INFORMATION TECHNOLOGY (IT) UNIT - I

UNIT - I

INFORMATION TECHNOLOGY: 

     Information Technology also know as IT is the use of computers, sstorage, networkingand other physical devices, infrastructure and process to create, process, store, secure and exchange all forms of electronic data. The term IT generally used as a synonym for computers and computer networks. Nowadays IT is used in almost every field like Education, Transport System, Banks, Business, etc.,

Definition: It is defined as the technology that is used to acquire, store, organize, process the data. The processed data can be used in specific applications. Information is processed data that improves our knowledge, enabling us to take decisions.

CHARACTERSTICS OF COMPUTER:

1. SPEED: Computer can process millions of instructions in a fraction of seconds. The speed of computer is calculatedin MIPS(Missions of Instructions Per Second) and MOPS(Millions of Operations Per Second).

2. ACCURACY: Computer provides a high degree of accuracy. Every calculation is performed with
the same accuracy. The errors are due to human and inaccurate data.

3. Diligence: Computer can work for hours without any break or boredom. It can perform complex calculations with the same speed & accuracy from the start till the end.

4. Versatality: Computer can be used to perform different types of tasks.

5. Large Storage Capacity: Computers can store very large amount of data. Various storage devices are also available which store data temporarily or permanently.

7. Programmable: The computers can be programmed to match our requirements. They can be programmed to work automatically.

8. Compactness: Computers come in varioous sizes. The size of computers is decreasing due to new technology. We can operate the computers fromo anywhere and at anytime.

LIMITATIONS OF COMPUTER:

1. Lack of Decision Making Power:  Computers cannot decide on their own. The are dependent on human instructions. Computers can only do what they are to to do.

2. Zero IQ: Computers are dumb machines with Zero IQ.

3. Needs Electricity: Computers work on electricity. They work as long as the power is supplied.

4. Security Issues: With the increasing technology, viruses, worms etc have developed which cause serious security threats.

5. Operational Costs: There are some costs involved like installation, maintenance, training costs.

6. Lack of Creativity: Computers lack creativity. They cannot sing, dance or draw.

GENERATIONS OF COMPUTER

First Generation (1944-1955): It used Vaccum Tubes which are very big and heavy in size, with large number of internal circuits and used to store small amount of information.
eg: UNIVAC, ENIAC, EDSAC, EDVAC

Second Generation(1956-1965): Transistor were developed and size was decreased.
eg: IBM 7094 series

Third Generation(1966-1975): It used IC- Integrated Circuits which can contain thousands of transistors.
eg: IBM 370

Fourth Generation(1976-1985): The first microprocessor  was developed by Ted Hoff in 1971 for intel.
eg: IBM PC, Apple MAcintosh
 
Fifth Generation (1986 onwards): It is based on Artificial Intelligence(AI) which are still under development.They will be intelligent to take decisions independently.

TYPE OF COMPUTER:

Computers are classified based on the type on INPUT, SPEED, SIZE etc.,..

• Based on Input: 
• Analog Computers: Analog type of data such as temperature, pressure, speed weight, voltage, depth etc are continuous and having infinite variety of values. ef: Thermometer, Analog Clock.
• Digital Computers: It operate on inputs which are ON-OFF type and output is also in the form of On-OFF signal. eg: Digital watches, calculators
• Hybrid Computers: It is combination of digital and analog computers. It has the speed of analog computer and memory and accuracy of digital computer. eg: Devices used in petrol pump. 
• Based on Size: 
• Micro computers: Also called as Personal Computers, generally used for entertainment, education and work purpose. eg: Desktop, Laptop
• Mini computers: These are used by small business and firms. 
• Mainframes: It is very large in size and capable of handling and processing very large amounts of data qickly. They are used by large institutions such as government agencies etc.
• Super computers:
• Based on Number of Users:
• Single User: Single user computer is also called as personal computer. It is acomputer in which only one used can do the job at a time.
• Multi Used: It can support many user ar a point of time. Unix and Linux are multi-user operating Systems.

HARDWARE
The physical components that make up a computer system and which we can touch is called Hardware.

Types of Hardware: 

• Input devices : Keyboard, Mouse, Scanner, Microphone, Joystick, Light Pen, Touch Pad, Trackball, Webcam.
• Output Devices: Monitor, Printer, Plotters, Speakers
• Memory Devices: Floppy Disk, Hard Disk, Compact Dist, Digital Video Disk(DVD), Pendrives.

SOFTWARE: It is a set of instructions and not a physical device.

Types of Software:

• System Software: It is a set of Programs which are responsible for running the computer and other hardware devices. eg: Operating System
• Utility Software: It consists of the programs which support system software. eg: Compilers, interpreters, linkekrs, loaders etc.
• ApplicationSoftware: It is a set of program which are written to perform specific tasks. Eg: Ms-Office, 'C', Java etc.

MEMORY:

 Memory unit is the storage area in the computer. Computer can store very huge amount of data. It can store not only text but also images, graphics video, audio etc. All these are stored in the form of bits(0 or 1).  The memory is measured in terms of number of bits. The word "Memory" refers to the main memory of the computer and "storage" refers to the memory that exists on the disks.

Types of Memory Devices:

• Primary Memory: Also called as main memory and holds only those data and instructions on which computer is currently working. It is volatile memory.
• Types:
• Random Access Memory(RAM): refers to random Acces Memory-temperory memory. SRAM, DRAM are the types of RAM
• Read Only Memory(ROM): it has memory cells paired transistor and capacitor. PROM, EPROM and EEPROM are the types of ROM.
• Cache memory: it is a very high speed semiconductor memory which will speed CPU.
• Secondary Memory: Also known as External memory or non-volatile or backup memory. 
• Types:
• Hard Disk, Magnetic Tape, Magnetic Disk,Floppy Disk, CD etc.