computer systems intermediate 2 revision. data representation represent positive numbers in binary...

Computer SystemsComputer Systems

Intermediate 2 Intermediate 2

RevisionRevision

Data RepresentationData Representation• Represent positive numbers in binary using examples Represent positive numbers in binary using examples

up to and including eight bitsup to and including eight bits• State the advantages of using binary numbersState the advantages of using binary numbers• Describe floating point representation of real numbers Describe floating point representation of real numbers

using the terms mantissa and exponentusing the terms mantissa and exponent• Describe file sizes, backing storage and main memory Describe file sizes, backing storage and main memory

capacities using the terms: bit, byte, kilobyte, capacities using the terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb)megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb)

• Describe the ASCII code including control charactersDescribe the ASCII code including control characters• Describe the term character setDescribe the term character set• Describe the bit map method of graphic representation Describe the bit map method of graphic representation

using examples of black and white bit mapsusing examples of black and white bit maps• Calculate storage requirements for a bitmap graphic Calculate storage requirements for a bitmap graphic

Represent positive numbers in Represent positive numbers in binary using examples up to and binary using examples up to and including eight bitsincluding eight bits• In our normal counting system we use digits 0 to 9 to represent any numberIn 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 numberIn 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) We use the following column headings for the denary (base 10)

systemsystem– Thousand Hundreds Tens UnitsThousand Hundreds Tens Units

22 3 6 5 3 6 5 = 2 x 1000 + 3 x 100 + 6 x 10 + 5 x 1= 2 x 1000 + 3 x 100 + 6 x 10 + 5 x 1= 2000 + 300 + 60 + 5= 2000 + 300 + 60 + 5= 2365= 2365

• We use the following column headings for the binary (base 2) systemWe use the following column headings for the binary (base 2) system– 128s 64s 32s 16s 8s 4s 2s Units128s 64s 32s 16s 8s 4s 2s Units

0 1 1 0 1 1 0 10 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 10 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 + 164 + 32 + 8 + 4 + 1 == 109 109

• Remember to use Remember to use all 8 bitsall 8 bits to represent the number, i.e. do not forget 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 to put in the leading zeros or you will not have written an 8-bit binary numbernumber

State the advantages of using State the advantages of using binary numbersbinary numbers

• Binary is a simple two-state system Binary is a simple two-state system (1 or 0) which is ideal when (1 or 0) which is ideal when representing a two-state system of representing a two-state system of “power on/power off”“power on/power off”

• A degraded signal can still be A degraded signal can still be detected as representing 1detected as representing 1

• There are only a few rules of There are only a few rules of addition, making calculations simpleraddition, making calculations simpler

Describe floating point Describe floating point representation of real numbers representation of real numbers using the terms mantissa and using the terms mantissa and exponentexponent• Very large and very small numbers would take up Very large and very small numbers would take up

too much space in memory so a different too much space in memory so a different technique called technique called floating point representation is floating point representation is used used to store these numbersto store these numbers

• The rule is to place the The rule is to place the binary pointbinary point in front of the in front of the digits and to count the number of places that it digits and to count the number of places that it has been movedhas been moved– This number is then the exponent of 2 This number is then the exponent of 2 – So the binary number 1101.001101110010 is written as;So the binary number 1101.001101110010 is written as;

• The exponent and mantissa are then stored The exponent and mantissa are then stored separately in memoryseparately in memory

Mantissa .Mantissa .11010011011100101101001101110010 x 2 x 20000010000000100 Exponent Exponent

Describe file sizes, backing storage and main Describe file sizes, backing storage and main memory capacities using the terms: bit, byte, memory capacities using the terms: bit, byte, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, kilobyte, megabyte, gigabyte, terabyte (Kb, Mb, Gb, Tb)Tb)• All data stored in memory is stored as bit patternsAll data stored in memory is stored as bit patterns

– Made up from digits 1 or 0Made up from digits 1 or 0– The storage of these bits are made more manageable by The storage of these bits are made more manageable by

grouping them in multiples of eight.grouping them in multiples of eight.• The term The term byte byte is widely used when referring to file sizeis widely used when referring to file size

• The following table represents the hierarchy of capacities The following table represents the hierarchy of capacities for file sizes, main memory and backing storage;for file sizes, main memory and backing storage;

Unit of MemoryUnit of Memory Composed ofComposed of Typical FilesTypical Files

1 bit1 bit Can be 1 or 0Can be 1 or 0

1 byte1 byte 8 bits8 bits 1 character1 character

1 kilobyte (Kb)1 kilobyte (Kb) 221010 = 1024 byte = 1024 byte Half an A4 pageHalf an A4 page

1 megabyte (Mb)1 megabyte (Mb) 222020 =1024 kilobytes =1024 kilobytes 500 A4 pages500 A4 pages

1 gigabyte (Gb)1 gigabyte (Gb) 223030 = 1024 Mb = 1024 Mb 500,000 A4 pages500,000 A4 pages

1 terabyte (Tb)1 terabyte (Tb) 224040= 1024 Gb= 1024 Gb Enormous!!!Enormous!!!

Describe the ASCII code including Describe the ASCII code including control characterscontrol 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 representThe code that is most commonly used to represent text text is theis the bit ASCII bit ASCII

code.code.• The letters stand for:The letters stand for:

– AAmericanmerican– SStandardtandard– CCode forode for– IInformationnformation– IInterchangenterchange

• Only 7 bits are required to store the code but we usually deal with bits 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 codein 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 equivalentThe table below shows a few ASCII codes and their decimal equivalentCharacterCharacter ASCII codeASCII code DecimalDecimal

AA

BB

ZZ

aa

22

BeepBeep

&&

0100 00010100 0001

0100001001000010

0101101001011010

0110000101100001

0011001000110010

0000011100000111

0010011000100110

6565

6666

9090

9797

5050

77

3838

Describe the ASCII code including Describe the ASCII code including control characters cont’dcontrol characters cont’d

• Control characters are keys on the keyboard that Control characters are keys on the keyboard that are not displayed on the screen.are not displayed on the screen.

