain readings. Therefore, we conclude that computers make this possible to deal with such complicated operations. It would be virtually impossible for a human to do this.
•  Diagnosis of Diseases
Computers are being used to diagnose diseases with the help of software. There are some Medical Software to diagnose diseases and prescribe medicine on the basis of symptoms.
• Life Support system
Life support systems are used to help disabled persons, for example hearing aid device for deaf people. Latest life support devices use computer technology to help the disable people, to overcome their disabilities.
•   Faster and Cheaper Communications
Doctors and other staff can use internet to communicate to doctors in other parts of the world, for sharing information on medical topics or even about a particular patient case. They can exchange pictures, reports and other documents, too.
•  Clinical Image Processing
Computers are being used in Medical Radiology / Diagnostic Imaging. Computers play an role in all types of clinical image processing like CT scan and ultrasound. Ultrasound uses sound waves that bounce off body parts, producing echoes. A computer translates the echoes into images, showing broken bones, muscle problems, or changes in organs, accurately.

# Uses Of Computer In Education Field

Computer can be used in education in the following ways:
• ## Computers In Teaching and Learning Process ( Computer Aided Learning - CAL )

Computers are being used actively in educational institutes to improve the learning process. Teachers can use audio video aids through computer to prepare lesson plans. They can use Microsoft Power Point to prepare electronic presentations about their lectures. These electronic presentations will be displayed on multimedia projectors in class rooms. This will be interesting and easy to learn for students. Multimedia presentations are easy to deliver for teachers too. Computers will be helpful for:

1.   Instructing the students using PowerPoint slides, Word documents or Web pages and using hyperlinks for better concept clarity.
2.  Helps in improving pronunciation of students by using microphones, headphones, speakers, specially
prepared software and special dedicated websites.

3. Encouraging the students to use internet, surf web pages and gather relevant detailed information
through search engines.

• ## CBT (Computer-Based Training)

CBT stands for Computer Based Training. In CBT, we prepare different educational programs with the help of professional teachers and audio visual aids. These educational programs are generally in the shape of lectures on a specific subject. These programs are provided on CDs.

• ## Online Education

Many web sites provide online education. You can read or download educational material and books. For example, Virtual University of Pakistan is an Online Educational Institution. Students use internet to access VU website. The students log in to their accounts and e-mail boxes. They interact with different teachers online. They receive and submit their assignments and work through internet to their teachers.
• ## Research

Computers are also used for research work. Internet is a huge source of information on any topic. Different researchers can share their research work using Internet.