1. Computer Systems Intermediate 2 Revision

2. Data Representation Represent positive numbers in binary using examples up to and including eight bits Represent positive numbers in binary using examples up to and including eight bits State the advantages of using binary numbers State the advantages of using binary numbers Describe floating point representation of real numbers using the terms mantissa and exponent Describe floating point representation of real numbers using the terms mantissa and exponent Describe file sizes, backing storage and main memory capacities using the terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb) Describe file sizes, backing storage and main memory capacities using the terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb) Describe the ASCII code including control characters Describe the ASCII code including control characters Describe the term character set Describe the term character set Describe the bit map method of graphic representation using examples of black and white bit maps Describe the bit map method of graphic representation using examples of black and white bit maps Calculate storage requirements for a bitmap graphic Calculate storage requirements for a bitmap graphic

3. Represent positive numbers in binary using examples up to and including eight bits In our normal counting system we use digits 0 to 9 to represent any number In our normal counting system we use digits 0 to 9 to represent any number In the binary counting system we use digits 0 and 1 to represent any number In the binary counting system we use digits 0 and 1 to represent any number We use the following column headings for the denary (base 10) system We use the following column headings for the denary (base 10) system – Thousand Hundreds Tens Units 2 3 6 5 2 3 6 5 = 2 x 1000 + 3 x 100 + 6 x 10 + 5 x 1 = 2000 + 300 + 60 + 5 = 2365 We use the following column headings for the binary (base 2) system We use the following column headings for the binary (base 2) system –128s 64s 32s 16s 8s 4s 2s Units 0 1 1 0 1 1 0 1 0 1 1 0 1 1 0 1 0 x 128 + 1 x 64 + 1 x 32 + 0 x 16 + 1 x 8 + 1 x 4 + 0 x 2 + 1 x 1 0 x 128 + 1 x 64 + 1 x 32 + 0 x 16 + 1 x 8 + 1 x 4 + 0 x 2 + 1 x 1 =64 + 32 + 8 + 4 + 1 =64 + 32 + 8 + 4 + 1 =109 =109 Remember to use all 8 bits to represent the number, i.e. do not forget to put in the leading zeros or you will not have written an 8-bit binary number Remember to use all 8 bits to represent the number, i.e. do not forget to put in the leading zeros or you will not have written an 8-bit binary number

4. State the advantages of using binary numbers Binary is a simple two-state system (1 or 0) which is ideal when representing a two- state system of “power on/power off” Binary is a simple two-state system (1 or 0) which is ideal when representing a two- state system of “power on/power off” A degraded signal can still be detected as representing 1 A degraded signal can still be detected as representing 1 There are only a few rules of addition, making calculations simpler There are only a few rules of addition, making calculations simpler

5. Describe floating point representation of real numbers using the terms mantissa and exponent Very large and very small numbers would take up too much space in memory so a different technique called floating point representation is used to store these numbers Very large and very small numbers would take up too much space in memory so a different technique called floating point representation is used to store these numbers The rule is to place the binary point in front of the digits and to count the number of places that it has been moved The rule is to place the binary point in front of the digits and to count the number of places that it has been moved –This number is then the exponent of 2 –So the binary number 1101.001101110010 is written as; The exponent and mantissa are then stored separately in memory The exponent and mantissa are then stored separately in memory Mantissa.1101001101110010 x 2 00000100 Exponent

6. Describe file sizes, backing storage and main memory capacities using the terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb) All data stored in memory is stored as bit patterns All data stored in memory is stored as bit patterns –Made up from digits 1 or 0 –The storage of these bits are made more manageable by grouping them in multiples of eight. The term byte is widely used when referring to file size The term byte is widely used when referring to file size The following table represents the hierarchy of capacities for file sizes, main memory and backing storage; The following table represents the hierarchy of capacities for file sizes, main memory and backing storage; Unit of Memory Composed of Typical Files 1 bit Can be 1 or 0 1 byte 8 bits 1 character 1 kilobyte (Kb) 2 10 = 1024 byte Half an A4 page 1 megabyte (Mb) 2 20 =1024 kilobytes 500 A4 pages 1 gigabyte (Gb) 2 30 = 1024 Mb 500,000 A4 pages 1 terabyte (Tb) 2 40 = 1024 Gb Enormous!!!

7. Describe the ASCII code including control characters Each character on a keyboard has a unique binary code allocated to it. Each character on a keyboard has a unique binary code allocated to it. The code that is most commonly used to represent text is the bit ASCII code. The code that is most commonly used to represent text is the bit ASCII code. The letters stand for: The letters stand for: –American –Standard –Code for –Information –Interchange Only 7 bits are required to store the code but we usually deal with bits in groups of 8 so and additional zero is added to the start of the code Only 7 bits are required to store the code but we usually deal with bits in groups of 8 so and additional zero is added to the start of the code The table below shows a few ASCII codes and their decimal equivalent The table below shows a few ASCII codes and their decimal equivalent Character ASCII code Decimal ABZa2Beep& 0100 0001 0100001001011010011000010011001000000111001001106566909750738

8. Describe the ASCII code including control characters cont’d Control characters are keys on the keyboard that are not displayed on the screen. Control characters are keys on the keyboard that are not displayed on the screen. They are action keys They are action keys –E.g. RETURN, TAB, DELETE They are used to send a control signal to a printer They are used to send a control signal to a printer Sometimes control characters are referred to as ‘non- printable characters’ Sometimes control characters are referred to as ‘non- printable characters’ They are the first 32 characters in ASCII They are the first 32 characters in ASCII

9. Describe the term character set The complete set of characters that is represented on the keyboard is called the character set The complete set of characters that is represented on the keyboard is called the character set –This includes all the letters of the alphabet (upper and lower case), the digits 0 to 9, punctuation marks, special symbols, such as %, £, & and #, and control characters. –Using 7 bits it is possible to store 2 7 = 2 x 2 x 2 x 2 x 2 x 2 x 2 = 128 different characters in ASCII However the English language requires fewer that 128 characters However the English language requires fewer that 128 characters

10. Describe the bit map method of graphic representation using examples of black and white bit maps Computers store graphical images in memory, on backing storage devices and display them on the monitor as bit maps. Computers store graphical images in memory, on backing storage devices and display them on the monitor as bit maps. A pixel is the most basic component of any computer graphic. A pixel is the most basic component of any computer graphic. –Every computer graphic is made up of a grid of pixels. The computer represents the image in memory as a file of 0s and 1s The computer represents the image in memory as a file of 0s and 1s –White pixels are represented by a 0 and black pixels by a 1 –The file is known as a bit map 0011110001000010 01000010 10100101 01000010 01011010 00100100 00011000 There is a one-to-one relationship between the pixels and the bit pattern