• They are action keysThey are action keys– E.g. RETURN, TAB, DELETEE.g. RETURN, TAB, DELETE

• They are used to send a control signal to a printerThey are used to send a control signal to a printer• Sometimes control characters are referred to as Sometimes control characters are referred to as

‘non-printable characters’‘non-printable characters’• They are the first 32 characters in ASCIIThey are the first 32 characters in ASCII

Describe the term character Describe the term character setset

• The complete set of The complete set of characters that is characters that is represented on the represented on the keyboard is called the keyboard is called the character setcharacter set – This includes This includes allall the letters the letters

of the alphabet (upper and of the alphabet (upper and lower case), the digits 0 to lower case), the digits 0 to 9, punctuation marks, 9, punctuation marks, special symbols, such as %, special symbols, such as %, £, & and #, and £, & and #, and control control characters.characters.

– Using 7 bits it is possible to Using 7 bits it is possible to store 2store 277 = 2 x 2 x 2 x 2 x 2 = 2 x 2 x 2 x 2 x 2 x 2 x 2 = 128 different x 2 x 2 = 128 different characters in ASCIIcharacters in ASCII

• However the English However the English language requires fewer language requires fewer that 128 charactersthat 128 characters

Describe the bit map method of Describe the bit map method of graphic representation using examples graphic representation using examples of black and white bit mapsof black and white bit maps• Computers store graphical Computers store graphical

images in memory, on images in memory, on backing storage devices backing storage devices and display them on the and display them on the monitor as bit maps.monitor as bit maps.

• A pixel is the most basic A pixel is the most basic component of any component of any computer graphic. computer graphic. – Every computer graphic is Every computer graphic is

made up of a grid of pixels.made up of a grid of pixels.

• The computer represents The computer represents the image in memory as a the image in memory as a file of 0s and 1sfile of 0s and 1s– White pixels are White pixels are

represented by a 0 and represented by a 0 and black pixels by a 1black pixels by a 1

– The file is known as a bit The file is known as a bit mapmap

00 00 11 11 11 11 00 00

00 11 00 00 00 00 11 00

00 11 00 00 00 00 11 00

11 00 11 00 00 11 00 11

00 11 00 00 00 00 11 00

00 11 00 11 11 00 11 00

00 00 11 00 00 11 00 00

00 00 00 11 11 00 00 00There is a one-to-one relationship betweenThere is a one-to-one relationship betweenthe pixels and the bit patternthe pixels and the bit pattern

Describe the bit map method of Describe the bit map method of graphic representation using examples graphic representation using examples of black and white bit maps cont’dof black and white bit maps cont’d

• The quality of a graphical image is directly The quality of a graphical image is directly related to the number of pixels used to related to the number of pixels used to produce it.produce it.

• A good quality image will have many small A good quality image will have many small pixels, e.g. a photograph pixels, e.g. a photograph

• A poor quality image will have few large A poor quality image will have few large pixels, e.g. teletext pixels, e.g. teletext

• The concentration or density of pixels is The concentration or density of pixels is called the called the resolutionresolution of the image of the image– This is measured in dots per inch or dpi (dpi is This is measured in dots per inch or dpi (dpi is

often used in regards to a printer or a scanner)often used in regards to a printer or a scanner)

Calculate storage requirements for a Calculate storage requirements for a

bitmap graphicbitmap 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 An image with a high resolution will have many pixels and so will take

up more storage space than a low resolution image.up more storage space than a low resolution image.• Imagine we want to calculate the storage requirement for an 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 that has a dpi of 1200 x 1200 dpi and has a length of 5 inches and a breadth of 4 inches.breadth of 4 inches.

lengthlength = 1200 x 5 = 6000 pixels= 1200 x 5 = 6000 pixelsbreadthbreadth = 1200 x 4 = 4800 pixels= 1200 x 4 = 4800 pixels

Total no of pixelsTotal no of pixels = 6000 x 4800= 6000 x 4800= 28,800,000 pixels= 28,800,000 pixels

1 pixel needs 1 bit of data 1 pixel needs 1 bit of data storage storage = 28,800,000 bits= 28,800,000 bits

= 3,600,000 bytes= 3,600,000 bytes= 3515.625 Kb= 3515.625 Kb= 3.46 Mb= 3.46 Mb

5 inches

4 in

ch

es

Computer StructureComputer 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 Represent the structure of a computer in the form of a simple five box diagram

representing:representing:– Input devicesInput devices– ProcessorProcessor– Main memoryMain memory– Output devicesOutput devices– Backing storageBacking 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 Describe the uses of embedded, palmtop, laptop, desktop and mainframe

computerscomputers• Compare the features of embedded, palmtop, laptop, desktop and mainframe Compare the features of embedded, palmtop, laptop, desktop and mainframe

computers:computers:– Type and speed of processorType and speed of processor– Size of main memorySize of main memory– Backing storageBacking storage– Input and output devicesInput and output devices

• Describe clock speed as a simple indicator of system performanceDescribe clock speed as a simple indicator of system performance

Describe purpose of a processorDescribe purpose of a processor• The processor is the hardware inside the The processor is the hardware inside the

CPU that controls the operation of the CPU that controls the operation of the computer computer – It could be said the processor is the computers It could be said the processor is the computers

brain.brain. • Within the processor are theWithin the processor are the

– Control unitControl unit– Arithmetic and logic unit (ALU)Arithmetic and logic unit (ALU)– RegistersRegisters

• Together they are responsible for the Together they are responsible for the overall operations that make the computer overall operations that make the computer workwork

• When comparing processors the most When comparing processors the most important measure is the speed they workimportant measure is the speed they work– This speed is measured in Hertz (Hz), This speed is measured in Hertz (Hz),

MegaHertz (MHz) or GigaHertz (GHz)MegaHertz (MHz) or GigaHertz (GHz)

List the parts of a processor as List the parts of a processor as ALU, control unit and registersALU, control unit and registers• Control UnitControl Unit

– The main functions of the control unit are: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:The main functions of the ALU are:

• To perform arithmetic calculations (addition, subtraction, To perform arithmetic calculations (addition, subtraction, multiplication, division)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 These are temporary storage areas within the processor that

are used to hold data that has been fetched from the memory are used to hold data that has been fetched from the memory or produced during a calculationor produced during a calculation

• In general the control unit is responsible for the running of In general the control unit is responsible for the running of the programs that are loaded into the main memory.the programs that are loaded into the main memory.

