A computer is an electronic device that operates under instructions stored in its memory to perform tasks. It has advantages like speed, memory, and storage but also disadvantages such as inability to think independently and potential health risks. There are different types of computers ranging from personal computers for individuals to supercomputers that process extremely large amounts of data. A computer consists of both hardware and software - hardware refers to the physical components while software refers to programs and applications. Key hardware components include the CPU, memory, storage devices, input devices like keyboards and mice, and output devices like monitors and printers. Software includes operating systems and applications.

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. FILE & FOLDER
Folders act as containers for files and sometimes other
folders, they are treated as storage spaces, and are used for
organizational purposes.
A file, on the other hand, is a unit of saved data, such as text
or program code. There are many different types of file,
examples can include a word document, an audio song track,
or a photo-editing program.

7. Difference Between File & Folder
1.Folders act as containers for files and other folders, but files can't
contain files or folders. Files are storage units for data, they can take
many forms, including text documents, audio tracks, movie clips,
and computer programs.
2.You can create new folders or sub-folders within a folder, but you
cannot create a new folder within a file.
3.Folders essentially take up zero space on the computer. Files can
take up anything from a few bytes to many gigabytes.
4.Folders are typically represented by a Manila folder icon. File icons
vary according to the type of file.
5. Folders don't have file extensions, but files do. (File extensions are
the group of letters after a period in a file name, indicating the format
of the file, such as ".doc", ".pdf", ".mp3" and ".txt").

8. TYPES OF MEMORIES
Computer memory is the storage space in computer
where data is to be processed and instructions
required for processing are stored.
• Memory is primarily of two types
• Internal Memory - cache memory and
primary/main memory
• External Memory - magnetic disk / optical disk
etc.

9. • Memory
– Volatile
• RAM
– SRAM
– DRAM
– Non volatile
• Difference between RAM and ROM
• Storage devices
– Hard disk
– Floppy disk
– Magnetic Disk
– Optical
• CD-ROM
• CD-Recordable (CD-R)
• CD-R/W
• DVD
– Magnetic Tape

11. VOLATILE MEMORY
• It also known as volatile storage &
temporary memory.
• Volatile memory retains the
information as long as power supply
is on, but when power supply is off
or interrupted the stored memory is
lost.
• Eg : RAM

12. NON – VOLATILE MEMORY
• Non-volatile memory is typically used
for the task of secondary storage, or long-
term persistent storage
• Examples of non-volatile memory
include read-only memory flash memory
and early computer storage methods such
as paper tape and punched cards.

13. RAM – RANDOM ACCESS MEMORY
• A RAM constitutes the internal
memory of the CPU for storing data,
program and program result
• It is read/write memory. It is called
random access memory (RAM).
• RAM is of two types:
– Static RAM (SRAM)
– Dynamic RAM (DRAM)

14. DIFFERENCE BETWEEN RAM &
ROM
RAM ROM
VOLATILE MEMORY NON VOLATILE
Data in ram is not permanently
written
when power off, data deleted
Permanently, not erased
Ram: DRAM & SRAM ROM: PROM & EPROM
It requires flow of electricity to
retain data
It does not requires electricity
to retain data
Ram is the memory available
for the operating system
programs and process to use
when the computer is running
Rom is the memory that comes
with your computer that is pre-
written to hold the instructions
for booting up the computer

15. Desktop – PC, iMac
Notebook – Laptop
Workstation
Personal Digital
Assistant
TYPES OF COMPUTERS
COMPUTERS FOR INDIVIDUALS

16. 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)…

17. 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.

18. TYPES OF COMPUTERS
THERE ARE 3 MAIN TYPES OF PCS
• DESKTOP
• PORTABLE (NOTEBOOK/LAPTOP)
• HAND-HELD

19. PARTS OF A COMPUTER
• THERE ARE TWO BASIC PARTS THAT MAKE UP
A COMPUTER...
Hardware Software

20. 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.

21. 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

22. HARDWARE (CONTINUED)
• THERE ARE THREE
TYPES/CATEGORIES
OF HARDWARE
1. Input Devices
2. Output Devices
3. Storage Devices

23. 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

24. INPUT DEVICES
© 2005 Prentice-Hall, Inc.
Keyboard Mouse – pointing device
Microphone –
speech-recognition
Digital Cameras

25. 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 MOVEMENT
• 1 TO 4 BYTES (VERTICAL &
HORIZONTAL)
• BUTTONS
• CLICKED, PRESSED,
ROLLED
b

26. OUTPUT DEVICES
• OUTPUT BASICALLY MEANS GETTING DATA OUT
OF THE COMPUTER.
Monitor
Printer
Speakers
Headphones
Modem
Fax

27. OUTPUT
DEVICES
© 2005 Prentice-Hall, Inc.
Slide 27
Monitor
Printer
Speakers

28. 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

29. STORAGE
DEVICES
© 2005 Prentice-Hall, Inc.
Slide 29
Hard Drive
Floppy Disk Drive
Zip
Drive
CD/DVD
Drive
Jaz
Drive
Tape
Drive
Micro Drive

30. HD/DVD
track
sector
head

31. SOFTWARE

32. SOFTWARE
• SOFTWARE IS THE PROGRAMS AND
APPLICATIONS THAT TELL THE COMPUTER
WHAT TO DO AND HOW TO DO.
• COMPUTER PROGRAMMERS WRITE THE
CODES/INSTRUCTIONS THAT MAKE-UP
SOFTWARE APPLICATIONS/PROGRAMS.

33. TYPES
• SYSTEM SOFTWARE
• OPERATING SYSTEM
• APPLICATION SOFTWARE
• MS OFFICE
• TALLY
• ADOBE
• OUTLOOK

34. 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

35. TWO TYPES OF SOFTWARE
• APPLICATION
SOFTWARE
• OPERATING SYSTEM
SOFTWARE

36. 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

37. 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.

38. • CUI (CHARACTER USER INTERFACE)
• GUI (GRAPHICAL USER INTERFACE)

39. 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

41. 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

43. APPLICATION SOFTWARE
• Programs that work with operating system software to help
the computer to do specific types of work.

44. 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’

45. 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.

46. APPLICATION SOFTWARE
• Tailormade software - custom software (also known as
bespoke software or tailor-made software) is software that
is specially developed for some specific organization or
other user.
• Gmail, microsoft outlook, etc. ...
• Accounting software applications – sage, tally, xero,
cashflow, etc.

47. 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

48. 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…

49. COMPILER INTERPRETER
Interpreter 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.

50. 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.