Fundamentals of computerPrepared by: Mr. Jitendra L. Patel : Fundamentals of computerPrepared by: Mr. Jitendra L. Patel Introduction : Introduction A computer is a device capable of accepting information or data, processing the info. and providing the results as output.
Data input------ Data processing Operation-------information output Characteristics : Characteristics Speed : high speed,
Units of speed: / milli sec, / micro sec, /nano sec
Storage: good storage capacity
Basic storage unit :bit (acronym of binary digit)
Bit: smallest unit of storage
KB: 1024 bytes
MB: 1024 KB
GB: 1024 MB Slide 4: Accuracy : high accuracy
Errors in computing are due to machine failure, imprecise programming logic, inaccurate data.
Versatility: can perform any task.
Can perform numeric and non-numeric tasks equally.
Algorithm : it is a step by step procedure, which applied to the problem, lead to solution.
Automation : once the process begins it would continue until completion Limitation of comp. : Limitation of comp. High speed and accuracy is a limitation when errors occur
Comp can understand only instruction and can not distinguish between suspicious and genuine information.
Can not posses intelligence hence can not take place a simple action unless instructed to do so.
Can not posses morals hence easily misused. Components of comp. : Components of comp. Input devices
2. arithmetic and logical unit
3. control unit
Output devices How the CPU Works : Copyright 2007 John Wiley & Sons, Inc. Technology Guide 1 7 How the CPU Works History : History Early methods of calculation
Abacus : it consists of rows of wires held in wooden frame, which have balls or beads strung on them.
Calculations are done by sliding the beads along the wires Slide 9: Type
Has 10 beads on each wire
Beads on the 1st wire present single unit,
Beads on 2nd wire presents 10s, third wire 100s and so on.
Calculations are done by sliding the beads along the wires.
2. Chinese abacus
A beam is divided in to 2 region known as heaven and earth.
Two beads (heaven) on one side and five on other (earth). Slide 10: Heaven beads (upper) have a value of five and earth bead (lower) value of one.
3. Japanese abacus
One bead in heaven and 4 beads in the earth.
Heaven beads (upper) have a value of five and earth bead (lower) value of one.
This abacus is called SORBON.
Pascals mechanical calculating machine: in 1642, Blaire Pascal, a French mathematician, invented a machine for addition and subtraction only.
In 1671, Goff pride ven Leibnitz, a german mathematician, invented a machine that could perform multiplication and divisions. Slide 11: In 1821, Charles Babbage, father of comp designed a difference engine to calculate and print tables.
In 1833-34 Babbage again designed his analytical engine which was a programmed mechanical comp.
In 1843, Lady Augusta ada, the world 1st programmer suggested the use of binary data in comp.
In 1887-1890 Herman Hollerith developed a punch card reading machine.
He used punch card as a input and output devices. Analytical engine by Babbage : Analytical engine by Babbage It consists of
1. The store: a mechanical memory unit consisting of sets of center wheels.
2. The mill: an arithmetic unit ,
Perform 4 basic arithmetic operations
A. operation cards: selects arithmetic operation
B. variable cards: selects the memory location to be used.
4.Output: could be directed to a printer. Slide 13: Howard Aiken developed a 1st electro mechanical comp MARKET.
1st general purpose ele. Comp.
Used 18000 vacuumed tubes
Weight: 30 tons
Space occupied: 5000 sq. feet
Speed: 300 multiplication/ sec
EDSAC : in 1949, the first ele. Delay storage automatic calculator (EDSAC) was made.
EDVAC; ele. Discreet Variable Automatic comp.
1st commercial data processing machine used to store data and program instructions. Slide 14: UNIVAC: Universal automatic comp. was developed by Eckert and Mauchly in 1951.
Used for business application.
1st generation comp:
Produced between 1940-1955
Characterized by Vaccume tubes
Placed in large air conditioned rooms
Small internal storage
Very low speed
Punch cards as a input devices
Magnetic tapes and magnetic drums as a secondary memory. Slide 15: 2nd generation comp.:
Produced after 1955-1964
More reliable than 1st generation
Transistor instead of vacuum tubes
Comp language such as FORTRAN and ALGOL were introduced.
E.g.. IBM 7090, CDC 1604, Philco 2000, IBM 1620, IBM 1401 and IBM 7094.
