2.2 Number system and representation

The binary (base 2) number system is used to represent the electronic status of the bits in memory. It also used for other purposes such as addressing the memory locations. Another number system commonly used with the computers is hexadecimal numbers (base 16). The computer uses the hexadecimal number system to communicate with the programmer when the problem with a program exists.

Decimal Number System

Familiar use in everyday life

Consists of numbers 0-9
Decimal digits are joined together to form longer decimal numbers
Example: 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12,……

A base 10 number system.
The base of the number system indicates how many symbols it uses.
It uses 10 symbols (0 – 9).
Each symbol has a value associated with it.
Example:
310 (3) represent the quantity of three.
 510 (5) represent the quantity of five.

2.1.3 Computer storage

Storage
- Holds data, instructions, and information for future use.

Storage medium
- Physical material on which a computer keeps data, instruction and information.

Storage Capacity
- Number of bytes (characters) a storage medium can hold.

Typical storage and capacities

Conversion
Example 1

Example 2

Convert 1.2 GB to KB.

Solution:

1.2 GB

= 1.2 x 210  x 210  KB

= 1.2 x 220   KB.

 

Example 3

Convert 1200 MB to GB.

Solution:

1200 MB

= 1200 / 210 GB

= 1.17   GB.

2.0 Computer System

 
2.1 System concept

 2.1.1 Overview of computer system

 What is Computer?

  an electronic device that accepts input process data and produces output

What is Computer System?

 a complete, working computer that includes operating system, software and hardware  which are  necessary to make the computer function

Components of Computer System

Hardware

Input devices

CPU

Output Devices

Storage Devices

Software

System Software

Application Software

Basic processes in computer

Input

Process

Output

Storage

Input-Process-Output (IPO) Model

2.1.2 Data representation

Data Representation

How does a computer represent data?
By using two unique binary digits 1 and 0 to represent the two states on and off.

Bit

• A binary digit (1 or 0)
• Represents an electrical state (on or off)
• Bit 1 represents On
• Bit 0 represents Off

Byte

• A group of 8 bits (ex:11110000)
• Represents a character such as a digit, a letter, a punctuation mark or any symbol in computer

Example :

00110100 represents 4

00110110 represents 6        

01000101 represents E

1.0 Introduction to Information Technology.

1.1    Overview of Information Technology and Computer 

1.1.1 Definition of Information Technology


Information technology
  
The use of computer hardware and software to store, retrieve, and manipulate information.

Information technology is any technology that helps to produce, manipulate,  store,  communicate, and/or disseminate information 

Information Technology is the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and  computer hardware.


1.1.2 Advantages and disadvantages of Information Technology

 Advantages of Information Technology 

Globalization
Talking about Globalization, IT has not only brought the world closer together, but it has allowed the world's economy to become a single interdependent system. This means that we can not only share information quickly and efficiently, but we can also bring down barriers of linguistic and geographic boundaries. The world has developed into a global village due to the help of information technology allowing countries like who are not only separated by distance but also by language to shares ideas and information with each other.  

Communication 
In communication, IT has helped to make communication cheaper, quicker, and more efficient. We can now communicate with anyone around the globe by simply text messaging them or sending them an email for an almost instantaneous response. The internet has also opened up face to face direct communication from different parts of the world thanks to the helps of video conferencing. 

Cost effectiveness 
IT has also brought about Cost Effectiveness by helping to computerize business processes thus streamlining business to make them extremely cost effective money making machines. This in turn increases productivity which ultimately gives rise to profits that means better pay and less strenuous working conditions. 

Bridging the cultural gap 
IT has also helped to bridge the cultural gap by helping people from different cultures to communicate with one another, and allow for the exchange of views and ideas, thus increasing awareness and reducing prejudice. 

More time 
IT has also made it possible for businesses to be open 24 x7 all over the globe. This means that a business can be open anytime anywhere, making purchases from different countries easier and more convenient. It also means that you can have your goods delivered right to your doorstep with having to move a single muscle. 

