Introduction to Information System

Definition of Information Technology

• Information technology is the technology that uses computing with high speed communication links to spread information from one place to another.
• Computer is a very important component of information technology
• The world has become "global village" due to advancement in IT.

What is a Computer?

• An electronic device that is programmed to accept data, process data into useful information and store it for later use.
• Computer consists of hardware and software.
• Software is a set of instructions that tells a Computer what to do.
• Hardware is the physical part of a computer E.g. keyboard, mouse etc
• Relationship between hardware and software

Few Basics

Types of Computers

1. Analog computers
2. Digital computers

Analog computers

• An analog computer recognizes data as a continuoUS measurement of a physical property.
• It has no state.
• Its output is usually displayed on a meter or graphs.
• Examples are Analog clock,speed ofa car, thermometer etc.

Digital Computers

• It works with numbers
• They breaks all types of information into tiny units and use numbers to represent those pieces of information.
• Everything is described in two states i.e. either ON (1) or OFF (o).
• They are very fast and have big memory.

History and Generations of computers

The six generations of computers are:

• Mechanical era(1623-1900)
• First generation electronic computers(1937-1953)
• Second generation (1954-1962)
• Third generation (1963-1972)
• Forth generation (1972-1984)
• Fifth generation (1984-1990)
• Sixth generation (1990 -present)

Mechanical Era

• Abacus (3ooo BC)

It was used to perform addition, subtraction,division and multiplication. It consists of wooden beads and calculation were performed by moving these beads properly.

• Napier's bone (17th century)

It was a cupboard multiplication calculator invented by john Napier.It was used to perform difficult multiplication operations to simple addition of entries in a table.

• Pascaline (17th century)

It was invented by Blaise Pascal.It was first mechanical adding machineIt had a series of wheels with teeth which could be turned using hands.

• Difference Engine and Analytical Engine(1823 and 1833)

It was designed by Charles Babbage who was English mathematician, engineer philosopher and inventor.He originated the concept of theprogrammable computer.A general purpose computer controlled by a list of instructions.

• Punched cards (1890)

They were able to read information that which have been punched into the cards automatically.

First generation Electronic computers

First generation computers were used during 1942-1955.They were based on Vacuum Tube which was a glass (tube) that controlled and amplified the electronic signals Consume more power with limited,pertormance,High cost.They Uses assembly language - to prepare programs. These were translated into machine level language for execution.

• Fixed point arithmetic was Used
• 100 to 1ooo fold increase in speed relative to the earlier mechanical and relay based electromechanical technology
• Punched cards and paper tape were invented to feed programs and data and to get results.
• Magnetic tape/ magnetic drum were Used as secondary memory
• Mainly used for scientific computations.

Example :are: UNIVAC, Havard Mark 1, ENIAC etc.

Second Generation (1955-1964)

• Bell Lab invented the transistor-function like vacuum tubes but smaller, lower power consumption, more reliable.
• Transistor is a small device that transfer electronic signals across a resister
• Lower cost
• Magnetic core memories were used as main memory which is a random-access nonvolatile memory
• Magnetic tapes and magnetic disks were Used as secondary memory
• Hardware for floating point arithmetic operations was developed.
• Index registers were introduced which increased flexibility of programming.
• High level languages such as FORTRAN, COBOL etc were used-ompilers were developed to translate the high-level program into corresponding assembly language program which was then translated into machine language.
• Separate input-output processors were developed that could operate in parallel with CPU.
• Punched cards continued during this period also.
• 1000 fold increase in speed.
• Examples are: TRADIC, iBM 704, LARC etc

Third Generation (1963-1971)

• Jack Kilby developed Integrated Circuit (IC)
• An IC combined several electronic comniitars on a small silicon chip
• IBM introduced
• System/36o-a highly configurable,highly backward compatible,mainframe computer system.
• Small Scale Integration and Medium Scale.Integration technology were implemented in CPU, 1/O processors etc.
• Smaller 8 better performance
• Comparatively lesser cost
• Faster processors
• In the beginning magnetic core memories were used. Later they were replaced by semiconductor memories (RAM & ROM)
• Introduced microprogramming
• Microprogramming, parallel processing (pipelining, multiprocessor system etc), multiprogramming, multi-user system (time shared system) etc were introduced.
• Operating system software were introduced
• Cache and virtual memories were introduced
• High level languages were standardized by ANSI e.g..ANSI FORTRAN, ANSI COBOL etc
• Database management, multi-user application,online systems like closed loop process control, airline reservation, interactive query systems, automatic industrial control etc emerged during this period.
• Examples are: INTEL 4004, 1BMSYSTEM/360 etc.