3rd generation comp:
Produced after 1964
I.C in hardware
High speed and storage capacity
More than one user can work with the comp at same time. Slide 16: Low cost
Reduction in power and cooling requirements
E.g.. The IBM system 360 family model 30, 40, 50, 65, 75.
4th generation comp.
Produced after 1970
They used large scale integrated circuits and very large scale I.C.
Had greater input and output capacity and system reliability.
Include microprocessors Slide 17: Microprocessors : it is a single chip which by itself can perform the control, arithmetic and logical function of the comp.
Intel 4004 1st microprocessors
Intel 8080 1st general purpose microprocessors.
5th generation comp:
They will incorporate artificial intelligence.
They will use stored reservoirs of knowledge to make expert judgment and decision.
They will process non-numerical information such as picture and graphs. Classification of comp. : Classification of comp. 3 type
1. Analog comp.: The comp which can process analog quantities , is called analog comp.
Used to solve differential equations.
2. Digital comp.: The comp which can process Digital quantities , is called Digital comp.
3. Hybrid comp.: it is a combination of digital and analog cop.
Used in medical field. Classification based on size : Classification based on size Type
1. Mainframe comp.
2. Mini comp.
3. Micro comp.
4. Super comp.
They are 32 bit machines
Just below super comp.
Van support more simultaneous programs
Suited for org. to manage high volume application.
E.g.. MEDHA, SPERY,DEC, IBM, HP, ICL. Slide 20: Features
Sensitive to temp, humidity and dust.
Trained operator requited
Wide range of peripherals attached.
Wide storage capacity.
Have wide variety of software.
Not user friendly
Used for mathematical problems.
Installed in large govt. organization. Mini comp. : Mini comp. Originated in1960.
They are 8, 12 and 16 bit machines
Super mini comp: 32 bit machines
Used in medium and large companies for accounting, design and manufacturing.
Have a less memory and storage capacity.
Limited range of peripherals
Can use limited range of software
End users can directly use it. Slide 22: Not very sensitive to external environment
Used for data processing
Its CPU has a microprocessors
1. personal comp.
2. work station.
1st P.C. produced by IBM was called IBMPC Slide 23: P.C comes in various sizes
Desktop models: designed to comfortably fit on top of the desk.
Also referred as a slim line models.
Portable models: they are small and light weight.
Small enough to carry
E.g.. Notebook and hand held comp, palmtops
Laptops : small enough to sit on lap
Extremely light weight comp
E.g. notebook comp comes with batteries
Nickel cadmiums and Nickel metal hybrid and Lithium gun. Slide 24: Pocket or hand held comp.:
Small enough to put in pocket
1. ele. Organizers: They are specialized pocket comp that mainly store appointments, addresses and to-do lists.
2. Palmtop: small enough to fits in palm.
Palmtop with a pen as a input devices are called as hand held comp or PDAs.
3. PDA: Personal digital Assistant.
PDA can function as cellular phone, fare sender and personal organizer Work station : Work station Workstations are comp which are used for engineering application, desktop publishing, software development and other type of application that require a moderate amount of computing power and relatively high quality graphics capabilities.
O.S. for workstation are UNIX, LINUX and Windows 2000
Feature of micro comp: known as P.C, cheap and user friendly, this type of comp uses wide range of software Super comp : Super comp Fastest type of comp is called super comp
Used for sp application
E.g. for weather forecasting, space technology, animated graphics, Nuclear energy, Nano technology research, biomedical application
They are designed in two ways
1. Vector processor
2. Parallel processors Slide 27: Features of super comp.
They are huge comp installed in space centers, Nuclear power station etc
Perform complete mathematical calculation
Only scientist and mathematician can operate
Have a huge memories and high speed
Used for weather forecasting, image processing, animation graphics etc. Computer system : Computer system System : A system is group of integrated parts that have common purpose of achieving some objectives.
Characteristic of system
Logically related elements
System goal should be achieved Computer system : Computer system Consist of
Hardware : it is a term used to represent the physical components of the computer. Which can be seen and touched.
E.g.. Input device, CPU
Output device, memory devices, communication devices. Software : Software It is defined as sets of instruction stored as programs that govern the operation of a comp. sys. And make the hardware run.
Software or a comp programs are the step by step instructions that tell the comp what to do.