11. Describe the bit map method of graphic representation using examples of black and white bit maps cont’d The quality of a graphical image is directly related to the number of pixels used to produce it. The quality of a graphical image is directly related to the number of pixels used to produce it. A good quality image will have many small pixels, e.g. a photograph A good quality image will have many small pixels, e.g. a photograph A poor quality image will have few large pixels, e.g. teletext A poor quality image will have few large pixels, e.g. teletext The concentration or density of pixels is called the resolution of the image The concentration or density of pixels is called the resolution of the image –This is measured in dots per inch or dpi (dpi is often used in regards to a printer or a scanner)

12. Calculate storage requirements for a bitmap graphic In a black and white image each pixel is represented by 1 bit. In a black and white image each pixel is represented by 1 bit. An image with a high resolution will have many pixels and so will take up more storage space than a low resolution image. An image with a high resolution will have many pixels and so will take up more storage space than a low resolution image. Imagine we want to calculate the storage requirement for an image that has a dpi of 1200 x 1200 dpi and has a length of 5 inches and a breadth of 4 inches. Imagine we want to calculate the storage requirement for an image that has a dpi of 1200 x 1200 dpi and has a length of 5 inches and a breadth of 4 inches. length= 1200 x 5 = 6000 pixels breadth= 1200 x 4 = 4800 pixels Total no of pixels= 6000 x 4800 = 28,800,000 pixels 1 pixel needs 1 bit of data storage = 28,800,000 bits = 3,600,000 bytes = 3515.625 Kb = 3.46 Mb 5 inches 4 inches

13. Computer Structure Describe purpose of a processorDescribe purpose of a processor List the parts of a processor as ALU, control unit and registersList the parts of a processor as ALU, control unit and registers Represent the structure of a computer in the form of a simple five box diagram representing:Represent the structure of a computer in the form of a simple five box diagram representing: –Input devices –Processor –Main memory –Output devices –Backing storage Distinguish between main memory and backing storageDistinguish between main memory and backing storage Describe the features of ROM and RAMDescribe the features of ROM and RAM Describe the uses of embedded, palmtop, laptop, desktop and mainframe computersDescribe the uses of embedded, palmtop, laptop, desktop and mainframe computers Compare the features of embedded, palmtop, laptop, desktop and mainframe computers:Compare the features of embedded, palmtop, laptop, desktop and mainframe computers: –Type and speed of processor –Size of main memory –Backing storage –Input and output devices Describe clock speed as a simple indicator of system performanceDescribe clock speed as a simple indicator of system performance

14. Describe purpose of a processor The processor is the hardware inside the CPU that controls the operation of the computerThe processor is the hardware inside the CPU that controls the operation of the computer –It could be said the processor is the computers brain. Within the processor are theWithin the processor are the –Control unit –Arithmetic and logic unit (ALU) –Registers Together they are responsible for the overall operations that make the computer workTogether they are responsible for the overall operations that make the computer work When comparing processors the most important measure is the speed they workWhen comparing processors the most important measure is the speed they work –This speed is measured in Hertz (Hz), MegaHertz (MHz) or GigaHertz (GHz)

15. List the parts of a processor as ALU, control unit and registers Control UnitControl Unit –The main functions of the control unit are: To control the timing of operations withing the processorTo control the timing of operations withing the processor To send out signals that fetch instructions from the main memoryTo send out signals that fetch instructions from the main memory To interpret these instructionsTo interpret these instructions To carry out instructions that are fetched from the main memoryTo carry out instructions that are fetched from the main memory Arithmetic and Logic UnitArithmetic and Logic Unit –The main functions of the ALU are: To perform arithmetic calculations (addition, subtraction, multiplication, division)To perform arithmetic calculations (addition, subtraction, multiplication, division) To perform logic functions involving branching, e.g. IF…THENTo perform logic functions involving branching, e.g. IF…THEN RegistersRegisters –These are temporary storage areas within the processor that are used to hold data that has been fetched from the memory or produced during a calculation In general the control unit is responsible for the running of the programs that are loaded into the main memory.In general the control unit is responsible for the running of the programs that are loaded into the main memory.

16. Represent the structure of a computer in the form of a simple five box diagram representing: input devices, processor, main memory, output devices and backing storage Processor Main Memory Input Backing Storage InputOutput five box diagram

17. Distinguish between main memory and backing storage Main memory Main memory –ROM and RAM are the chips inside memory that allow the computer to keep track of what it is doing. –The computer needs two different types of memory main because each has a different job to do. ROM is used to stored a small part of the OS called the bootstrap loader. This program starts up the computer. ROM is used to stored a small part of the OS called the bootstrap loader. This program starts up the computer. A RAM CHIP RAM is the largest part of main memory, it is used to store the OS, RAM is the largest part of main memory, it is used to store the OS, programs and data WHILE THE COMPUTER IS ON. programs and data WHILE THE COMPUTER IS ON. RAM CAN NOT store things after the computer has been switched off RAM CAN NOT store things after the computer has been switched off NOTHING can be written to ROM, it is read only. NOTHING can be written to ROM, it is read only.

18. Distinguish between main memory and backing storage cont’d Backing Storage Backing Storage –Examples of this are floppy disks, flash drives, hard drives, CD, etc. –By saving files and programs onto backing storage they will still be there even after the computer is switched off Main memory is not as large as backing storage devices Main memory is not as large as backing storage devices BACKING STORAGE DEVICES

19. Describe the features of ROM and RAM The main memory is composed of ROM and RAM. The main memory is composed of ROM and RAM. ROM has the following features ROM has the following features –Data in ROM is permanently etched onto a microchip –ROM is read-only so it cannot be changed –Data on ROM is not lost when the computer is switched off RAM has the following features: RAM has the following features: –The data in RAM is read/write so it can be changed –All data stored in RAM is lost when the computer is switched off –RAM is sometimes referred to as primary storage

20. Describe the uses of embedded, palmtop, laptop, desktop and mainframe computers Embedded Systems Embedded Systems –A combination of hardware and software to perform a specific function, E.g. a mobile phone, interactive game boxes, elevators E.g. a mobile phone, interactive game boxes, elevators Palmtop Palmtop –Simple version of basic computer application, web browsing and email, maybe a cellular phone connection Laptop Laptop –Mainly used as a portable computer system between the user’s place of work and home Desktop Desktop –This is a computer system that can fit on your desk at home, work, school or college –Some users need a general-purpose desktop computer to run a range off applications; others need a desktop computer that will form a workstation on a network Mainframe computers Mainframe computers –Used by large companies, such as banks and insurance companies to allow remote access to the processor which is held in a central location. –Their processor is very powerful as hugh amounts of data is dealt with.

