Fundamentals of computer

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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 Byte:8 bits 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 CPU 1. memory 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 Finger 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 1.Russian abacus 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).

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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.

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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 3. Cards A. operation cards: selects arithmetic operation B. variable cards: selects the memory location to be used. 4.Output: could be directed to a printer.

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Howard Aiken developed a 1st electro mechanical comp MARKET. ENIAC: 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.

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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.

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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 Less size More than one user can work with the comp at same time.

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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

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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. Mainframe 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. characteristic: Have a less memory and storage capacity. Limited range of peripherals Can use limited range of software End users can directly use it.

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Not very sensitive to external environment Used for data processing Micro comp.: Its CPU has a microprocessors Type 1. personal comp. 2. work station. Personal comp: 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 3 type 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 Very expensive 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 >1 element Logically related elements System goal should be achieved

Computer system : 

Computer system Consist of 1.Hardware 2. Software 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. Type 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 Type 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 keyboard 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 Arrows 3. Numeric keys 0-9 Function key: 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. 3 optical: 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 Scanner: 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. Sensors: 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. Classes 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. Two type 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. Two type 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

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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 Costlier 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 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. Line 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 Chain printer: 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 Laser printer: 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. Types 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.

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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 Volatile Temporary Secondary storage Nonvolatile Permanent Secondary storage characteristics Media Capacity Storage devices 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 Serial Devices 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: Diskettes Floppies 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 Zip disks HiFD disks SuperDisks Page 214

Hard Disks : 

CE06_PP08-61 Hard Disks Use thicker, metallic platters for storage Faster than a floppy diskette Large capacity Sensitive instruments There are three types of hard disks: Internal Hard-disk cartridge 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 Access speed 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 Permanent storage Laser beams reflect off pits Two common types CD DVD Page 219

Compact Disc : 

CE06_PP08-67 Compact Disc Optical format From 650 MB to 1 GB capacity Rotation speeds vary Types Read only: CD-ROM Write once: CD-R Rewriteable: CD-RW 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 Types 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 Symptoms Classifying Viruses Examples Protection/Prevention 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 C/C++ Pascal VBA Unix Shell Scripts JavaScript 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 Discovery Date: Origin: Length: Type: SubType: Risk Assessment: Category:

Classifying Virus - Categories : 

Classifying Virus - Categories Stealth Polymorphic Companion Armored

Classifying Virus - Types : 

Classifying Virus - Types Trojan Horse Worm Macro

Trojan Horse : 

Trojan Horse Covert Leaks information Usually does not reproduce

Trojan Horse : 

Trojan Horse Back Orifice Discovery Date: 10/15/1998 Origin: Pro-hacker Website Length: 124,928 Type: Trojan 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 logs keystrokes edit registry server control receive and send files display a message box

Worms : 

Worms Spread over network connection Worms replicate 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 (?) Length: 4992 Type: Worm/Macro SubType: VbScript 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 Type: Macro/Worm Subtype: Macro 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 Proper configurations 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

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