This document provides an overview of basic concepts in information technology, including definitions of information, computers, and their components. It explains that information is data that has been processed and communicated for a purpose. Computers are general purpose, programmable devices that process and store information. The document outlines the typical hardware components of a computer system, including the processor, memory, storage, and input/output devices. It also discusses system and application software, and how software is developed.

1. Basic Concepts Of Information
Technology (IT)
Dheeraj Mehrotra
www.computerscienceexpertise.com

2. The Basics – What is Information?
• Information is data processed for some purpose
• Information can only be considered to be 'real'
Info if it meets certain criteria i.e.
• 1. it must be communicated to the recipient
• 2. it must be in a language that is understood
• 3. it must be in a suitable form
• 4. it must be relevant for achieving some
purpose

3. Information -
zis any form of communication
that provides understandable
and useful knowledge for the
person receiving it.

4. What Is A Computer?
z A computer is a general purpose,
programmable device that is used
for the production and processing of
information
z capable of calculating and storing
results

5. What do we mean by general
purpose?
z Most devices can be described by their function e.g
Washing Machine, DVD Player
z Computers, however, can be used for almost any
purpose:
- typewriter
- video editor
- accounts tracker
- database / address book
- DVD / CD Player
- and many others…

6. Computers Are Programmable
z Computers repond to instructions in the form of
programs
z Programs are written in order to make
computers behave in specific ways i.e. word
processor, systems control
z Programs are stored in the Computer memory

7. How computers process information
z Computers accept inputs ( i.e. data)
z The input is translated into binary numbers and
‘processed’
z The process produces output (i.e information)
z This sequence can repeat endlessly: outputs
can be inputs!
z Illustrating this - the ‘Black Box’ model

8. Processing - the ‘Black Box’ model
z We can think of a computer as a ‘black
box’ :
3+5
input process output
8

9. Components of a Computer System
z Computer Systems are made up of:
z Hardware – the physical parts
z Software - the instructions or programs that
control the hardware
z The Human Being – the brains behind the
whole system!

10. Types Of Computer
z Mainframe Computer
z Minicomputer
z Personal Computer (Microcomputer / Desktop)
z Laptop
z Network Computer / Server
– Uses two types of terminal: “Dumb” and “Intelligent”

11. Computer Organisation – the Von
Neumann model
z Most Computers are based on a model
proposed by John Von Neumann in 1946
z The ‘logical’ units of this model are:
– Stored program
– Central Processing Unit: fetches and executes the
program instructions sequentially
– Memory
– Input and Output devices

12. Computer Hardware components
z A typical PC System is made up of:
– System Unit
– Keyboard
– Monitor (VDU)
– Mouse
– Printer
– Modem
– Multimedia Devices

13. Hardware – The System Unit
z The central component of the system
z Houses:
– The Processor: corresponds to the CPU
– Memory: RAM and ROM
– Storage: Hard Disk, Removable Storage devices

14. The Processor (CPU)
z Types include Intel Pentium series, Celerion,
AMD Athlon
z Chip at the heart of the computer- does the
calculations
z Speed is very important – measured in
megahertz (MHz): the faster the processor the
more calculations performed per second.

15. Memory
z A computer must be able to store its calculations
and programs
z Two types of memory: “Volatile” and permanent.
z Measured in bytes
z One byte = eight bits

16. Random Access Memory (RAM)
z Used by the Computer as the working area
z Holds the working program, the data being
processed and the interim results
z Volatile - contents are erased if power is cut
z Can be accessed randomly: can get any piece
of data directly.
z Faster than perminant storage
z Not to be confused with ROM (Read-Only
Memory)

17. Storage - Hard Disk
z Permanent Memory - records and stores all
programs and data / information magnetically
z Larger than RAM - average 12 - 120GB
z Slower - involves mechanical movement
(read/write head, revolving disk)

18. Other types of Storage
z Floppy Disks
z CD/DVD ROM
z Zip Drive
z Magnetic Tape

19. Input Devices
z Keyboard
z Mouse: used in conjunction with the GUI
(Graphical User Interface), point and click
z Other types of Input Devices:
– Trackballs
– Light Pens
– Touch Screens
– Tablets

20. Output Devices
z Monitor: also known as the Visual Display Unit
(VDU)
z Printers
– Laser Printer
– Inkjet Printer
– Impact

21. Software
z Generic name of all programs
z Made up of code interpreted by the hardware
z Written in programming languages - Java, C,
C++, Perl
z Two kinds of Software:
– System
– Application

22. System Software
z Concerned with the computer itself: devices,
file and storage management, error correction
z Main piece of SS: Operating System (OS)
z OS: the driving program of the computer
– communicates between all programs and the
hardware
– controls timing and sequence of events
– manages data to ensure security and integrity
– Examples: Windows, Mac OS, Unix

23. Applications Software
z Concerned with the world outside the computer
z Gives the computer its general purpose nature
z Used for the things you want the computer to
do
z Common Examples - Word, Excel, Internet
Explorer
z Applications can be more specialised: e.g.
Architecture package

24. How Software is made
z Involves a cycle of research, analysis,
development and testing
z Systems Analysts - study the business
processes and designs the software
z Programmers - develops the software

25. Problems with Software
z Software is complex
z Difficult to test comprehensivly
z Can have bugs: these can be trivial or major
z Symptoms of bugs
– hanging
– crashes

26. The Graphical User Interface (GUI)
z Represents all the program / computer
resources as icons
z Workspace represented graphically - creates
‘virtual’ documents
z More usable: led to wider use of computers
z Adds to the unique nature of the computer as
both a tool and a medium

27. Do’s and Don’t’s
z DO
z give the computer room
to breathe
z keep it in a dry place
z dust free
z shut down properly
z keep removable storage
away from the screen
z DON’T
z block air vents
z eat or drink while using
the computer
z expose to extremes of
temperature
z just switch off
z move while the computer
is in operation

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