Represent the structure of a computer in the Represent the structure of a computer in the form of a simple five box diagram form of a simple five box diagram representing: input devices, processor, main representing: input devices, processor, main memory, output devices and backing memory, output devices and backing storagestorage

Processor

Main Memory

Input

BackingStorage

Input

Output

five box diagram

Distinguish between main memory and Distinguish between main memory and backing storagebacking storage• Main memoryMain memory

– ROM and RAM are the chips ROM and RAM are the chips inside memory that allow the inside memory that allow the computer to keep track of computer to keep track of what it is doing.what it is doing.

– The computer needs two The computer needs two different types of memory different types of memory main because each has a main because each has a different job to do.different job to do.• ROM is used to stored a small ROM is used to stored a small

part of the OS called the part of the OS called the bootstrap loader. This program bootstrap loader. This program starts up the computer.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 offRAM 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.

http://www.nelslindahl.net/pcguide/RAM.JPG

Distinguish between main memory Distinguish between main memory and backing storage cont’dand backing storage cont’d

• Backing StorageBacking Storage– Examples of this are floppy Examples of this are floppy

disks, flash drives, hard drives, disks, flash drives, hard drives, CD, etc.CD, etc.

– By saving files and programs By saving files and programs onto backing storage they will onto backing storage they will still be there even after the still be there even after the computer is switched offcomputer is switched off

• Main memory is not as large Main memory is not as large as backing storage devicesas backing storage devices

BACKING STORAGEDEVICES

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Describe the features of ROM and Describe the features of ROM and RAMRAM• The main memory is composed of ROM and The main memory is composed of ROM and

RAM.RAM.• ROM has the following featuresROM has the following features

– Data in ROM is permanently etched onto a Data in ROM is permanently etched onto a microchipmicrochip

– ROM is read-only so it cannot be changedROM is read-only so it cannot be changed– Data on ROM is not lost when the computer is Data on ROM is not lost when the computer is

switched offswitched off• RAM has the following features:RAM has the following features:

– The data in RAM is read/write so it can be The data in RAM is read/write so it can be changedchanged

– All data stored in RAM is lost when the computer All data stored in RAM is lost when the computer is switched offis switched off

– RAM is sometimes referred to as primary storageRAM is sometimes referred to as primary storage

Describe the uses of embedded, Describe the uses of embedded, palmtop, laptop, desktop and palmtop, laptop, desktop and mainframe computersmainframe computers• Embedded SystemsEmbedded Systems

– A combination of hardware and software to perform a specific function,A combination of hardware and software to perform a specific function,• E.g. a mobile phone, interactive game boxes, elevatorsE.g. a mobile phone, interactive game boxes, elevators

• PalmtopPalmtop– Simple version of basic computer application, web browsing and email, Simple version of basic computer application, web browsing and email,

maybe a cellular phone connectionmaybe a cellular phone connection• LaptopLaptop

– Mainly used as a portable computer system between the user’s place Mainly used as a portable computer system between the user’s place of work and homeof work and home

• DesktopDesktop– This is a computer system that can fit on your desk at home, work, This is a computer system that can fit on your desk at home, work,

school or collegeschool or college– Some users need a general-purpose desktop computer to run a range Some users need a general-purpose desktop computer to run a range

off applications; others need a desktop computer that will form a off applications; others need a desktop computer that will form a workstation on a networkworkstation on a network

• Mainframe computersMainframe computers– Used by large companies, such as banks and insurance companies to Used by large companies, such as banks and insurance companies to

allow remote access to the processor which is held in a central location.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.Their processor is very powerful as hugh amounts of data is dealt with.

Compare the features of embedded, palmtop, laptop, desktop and Compare the features of embedded, palmtop, laptop, desktop and mainframe computers: type and speed of processor, size of main mainframe computers: type and speed of processor, size of main memory, backing storage, input and output devicesmemory, backing storage, input and output devices

EmbeddedEmbedded PalmtopPalmtop LaptopLaptop DesktopDesktop Mainframe Mainframe ComputersComputers

Processor PowerProcessor Power Up to 60 MhzUp to 60 Mhz 200-500 MHz200-500 MHz 2.4 GHz2.4 GHz 3.2 GHz3.2 GHz Several Several processorsprocessors

Memory SizeMemory Size 1 bit – 512Mb +1 bit – 512Mb + 64 Mb64 Mb 512 Mb512 Mb 256 MB256 MB 32Gb memory32Gb memory

Backing StoreBacking Store •nonenone

•Flash memoryFlash memory•RAM so a RAM so a constant current constant current has to be applied.has to be applied.