1. system software
2. application software Continue…………………… : Continue…………………… system software : it contributes to the control and manage its internal resources and give optimum performance from the system
1. operating system and control programs
2. Utilities and service programs
application software: it is defined as software that can be used to perform a general purpose or sp work. Application software : Application software Type
1. Database software: it is used to create database for a sp purpose
E.g.. DTP software used to create a doc for electronic publishing.
2. Customized software: it is designed for a particular customer and for particular use Hardware : Hardware Input devices:
Used to input data and instructions
It converts input data and instruction in to a suitable binary form accepted by comp
Used to enter data and programs
When key is pressed ele. Signal is produced and it is detected by a keyboard encoder which may be I.C or a single chip-micro comp used as a encoder. Encoder send a binary code to the comp. binary code may be ASCII, EBCDIC, HEX code. Keyboard : Keyboard Various keys
1. std typewriter keys: QWERTY
Spacebar, Shift, Tab, Caps lock
2. Cursor-movement keys
3. Numeric keys
F1- F12 Input devices : Input devices Light pen: it is a pointing devices used to select a displayed menu option.
It is photosensitive pen like device.
When its tip is moved over the screen surface, its photocell sensing element detects the light coming from and correspondence signals are sent to the user.
Mouse : it is a device used to control movement of the cursor or pointer.
Contains buttons and scroll wheel Slide 36: Type
1. mechanical: has a rubber or metal ball on its underside that can roll in all direction
Mechanical sensor detect direction
Ball is rolling and move the pointer accordingly.
2. opt mechanical: same as mechanical but uses optical sensors to detect the motion of the ball.
Use laser to detect the mouse movement
No mechanical parts
Respond more quickly and precisely. Slide 37: Joy stick:
A pointing device
Similar to mouse
The pointer continues moving in the direction the joystick is pointing
Used for game and CAD/CAM system
It translates images of text, drawings, photos in to digital form
Enter direct information in to p.c
Provide faster and accurate data entry. Slide 38: Type
1. optical scanner
2. magnetic ink character detector
Optical character Reader(OCR):
Detects alphanumeric character printed or typewritten on paper.
Light is absorbed by dark area and reflected by light areas.
Reflected light is received by photocells which provides binary data corresponding to dark and light areas
Can scan several thousands characters per sec Slide 39: Optical Mark readers (OMR):
it is used to detect sp marks such as square and bubbles prepared on examination answer sheets.
An OMR detects marks and send signals to the processor.
The amt of reflected light is used to detect the presence of the mark.
Optical bar code readers:
This method uses a number of bars (lines) of varying thickness and spacing between them.
It is used in most of manufactured retail product. Slide 40: The most commonly used bar code is Universal Product code.
These bars are detected as a ten digits.
The first five digits identify supplier or manufacturer.
The second five digits identify the product.
Magnetic ink character reader:
It is used in banks to read large volumes of cheques and deposit forms.
A magnetic ink is used to write.
The MICR reads the magnetic pattern and compare it with std.
An MICR processes up to 2,600 cheques per minute. Slide 41: CCD camera:
it is used ton provide vision to comp.
It is input device that collects sp kinds of data directly from the environments and transmits it to a comp. Out put device : Out put device Display Screen :
It is called as a monitor.
1. Monochrome: it display two colors, one for background and one for foreground. The color can be a black and white , Green and Black, or Amber and Black.
2. Gray Scale: it is monochrome monitor that can display diff. shades of Gray.
3. Color: they can display anywhere from 16 to over 1 million diff colors. They are called as RGB monitors as they display 3 diff signals – red, green, blue Video display Unit (VDU) : Video display Unit (VDU) Video display units are also called as monitors or CRT.
1. Cathode Ray tubes: it is a vacuum tube used as a display screen. Images are displayed on the screen or “Picture elements” by a individual dots is called as a pixel. The inside of the front of the CRT Screen is coated with phosphor.
2. Flat panel Displays: flat panel display is much thinner, less weight and consume less power and thus used as a portable comp. 3 type (a) liquid crystal display (b) electroluminescent display and gas plasma display. Printer : Printer Printer, Plotter and multifunctional devices produce printed text or images on paper.
