A computer is an electronic device that operates under instructions stored in its memory (1). Computers have advantages like speed and memory but also disadvantages such as inability to think and potential health risks (2). There are several types of computers including desktops, laptops, supercomputers, and mainframes, each suited to different uses like business, research, or personal use (3).

1. Introduction to computers

2. The computer
What is a Computer?
A computer is an electronic device, operating under the control
of instructions stored in its own memory

3. Characteristics of Computers

4. Advantages & Disadvantages
of Computers
Advantages Disadvantages
Speed Cannot think on its own
Memory
Cannot correct wrong
Instructions
Storage Health Risks
Reliability and accuracy Expensive

5. Applications of Computers

6. Desktop – PC, iMac
Notebook – Laptop
Workstation
Personal Digital
Assistant
Types of Computers
Computers for Individuals

7. Types of Computers
• Supercomputers...are used to process very large amounts
of information including processing information to predict
hurricanes, satellite images and navigation, and process
military war scenarios.
• Mainframes...are used by government and businesses to
process very large amounts of information.
• Mini-Computers...are similar to mainframes...they are used
by business and government to process large amounts of
information.
• Personal Computers (PC)…

8. Types of Computers
• Personal Computers (Continued)
Personal Computers...also known as
PC’s...are smaller and less powerful than
the others. They are used in homes,
schools, and small businesses.

9. Types of Computers
There are 3 main types of PCs
• Desktop
• Portable (Notebook/Laptop)
• Hand-Held

10. Parts of a Computer
• There are two basic parts that make up a
computer...
Hardware Software

11. FIRMWARE
LIVEWARE
Firmware is like prewritten program that is
permanently stored in read-only memory. BIOS (
Basic Input Output Services ) instructions are an
example of firmware.
It is the term generally used for the people associated
with and benefited from the computer system.

12. Hardware
• Hardware is basically anything that you
can touch with your fingers.
Computer Case
CPU (central processing unit...Pentium chip)
Monitor
Keyboard & Mouse
Disk Drive, Zip Drive, CD-ROM, DVD,
Hard Drive
Memory (RAM)
Speakers
Printer

13. Hardware (Continued)
• There are three
types/categories of
hardware
1. Input Devices
2. Output Devices
3. Storage Devices

14. Input Devices
• Input basically means getting data into the
computer to be processed.
Keyboard, Mouse,
Trackball, Touch Pad
Light Pen, Laser Scanner,
Pointing Stick
Touch Screen,
Bar Code Reader, Scanner
Microphone, Joystick

15. © 2005 Prentice-Hall, Inc.
Keyboard Mouse – pointing device
Microphone –
speech-recognition
Digital Cameras
Input Devices

16. Keyboard/Mouse
• Each key (or combination
of keys) of the keyboard
sends a code to the
computer.
• The code is interpreted and
converted to the
corresponding ASCII or
Unicode number.
• The mouse movements
 1 to 4 bytes (vertical &
horizontal)
• Buttons
 Clicked, pressed, rolled
buttons

17. Output Devices
• Output basically means getting data out of the
computer.
Monitor
Printer
Speakers
Headphones
Modem
Fax

18. Slide 18 © 2005 Prentice-Hall, Inc.
Monitor
Printer
Speakers
Output
Devices

19. Storage Devices
• Storage devices are both input and output
devices in one. A storage device is a
place to keep data that has been
processed so that it can be retrieved at a
later time to be used again.
Hard Disk
Floppy Disk
CD’s, DVD’s
Magnetic Tape
Flash Memory, Jump Drive

20. Slide 20 © 2005 Prentice-Hall, Inc.
Hard Drive
Floppy Disk Drive
Zip
Drive
CD/DVD
Drive
Jaz
Drive
Tape
Drive
Micro Drive
Storage
Devices

21. HD/DVD
track
sector
head

22. Software

23. Software
• Software is the programs and applications that tell
the computer what to do and how to look.
• Computer programmers write the codes/instructions
that make-up software applications/programs.