Creation of new jobs 
IT has helped in the creation of new and interesting jobs like Computer programming, Systems analyzing, Hardware and Software developing and Web designing.


Disadvantages of Information Technology

Unemployment 
Technology has replaced most positions which humans used to occupy.
Example : Accounting is now being done by software, so accountants run out of
opportunities. 

Privacy 
Though information technology may have made communication quicker, easier and more convenient, it has also brought along privacy issues. From cell phone signal interceptions to email hacking, people are now worried about their once private information becoming public knowledge. 

Lack of job security 
Industry experts believe that the internet has made job security a big issue as since technology keeps on changing with each day. This means that one has to be in a constant learning mode, if he or she wishes for their job to be secure.

Dominant culture 
One culture dominating another weaker one.
For example it is now argued that US influences how most young teenagers all over the world now act, dress and behave.Languages too have become overshadowed, with English becoming the primary mode of communication for business and everything else.

1.2    The application of Information Technology

Education
Education is the process of acquiring knowledge.
In the traditional model, people learn from other people such as parents, teachers, and employers.
Many forms of printed material such as books and manuals are used as learning tools.
Today, educators also are turning to computers to assist with education.
Many schools and companies equip labs and classrooms with computers. 
Sometimes, the delivery of education occurs at one place while the learning occurs at other location.
For example : Distance learning and self-access learning.  

Finance 
Many people and companies use computers to help manage their finances.Some use finance software to balance checkbooks, pay bill, track personal income and expenses, manage investments, and evaluate financial plans.This software usually includes variety of online services. With online banking, users access account balance, pay bills, and copy monthly transactions from the bank's computer right into their personal computer.
Investors often use online investing to buy and sell stocks and bond - without using a broker.

Government  
A government provides society with direction by making and administering policies.
To provide citizens with up to date information, most government offices have Web sites.
Examples of Websites:
JobsMalaysia: Website that advertise  jobs to job seekers and also used by the employers to offer jobs.

Health Care
Nearly every area of health care today uses computers.
Examples :
Hospitals and doctors use computers and mobile devices to maintain and access patient records.
Computers monitor patients’ vital signs in hospital rooms and at home.
Robots deliver medication to nurse stations in hospitals.
Computers and computerized devices assist doctors, nurses, and technicians with medical tests.
Doctors use the Web and medical software to assist with researching and diagnosing health conditions.
Doctors use e-mail to correspond with patients.
Pharmacists use computers to file insurance claims. 

Science 
All branch of science, from biology to astronomy to meteorology, use computers to assist them with collecting, analyzing, and modeling data.
Examples :
Tiny computers now imitate functions of the central nervous system, retina of the eye, and cochlea of the ear.
A cochlear implant allows a deaf person to listen. 
Electrodes implanted in the brain stop tremors associated with Parkinson’s disease.
Cameras small enough to swallow — sometimes called a camera pill — take pictures inside your body to detect polyps, cancer, and other abnormalities 

Publishing 
The process of making works available to the public.
These works include books, magazines, newspapers, music, film, and video. 
Special software assists graphic designers. 
Example :
Composing and enhancing songs.
Filmmakers in creating and editing film;
Journalists and mobile users in capturing and modifying video clips.
Many publishers make their works available online. (karangkraf, pelangi,telaga biru, uprint, pixajoy) 

Travel
Vehicles manufactured today often include some type of onboard navigation system, such as OnStar.
Many mobile devices such as smart 
Phones have built-in navigation systems.
Some mobile users prefer to carry specialized handheld navigation devices.
In preparing for a trip, you may need to
Reserve a car, hotel, or flight.
Many Web sites offer these services to the public.
For example, you can order airline tickets on the Web. If you plan to drive somewhere and are unsure of the road to take to your destination, you can print directions and a map from the Web. 