21. Compare the features of embedded, palmtop, laptop, desktop and mainframe computers: type and speed of processor, size of main memory, backing storage, input and output devices EmbeddedPalmtopLaptopDesktop Mainframe Computers Processor Power Up to 60 Mhz 200-500 MHz 2.4 GHz 3.2 GHz Several processors Memory Size 1 bit – 512Mb + 64 Mb 512 Mb 256 MB 32Gb memory Backing Store none none Flash memory Flash memory RAM so a constant current has to be applied. RAM so a constant current has to be applied. Additional backing storage can be purchased Additional backing storage can be purchased 40 Gb hard drive 40 Gb hard drive Removable 3.5” floppy drive Removable 3.5” floppy drive A combination 8x DVD-ROM and 8x/4x/24x CD-RW drive A combination 8x DVD-ROM and 8x/4x/24x CD-RW drive Large capacity hard-disk Large capacity hard-disk CD-ROM/DVD drive CD-ROM/DVD drive 100Gb hard disk 100Gb hard disk Tape drive Tape drive Input Devices Field probes/sensors, keyboards, microphone, wands, disk heads, strain gauges Touch screen Touch screen Voice input Voice input Keyboard Keyboard Infrared receiver Infrared receiver Modem Modem Touch pad Touch pad Keyboard Keyboard Microphone Microphone Webcam Webcam Graphics tablet Graphics tablet Scanner Scanner Joystick JoystickKeyboard OutputDevices Speakers, projectors, network cables, disk heads, impact printers, card punches LCD screen LCD screen a speaker a speaker Infrared transmitter Infrared transmitter Wireless connection Wireless connection LCD screen LCD screen Speakers Speakers Infrared transmitter Infrared transmitter Modem NIC Modem NIC USB or Firewire interface USB or Firewire interface Inkjet/laser printer Inkjet/laser printer 17” monitor 17” monitor Speakers Speakers Modem Modem NIC NIC Line printers Line printers Page printers Page printers monitors monitors

22. Describe clock speed as a simple indicator of system performance Clock speed is often used as an indicator of the processing power of a systemClock speed is often used as an indicator of the processing power of a system The clock in a computer system is a regular stream of electronic pulses in the control circuit that keeps everything working in timeThe clock in a computer system is a regular stream of electronic pulses in the control circuit that keeps everything working in time –The faster the clock speed of a computer systems the quicker it processes instructions The speed of the clock is measured in MHz (MegaHertz) or GHz (GigaHertz)The speed of the clock is measured in MHz (MegaHertz) or GHz (GigaHertz) –A processor working at 900 MHz sends out 900 million clock pulses per second

23. Peripherals Describe the features, functions and uses of the following input devices:Describe the features, functions and uses of the following input devices: –Keyboard, Mouse, Microphone, Touchpad, Digital camera, Scanner Compare input devices using appropriate characteristics includingCompare input devices using appropriate characteristics including – resolution, capacity, speed of data transfer, cost Describe the features, functions and uses of aDescribe the features, functions and uses of a –monitor, LCD panel, inkjet and laser printers, loud speakers Compare output devices using appropriate characteristics includingCompare output devices using appropriate characteristics including –resolution, capacity, speed of data transfer, cost Describe the features, functions and uses of current magnetic storage devices and media includingDescribe the features, functions and uses of current magnetic storage devices and media including –floppy drive, hard drive, zip drive, magnetic tape drive Describe the features, functions and uses of current optical storage devices and media includingDescribe the features, functions and uses of current optical storage devices and media including –CD-ROM, CD-R, CD-RW, DVD-ROM, rewitable DVD Compare storage devices using appropriate characteristics includingCompare storage devices using appropriate characteristics including – type of access, capacity, speed of data transfer, cost Describe the need for interfaces with reference to the following functions:Describe the need for interfaces with reference to the following functions: –Compensating for differences in speed between the CPU and peripherals, data conversion from analogue to digital forms and temporary data storage

24. Describe the features, functions and uses of the following input devices: Keyboard, Mouse, Microphone, Touchpad, Digital Camera, Scanner, Webcam See tables below! See tables below!

25. FEATURESFUNCTIONSUSES KEYBOARD accuracy: most errors due to the fault of the user Each key sends a unique scan code to the OS. The OS translates this code into ASCII code. Text entry in a word processor Text entry in a word processor Keying in number/data to a spreadsheet Keying in number/data to a spreadsheet Entering a URL for a website Entering a URL for a website MOUSE accuracy: few errors using a mouse, ten to occur when the user attempts to select small items on screen The movement of the mouse ball inside the mouse is detected by a sensor and sent to the OS. The OS uses this info to control the position of the pointer on the screen. General input device, used for pointing. General input device, used for pointing. Ideal for to accessing menus and making selections as required. Ideal for to accessing menus and making selections as required.

26. FEATURESFUNCTIONSUSES MICROPHONE accuracy: depends how well the sound card carries out sound sampling Inputs sound to the computer. The microphone takes a sound and converts it into an electronic signal. This signal must now be converted from analogue to digital signal.  As a means of issuing commands to the operating system or applications. (voice recognition)  To record music To use the computer as a telephone To use the computer as a telephone TOUCHPAD accuracy: as few errors as using a mouse, tend to occur when the user attempts to select small items on screen By moving an object along the pad, the pointer moves on the display. Beneath the pad there are two layers that create an electromagnetic field. On contact the properties of the field change & the details are input to the computer.  Used as a pointing device on some portable computers

27. FEATURESFUNCTIONSUSES DIGITAL CAMERA accuracy: based on the quality (dpi) of the image: Often 3 different settings: 480x640, 1024x768, 1600x1200 Additional Features: Special effects: Zoom (optical and digital) Photo Imaging Software Direct printing without using a computer In a digital camera the film used in a conventional camera is replaced with an array of image sensors and a storage device. The image sensor is made from an array of photosensitive cells. Each cell converts the light that strikes it into an electronic signal that is proportional to intensity of the light. To take photographs To take photographs Input images into the computer these can then be edited using photo imaging software. Input images into the computer these can then be edited using photo imaging software.