•Additional Additional backing storage backing storage can be purchasedcan be purchased

•40 Gb hard 40 Gb hard drivedrive

•Removable Removable 3.5” floppy 3.5” floppy drivedrive

•A combination A combination 8x DVD-ROM 8x DVD-ROM and 8x/4x/24x and 8x/4x/24x CD-RW driveCD-RW drive

•Large capacity Large capacity hard-diskhard-disk

•CD-ROM/DVD CD-ROM/DVD drivedrive

•100Gb hard 100Gb hard diskdisk

•Tape driveTape drive

Input DevicesInput Devices Field Field probes/sensors, probes/sensors, keyboards, keyboards, microphone, microphone, wands, disk wands, disk heads, strain heads, strain gaugesgauges

•Touch screenTouch screen

•Voice inputVoice input

•KeyboardKeyboard

•Infrared receiverInfrared receiver

•ModemModem

•Touch padTouch pad

•KeyboardKeyboard•MicrophoneMicrophone

•WebcamWebcam

•Graphics tabletGraphics tablet

•ScannerScanner

•JoystickJoystick

KeyboardKeyboard

OutputOutput

DevicesDevicesSpeakers, Speakers, projectors, projectors, network cables, network cables, disk heads, disk heads, impact printers, impact printers, card punchescard punches

•LCD screenLCD screen

•a speakera speaker

•Infrared Infrared transmittertransmitter

•Wireless Wireless connectionconnection

•LCD screenLCD screen

•SpeakersSpeakers

•Infrared Infrared transmittertransmitter

•Modem NICModem NIC

•USB or USB or Firewire Firewire interfaceinterface

•Inkjet/laser Inkjet/laser printerprinter

•17” monitor17” monitor

•SpeakersSpeakers

•ModemModem

•NICNIC

•Line printersLine printers

•Page printersPage printers

•monitorsmonitors

Describe clock speed as a simple Describe clock speed as a simple indicator of system performanceindicator of system performance• Clock speed is often used as an indicator of Clock speed is often used as an indicator of

the processing power of a systemthe processing power of a system• The clock in a computer system is a regular The clock in a computer system is a regular

stream of electronic pulses in the control stream of electronic pulses in the control circuit that keeps everything working in circuit that keeps everything working in timetime– The faster the clock speed of a computer The faster the clock speed of a computer

systems the quicker it processes instructionssystems the quicker it processes instructions

• The speed of the clock is measured in MHz The speed of the clock is measured in MHz (MegaHertz) or GHz (GigaHertz) (MegaHertz) or GHz (GigaHertz)– A processor working at 900 MHz sends out 900 A processor working at 900 MHz sends out 900

million clock pulses per secondmillion clock pulses per second

PeripheralsPeripherals

• Describe the features, functions and uses of the following input Describe the features, functions and uses of the following input devices:devices:– Keyboard, Mouse, Microphone, Touchpad, Digital camera, ScannerKeyboard, 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, costresolution, capacity, speed of data transfer, cost

• Describe the features, functions and uses of a Describe the features, functions and uses of a – monitor, LCD panel, inkjet and laser printers, loud speakersmonitor, 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, costresolution, capacity, speed of data transfer, cost

• Describe the features, functions and uses of current magnetic Describe the features, functions and uses of current magnetic storage devices and media including storage devices and media including – floppy drive, hard drive, zip drive, magnetic tape drivefloppy drive, hard drive, zip drive, magnetic tape drive

• Describe the features, functions and uses of current optical storage Describe the features, functions and uses of current optical storage devices and media includingdevices and media including– CD-ROM, CD-R, CD-RW, DVD-ROM, rewitable DVDCD-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, costtype of access, capacity, speed of data transfer, cost

• Describe the need for interfaces with reference to the following Describe the need for interfaces with reference to the following functions:functions:– Compensating for differences in speed between the CPU and peripherals, Compensating for differences in speed between the CPU and peripherals,

data conversion from analogue to digital forms and temporary data data conversion from analogue to digital forms and temporary data storagestorage

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

FEATURESFEATURES FUNCTIONSFUNCTIONS USESUSES

KEYBOARDKEYBOARD accuracyaccuracy: : most errors most errors due to the fault of the due to the fault of the useruser

Each key sends a Each key sends a unique scan code unique scan code to the OS. The OS to the OS. The OS translates this translates this code into ASCII code into ASCII code.code.

•Text entry in a Text entry in a word processorword processor

•Keying in Keying in number/data to a number/data to a spreadsheetspreadsheet

•Entering a URL Entering a URL for a websitefor a website

MOUSEMOUSE accuracyaccuracy: : few errors few errors using a mouse, ten to using a mouse, ten to occur when the user occur when the user attempts to select attempts to select small items on screensmall items on screen

The movement of The movement of the mouse ball the mouse ball inside the mouse inside the mouse is detected by a is detected by a sensor and sent sensor and sent to the OS. The OS to the OS. The OS uses this info to uses this info to control the control the position of the position of the pointer on the pointer on the screen. screen.

•General input General input device, used for device, used for pointing. pointing.

•Ideal for to Ideal for to accessing menus accessing menus and making and making selections as selections as required.required.


MICROPHONEMICROPHONE accuracyaccuracy: : depends depends how well the sound how well the sound card carries out sound card carries out sound samplingsampling

Inputs sound to Inputs sound to the computer. the computer. The microphone The microphone takes a sound and takes a sound and converts it into an converts it into an electronic signal. electronic signal. This signal must This signal must now be converted now be converted from analogue to from analogue to digital signal. digital signal.

As a means of As a means of issuing issuing commands to the commands to the operating system operating system or applications. or applications. (voice (voice recognition)recognition)To record musicTo record music

•To use the To use the computer as a computer as a telephonetelephone

TOUCHPADTOUCHPAD accuracyaccuracy: as : as few few errors as using a errors as using a mouse, tend to occur mouse, tend to occur when the user when the user attempts to select attempts to select small items on screensmall items on screen

By moving an By moving an object along the object along the pad, the pointer pad, the pointer moves on the moves on the display. Beneath display. Beneath the pad there are the pad there are two layers that two layers that create an create an electromagnetic electromagnetic field. On contact field. On contact the properties of the properties of the field change & the field change & the details are the details are input to the input to the computer.computer.