Manufacturing 
Computer-aided manufacturing (CAM) - Refers to the use of computers to assist with manufacturing processes such as fabrication and assembly.
Industries use CAM to reduce product development costs, shorten a product’s time to market, and stay ahead of the competition.
Special computers on the shop floor record actual labor, material, machine, and computer time used to manufacture a particular product.
The computers process this data and automatically update inventory, production, payroll, and accounting records on the company’s network.
Often, robots carry out processes in a CAM environment.
CAM is used by a variety of industries, including oil drilling, power generation,
Food production and automobile manufacturing.
Automobile plants, for example, have an entire line of industrial robots that assemble a car.

1.3 Categories of computer

Supercomputer
The fastest, most powerful, and most expensive computer.
Capable of processing more than one quadrillion instructions in a single second.
Supercomputers generally run one program at a time, as fast as possible.
Applications requiring complex, sophisticated mathematical calculations use supercomputers.
Example: Large-scale simulations and applications in medicine, aerospace, automotive design, online banking, weather forecasting, nuclear energy research, and petroleum exploration.

Mainframe
A large, expensive, powerful computer that can handle hundreds or thousands of connected user simultaneously.
Second largest computers after supercomputers.
Capable of great processing speeds and data storage.
With mainframes, enterprises are able to bill millions of customers, prepare payroll for thousands of employees, and manage thousands of items in inventory.
Example: Mainframe is used in large organizations such as hospitals, universities, large businesses, banks or insurance companies that need to manage large amount of centralized data.

Personal computer
A personal computer is a computer that can perform all of its input, processing, output, and storage activities by itself.
A personal computer contains a processor, memory, and one or more input, output, and storage devices. Personal computers also often contain a communications device.
Two types of personal computers are desktop computers and notebook computers.

Mobile Computers and Mobile Devices
A mobile computer is a personal computer you can carry from place to place. Similarly, a mobile device is a computing device small enough to hold in your hand.

Mobile computers

i.              Notebook Computers

A notebook computer, also called a laptop computer, is a portable, personal computer often designed to fit on your lap. Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer.

ii.            A net book

Smaller, lighter, and often not as powerful as a traditional notebook computer. Most net books cost less than traditional notebook computers, usually only a few hundred dollars.

iii.           Tablet PCs

Tablet PC is a special type of notebook computer that allows you to write or draw on the screen using a digital pen. Tablet PCs are useful especially for taking notes in lectures, at meetings, conferences, and other forums where the standard notebook computer is not practical.

Mobile devices
Some mobile devices are Internet-enabled, meaning they can connect to the Internet wirelessly.
Five popular types of mobile devices are smart phones, PDAs, handheld computers, portable media players, and digital cameras.

     i.      Smart Phones

Internet-enabled phone.
Provides personal information management function such as a calendar, an appointment book, an address book, a calculator, and a notepad.
Send and receive e-mail messages and access the web.
Include built-in digital cameras  
ii.      PDAs A PDA (personal digital assistant)
Provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad.
Most PDAs also offer a variety of other application software such as word processing, spreadsheet, personal finance, and games.
iii.    Handheld Computers
Small enough to fit in one hand.
Communicate wirelessly with other devices or computers and also include a digital pen or stylus for input.
Industry-specific and serve the needs of mobile employees, such as meter readers and parcel delivery people , whose jobs require them to move from place to place.
iv.    Portable Media Players
A mobile device can store, organize, and play digital media.
Can listen to music; watch videos, movies, and television shows; and view photos on the device’s screen.
v.      Digital Cameras
Device that allows users to take pictures and store the photographed images digitally, instead of on traditional film.
While many digital cameras look like a traditional camera, some are built into smart phones and other mobile devices.

Embedded Computers  
Special-purpose computer that functions as a component in a larger product.
Embedded computers are everywhere — at home, in your car, and at work.
Perform various functions, depending on the requirements of the product in which they reside.