Forth generation (1972-1984)

• Microprocessors were introduced as CPU Complete processors and large section of main memory could be implemented in a single chip
• Tens or thousandS oT transistors can be placed in a single chip (VLSI design implemented)
• CRT screen, laser & inkjet printers, Scanners etc were developed.
• Semiconductor memory chips were used as the main memory.
• Secondary memory was composed of hard disks.Floppy disks & magnetic tapes were used for backup memory.
• Parallelism, pipelining cache memory and virtual memory were applied in a better way
• LAN and WANS were developed (where desktop work stations interconnected)
• Introduced C language and Unix OS
• IntrodUced Graphical User Interface
• Less power consumption
• High pertormance, lower cost and very compact
• Much increase in the speed of operation
• Examples are Apple Macintosh and BM PC

Fifth Generation (1983-199o)

• Computers based on artificial intelligence are available
• Computers use extensive parallel processing, multiple pipelines,multiple processors etc
• Massive parallel machines and extensively distributed system connected by communication networks fall in this category.
• Introduced ULSI (Ultra Large Scale Integration) technology.Intel's Pentium 4 microprocessor contains 55 million transistors.millions of components on a single IC chip.
• Superscalar processors, Vector processors, SIMD processors, 32 bit.micro controllers and embedded processors, Digital Signal.Processors (DSP) etc have been developed.
• Memory chips up to 1 GB, hard disk drives up to 180 GB and optical disks up to 27 GB are available (still the capacity is increasing)
• Object oriented language like JAVA suitable for internet programming has been developed.
• Portable note book computers introduced
• Storage technology advanced- large main memory and disk storage available
• Introduced World Wide Web. (and other existing applications like e-mail, e Commerce,Virtual libraries/Classrooms, multimedia applications etc.)
• New operating systems developed- Windows 95/98/XP/.., LINUX, etc.
• Got hot pluggable features-which enable a failed component to be replaced with a new one without the need to shutdown the system, allowing the uptime of the system to be very high.
• The recent development in the application of internet is the Grid technology which is still in its upcoming stage.

Sixth Generation Computers(1990-till date)

• Some inventions of the time are www, HTML, HTTP, Web,TV, java, DVD, iPod, Youtube etc.
• Examples are: iMac, Sun ultra workstation etc

Computers Systems and its Components

1. Input Devices
2. Output devices
3. System Unit
4. Storage devices
5. Communication devices

Input Devices

The devices that are used to enter data and instructions into the computers Most commonly used input devices are Keyboard and Mouse.

Output devices

Output devices are used to display processed data to the user Most commonly used output devices are Monitor, Printer and speakers Hard Copy is paper copy - tangible Soft copy is intangible.

System Unit

Its a box that contains different components of a computer system.All electronic components in the system.unit are connected to motherboard Important components of system units are:Central processing Unit(Processor)
Memory

Storage devices

These are used to store data permanently.even when the computer is turned off.It is non volatile memory. Examples:Floppy Disk, Hard disk, CD ROM

Communication devices

A communication device is a hardware component that enables a computer to send and receive data, instructions and information to and from one or more computers. A widely used communition Modem,Wired media,Wireless media.

Modulation and Demodulation

Modulation :
Conversion from Digital signals to Analog signals.

Demodulation :
Conversion from Analog signals to Digital signals.

Computers in society

• Home
• Education
• Small business
• Industry
• Government
• Health care
• Banking
• Communication
• Police Department
• Retail

Information Processing cycle

Data
A collection of raw facts and figures is called data. It may consist of numbers, characters,symbols or pictures etc

Information
Processed data is called information. It is more meaningful than data.

Information Processing Cycle

Data is collected and given to the computer for processing.Computer process data to the required.information.The information is given to the user as Output.Information is stored in the computer for further use.

Advantages of computers

• Speed
• Reliability
• Consistency
• Storage
• Communications

Disadvantages of computers

• Violation of Privacy
• Public Safety
• Impact on Labor Force
• Health Risks
• Impact on Enironment

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