1. Impact printer
A) character printer
a) Dot matrix impact type character printer
b) Letter quality impact character printer (Daisy wheel printers)
2. Non printer
a) Thermal Character printers
b) Ink-jet character printer
c) Line printer Slide 45: i) Drum printer
ii) Chain printer
iii) Band printer
d) Laser printer
Impact printer : an elecro-mechanical that causes hammers or pins to strike against a ribbon and paper to print the text.
Non impact printers do not use any electro-mechanical printing head to strike against ribbon and paper. They use thermal, chemical, electrostatic, laser beam or inkjet technology for printing text. It is faster than impact type. Slide 46: Character printer:
it prints one character at a time.
Low Speed 60-600 character/ sec.
A)Dot matrix impact type character printer:
A character is printed by printing selected number of dots from a matrix of dots.
Faster than a letter quality printer.
Speed 80- 600 CPS
We can change speed
Low speed good quality
B) letter quality printer (Daisy wheel printers)
it is used for good quality printing Slide 47: Slow compare to dot matrix printer
Can not print graphics
2. non impact character printers
A) Thermal character printer
it uses a heat sensitive paper
A character is printed with a matrix of dot
Speed 200 cps
Highest quality color printing obtained
Expensive paper required Slide 48: Ink jet character printer:
Uses a dot matrix approach to print text
Uses a one or more nozzles in print head to emit a steady stream of tiny ink drops.
Speed 40 – 300 Cps
Average life is about 10 million characters.
Most colour printing is done on ink jet printer.
Prints one line of a text at a time
Speed 300-3000 lines per minute Slide 49: Drum printer:
It uses a rapidly rotating drum having a complete set of raised character in each band around the drum.
Speed 200- 2000 lines per minute
Noise level is high
It uses a rapidly rotating chain
A chain may contain more than one character set
Speed 400-2400 lines per minute Slide 50: Band printer:
It is like a chain printer.
It contains fast rotating steel print bands in place of chains
The band contains a character set
Speed up to 3000 lines per minute
It utilize a laser beam to produce an image on drum
Called as a page printer as they print entire page. Memory Capacity : Copyright 2007 John Wiley & Sons, Inc. Technology Guide 1 51 Memory Capacity Bit: Short for binary digit (0s and 1s), the only data that a CPU can process.
Byte: An 8-bit string of data, needed to represent any one alphanumeric character or simple mathematical operation. Hierarchy of Memory Capacity : Copyright 2007 John Wiley & Sons, Inc. Technology Guide 1 52 Hierarchy of Memory Capacity Kilobyte (KB): approximately one thousand bytes.
Megabyte (MB): approximately one million bytes (1,048,576 bytes, or 1,024 x 1,024).
Gigabyte (GB): actually 1,073,741,824 bytes (1,024 x 1,024 x 1,024 bytes).
Terabyte: One trillion bytes.
Petabyte: Approximately 1015 bytes.
Exabyte: Approximately 1018 bytes. Primary storage : Primary storage It is main memory working storage or temporary storage
It is volatile. 3 type
1. RAM ( Random Access Memory)
Two type of RAM
A) Dynamic RAM (DRAM): the term dynamic indicates that the memory must be continuously refreshed else it will lose its contents.
B) Static RAM (SRAM) : it is faster and less volatile but it requires more power and more expensive. Slide 54: 2.ROM ( Read only Memory)
Once data has been written on ROM chip , it can not be removed or edited.
It retains its memory ever
It is non volatile
It stores critical programs that boots the computer.
A) PROM: Programmable read only memory.
It is a memory chip on which data can be written once.
ROM is programmed during mfg process, whereas PROM is manufactured as a blank memory. Slide 55: B) EPROM : Erasable programmable read only memory. Ultraviolet light clears its contents
A special device called EPROM burner is required.
C) EEPROM : Eclectically Erasable programmable read only memory. Erased by exposing to electrical charges
3) Cache Memory: A type of primary storage where the computer can temporarily store blocks of data used more often.