28. FEATURESFUNCTIONSUSES SCANNER accuracy: based on the quality (dpi) of the image: for display purposes on a moniotr : 72 dpi Flat bed scanners up to: 2400x4800 To capture data, the scanner reflects light off a paper image that is placed on a sheet of glass. The reflected light is gathered by photosensitive cells. Passed through an A to D converter to create a bit map. Converting photographic prints into digital form. Scanning documents for OCR. WEBCAM accuracy: max number of pixels: approx. 640x480 Consists of a digital camera that has a piece of software connected that periodically grabs a frame. Video chat Video chat Video conferencing Video conferencing Live streaming internet webcam Live streaming internet webcam Still image captures Still image captures Video e-mail Video e-mail

29. Compare input devices using appropriate characteristics including resolution, capacity, speed of data transfer, cost See table below See table below

30. ResolutionCapacity Speed of data transfer cost KeyboardN/AN/A restricted by users typing skills, max input speed 10 characters per sec £12 - £30 MouseN/AN/A the actual data transfer rate does not change the OS can be set by the user £3 - £15 MicrophoneN/A Unlikely to have much of its own cache. Generally depend upon fast access via a sound card to hard disk space to store the sample. speed of conversion from analogue to digital depends on the processor and the amount of RAM £10 - £40

31. ResolutionCapacity Speed of data transfer cost TouchpadN/AN/A based on USB 1.0: 12 Mbits per sec approx £175 Digital Camera Often 3 settings: 480x640, 1024x768, 1600x1200 Vary from 16 MB – 2 Gb USB 1.0: 12 Mbit s USB 2.0: 480 Mbit per sec depends on make and quality. £100 - £3000+ Scanner for display purposes on a monitor : 72 dpi Flat bed scanners up to: 2400x4800 The scanner itself doesn’t have any RAM so the data is sent directly to computer. USB 2.0: 480 Mbit per sec £40 – £300+ Webcam max number of pixels: approx. 640x480 N/A USB 2.0: 480 Mbit per sec £12 - 50

32. Describe the features, functions and uses of a monitor, LCD panel, inkjet and laser printers, loud speakers See table below See table below

33. FeaturesFunctionsUses CRT Monitor Heavy, tend to be fairly large. Sealed glass tube that has no air inside it. An electronic gun at one end fires a stream of tiny electrons at the screen located as the other end. The image is made by illuminating particles on the screen. Since they are heavy and not easily moved they are usually used with desktop computers. LCD Panel Lightweight, compact and require little power compared to CRT monitors Allows different amounts of white backlight through an active filter. The red, green and blue of each pixel are achieved by filtering the white light that is allowed through. Ideal for use in laptops, tablets and palmtops. Full sized LCD monitors are becoming increasingly popular with desktop computers

34. FeaturesFunctionsUses Inkjet Printer Come in both black and white and colour These work by spraying a fine jet of ink, which is both heated and under pressure onto paper. Ideal for the occasional presentation and livening up mostly text documents. Also for Invitations Greeting cards, etc. Laser Printer Come in both black and white and colour. Tend to be fairly large in comparison to an inkjet printer. 16pp print speed, 1 st page in 12 secs, USB 2 By using a laser beam to trace the image of the page layout onto a photosensitive drum. This image then attracts toner by means of an electrostatic charge. The toner is fused to the paper by heat and pressure. Ideal for printing a lot of printouts. Commonly found in schools and offices.

35. FeaturesFunctionsUses Loudspeaker Two types: Inbuilt (poor quality) Inbuilt (poor quality) External External Inbuit: To produce a sound from the computer External: To produce good sound quality that is comparable to hi-fi systems

36. Compare output devices using appropriate characteristics including resolution, capacity, speed of data transfer, cost ResolutionCapacity Speed of Transfer Cost Monitor 17” monitor: max 1280x1024 800x600 or 1024x768 15” monitor: 640x480 or 800x600 N/A 17” monitor: £80 25” monitor: £1800 LCD Panel Max 1280x1024 17” monitor: £300

37. ResolutionCapacity Speed of Transfer Cost Inkjet Printer Typically 2880x1440 Black and white: 10 ppm Colour: 6 ppm Some are as cheap as £25 because the profit comes form the consumables, e.g. ink cartridges. 5p to print a page of text more for graphics. Top of the range models approx. £220 Laser Printer From 600 to 2400 dpi Black & white: 8 Mb RAM expanda ble to 136 Mb 12 seconds Black & white: £150 to £800 Cheaper consumables, typically costs less than 1p per page of text. Colour: £550 to £ 2000

38. ResolutionCapacity Speed of Transfer Cost LoudspeakerN/AN/A Depends on sound card Varies but approx. £100 to £300

39. Describe the features, functions and uses of current magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape drive FeaturesFunctionsUses Floppy Drive/Disks Disk is made of circular plastic plates coated in ferric oxide. Disk is made of circular plastic plates coated in ferric oxide. Surface of the disk is divided into tracks and sectors on which data is stored as magnetic patterns Surface of the disk is divided into tracks and sectors on which data is stored as magnetic patterns The disk itself is floppy but covered in hard plastic The disk itself is floppy but covered in hard plastic The standard size is 3.5” The standard size is 3.5” Direct access Direct access Means of storing small files Means of storing small files Transferring files from one computer to another Transferring files from one computer to another Storing small files, unsuitable for storing anything but small files.

40. Describe the features, functions and uses of current magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape drive FeaturesFunctionsUses Hard Drive A rigid disk with a magnetised surface. A rigid disk with a magnetised surface. The surface is divided into tracks and sectors on which data is stored magnetically. The surface is divided into tracks and sectors on which data is stored magnetically. The data is read with a read/write head fixed to an arm that moves across the surface of the disk. The data is read with a read/write head fixed to an arm that moves across the surface of the disk. Hard disks are usually sealed in a protective container to prevent dust corrupting the data. Hard disks are usually sealed in a protective container to prevent dust corrupting the data. Direct access Direct access Used in ALL computers Typical hard disk will store: The OS The OS Applications Applications User files User files Internal backing storage device. An essential component of the modern computer, particularly with the increase in video editing, which demands a great deal of storage space.

41. Describe the features, functions and uses of current magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape drive FeaturesFunctionsUses Zip Drive A removable storage device that securely stored computer data magnetically. It is durable and portable. A 100 Mb zip drive can hold the equivalent of 70 floppy disks. Direct Access Good for storing large files on a portable medium. Stores large files, e.g. photo images, desktop publishing files and video. Often used to back up data. Magnetic Tape Drive Inexpensive, well understood and easy to remove and replace. Traditionally large real-to-reel tapes used. Currently tends to be cassettes. Some of these are even smaller than an audio cassette but hold mmore data than the huge reels. Sequential Access used for permanent storage Often used for back-up of hard disks. This is automatically done overnight and is suitable for network or mainframe backups.