Used as a Used as a pointing device pointing device on some portable on some portable computerscomputers


DIGITAL DIGITAL CAMERACAMERA

accuracyaccuracy: : based on based on the quality (dpi) of the quality (dpi) of the image: Often 3 the image: Often 3 different settings: different settings: 480x640, 1024x768, 480x640, 1024x768, 1600x12001600x1200

Additional Additional FeaturesFeatures::

Special effects:Special effects:

Zoom (optical and Zoom (optical and digital)digital)

Photo Imaging Photo Imaging SoftwareSoftware

Direct printing Direct printing without using a without using a computercomputer

In a digital In a digital camera the film camera the film used in a used in a conventional conventional camera is camera is replaced with replaced with an array of an array of image sensors image sensors and a storage and a storage device. The device. The image sensor is image sensor is made from an made from an array of array of photosensitive photosensitive cells. Each cell cells. Each cell converts the converts the light that strikes light that strikes it into an it into an electronic signal electronic signal that is that is proportional to proportional to intensity of the intensity of the light.light.

•To take To take photographsphotographs

•Input images Input images into the into the computer these computer these can then be can then be edited using edited using photo imaging photo imaging software.software.


SCANNERSCANNER accuracyaccuracy: : based on based on the quality (dpi) of the quality (dpi) of the image: for the image: for display purposes on display purposes on a moniotr : 72 dpia moniotr : 72 dpi

Flat bed scanners up Flat bed scanners up to: 2400x4800to: 2400x4800

To capture To capture data, the data, the scanner reflects scanner reflects light off a paper light off a paper image that is image that is placed on a placed on a sheet of glass. sheet of glass. The reflected The reflected light is gathered light is gathered by by photosensitive photosensitive cells. Passed cells. Passed through an A to through an A to D converter to D converter to create a bit create a bit map.map.

Converting Converting photographic photographic prints into prints into digital form. digital form. Scanning Scanning documents for documents for OCR.OCR.

WEBCAMWEBCAM accuracyaccuracy: : max max number of pixels: number of pixels: approx. 640x480approx. 640x480

Consists of a Consists of a digital camera digital camera that has a piece that has a piece of software of software connected that connected that periodically periodically grabs a frame.grabs a frame.

•Video chatVideo chat

•Video Video conferencingconferencing

•Live streaming Live streaming internet internet webcamwebcam

•Still image Still image capturescaptures

•Video e-mailVideo e-mail

Compare input devices using Compare input devices using appropriate characteristics including appropriate characteristics including resolution, capacity, speed of data resolution, capacity, speed of data transfer, costtransfer, cost

• See table belowSee table below

ResolutionResolution CapacityCapacity Speed of data Speed of data transfertransfer

costcost

KeyboardKeyboard N/AN/A N/AN/A restricted by restricted by users typing users typing skills, max input skills, max input speed 10 speed 10 characters per characters per secsec

£12 - £12 - £30£30

MouseMouse N/AN/A N/AN/A the actual data the actual data transfer rate transfer rate does not change does not change the OS can be the OS can be set by the userset by the user

£3 - £15£3 - £15

MicrophoneMicrophone N/AN/A Unlikely to Unlikely to have much have much of its own of its own cache. cache. Generally Generally depend depend upon fast upon fast access via a access via a sound card sound card to hard disk to hard disk space to space to store the store the sample.sample.

speed of speed of conversion from conversion from analogue to analogue to digital depends digital depends on the processor on the processor and the amount and the amount of RAMof RAM

£10 - £10 - £40£40

ResolutionResolution CapacityCapacity Speed of data Speed of data transfertransfer

costcost

TouchpadTouchpad N/AN/A N/AN/A based on USB 1.0: based on USB 1.0: 12 Mbits per sec12 Mbits per sec

approx approx £175£175

Digital Digital CameraCamera

Often 3 Often 3 settings: settings: 480x640, 480x640, 1024x768, 1024x768, 1600x12001600x1200

Vary from Vary from 16 MB – 2 16 MB – 2 GbGb

USB 1.0: 12 Mbit sUSB 1.0: 12 Mbit s

USB 2.0: 480 Mbit USB 2.0: 480 Mbit per secper sec

depends depends on make on make and and quality. quality. £100 -£100 -£3000+£3000+

ScannerScanner for display for display purposes on a purposes on a monitor : 72 dpimonitor : 72 dpi

Flat bed Flat bed scanners up to: scanners up to: 2400x48002400x4800

The scanner The scanner itself itself doesn’t doesn’t have any have any RAM so the RAM so the data is sent data is sent directly to directly to computer.computer.

USB 2.0: 480 Mbit USB 2.0: 480 Mbit per secper sec

£40 – £40 – £300+£300+

WebcamWebcam max number of max number of pixels: approx. pixels: approx. 640x480640x480

N/AN/A USB 2.0: 480 Mbit USB 2.0: 480 Mbit per secper sec

£12 - 50£12 - 50

Describe the features, functions and Describe the features, functions and uses of a monitor, LCD panel, inkjet uses of a monitor, LCD panel, inkjet and laser printers, loud speakersand laser printers, loud speakers

• See table belowSee table below

FeaturesFeatures FunctionsFunctions UsesUses

CRT MonitorCRT Monitor Heavy, tend to be Heavy, tend to be fairly large. fairly large. Sealed glass tube Sealed glass tube that has no air that has no air inside it.inside it.

An electronic gun An electronic gun at one end fires a at one end fires a stream of tiny stream of tiny electrons at the electrons at the screen located as screen located as the other end. The the other end. The image is made by image is made by illuminating illuminating particles on the particles on the screen.screen.

Since they are Since they are heavy and not heavy and not easily moved they easily moved they are usually used are usually used with desktop with desktop computers.computers.