Its sp high speed storage mechanism
It can be either a reserve section of main memory or independent high speed storage device
Two type of caching 1) memory caching. 2) disk caching. Storage : CE06_PP08-56 Storage Primary storage
Temporary Secondary storage
Secondary storage characteristics
Access speed RAM Page 212 Secondary Storage Devices : CENG 351 57 Secondary Storage Devices Two major types of secondary storage devices:
Direct Access Storage Devices (DASDs)
Magnetic Discs Hard disks (high capacity, low cost, fast) Floppy disks (low capacity, lower cost, slow)
Optical Disks CD-ROM = (Compact disc, read-only memory
Magnetic tapes (very fast sequential access) Secondary Storage Devices : CE06_PP08-58 Secondary Storage Devices Most desktop microcomputer systems have floppy disks, hard disks, and optical disk drives Page 212 Traditional Floppy Disk : CE06_PP08-59 Traditional Floppy Disk Also known as:
Portable storage media
Floppy disk drives (FDD) Page 212 Insert Art Work top of page 213 High Capacity Floppy Disks : CE06_PP08-60 High Capacity Floppy Disks Known as a floppy-disk cartridge
Require special disk drives
Three well known types
SuperDisks Page 214 Hard Disks : CE06_PP08-61 Hard Disks Use thicker, metallic platters for storage
Faster than a floppy diskette
There are three types of hard disks:
Hard-disk pack Page 215 Internal Hard Disk : CE06_PP08-62 Internal Hard Disk Located inside system unit
Known as a fixed disk
Designated as the C drive
Advantages over floppies
Capacity Page 215 Hard-Disk Cartridges : CE06_PP08-63 Hard-Disk Cartridges Removable hard disks
Used to complement internal hard disk
Capacities of 10 to 20 GB Page 216 Hard-disk cartridge Hard-Disk Packs : CE06_PP08-64 Hard-Disk Packs Removable hard disk
Massive storage capacity
Common in mainframes
Resembles stack of vinyl records Page 216 Hard Disk Performance Enhancements : CE06_PP08-65 Hard Disk Performance Enhancements Disk caching
Redundant arrays of inexpensive disks (RAID)
File compression and decompression Page 217 RAID storage device Optical Disks : CE06_PP08-66 Optical Disks Compact
Laser beams reflect off pits
Two common types
DVD Page 219 Compact Disc : CE06_PP08-67 Compact Disc Optical format
From 650 MB to 1 GB capacity
Rotation speeds vary
Read only: CD-ROM
Write once: CD-R
Picture CDs and Photo CDs Page 219 Digital Versatile Disc : CE06_PP08-68 Digital Versatile Disc Digital Versatile Disk or Digital Video Disk (DVD)
Similar to CDs, but can store more data
Read only: DVD-ROM
Write once: DVD+R; DVD-R
Rewritable: DVD+RW; DVD-RW; DVD-RAM Page 220 Other Types of Secondary Storage : CE06_PP08-69 Other Types of Secondary Storage Solid-state storage
Internet hard drives
Magnetic tape Page 221 Solid-State Storage : CE06_PP08-70 Solid-State Storage Flash memory cards
Widely used in notebook computers
Used to record MP3 music files
Key chain hard drives
Key chain flash memory devices
Connects to a USB port Page 221 Return Internet Hard Drives : CE06_PP08-71 Internet Hard Drives Known as i-drive or online storage Page 224 Return Magnetic Tape : CE06_PP08-72 Magnetic Tape External storage
Provides sequential access
Information stored in sequence
Slower than disks which provide direct access
Magnetic tape streamers or tape cartridges used by both mainframes and microcomputers Page 225 Return Computer Viruses : Computer Viruses Introduction : Introduction Computer virus have become today’s headline news
With the increasing use of the Internet, it has become easier for virus to spread
Virus show us loopholes in software
Most virus are targeted at the MS Windows OS Definition : Definition Virus : A true virus is capable of self replication on a machine. It may spread between files or disks, but the defining character is that it can recreate itself on it’s own with out traveling to a new host.
A computer virus is a computer program that can copy itself and infect a comp. without a permission or the knowledge of the owner. The term "virus" is also commonly but erroneously used to refer to other types of malware, adware, and spyware programs that do not have the reproductive ability. Slide 76: A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive.
Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer Overview : Overview Background
Conclusion Background : Background There are estimated 30,000 computer viruses in existence
Over 300 new ones are created each month
First virus was created to show loopholes in software Virus Languages : Virus Languages ANSI COBOL
Unix Shell Scripts
Basically any language that works on the system that is the target Symptoms of Virus Attack : Symptoms of Virus Attack Computer runs slower then usual
Computer no longer boots up
Screen sometimes flicker
PC speaker beeps periodically
System crashes for no reason
Files/directories sometimes disappear
Denial of Service (DoS) Virus through the Internet : Virus through the Internet Today almost 87% of all viruses are spread through the internet (source: ZDNet)
Transmission time to a new host is relatively low, on the order of hours to days
“Latent virus” Classifying Virus - General : Classifying Virus - General Virus Information
Category: Classifying Virus - Categories : Classifying Virus - Categories Stealth
Armored Classifying Virus - Types : Classifying Virus - Types Trojan Horse
Macro Trojan Horse : Trojan Horse Covert
Usually does not reproduce Trojan Horse : Trojan Horse Back Orifice
Discovery Date: 10/15/1998
Origin: Pro-hacker Website
SubType: Remote Access
Risk Assessment: Low
Category: Stealth Trojan Horse : Trojan Horse About Back Orifice
requires Windows to work
distributed by “Cult of the Dead Cow”
similar to PC Anywhere, Carbon Copy software
allows remote access and control of other computers
install a reference in the registry
once infected, runs in the background
by default uses UDP port 54320
TCP port 54321
In Australia 72% of 92 ISP surveyed were infected with Back Orifice Trojan Horse : Trojan Horse Features of Back Orifice
pings and query servers
reboot or lock up the system
list cached and screen saver password
display system information
receive and send files
display a message box Worms : Worms Spread over network connection
First worm released on the Internet was called Morris worm, it was released on Nov 2, 1988. Worms : Worms Bubbleboy
Discovery Date: 11/8/1999
Origin: Argentina (?)
Risk Assessment: Low
Category: Stealth/Companion Worms : Worms Bubbleboy
requires WSL (windows scripting language), Outlook or Outlook Express, and IE5
Does not work in Windows NT
Effects Spanish and English version of Windows
2 variants have been identified
Is a “latent virus” on a Unix or Linux system
May cause DoS Worms : Worms How Bubbleboy works
Bubbleboy is embedded within an email message of HTML format.
a VbScript while the user views a HTML page
a file named “Update.hta” is placed in the start up directory
upon reboot Bubbleboy executes Worms : Worms How Bubbleboy works
changes the registered owner/organization
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RegisteredOwner = “Bubble Boy”
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RegisteredOrganization = “Vandalay Industry”
using the Outlook MAPI address book it sends itself to each entry
marks itself in the registry
HKEY_LOCAL_MACHINE\Software\Outlook.bubbleboy = “OUTLOOK.Bubbleboy1.0 by Zulu” Macro : Macro Specific to certain applications
Comprise a high percentage of the viruses
Usually made in WordBasic and Visual Basic for Applications (VBA)
Microsoft shipped “Concept”, the first macro virus, on a CD ROM called "Windows 95 Software Compatibility Test" in 1995 Macro : Macro Melissa
Discovery Date: 3/26/1999
Origin: Newsgroup Posting
Length: varies depending on variant
Risk Assessment: High
Category: Companion Macro : Macro Melissa
requires WSL, Outlook or Outlook Express Word 97 SR1 or Office 2000
105 lines of code (original variant)
received either as an infected template or email attachment
lowers computer defenses to future macro virus attacks
may cause DoS
infects template files with it’s own macro code
80% of of the 150 Fortune 1000 companies were affected Macro : Macro How Melissa works
the virus is activated through a MS word document
document displays reference to pornographic websites while macro runs
1st lowers the macro protection security setting for future attacks
checks to see is it has run in current session before
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Melissa = “by Kwyjibo”
propagates itself using the Outlook MAPI address book (emails sent to the first 50 addresses) Macro : Macro How Melissa works
infects the Normal.dot template file with it’s own code
Lastly if the minutes of the hour match up to the date the macro inserts a quote by Bart Simpson into the current document
“Twenty two points, plus triple word score, plus fifty points for using all my letters. Game’s over. I’m outta here.” Protection/Prevention : Protection/Prevention Knowledge
Run only necessary programs
Anti-virus software Conclusion : Conclusion You know know more about virus and how:
viruses work through your system
to make a better virus
Have seen how viruses show us a loophole in popular software
Most viruses show that they can cause great damage due to loopholes in programming Slide 101: Thank You