42. Describe the features, functions and uses of current optical storage devices and media including CD-ROM, CD-R, CD-RW, DVD-ROM, rewritable DVD FeaturesFunctionsUses CD-ROM CD-ROM writers use a high- powered laser to store data by making tiny pits in the surface of the CD-ROM disk. The patterns of these pits is read by a sensor in the CD-ROM drive that detects light reflected off the surface of the disk. The patterns are then turned into binary numbers. Direct Access These can only be used to read information on them- the user cannot save data to a CD- ROM disk. Store encyclopaedias Store Software CD-R Compact disk recordable Can be recorded on once only. Several different formats, some won’t work in a CD-ROM drive Once the disk has been recorded on it cannot be recorded over. Distribution of a finished product/program Permanent backing storage and archiving encyclopaedias

43. Describe the features, functions and uses of current optical storage devices and media including CD-ROM, CD-R, CD-RW, DVD-ROM, rewritable DVD FeaturesFunctionsUses CD-RW Compact disk rewritable. Same size and shape as other CD media but you can write and rewrite onto a CD-RW The disk can be recorded on and recorded over as desired. Portable media for transferring files to another computer. Back-up of hard drive (drive image) Storing photos/movie files (large size) DVD- ROM Digital versatile disk read only memory Same size and composition as CDs, but store more information as a consequence of smaller track spacing and smaller ‘land and pits’ (bits) Can be recorded on both sides. These can only be used to read information on them- the user cannot save data to a DVD- ROM disk. EncyclopaediasGamesMovies

44. Describe the features, functions and uses of current optical storage devices and media including CD-ROM, CD-R, CD-RW, DVD-ROM, rewritable DVD FeaturesFunctionsUses DVD-R Allows the user to record in a single session or in multiple sessions until the disk is complete Can only record on to the DVD until the DVD is full. The DVD cannot be overwritten Distribution of a finished product/program Permanent backing storage and archiving encyclopaedias DVD-RW Can be used over 1000 times to write and re-write data onto the RW disk. Two different types of disk DVD-RW and DVD+RW. Can record on the DVD as often as desired. Distribution of a finished product/program Permanent backing storage and archiving encyclopaedias

45. Compare storage devices using appropriate characteristics including type of access, capacity, speed of data transfer, cost DriveCapacityTransfer Type of Access Drive Cost Media Cost Floppy disk LowSlowDirect Very low Hard disk Very high Very fast DirectLow/medium- Tape Very high Fast (but sequential) SerialHighHigh CD-RHighFastDirectLow Very Low CD-RWHighFastDirectLowLow Rewritable DVD Very high FastDirectLow/mediumLow FlashHighFastDirectLow/mediumN/A

46. Describe the need for interfaces with reference to the following functions: Compensating for differences in speed between the CPU and peripherals, data conversion from analogue to digital forms and temporary data storage An interface is required because there are differences between the peripheral device and the processor.An interface is required because there are differences between the peripheral device and the processor. –These characteristics include; Data conversionData conversion –The peripheral devices accept analogue signals that must be converted into digital for the processor to understand them Speed of operationSpeed of operation –Peripherals tend to be in terms of ppm or frames per second, however the processor works much faster, e.g. 28 billion cycles per sec. This difference in the speed of operation between the devices requires an interface as the processor can deliver data much faster than the peripherals can handle. Temporary storage of dataTemporary storage of data

47. Networking Describe the following features of LANs, WANs and the Internet:Describe the following features of LANs, WANs and the Internet: –Transmission media, bandwidth, graphical spread and functions Describe the benefits of networksDescribe the benefits of networks Describe the following features and functions of e-mail:Describe the following features and functions of e-mail: –E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features of the World Wide Web:Describe the following features of the World Wide Web: –Web pages, hyperlinks, browser, search engines Describe the following economic factors which have led to the development of computer networks:Describe the following economic factors which have led to the development of computer networks: –Falling cost of telecommunication technologies and services, shared access to expensive equipment, geographical spread of organisation, demand for up-to-date information Describe the main features of the Computer Misuse Act, the Copyright, Designs and Patents Act and the Data Protection ActDescribe the main features of the Computer Misuse Act, the Copyright, Designs and Patents Act and the Data Protection Act

48. Describe the following features of LANs, WANs and the Internet: Transmission media, bandwidth, graphical spread and functions FeaturesLANWAN Transmission media Twisted pair Coaxial cable Fibre optics WirelessMicrowaveSatelliteRadio Bandwidth 10 Mb per sec 500 Mb per sec 30 Gb per sec 54 Mb per sec 100 Mb per sec 2 MB per sec Geographical spread Can be in a single building or a site linking buildings together Spread throughout a country or the world Functions A LAN allows users to share data files, applications, and peripherals A LAN allows users to share data files, applications, and peripherals Users can access their work from any station on the network Users can access their work from any station on the network Different levels of access can be granted to users Different levels of access can be granted to users Users can communicate through e-mail Users can communicate through e-mail Allows users to share data files and equipment Allows users to share data files and equipment Permits ‘live’ chat Permits ‘live’ chat Allows users to e-mail each other Allows users to e-mail each other Allows users video conferencing Allows users video conferencing Allows access to databases Allows access to databases E-commerce E-commerce Entertainment Entertainment

49. Describe the following features of LANs, WANs and the Internet: Transmission media, bandwidth, graphical spread and functions. Questions and Answers. 1. What does the bandwidth determine? The amount of information that can be transferred at a time 2. What is the difference between the geographical spread of a WAN and a LAN. LAN:Can be in a single building or a site linking buildings together WAN:Spread throughout a country or the world 3. State two functions of a LAN A LAN allows users to share data files, applications, and peripherals Users can access their work from any station on the network 4. State two functions of a WAN Allows users to e-mail each other Allows users video conferencing

50. Describe the benefits of networks SecuritySecurity –Tampering with programs and files is prevented through restricted access rights –Personal work is saved in private spaces on hard disks that are password protected from inadvertent or malicious copying and/or deletion CommunicationCommunication –Data files, programs and peripheral devices can be shared –Communication is improved via e-mail/chat/bulletin boards ManagementManagement –Centralised back-up of files –Stations can be managed remotely.

51. Describe the benefits of networks Questions and Answers 1. List three advantages of a network Security Security –Tampering with programs and files is prevented through restricted access rights –Personal work is saved in private spaces on hard disks that are password protected from inadvertent or malicious copying and/or deletion CommunicationCommunication –Data files, programs and peripheral devices can be shared –Communication is improved via e-mail/chat/bulletin boards ManagementManagement –Centralised back-up of files –Stations can be managed remotely.

52. Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders E-mail addressE-mail address –To send an e-mail message you must first have their e-mail address. –This is the location of the server on the internet where the person’s mailbox can be found. E.g. jsmith@westlothian.org.ukE.g. jsmith@westlothian.org.ukjsmith@westlothian.org.uk The part before the ‘@’ symbol is the username of the person on that server and the ‘westlothian.org.uk’ part is the domain name. Together they make up the e-mail addres of the person to whom the message is being sent.The part before the ‘@’ symbol is the username of the person on that server and the ‘westlothian.org.uk’ part is the domain name. Together they make up the e-mail addres of the person to whom the message is being sent.

53. Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders SendingSending –After entering the address of the recipient it is usual to enter a subject. This will appear as a short line of text telling them what the massage is about.This will appear as a short line of text telling them what the massage is about. It is possible to send a message without a subject but it is not good etiquette.It is possible to send a message without a subject but it is not good etiquette. –The body of the massage is entered in the box below the subject heading. –Attachments can be added to the email in the form of documents, files, pictures or video. –When ready the user clicks on the send button and the message is delivered.

54. Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders cont’d What is the domain name of the following e-mail address? What is the domain name of the following e-mail address? apupil@westlothian.org.uk Why do we add a subject line to our outgoing e- mails? Why do we add a subject line to our outgoing e- mails? What is the simplest way to reply to an email? What is the simplest way to reply to an email? Why do we use electronic address books? Why do we use electronic address books? What is a mailing list? What is a mailing list? Why do we set up folders in our inbox? Why do we set up folders in our inbox?

55. Describe the following features and functions of e- mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features and functions of e- mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders ReadingReading –In the e-mail software there is a send/receive button that will send any unposted e-mails and at the same time download any that are waiting on the server. –On web-based systems any new mail is automatically made available when you log on to the server. ReplyingReplying –The simplest way to reply to an e-mail is; Every e-mail client’s software has a reply button that not only enables the recipient to reply directly without having to type in the e-mail address but adds the reply to the current e-mail so that the recipient can scroll down the message to read any previous correspondence.Every e-mail client’s software has a reply button that not only enables the recipient to reply directly without having to type in the e-mail address but adds the reply to the current e-mail so that the recipient can scroll down the message to read any previous correspondence.

56. Describe the following features and functions of e- mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features and functions of e- mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Setting up an address bookSetting up an address book –If you send e-mails regularly to the same people it is a good idea to set up an electronic address book –The best time to add an address to your address book is just after you have received an e-amil from someone; all e-mail software allows the option of adding a sender’s e-mail address directly to the address book without having to type it in.

57. Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Describe the following features and functions of e-mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders Setting up mailing listsSetting up mailing lists –A mailing lists is a pre-prepared list that include all the addresses of the people whom you wish to send a message to –They are useful if you send messages to several people at the same time. You can create a list of friends or family made up of a combination of addresses from your address book.You can create a list of friends or family made up of a combination of addresses from your address book. –If for example you name one of the mailing lists ‘friends’ then it can be selected in a single operation.

58. Describe the following features and functions of e- mail: E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up folders cont’d Setting up foldersSetting up folders –Creating folders is one way of preventing your inbox from looking very cluttered. –This is similar to creating folders on you computer to store work in an organised fashion. –It is possible to create an entire hierarchy of folders within folders –Once the structure of folders has been set up, some e- mail programs allow the creation of ‘message rules’, which automatically move mail messages into the correct folder as soon as it is downloaded from the server. This is a major benefit to people who receive many e- mail messages each day.This is a major benefit to people who receive many e- mail messages each day.

59. Describe the following features of the World Wide Web: Web pages, hyperlinks, browser, search engines Web PagesWeb Pages –A web page is a document that usually contains text, images, and perhaps multimedia files containing additional information formatting information in HTML –It is possible to create a web page in a simple text editor or a word processing application; all you have to do is add the extra HTML code to the document so that the web browser knows how to display the page.

60. Describe the following features of the World Wide Web: Web pages, hyperlinks, browser, search engines HyperlinksHyperlinks –Hyperlink allow any page on the web to connect to any other. If the user clicks on the link then the browser will load the URL of the page it is seeking and try to find it on the web.If the user clicks on the link then the browser will load the URL of the page it is seeking and try to find it on the web. Sometimes a page will not be retrieved as it has been removed from the server by the owner; this is known as a ‘dead’ link.Sometimes a page will not be retrieved as it has been removed from the server by the owner; this is known as a ‘dead’ link. –Hyperlinks are normally identified in blue and underlined when they are text links. –Hyperlinks can be associated with images as well as text and normally the pointer turns into a hand with a pointing finger when placed on an image that has a hyperlink attached to it.

61. Describe the following features of the World Wide Web: Web pages, hyperlinks, browser, search engines cont’d BrowserBrowser –A browser is a program that allows a user to read and navigate web pages. –Two of the most common browsers are Internet Explorer and Netscape Navigator. Safari is rapidly replacing Netscape, particularly on Macs.

62. Describe the following features of the World Wide Web: Web pages, hyperlinks, browser, search engines cont’d Search EnginesSearch Engines –A search engine, such as Google, is a web site that users can go to to search for a site or information if they do not know the URL. –A search engine regularly runs programs called web crawlers to gather information about what pages are on the internet. –When the web crawler comes across a document it sends the URL along with extracts of the content back to the site, where it is stored on a database. –When you enter a search you are really searching the database for words that match your entry.

63. Describe the following economic factors which have led to the development of computer networks: Falling cost of telecommunication technologies and services, shared access to expensive equipment, geographical spread of organisation, demand for up-to-date information Falling cost of telecommunication technologies and servicesFalling cost of telecommunication technologies and services –Cheaper to have the internet in your home or offices Shared access to expensive equipmentShared access to expensive equipment –Peripherals such as printers can be shared by a number of computers. This saves a great deal of money as one printer can be shared by an entire office, classroom, etc. Geographical spread of organisationGeographical spread of organisation –Companies can use the public telecommunications infrastructure to create their own WANs through a leased line and in come cases a dedicated line. –This acted as a catalyst for large organisations to expand their businesses on a national and global scale Demand for up-to-date informationDemand for up-to-date information –The growth in home computers and the demand for up-to-date information fuelled the desire for individuals to connect to the internet; members of the public were encouraged to purchase a dial-up connection using their phone line. –At the turn of the millennium the telecommunication companies began to offer broadband.

