This document provides information about computers and their components. It defines a computer as a machine that manipulates data according to programmed instructions. It then describes different types of computers like supercomputers, mainframes, PCs and laptops. It explains the components of a computer like the CPU, memory, ALU, input/output devices and control circuitry. It also discusses computer software, applications, operating systems and programming languages. Finally, it outlines the major internal and external hardware components of a personal computer.

2. What is Computer?
A computer is a machine designed
for manipulating data according to a
list of instructions known as a
program.

3. Types of Computer
 Super Computers
 Main Frames
 Personal Computers
 Laptop Computers
 Embedded Computers

4. Super Computers
• is a computer that leads the world in terms
of processing capacity, particularly speed
of calculation, at the time of its
introduction.
• Today, supercomputers are typically one-of-
a-kind custom designs produced by
"traditional" companies such as IBM and
HP

5. Main Frames
• Are large and expensive computers used
mainly by government institutions and
large companies for mission critical
applications, typically bulk data processing
such as censuses, industry/consumer
statistics, ERP, and financial transaction
processing.

6. Personal Computers
• A personal computer (PC) is usually a
microcomputer whose price, size, and
capabilities make it suitable for personal usage.
• Personal computers are normally operated by
one user at a time to perform such general
purpose tasks as word processing, internet
browsing, e-mail and other digital messaging,
multimedia playback, video game play,
computer programming, etc.

7. Laptop Computers
• A laptop computer or simply laptop (also
notebook computer or notebook) is a small
mobile personal computer, usually weighing
from one to three kilograms, depending on size,
materials and other factors.
• Laptops usually run on a single battery or from
an external AC/DC adapter ("power brick") which
can charge the battery while also supplying the
computer itself.

8. Embedded Computers
• An embedded system is a special-purpose system in
which the computer is completely encapsulated by the
device it controls.
• Unlike a general-purpose computer, such as a personal
computer, an embedded system performs pre-defined
tasks, usually with very specific requirements.
• The core of any embedded system is formed by one or
several microprocessors or microcontrollers,
programmed to perform a small number of tasks.

9. Examples of Embedded Systems
• Automated teller machine (ATMs)
• Internal guidance system (aircrafts and missiles)
• Mobile phones
• Engine controllers (for automobiles)
• Household appliances (TV, washing machines,
etc.)
• Personal digital assistants (PDAs)
• Game consoles (Ps2, PsP, GbA, Xbox)

10. History of Computers
• 3000 BC: Abacus was invented
• 1617: Scottish inventor John Napier uses bones to demonstrate
division by subtraction and multiplication by addition.
• 1642: Blaise Pascal builds the first numerical calculating machine in
Paris.
• 1673: Gottfried Leibniz builds a mechanical calculating machine that
multiplies, divides, adds and subtracts.
• 1822: In England Charles Babbage designs a Difference Engine to
calculate logarithms, but the machine is never built.
• 1833: Charles Babbage designs the Analytical Machine that follows
instructions from punched-cards. It is the first general purpose
computer.
• 1842: Lady Ada Byron, Countess of Lovelace and daughter of Lord
Byron, the poet, documents Babbage's work and writes programs
for Babbage.

11. Continued…
• 1884: Herman Hollerith applies for patents for automatic
punch-card tabulating machine.
• 1944: Mark I (IBM ASCC) is completed, based on the
work of Professor Howard H. Aiken at Harvard and IBM.
It is a relay-based computer.
• 1945: John von Neumann paper describes stored-program
concept for EDVAC.
• 1946: ENIAC (Electronic Numerical Integrator and
Computer), with 18,000 vacuum tubes, is dedicated at
the University of Pennsylvania. It was 8 by 100 feet and
weighed 80 tons. It could do 5,000 additions and 360
multiplications per second.

