Bahasa Inggris

Meeting-1

What is a Computer
The first use of the word "computer" was
recorded in 1613, referring to a person who
carried out calculations, or computations,
and the word continued with the same
meaning until the middle of the 20th
century.
What is the Computer
A computer is a general purpose
device that can be programmed to
carry out a finite set of arithmetic or
logical operations. Since a sequence
of operations can be readily changed,
the computer can solve more than
one kind of problem.
What is the Computer
Also we can say …..
An electronic device that stores, retrieves, and
processes data, and can be programmed with
instructions. A computer is composed of
hardware and software, and can exist in a
variety of sizes and configurations.
Types of Computers
Mini and Mainframe Computers
Very powerful, used by large organisations
such an banks to control the entire business
operation. Very expensive!
Personal Computers
Cheap and easy to use. Often used as
stand-alone computers or in a network.
May be connected to large mainframe
computers within big companies.

Meeting-2

Inside a Computer
A general purpose computer has four main
components: the Arithmetic Logic Unit (ALU), the
Control Unit, the Memory, and the Input and Output
devices (collectively termed I/O). These parts are
interconnected by busses, often made of groups of
wires.
Meeting-2
Arithmetic Logic Unit (ALU)
The ALU is capable of performing two classes of operations:
arithmetic and logic
Control unit
The control unit (often called a control system or
central controller) manages the computer's
various components; it reads and interprets
(decodes) the program instructions, transforming
them into a series of control signals which
activate other parts of the computer
Memory
A computer's memory can be viewed as a list of cells into which
numbers can be placed or read. Computer main memory comes
in two principal varieties: random-access memory or RAM and
read-only memory or ROM. RAM can be read and written to
anytime the CPU commands it, but ROM is pre-loaded with data
and software that never changes, therefore the CPU can only
read from it.
Memory
Input/Outpu
I/O is the means by which a computer exchanges
information with the outside world. Devices that
provide input or output to the computer are called
peripherals.  On  a  typical  personal  computer,
peripherals include input devices like the keyboard and
mouse, and output devices such as the display and
printer. Hard disk drives, floppy disk drives and optical
disc drives serve as both input and output devices.
Hardware Components
Input Devices
Input Device is any peripheral (piece of computer hardware
equipment) used to provide data and control signals to an
information processing system such as a computer or other
information appliance. Examples of input devices include
keyboards, mice, scanners, digital cameras and joysticks.
Output Devices
An output device is any piece of computer hardware
equipment used to communicate the results of data
processing carried out by an information processing system
(such as a computer) which converts the electronically
generated information into human-readable form.
Input Devices :
The Mouse
A mouse is a pointing device that functions by
detecting two-dimensional motion relative to its
supporting surface. Physically, a mouse consists of an
object held under one of the user's hands, with one
or more buttons.
The Keyboard
The keyboard is still the commonest way of entering
information into a computer
Tracker Balls
an alternative to the traditional mouse and often
used by graphic designers
Input Devices :
Scanners
A scanner allows you to scan printed material
and convert it into a file format that may be
used within the PC
Touch Pads
A device that lays on the desktop and responds to pressure
Light Pens
Used to allow users to point to areas on a screen
Joysticks
Many games require a joystick for playing of the game
Output Devices :
Monitor/LCD
The computer screen is used for outputting information in an
understandable format
Printers
There are many different types of printers. In large
organizations laser printers are most commonly used due to
the fact that they can print very fast and give a very high
quality output.
Output Devices
Plotters
A plotter is an output device similar to a printer, but
normally allows you to print larger images.
Speakers
Enhances the value of educational and presentation
products.
Speech synthesisers
Gives you the ability to not only to display text on a
monitor but also to read the text to you
Storage Device
Storage Devices -- "How it saves data and
programs“
Hard disk drives are an internal, higher capacity drive
which also stores the operating system which runs
when you power on the computer.
Flash disk drives allow you to save work on small disks
and take the data with you.
Hard Disks
Speed:
Very fast!
The speed of a hard disk is often quoted as "average
access time" speed, measured in milliseconds. The
smaller this number the faster the disk.
Capacity:
Enormous! Often 1000/5000 Gigabytes. A Gigabyte is
equivalent to 1024 Megabytes.
Cost:
Hard disks costs are falling rapidly and normally represent
the cheapest way of storing data.
Storage Device
Main Parts of Computer
Memory -- "How the processor stores and uses
immediate data“
RAM - Random Access Memory
The main 'working' memory used by the computer. When
the operating system loads from disk when you first
switch on the computer, it is copied into RAM.
As a rough rule, a Microsoft Windows based computer
will operate faster if you install more RAM. Data and
programs stored in RAM are volatile (i.e. the information
is lost when you switch off the computer).
How Computer Memory Is Measured
• Bit
All computers work on a binary numbering system, i.e. they
process data in one's or zero's. This 1 or 0 level of storage is
called a bit.
• Byte
A byte consists of eight bits.
• Kilobyte
A kilobyte (KB) consists of 1024 bytes.
• Megabyte
A megabyte (MB) consists of 1024 kilobytes.
• Gigabyte
A gigabyte (GB) consists of 1024 megabytes .
How Computer Memory is Measured
• Microprocessors -- "The brain of the computer“
- PCs primarily use microprocessors (sometimes called the chip).
The older Intel versions include the 386, 486 and now the
Pentium line.
• The CPU (Central Processing Unit) is normally an Intel
Pentium (or equivalent) and it is one of the most important
components within your computer.
• It determines how fast your computer will run and is
measured by its MHz speed.
• Thus a 3200 MHz Pentium is much faster than say a 4200
MHz Pentium CPU.
• It is the CPU that performs all the calculations within the computer.