64. Describe the main features of the Computer Misuse Act, the Copyright, Designs and Patents Act and the Data Protection Act Three Acts That Affect I.T.Three Acts That Affect I.T. –Computer Misuse Act (1990) –Copyright, Design and Patents Act (1988) –Data Protection Act (1998)

65. The Computer Misuse Act (1990) Created as a result of high profile crimes where individuals had gained access to computers. Belonging to; Created as a result of high profile crimes where individuals had gained access to computers. Belonging to; Large companies, e.g. banks. Large companies, e.g. banks. Government Organizations, e.g. the army. Government Organizations, e.g. the army.

66. The Act makes the following an offence: Unauthorised access to computer material Unauthorised access to computer material Unauthorised access with intent to commit further offences Unauthorised access with intent to commit further offences Unauthorised modification of computer material Unauthorised modification of computer material

67. Unauthorised access to computer material: Also known as ‘Hacking.’Also known as ‘Hacking.’ Hacking is the act of trying to gain access to another persons computer files without their permission.Hacking is the act of trying to gain access to another persons computer files without their permission. Hacking can be done via the telephone system and a modem.Hacking can be done via the telephone system and a modem. –Hackers are hard to catch, since they may be miles away from the computer they access.since they may be miles away from the computer they access.

68. Example “American hacker Kevin Lee Poulsen (who called himself Dark Dante) served five years in prison after being captured and indicted for stealing military documents. He also broke into an number of phone company systems. His most amusing exploit was breaking into a radio station’s phone umber on a number of occasions in 1990, and rigging it so that it would only let calls through from him and two friends. The three them proceeded to ring in and win prizes including two Porsche cars, $20,000 and a holiday to Hawaii.“ “American hacker Kevin Lee Poulsen (who called himself Dark Dante) served five years in prison after being captured and indicted for stealing military documents. He also broke into an number of phone company systems. His most amusing exploit was breaking into a radio station’s phone umber on a number of occasions in 1990, and rigging it so that it would only let calls through from him and two friends. The three them proceeded to ring in and win prizes including two Porsche cars, $20,000 and a holiday to Hawaii.“

69. Unauthorised access with intent to commit further offences: For e.g. computer fraud. For e.g. computer fraud. “In 1998 a European hacker calling himself the Eastern Prowler broke into the computer system of an organised crime gang based in Bulgaria and Romania. He uncovered the financial records of the gang and sent them to prosecutors in both countries, and he stole $3.2 million from them and redistributed it by International Wire. The money is believed to have arrived in at least 17 different bank accounts belonging to children’s charities in Romania and Bulgaria. It was transferred through a complex series of banks in many different countries making it practically impossible to trace.”

70. Unauthorised modification of computer material: This would include the distribution of computer viruses. This would include the distribution of computer viruses. A computer virus is a ‘rogue’ program that someone has deliberately created and written onto disk. A computer virus is a ‘rogue’ program that someone has deliberately created and written onto disk. Viruses can cause a lot of damage by destroying and corrupting files. Viruses can cause a lot of damage by destroying and corrupting files.

71. “Love Bug” Virus In the form of an email. In the form of an email. Subject header said “I LOVE YOU.” Subject header said “I LOVE YOU.” Once opened automatically forwards itself to every person in your email address books. Once opened automatically forwards itself to every person in your email address books. Deletes files, including MP3 music files and images. Deletes files, including MP3 music files and images.

72. How can we prevent viruses spreading? Don’t share disks. Don’t share disks. Don’t copy software. Don’t copy software. Do check all your computer disks regularly with an anti-virus program. Do check all your computer disks regularly with an anti-virus program. Firewall Firewall

73. The Copyright, Design & Patents Act (1988) Note that this act covers more than I.T.Note that this act covers more than I.T. –E.g. dramatic works, sound recordings, films, etc. However, when related to IT, it often refers to copying software, including operating systems, games, copying images, music, videos, etc.However, when related to IT, it often refers to copying software, including operating systems, games, copying images, music, videos, etc.

74. The Act Companies and individuals are required to register the data and designs related to a product. Companies and individuals are required to register the data and designs related to a product. This in turn gives them ownership of the product, making it illegal for anyone to copy the product. This in turn gives them ownership of the product, making it illegal for anyone to copy the product. The act provides a system of protection for original material. The act provides a system of protection for original material.

75. For Example: Generally software is licensed for one machine only.Generally software is licensed for one machine only. –Unless a multiple license pack is bought. If you put software onto more computers than it is licensed for you are breaking the Copyright, Design and Patents Act.If you put software onto more computers than it is licensed for you are breaking the Copyright, Design and Patents Act.

76. Federation Against Software Theft FAST is an organization who try to prevent individuals and companies breaking the law. FAST is an organization who try to prevent individuals and companies breaking the law. Those that are found breaking the law will be prosecuted. Those that are found breaking the law will be prosecuted. FAST have the power to examine your computer! FAST have the power to examine your computer!

77. The Data Protection Act This act is concerned with information abut living individuals that is processed both manually and automatically. This act is concerned with information abut living individuals that is processed both manually and automatically. It gives rights to those individuals about whom information is recorded. It gives rights to those individuals about whom information is recorded. If someone holds data electronically about an individual, then that individual has the following rights: If someone holds data electronically about an individual, then that individual has the following rights: 1. To view a copy of the data being held on them 2. To have any inaccurate data corrected 3. To prevent junk mail: by registering with the mailing preferences services you should be exempt from receiving junk mail The data controller who is in charge of managing the data that is held must: The data controller who is in charge of managing the data that is held must: 1. Ensure that the data is accurate, up-to-date and relevant 2. Allow access to the data if requested by a data subject 3. Change in formation that is incorrect 4. Store data securely

78. Computer Software Distinguish between an operating system and an application program with examples of eachDistinguish between an operating system and an application program with examples of each Explain the need for standard file formatsExplain the need for standard file formats Describe the following standard file formats for text files:Describe the following standard file formats for text files: –Text, ASCII, rich text file Identify data objects and operations in the context of word processing, databases, spreadsheets, and graphic packagesIdentify data objects and operations in the context of word processing, databases, spreadsheets, and graphic packages Define a virusDefine a virus Describe how a virus operatesDescribe how a virus operates Describe the following common symptoms of virus infection:Describe the following common symptoms of virus infection: –Displaying unwanted messages, unusual visual/sound effects, computers rebooting unexpectedly, unwanted generation of e- mails Describe how viruses are spread via floppy disk, homemade CDs, ‘fun’ websites and e-mail attachmentsDescribe how viruses are spread via floppy disk, homemade CDs, ‘fun’ websites and e-mail attachments Explain the need for anti-virus softwareExplain the need for anti-virus software

79. Distinguish between an operating system and an application program with examples of each. The software used on a computer is stored in one of two types of file. We are going to look at one of these types, the program files closerThe software used on a computer is stored in one of two types of file. We are going to look at one of these types, the program files closer –Program files fit into two general types, system software and application software System software: the programs which manage the computer and let us control its functionsSystem software: the programs which manage the computer and let us control its functions The most important program of this type is the operating system.The most important program of this type is the operating system.