12. Continued...
• 1954: FORTRAN is created by John Backus at IBM.
Harlan Herrick runs the first successful FORTRAN
program
• 1964: BASIC (Beginners All-purpose Symbolic
Instruction Language) is created by Tom Kurtz and John
Kemeny of Dartmouth. First time-sharing BASIC
program runs.
• 1969: PASCAL compiler is written by Nicklaus Wirth and
installed on the CDC 6400.
• 1975: Microsoft is founded after Bill Gates and Paul
Allen adapt and sell BASIC to MITS for the Altair PC. .

13. How Computers Work?
• since the first electronic, general-purpose computers of the 1940s,
most still use the stored program architecture (sometimes called
the von Neumann architecture)
• The architecture describes a computer with four main sections:
– Arithmetic and logic unit (ALU)
– Control circuitry
– Memory
– Input and Output devices (I/O)
• These parts are interconnected by bundles of wires (called "buses"
when the same bundle supports more than one data path) and are
usually driven by a timer or clock (although other events could drive
the control circuitry).

14. Memory
Conceptually, a computer's memory can
be viewed as a list of cells. Each cell has a
numbered "address" and can store a
small, fixed amount of information. This
information can either be an instruction,
telling the computer what to do, or data,
the information which the computer is to
process using the instructions that have
been placed in the memory.

15. Arithmetic Logic Unit (ALU)
The ALU is in many senses the heart of the
computer. It is capable of performing two
classes of basic operations. The first is
arithmetic operations; for instance, adding or
subtracting two numbers together.
The second class of ALU operations involves
comparison operations: given two numbers,
determining if they are equal, or if not equal
which is larger.

16. Input and Output devices
• The I/O systems are the means by which the
computer receives information from the outside
world, and reports its results back to that world.
• Input devices:
– keyboard
– Mouse
• Output devices:
– Monitors
– Printers

17. Control Circuit
The functioning of such a computer is in
principle quite straightforward. Typically, on each
clock cycle, the computer fetches instructions
and data from its memory. The instructions are
executed, the results are stored, and the next
instruction is fetched. This procedure repeats
until a halt instruction is encountered.

18. Memory/Storage
Computer storage, computer memory, and often
casually memory refer to computer components, devices
and recording media that retain data for some interval of
time.
memory usually refers to a form of solid state storage
known as random access memory (RAM) and
sometimes other forms of fast but temporary storage.
storage more commonly refers to optical discs, forms of
magnetic storage like hard disks, and other types of
storage which are slower than primary storage, but of a
more permanent nature.

19. Magnetic and Optical Storage
Magnetic storage uses different patterns of magnetization on a magnetically
coated surface to store information. Magnetic storage is non-volatile.
– Floppy Disk
– Hard Disk
Optical disc storage uses tiny pits etched on the surface of a circular disc to
store information, and reads this information by illuminating the surface with
a laser diode and observing the reflection. Optical disc storage is non-volatile
– CD, CD-ROM, DVD: Read only storage, used for mass distribution of
digital information (music, video, computer programs)
– CD-R, DVD-R, DVD+R: Write once storage
– CD-RW, DVD-RW, DVD+RW, DVD-RAM: Slow write, fast read storage

20. Memory Sizes
bit = 0 or 1
byte = 8 bits (1 character)
kb (kilobyte) = 1024 bytes
Mb (megabyte) = 1 million bytes
Gb (gigabyte) = 1 billion bytes

21. Computer Software
Computer software (or simply software) is the
programs and procedures required to enable a
computer to perform a specific task, as opposed
to the physical components of the system
(hardware). This includes application software
such as a word processor, which enables a user
to perform a task, and system software such as
an operating system, which enables other
software to run properly, by interfacing with
hardware and with other software.

22. Major Classes of Computer Software
• System software helps run the computer hardware and
computer system. It includes operating systems, device drivers,
diagnostic tools, servers, windowing systems, utilities and more.
• Programming software usually provides tools to assist a
programmer in writing computer programs and software using
different programming languages in a more convenient way. The
tools include text editors, compilers, interpreters, linkers,
debuggers, and so on.
• Application software allows humans to accomplish one or more
specific (non-computer related) tasks. Typical applications
include industrial automation, business software, educational
software, medical software, databases and computer games.