Meeting-3

Software and Operating System

Software refers to parts of the computer which do not have
a material form, such as programs, data, protocols, etc.
When software is stored in hardware that cannot easily be
modified (such as BIOS ROM in an IBM PC compatible), it is
sometimes called "firmware" to indicate that it falls into an
uncertain area somewhere between hardware and software.
Software and Operating System
Operating Sytems Software
The operating system is a special type of program
that loads automatically when you start your
computer.
The operating system allows you to use the
advanced features of a modern computer without
having to learn all the details of how the hardware
works The link between the hardware and you, the
user Makes the computer easy to use without
having to understand bits and bytes!
Application software
An application program is the type of program that you
use once the operating system has been loaded.
Examples include word-processing programs,
spreadsheets and databases
Example Operating System :
Windows : Windows 95, Windows 98, Windows NT,
Windows 2000, Windows Me, Windows XP, Windows
Vista, Windows 7
Linux : Red Hat, Ubuntu, GNOME, KDE
Mac OS : Mac OS Classic, Mac OS X
Example Application
• Microsoft Office
• Payroll
• Presentation tools
• Microsoft PowerPoint
• Desktop publishing
• Adobe Photoshop
• Multimedia applications
• Microsoft's Encarta CD-ROM based
• Encyclopaedias
Example Application
Information worker software
• Enterprise resource planning
• Accounting software
Data management
• Contact management
• Spreadsheet
• Personal database
Documentation
• Document automation/assembly
• Word processing
• Desktop publishing software
Banking software
Example Application
Software, Programming Language, Networking
A programming language is an artificial language designed to
communicate instructions to a machine, particularly a computer.
Programming languages can be used to create programs that
control the behavior of a machine and/or to express algorithms
precisely.
We can find to many programming language :
• Pascal
• C++
• Visual Basic
• Visual Foxpro
• JAVA
Information Network
• LAN
A LAN (Local Area Network) is a system whereby
individual PCs are connected together within a
company or organization
• WAN
A WAN (Wide Area Network) as the name implies
allows you to connect to other computers over a
wider area (i.e. the whole world).
Use network
If ten people are working together within an office it
makes sense for them all to be connected.
• In this way the office can have a single printer and all
ten people can print to it.
• In a similar way other devices such as modems or
scanners can be shared.
• Even more useful is the ability to share information
when connected to a network.
Computers in Daily Life
• Accounts
• Games
• Educational
• On-line banking
• Smart ID cards
• Supermarkets
• Working from home (Tele-working)
• Internet
Computer Virus
Viruses are small programs that hide themselves on your
disks (both flashdisk and your hard disk).
Unless you use virus
detection software the first
time that you know that you
have a virus is when it activates.
Different viruses are
activated in different ways.
How do viruses infect PCs?
Viruses hide on a disk and when you access the
disk (either a diskette or another hard disk over
a network) the virus program will start and
infect your computer.
The worst thing about a computer virus is that
they can spread from one computer to another,
either via use of infected flashdisk, or over a
computer network, including the Internet.
Software Copyright
• Be aware on software copyright issues
• Freeware
• Shareware
• What about software that you find on the
Internet?
• Software site licenses
Software Copyright
• If your computer system holds
information about individuals then you
have a moral and legal duty to treat
that information with respect.
• In a free society you have a right to
ensure that information held about
you is not abused.
• In many countries this right is
enshrined under data protection laws