80. Distinguish between an operating system and an application program with examples of each. Cont’d The OS is a group of programs that automatically load from your hard disk when you turn on your computer.The OS is a group of programs that automatically load from your hard disk when you turn on your computer. –These programs remain in RAM until you turn your computer off. –they control the hardware and software running on the computer, allowing the user to communicate with application programs and peripheral devices. Whether you load or save a file, access the internet, print a hard copy or just type on the keyboard, the OS is involved working in the background.Whether you load or save a file, access the internet, print a hard copy or just type on the keyboard, the OS is involved working in the background. –There are four main types of OS in popular use today: MS-DOS, Windows, UNIX and MacOSMS-DOS, Windows, UNIX and MacOS

81. Distinguish between an operating system and an application program with examples of each. Application software: the programs that we run on the computer when we have a tsk to do. There are an enormous number of different application programs.Application software: the programs that we run on the computer when we have a tsk to do. There are an enormous number of different application programs. –E.g. word processing is used to create, edit, format and save documents, e.g. WordPerfect and Microsoft Word –Spreadsheets are used to perform numerical calculations and accounting tasks. E.g. Excel and Quattro Pro –Database management is used to organise a set of related information. E.g. dBase and Access –Desktop Publishing is used to produce documents with sophisticated formatting that includes text and graphics. E.G. Quark, CorelDraw and PageMaker –Presentation software is used to produce slide shows. E.g. PowerPoint, Harvard Graphics and Lotus Freelance Graphics –E-mail programs are used to compose and send e-mails. E.g. Outlook, Eudora Pro and Pegasus Mail.

82. Explain the need for standard file formats Before standard file formats were produces one of the main problems was that a file produced in one application packages could not be opened in another.Before standard file formats were produces one of the main problems was that a file produced in one application packages could not be opened in another. To solve this problem standard file formats were produced, e.g. ASCII, plain text and RTF.To solve this problem standard file formats were produced, e.g. ASCII, plain text and RTF. Standard file formats make documents more portable, e.g. if you save a MS Word document in ASCII file format you will be able to open it in a Claris Works word processor or Wordperfect, etc.Standard file formats make documents more portable, e.g. if you save a MS Word document in ASCII file format you will be able to open it in a Claris Works word processor or Wordperfect, etc.

83. Explain the need for standard file formats Cont’d However there was still a problem!However there was still a problem! –Documents saved as ASCII or plain text do not include the formatting information of the original document (font, bold, italic, etc.) So to solve this problem rich text format (RTF) was developed.So to solve this problem rich text format (RTF) was developed. –RTF includes formatting codes.

84. Describe the following standard file formats for text files: Text, ASCII, rich text file Text and ACSIIText and ACSII –Documents saved as.txt or.ASCII are known as plain text documents –Text and ASCII are standard file format for text documents –They do not save any of the formatting of the original document Rich Text Format (RTF)Rich Text Format (RTF) –RTF is a standard file format for text documents –It does save the formatting of the original document –It is still in popular use today.

85. Identify data objects and operations in the context of word processing, databases, spreadsheets, and graphic packages PackageObjectsOperations Word Processor CharacterWordSentenceParagraphTableDrawing Enter, insert, edit, delete, copy, paste, format, spell check, search and replace Import/export Add row, ass column, Split cell, merge cell Group, scale, move forward/back DatabaseFieldRecordFileLayout Enter, insert, edit, delete, copy, paste, format, search, sort, calculate, query Import/exportReport

86. PackageObjectsOperations SpreadsheetCellsRowColumnNumberTextFormulaChart Enter, insert, edit, delete, copy, paste, set attributes Format, import/export Calculate (sum, average, max, min, if) Chart scale GraphicsPixelLineCircle Rectangl e Polygon Enter, insert, edit, delete, copy, paste, format, scale, rotate, layer, group, ungroup, crop

87. Define a virus A computer virus is a self replicating piece of computer code that someone has deliberately created and written onto disk. It can partially or fully attach itself to files or applications and can cause your program to do something you don’t want it to do. A computer virus is a self replicating piece of computer code that someone has deliberately created and written onto disk. It can partially or fully attach itself to files or applications and can cause your program to do something you don’t want it to do.

88. Describe how a virus operates Viruses enter your computer via e-mail, downloads form the internet, infected floppy disks, homemade CDs and ‘fun’ websites.Viruses enter your computer via e-mail, downloads form the internet, infected floppy disks, homemade CDs and ‘fun’ websites. When a virus program is executed it tends to perform four actions:When a virus program is executed it tends to perform four actions: 1.Replication: copies itself to other files, particularly to.com and.exe files and the boot sector record 2.Camouflage: attempts to disguise itself to avoid detection from anti-virus software 3.Event watching: whenever the virus runs it checks for certain events, e.g. a specific date, when the virus will activate 4.Delivery: this is the purpose of the virus or what it does. This may be simple jumbling up of letters or wiping an entire hard drive.

89. Describe the following common symptoms of virus infection: Displaying unwanted messages, unusual visual/sound effects, computers rebooting unexpectedly, unwanted generation of e- mails There are a number of tell tale signs that can indicate that your computer has been infected with a virus.There are a number of tell tale signs that can indicate that your computer has been infected with a virus. They include;They include; –Displaying unwanted messages –Unusual visual/sound effects –Computers rebooting unexpectedly –A flood of unexpected e-mails

90. Describe how viruses are spread via floppy disk, homemade CDs, ‘fun’ websites and e- mail attachments Floppy DisksFloppy Disks –The disk acts as a carries spreading the virus into each machine when it is placed into the drive. Homemade CDsHomemade CDs –CDs spread viruses in a asimilar fashion when the original CD has been infected during its compilation ‘fun’ websites‘fun’ websites –Programs such as Napster or Kazaa allow users to share files on each others hard drives via the internet –There are concerns that this is being used as a means of spreading viruses –According to an articles in the UK-based IT site, The Register, 6% of all the music downloaded from Kazaa is virus-laden

91. Explain the need for anti-virus software Having learnt what we have about how destructive a virus can be the need for anti-virus software is obviousHaving learnt what we have about how destructive a virus can be the need for anti-virus software is obvious –It can prevent the spread of viruses

92. THE END