LCD PanelLCD Panel Lightweight, Lightweight, compact and compact and require little require little power compared power compared to CRT monitorsto CRT monitors

Allows different Allows different amounts of white amounts of white backlight through backlight through an active filter. an active filter. The red, green The red, green and blue of each and blue of each pixel are achieved pixel are achieved by filtering the by filtering the white light that is white light that is allowed through.allowed through.

Ideal for use in Ideal for use in laptops, tablets laptops, tablets and palmtops. and palmtops.

Full sized LCD Full sized LCD monitors are monitors are becoming becoming increasingly increasingly popular with popular with desktop desktop computerscomputers


Inkjet PrinterInkjet Printer Come in both Come in both black and black and white and white and colourcolour

These work by These work by spraying a fine jet spraying a fine jet of ink, which is of ink, which is both heated and both heated and under pressure under pressure onto paper.onto paper.

Ideal for the Ideal for the occasional occasional presentation presentation and livening up and livening up mostly text mostly text documents.documents.

Also for Also for InvitationsInvitations

Greeting cards, Greeting cards, etc.etc.

Laser PrinterLaser Printer Come in both Come in both black and black and white and white and colour. Tend colour. Tend to be fairly to be fairly large in large in comparison comparison to an inkjet to an inkjet printer.printer.

16pp print 16pp print speed, 1speed, 1stst page in 12 page in 12 secs, USB 2secs, USB 2

By using a laser By using a laser beam to trace the beam to trace the image of the page image of the page layout onto a layout onto a photosensitive photosensitive drum. This image drum. This image then attracts toner then attracts toner by means of an by means of an electrostatic electrostatic charge. The toner charge. The toner is fused to the is fused to the paper by heat and paper by heat and pressure.pressure.

Ideal for Ideal for printing a lot of printing a lot of printouts. printouts. Commonly Commonly found in schools found in schools and offices.and offices.


LoudspeakerLoudspeaker Two types:Two types:

•Inbuilt (poor Inbuilt (poor quality)quality)

•ExternalExternal

InbuitInbuit::

To produce a To produce a sound from the sound from the computercomputer

ExternalExternal::

To produce To produce good sound good sound quality that is quality that is comparable to comparable to

hi-fi systemshi-fi systems

Compare output devices using Compare output devices using appropriate characteristics including appropriate characteristics including resolution, capacity, speed of data resolution, capacity, speed of data transfer, costtransfer, cost

ResolutionResolution CapacitCapacityy

Speed of Speed of TransferTransfer

CostCost

MonitorMonitor 17” monitor17” monitor: :

max 1280x1024max 1280x1024

800x600 or 800x600 or 1024x768 1024x768

15” monitor15” monitor: : 640x480 or 640x480 or 800x600800x600

N/AN/A 17” monitor17” monitor::

£80£80

25” monitor25” monitor::

£1800£1800

LCD PanelLCD Panel Max 1280x1024Max 1280x1024 17” monitor17” monitor::

£300£300

ResolutioResolutionn

CapacitCapacityy


CostCost

Inkjet PrinterInkjet Printer Typically Typically 2880x1442880x14400

Black and Black and white:white:

10 ppm10 ppm

Colour: Colour:

6 ppm6 ppm

Some are as cheap Some are as cheap as £25 because as £25 because the profit comes the profit comes form the form the consumables, e.g. consumables, e.g. ink cartridges.ink cartridges.

5p to print a page 5p to print a page of text more for of text more for graphics.graphics.

Top of the range Top of the range models approx. models approx. £220£220

Laser PrinterLaser Printer From 600 From 600 to 2400 to 2400 dpidpi

Black & Black & white: white: 8 Mb 8 Mb RAM RAM expandexpandable to able to 136 Mb136 Mb

12 12 secondsseconds

Black & white:Black & white:

£150 to £800£150 to £800

Cheaper Cheaper consumables, consumables, typically costs less typically costs less than 1p per page than 1p per page of text.of text.

Colour:Colour:

£550 to £ 2000£550 to £ 2000

ResolutioResolutionn

CapacitCapacityy


CostCost

LoudspeakerLoudspeaker N/AN/A N/AN/A Depends Depends on sound on sound cardcard

Varies but approx. Varies but approx. £100 to £300£100 to £300

Describe the features, functions and uses of current Describe the features, functions and uses of current magnetic storage devices and media including floppy magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape drivedrive, hard drive, zip drive, magnetic tape drive


Floppy Floppy Drive/DisksDrive/Disks

•Disk is made of circular Disk is made of circular plastic plates coated in ferric plastic plates coated in ferric oxide.oxide.

•Surface of the disk is Surface of the disk is divided into tracks and divided into tracks and sectors on which data is sectors on which data is stored as magnetic patternsstored as magnetic patterns

•The disk itself is floppy but The disk itself is floppy but covered in hard plasticcovered in hard plastic

•The standard size is 3.5”The standard size is 3.5”

•Direct accessDirect access

•Means of Means of storing storing smallsmall files files

•TransferriTransferring files ng files from one from one computer computer to anotherto another

Storing Storing small small files, files, unsuitablunsuitable for e for storing storing anything anything but small but small files.files.

Describe the features, functions and uses of current Describe the features, functions and uses of current magnetic storage devices and media including magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape floppy drive, hard drive, zip drive, magnetic tape drivedrive


Hard Hard DriveDrive

•A rigid disk with a A rigid disk with a magnetised surface.magnetised surface.

•The surface is divided The surface is divided into tracks and sectors on into tracks and sectors on which data is stored which data is stored magnetically.magnetically.

•The data is read with a The data is read with a read/write head fixed to read/write head fixed to an arm that moves an arm that moves across the surface of the across the surface of the disk.disk.

•Hard disks are usually Hard disks are usually sealed in a protective sealed in a protective container to prevent dust container to prevent dust corrupting the data. corrupting the data.