23. System Software
An operating system (OS) is a software
program that manages the hardware and
software resources of a computer. The OS
performs basic tasks, such as controlling and
allocating memory, prioritizing the processing of
instructions, controlling input and output devices,
facilitating networking, and managing files.

24. Application Software
Application software is a loosely defined
subclass of computer software that employs the
capabilities of a computer directly to a task that
the user wishes to perform. This should be
contrasted with system software which is
involved in integrating a computer's various
capabilities, but typically does not directly apply
them in the performance of tasks that benefit the
user.

25. Application Software Classifications
• Computer-mediated communication
– E-mail
– Web browser
• Multimedia
– Media players
– 3D graphics
– Art software
– Video editing software
– Computer-aided design (CAD)
• Entertainment software
– Arcade
– Computer and Video Games
– Handheld Game Consoles Games
– Video Game Console Games
– Wireless or Mobile Phone Games

26. Application Software Classifications
• Computer-mediated communication
– E-mail
– Web browser
• Multimedia
– Media players
– 3D graphics
– Art software
– Video editing software
– Computer-aided design (CAD)
• Entertainment software
– Arcade
– Computer and Video Games
– Handheld Game Consoles Games
– Video Game Console Games
– Wireless or Mobile Phone Games

27. Computer Hardware
Computer hardware is the physical part of a
computer, including the digital circuitry, as
distinguished from the computer software that
executes within the hardware.

28. Familiarization with Computer
Hardware
1. Display
2. Motherboard
3. CPU
4. Primary Storage (RAM)
5. Expansion Cards
6. Power Supply
7. Optical Disc Drives
8. Secondary Storage (HD)
9. Keyboard
10. mouse

29. Personal Computer Hardware
A typical personal computer consists of a case or chassis in desktop
or tower shape and the following parts:
• Motherboard or system board with slots for expansion cards and
holding parts including:
– Central processing unit (CPU)
– Random Access Memory (RAM) - for program execution and short term data
storage, so the computer doesn't have to take the time to access the hard drive
to find something. More RAM can contribute to a faster PC. RAM is normally
removable by being in slots on the motherboard.
– Basic Input-Output System (BIOS)
– Buses :
• PCI bus
• PCI-E or AGP bus
• ISA bus (outdated)
• EISA bus (outdated)
• USB

30. Continue…
• Power supply - a case that holds a transformer, voltage
control and fan
• Storage controllers of IDE, SATA, SCSI or other type,
that control hard disk, floppy disk, CD-ROM and other
drives; the controllers sit directly on the motherboard
(on-board) or on expansion cards
• Video display controller that produces the output for
the computer display
• Computer bus controllers (parallel, serial, USB,
FireWire) to connect the computer to external peripheral
devices such as printers or scanners

31. Continue…
• Some type of a removable media writer:
– CD - the most common type of removable media,
cheap but fragile.
• CD-ROM Drive
• CD Writer
– DVD
• DVD-ROM Drive
• DVD Writer
– Floppy disk
– USB Flash Drive

32. Continue…
• Internal storage - keeps data inside the computer for
later use.
• Hard disk - for medium-term storage of data.
• Disk array controller
• Sound card - translates signals from the system board
into analog voltage levels, and has terminals to plug in
speakers.
• Modem - for dial-up connections
• Network card - for DSL/Cable internet, and/or
connecting to other computers.
• Other peripherals

33. Continue…
• Input or Input Devices
– Text input devices
• Keyboard
– Pointing devices
• Mouse
• Trackball
– Gaming devices
• Joystick
• Gamepad
• Game controller
– Image, Video input devices
• Image scanner
• Webcam
– Audio input devices
• Microphone

34. Continue…
• Output or Output devices
– Image, Video output devices
• Printer
• Monitor
– Audio output devices
• Speakers
• Headset