1. Introduction to IT
Zeeshan A. Bhatti

2. Information System
An apparatus for handling information within the organization
In order to achieve its objective, organizations must be able to plan ahead and control and coordinate activities
Depends on the provision and communication of information
Data Processing
Collection and manipulation of items of data to produce meaningful information – when IS/IT is used its called Electronic Data Processing

3. Data is the term used to describe basic facts about the activities of a business (e.g., no. of working hours of an employee, his rate of pay etc.)
Information is obtained by assembling data into a meaningful form (e.g., an invoice, a financial statement etc.)
The Computer is a device that processes data to produce further data or information
The form in which data is accepted or produced vary from simple words or numbers to signals sent to different other technologies

4. When a computer processes data it performs a no. of function:
Input
Computer accepts data from outside for processing within
Storage
Computer holds data internally before, during and after processing
Processing
Computer performs operations on the data it holds
Output
Computer produces data from within for external use

13. A Program is a set of instructions that is written in the language of the computer
Used to make the computer perform a specific task (e.g., calculation)
So the computer works under the control of stored programs
Hardware and Software
Hardware: Physical devices found in a computer system
Software: all the various programs that maybe used on a computer together with their associated documentation

14. Computer Types Special Purpose Computers General Purpose Computers
Designed for a specific operation or job (e.g., Digital Watches, Calculators etc.)
General Purpose Computers
Designed to solve a variety of problems.
They can be adapted to perform particular tasks by means of specifically written programs

15. Computer Classification by Use
Word Processor is a special purpose computer used in the production of documents, letters etc.
A general purpose computer can run a word processing program
Personal Computer is a low-cost microcomputer of limited capability designed for domestic use with programs that are typically used
Desktop Computer any computer design for use on a desk in an office/home environment

16. Workstation is another kind of desktop computer commonly connected to a number of other computers
High end computer with advanced capabilities

17. Laptop Computer is a PC sufficiently small and light for its user
Mainly operates on rechargeable batteries (portable)
Built in disk drives and flat screens called LCDs (Liquid Crystal Displays)

18. Computer Classification by Size
Classification is in order of decreasing power and size
Mainframe Large general purpose computers with extensive processing, storage and input/output capabilities
Primarily used by MNCs and large organizations (e.g., bulk data processing such as census data

19. Minicomputers Physically smaller computers compared with mainframes
General purpose
Medium Scale data processing is done on these machines
Microcomputers further miniaturization in which various integrated circuits and elements of a computer are replaced by a single chip (e.g., IBM PCs, Apple MACs etc.)

20. Computer Generations First Generation: started in 1946 by ENIAC
Used electronic valves (i.e., vacuum tubes)
Second Generation: 1950s – use of transistors
Third Generation: (1960s and 1970s)
Use of Integrated Circuits
Fourth Generation: (used today)
Use of Large Scale Integration into one single chip, VLSI etc
Fifth Generation: Artificially intelligent computers