24. Software layers
ROM
Hardware
Operating System
User Interface
Software
Files
CPU, RAM, HD, DVD
Word, Powerpoint, mail, web browser…
Data (.doc, .mp3)
BIOS
Linux
CLI, X-Windows
Windows
Windows
MacOSX
Firmware
Quartz

25. Two Types of Software
• Application Software
• Operating System
Software

26. Operating System Software
• An Operating System (OS) is an interface between a
computer user and computer hardware.
• Directs all the activities and sets all the rules for
how the hardware and software will work
together.
Examples would be:
DOS, Windows 95, 98, ME, NT, XP, Vista,
Windows 7
Unix, Linux,
MAC system OS 6,7,8,9,10

27. Functions of Operating Systems
• An operating system is a software which performs
all the basic tasks like :
• File Management
• Memory Management
• Process Management
• Handling input and output
• Controlling peripheral devices such as disk drives and
printers.

28. Command Line Operating Systems
DOS is an example of a command line operating
system.
On the next slide, Notice that there are no:
• Icons (pictures)
• Colors
• Mouse Pointer
• Buttons
• You have to memorize commands in order to
use this text based operating system.

30. Operating Systems: GUI
• GUI stands for Graphical User Interface
Uses pictures (icons) to represent files, folders, disk
drives, modems, printers, etc.
GUI’s were created to make using a computer easier,
more interesting, non-threatening to inexperienced users.
A mouse allows users to point at something and click to
make it work. With command line you have to have all of
the commands to make your programs work.
Here is an example of a GUI

32. Application Software
• Programs that work with operating
system software to help the computer to
do specific types of work.

33. Application Software
Application software:
• General Purpose - A general purpose application,
sometimes known as ‘off-the-shelf’ is the sort of software
that you use at home and school. Examples include
word processors, spreadsheets, databases, desktop
publishing packages, graphics packages etc.
• This type of software tries to be a ‘jack-of-all-trades’

34. Application Softwares
• Packaged Software - Packaged software, also called
a software package, is software that is often used
together, performs similar functions, or includes similar
features, and is bundled together as a set
of software programs.
• Microsoft Office is packaged software, including multiple
software programs used in a home or office, such as
Microsoft Excel, Microsoft Word, and
Microsoft Powerpoint.

35. Application Softwares
• Tailormade software - Custom software (also
known as bespoke software or tailor-made
software) issoftware that is specially developed
for some specific organization or other user.
• Gmail, Microsoft Outlook, etc. ...
• Accounting software applications – Sage, Tally,
Xero, KashFlow, etc.

36. File and Folder
• A file is the common storage unit in a
computer, and all programs and data are
"written" into a file and "read" from a file.
• A folder holds one or more files, and a
folder can be empty until it is filled. A
folder can also contain other folders
(subfolders). Folders provide a method for
organizing files

37. File systems
• Method the OS uses to store information
 Storage unit, directories, subdirectories (Windows,
VMS)
 Single arborescence (Linux, MacOSX, all Unix)
• What exactly is a file?
 a piece of information (text, graphic, data, music
program, script)
 it is identified by a name and an logical address (or
path)
 other informations: date, size, type, creator,
ownership, physical address…

38. Compiler Interpretor
nterpreter Compiler
Translates program one statement at a time.
Scans the entire program and translates it as a
whole into machine code.
It takes less amount of time to analyze the
source code but the overall execution time is
slower.
It takes large amount of time to analyze the
source code but the overall execution time is
comparatively faster.
Continues translating the program until the first
error is met, in which case it stops. Hence
debugging is easy.
It generates the error message only after
scanning the whole program. Hence debugging
is comparatively hard.
Programming language like Python, Ruby use
interpreters.
Programming language like C, C++ use
compilers.

39. Networks
• A network is a group of computers that share information
and hardware.
• The computers are connected together using copper phone
wires, fiber optic cables, or radio waves.
• Our computers are on a network here at school...Look under
the table and see the blue wires that connect your computer
to the network.
• The internet is many networks around the world that are all
connected together to make 1 huge network.