Meeting-5

MALICIOUS SOFTWARE

In computer world, there is also a software
which is created to do something bad and
to perform criminal intension. This kind of
software is called malicious software or
malware. Malicious software can bedivided
into some categories:
VIRUS
a.VIRUS
Virus is a software that can replicate by injecting or infecting its
own code into other file. By its way to infect other file, virus can
be divided into three categories:
1. Overwriting
A type of computer virus that will copy its own code
over the host computer system's file data, which
destroys the original program. After your computer
system has been cleaned using an antivirus
program, users will need to install the original
program again.
2. Appending
A virus that inserts a copy of its malicious
code at the end of the file. The goal of an
appending virus is not to harm the host
program, but to modify it to hold the virus
code and then be able to run itself.
3.Prepending
A virus defines the method it uses of infecting
files by adding their code to the beginning of the
file. By doing this, these viruses ensure that they
are activated when an infected file is used.
WORM
b. WORM
Worm is also a kind of malicious software. It is different from
virus which is worm can not inject of infect other files. A worm
is a software which replicates by creating its own copy. And
without infecting other file. Worm actually spreads through a
network or the Internet using email. Below is a sample of worm
called I Love You. Worm I Love You spreads through the
Internet as an email attachment.
Usually worm will do something tricky to cheat email
receiver. The first is using double file extension. At the left
sample, worm I Love You uses two extension, those are
TXT.VBS. The second trick is using social engineering. At
the above sample, the worm uses a name “I LOVE YOU”
which might interested to every email receiver. Who
doesn’t need love? So, the effect of these tricks are any
body –the email receiver- will click that attachment which
is actually a worm code.
TROJAN
c. TROJAN HORSE
Trojan horse is derived from ancient Greek. Trojan Horse is
a program that looks like a good program but actually
contains destructive code or destructive feature. Trojan
horse is different from virus and worm, trojan horse can
not replicate and cannot infect other file.
There are many kind of trojan horse. Below are some of
them:
a. Password stealer e. Remote monitoring
b. Keylogger f. Remote administrator, etc
c. Fake Program
d. Anonymous emailer

Meeting-6

HARDWARE

Hardware is physical equipment of computer
system. Hardware can be divided into two
categories:
Input Device and Output Device.
INPUT DEVICE
Input device is computer device that is used to
input data into computer system.
Input device can be divided into some
categories:
1. Text input devices
Such as keyboard, a device to input text and characters by
depressing buttons (referred to as keys), similar to a
typewriter. The most common English-language key layout is
the QWERTY layout. Below is a picture of a keyboard using
QWERTY layout.
2. Pointing devices
The most common pointing device is mouse. In
computing, a mouse (plural mice or mouse devices) is a
pointing device that functions by detecting two-
dimensional motion relative to its supporting surface.
Physically, a mouse consists of an object held under one
of the user's hands, with one or more buttons, other
elements, such as "wheels", or extra buttons.
Other alternative of pointing device is trackball, a
pointing device consisting of an
exposed protruding ball housed in a socket that
detects rotation about two axes. The trackball
was invented by Tom Cranston and Fred Longstaff
as part of the Royal Canadian Navy‘s DATAR
system in 1952[1], eleven years before the mouse
was invented. Below is a picture of a trackball.
3. Gaming devices
One example of gaming device is a joystick. A
joystick is a general control device that consists of a
handheld stick that pivots around one end, to
detect angles in two or three dimensions.
4. Image, Video input devices
There are two common input devices in this type. First is
Image scanner, a device that provides input by analyzing
images, printed text, handwriting, or an object. Below is a
picture of image scanner.
Second type is a webcam. Webcams are video capturing
devices connected to computers or computer networks, often
using USB or, if they connect to networks, ethernet or Wi-Fi.
They are well-known for their low manufacturing costs and
flexible applications. Below is a picture of a webcam.
5. Audio input devices
One example of audio input device is a microphone.
Microphone sometimes referred to as a mic or mike, is
an acoustic-to-electric transducer or sensor that
converts sound into an electrical signal. Microphones
are used in many applications such as telephones, tape
recorders, hearing aids, motion picture production, live
and recorded audio engineering, in radio and television
broadcasting and in computers for recording voice,
VoIP, and for non-acoustic purposes such as ultrasonic
checking.
Output Device
1. Image, Video Output Devices
First example is a printer. In computing, a printer is a
peripheral which produces a hard copy (permanent
human readable text and/or graphics) of documents
stored in electronic form, usually on physical print media
such as paper or transparencies. Many printers are
primarily used as local peripherals, and are attached by a
printer cable or, in most newer printers, a USB cable to a
computer which serves as a document source.
Output Device
2. Audio Output Devices
Speakers. Computer speakers, or multimedia speakers, are
external speakers,
commonly equipped with a low-power internal amplifier.
Headsets. Headphones are a pair of small loudspeakers, or
less commonly a single speaker, with a way of holding them
close to a user's ears and a means of connecting them to a
signal source such as an audio amplifier, radio or CD player.