•Direct accessDirect access

Used in Used in ALLALL computerscomputers

Typical hard Typical hard disk will disk will store:store:

•The OSThe OS

•ApplicationsApplications

•User filesUser files

Internal Internal backing backing storage storage device.device.

An essential An essential component of component of the modern the modern computer, computer, particularly particularly with the with the increase in increase in video editing, video editing, which which demands a demands a great deal of great deal of storage space. storage space.

Describe the features, functions and uses of current Describe the features, functions and uses of current magnetic storage devices and media including floppy magnetic storage devices and media including floppy drive, hard drive, zip drive, magnetic tape drivedrive, hard drive, zip drive, magnetic tape drive


Zip DriveZip Drive A removable storage device A removable storage device that securely stored that securely stored computer data magnetically.computer data magnetically.

It is durable and portable.It is durable and portable.

A 100 Mb zip drive can hold A 100 Mb zip drive can hold the equivalent of 70 floppy the equivalent of 70 floppy disks.disks.

Direct AccessDirect Access

Good for Good for storing storing large files large files on a on a portable portable medium.medium.

Stores large Stores large files, e.g. files, e.g. photo images, photo images, desktop desktop publishing publishing files and files and video.video.

Often used to Often used to back up data.back up data.

Magnetic Magnetic Tape Tape DriveDrive

Inexpensive, well understood Inexpensive, well understood and easy to remove and and easy to remove and replace.replace.

Traditionally large real-to-Traditionally large real-to-reel tapes used.reel tapes used.

Currently tends to be Currently tends to be cassettes.cassettes.

Some of these are even Some of these are even smaller than an audio smaller than an audio cassette but hold mmore cassette but hold mmore data than the huge reels.data than the huge reels.

Sequential AccessSequential Access

used for used for permanenpermanent storaget storage

Often used for Often used for back-up of back-up of hard disks. hard disks. This is This is automatically automatically done done overnight and overnight and is suitable for is suitable for network or network or mainframe mainframe backups.backups.

Describe the features, functions and uses of current Describe the features, functions and uses of current optical storage devices and media including CD-ROM, CD-optical storage devices and media including CD-ROM, CD-R, CD-RW, DVD-ROM, rewritable DVDR, CD-RW, DVD-ROM, rewritable DVD


CD-CD-ROMROM

CD-ROM writers use a CD-ROM writers use a high-powered laser to high-powered laser to store data by making tiny store data by making tiny pits in the surface of the pits in the surface of the CD-ROM disk. The patterns CD-ROM disk. The patterns of these pits is read by a of these pits is read by a sensor in the CD-ROM sensor in the CD-ROM drive that detects light drive that detects light reflected off the surface of reflected off the surface of the disk. The patterns are the disk. The patterns are then turned into binary then turned into binary numbers.numbers.

Direct AccessDirect Access

These can These can only be used only be used to read to read information on information on them- the them- the user cannot user cannot save data to a save data to a CD-ROM disk.CD-ROM disk.

Store encyclopaediasStore encyclopaedias

Store SoftwareStore Software

CD-RCD-R Compact disk recordableCompact disk recordable

Can be recorded on once Can be recorded on once only.only.

Several different formats, Several different formats, some won’t work in a CD-some won’t work in a CD-ROM driveROM drive

Once the disk Once the disk has been has been recorded on it recorded on it cannot be cannot be recorded over.recorded over.

Distribution of a Distribution of a finished finished product/programproduct/program

Permanent backing Permanent backing storage and archivingstorage and archiving

encyclopaediasencyclopaedias



CD-CD-RWRW

Compact disk Compact disk rewritable. rewritable.

Same size and shape Same size and shape as other CD media as other CD media but you can write but you can write and rewrite onto a and rewrite onto a CD-RWCD-RW

The disk can The disk can be recorded be recorded on and on and recorded over recorded over as desired.as desired.

Portable media for Portable media for transferring files to another transferring files to another computer.computer.

Back-up of hard drive (drive Back-up of hard drive (drive image)image)

Storing photos/movie files Storing photos/movie files (large size)(large size)

DVD-DVD-ROMROM

Digital versatile disk Digital versatile disk read only memoryread only memory

Same size and Same size and composition as CDs, composition as CDs, but store more but store more information as a information as a consequence of consequence of smaller track spacing smaller track spacing and smaller ‘land and smaller ‘land and pits’ (bits)and pits’ (bits)

Can be recorded on Can be recorded on both sides.both sides.

These can These can only be used only be used to read to read information information on them- the on them- the user cannot user cannot save data to save data to a DVD-ROM a DVD-ROM disk.disk.

EncyclopaediasEncyclopaedias

GamesGames

MoviesMovies



DVD-RDVD-R Allows the user to Allows the user to record in a single record in a single session or in session or in multiple sessions multiple sessions until the disk is until the disk is completecomplete

Can only Can only record on to record on to the DVD until the DVD until the DVD is the DVD is full. The DVD full. The DVD cannot be cannot be overwrittenoverwritten

Distribution of a finished Distribution of a finished product/programproduct/program

Permanent backing storage Permanent backing storage and archivingand archiving


DVD-RWDVD-RW Can be used over Can be used over 1000 times to 1000 times to write and re-write write and re-write data onto the RW data onto the RW disk. disk.

Two different Two different types of disk DVD-types of disk DVD-RW and DVD+RW.RW and DVD+RW.

Can record on Can record on the DVD as the DVD as often as often as desired.desired.

