Introduction to IT Zeeshan A. Bhatti

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

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

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

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

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

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

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

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)

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

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.)

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