Distribution of a finished Distribution of a finished product/programproduct/program

Permanent backing storage Permanent backing storage and archivingand archiving


Compare storage devices using Compare storage devices using appropriate characteristics including appropriate characteristics including type of access, capacity, speed of data type of access, capacity, speed of data transfer, costtransfer, cost

DriveDrive CapacitCapacityy

TransferTransfer Type of Type of AccessAccess

Drive CostDrive Cost Media Media CostCost

Floppy Floppy diskdisk

LowLow SlowSlow DirectDirect Very lowVery low Very lowVery low

Hard diskHard disk Very Very highhigh

Very fastVery fast DirectDirect Low/Low/mediummedium

--

TapeTape Very Very highhigh

Fast (but Fast (but sequentialsequential

))

SerialSerial HighHigh HighHigh

CD-RCD-R HighHigh FastFast DirectDirect LowLow Very LowVery Low

CD-RWCD-RW HighHigh FastFast DirectDirect LowLow LowLow

RewritablRewritable DVDe DVD

Very Very highhigh

FastFast DirectDirect Low/Low/mediummedium

LowLow

FlashFlash HighHigh FastFast DirectDirect Low/Low/mediummedium

N/AN/A

Describe the need for interfaces with reference to the Describe the need for interfaces with reference to the following functions:following functions:Compensating for differences in speed between the CPU and Compensating for differences in speed between the CPU and peripherals, data conversion from analogue to digital forms and peripherals, data conversion from analogue to digital forms and temporary data storagetemporary data storage

• An interface is required because there are An interface is required because there are differences between the peripheral device and the differences between the peripheral device and the processor.processor.– These characteristics include;These characteristics include;

• Data conversionData conversion– The peripheral devices accept analogue signals that must be The peripheral devices accept analogue signals that must be

converted into digital for the processor to understand them 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, Peripherals tend to be in terms of ppm or frames per second,

however the processor works much faster, e.g. 28 billion cycles per however the processor works much faster, e.g. 28 billion cycles per sec. This difference in the speed of operation between the devices sec. This difference in the speed of operation between the devices requires an interface as the processor can deliver data much faster requires an interface as the processor can deliver data much faster than the peripherals can handle. than the peripherals can handle.

• Temporary storage of dataTemporary storage of data

NetworkingNetworking

• 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 functionsTransmission 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 E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up foldersbook, 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 enginesWeb pages, hyperlinks, browser, search engines

• Describe the following economic factors which have led to the Describe the following economic factors which have led to the development of computer networks:development of computer networks:– Falling cost of telecommunication technologies and services, shared Falling cost of telecommunication technologies and services, shared

access to expensive equipment, geographical spread of access to expensive equipment, geographical spread of organisation, demand for up-to-date informationorganisation, demand for up-to-date information

• Describe the main features of the Computer Misuse Act, the Describe the main features of the Computer Misuse Act, the Copyright, Designs and Patents Act and the Data Protection ActCopyright, Designs and Patents Act and the Data Protection Act

Describe the following features of LANs, WANs and Describe the following features of LANs, WANs and the Internet:the Internet:Transmission media, bandwidth, graphical spread Transmission media, bandwidth, graphical spread and functionsand functions

FeaturesFeatures LANLAN WANWAN

TransmissioTransmission median media

TwisteTwisted paird pair

CoaxiaCoaxial cablel cable

Fibre Fibre opticsoptics

WirelesWirelesss

MicrowavMicrowavee

SatellitSatellitee

RadioRadio

BandwidthBandwidth 10 Mb 10 Mb per per secsec

500 500 Mb per Mb per secsec

30 Gb 30 Gb per secper sec

54 Mb 54 Mb per secper sec



2 MB 2 MB per per secsec

GeographicGeographical spreadal spread

Can be in a single building or a Can be in a single building or a site linking buildings togethersite linking buildings together

Spread throughout a Spread throughout a country or the worldcountry or the world

FunctionsFunctions •A LAN allows users to share data A LAN allows users to share data files, applications, and peripheralsfiles, applications, and peripherals

•Users can access their work from any Users can access their work from any station on the networkstation on the network

•Different levels of access can be Different levels of access can be granted to usersgranted to users

•Users can communicate through e-Users can communicate through e-mailmail

•Allows users to share data Allows users to share data files and equipmentfiles and equipment

•Permits ‘live’ chatPermits ‘live’ chat

•Allows users to e-mail each Allows users to e-mail each otherother

•Allows users video Allows users video conferencingconferencing

•Allows access to databasesAllows access to databases

•E-commerceE-commerce

•EntertainmentEntertainment

Describe the following features of LANs, WANs and Describe the following features of LANs, WANs and the Internet:the Internet:Transmission media, bandwidth, graphical spread Transmission media, bandwidth, graphical spread and functions. Questions and Answers.and functions. Questions and Answers.

1.1. What does the bandwidth determine?What does the bandwidth determine?The amount of information that can be transferred at a timeThe amount of information that can be transferred at a time

2.2. What is the difference between the geographical spread What is the difference between the geographical spread of a WAN and a LAN.of a WAN and a LAN.LAN:LAN: Can be in a single building or a site linking buildings Can be in a single building or a site linking buildings togethertogetherWAN:WAN: Spread throughout a country or the worldSpread throughout a country or the world

3.3. State two functions of a LANState two functions of a LANA LAN allows users to share data files, applications, and A LAN allows users to share data files, applications, and peripheralsperipheralsUsers can access their work from any station on the networkUsers can access their work from any station on the network

4.4. State two functions of a WANState two functions of a WANAllows users to e-mail each otherAllows users to e-mail each otherAllows users video conferencingAllows users video conferencing

Describe the benefits of Describe the benefits of networksnetworks

• SecuritySecurity– Tampering with programs and files is Tampering with programs and files is

prevented through restricted access rightsprevented through restricted access rights– Personal work is saved in private spaces on Personal work is saved in private spaces on

hard disks that are password protected from hard disks that are password protected from inadvertent or malicious copying and/or inadvertent or malicious copying and/or deletiondeletion

• CommunicationCommunication– Data files, programs and peripheral devices Data files, programs and peripheral devices

can be sharedcan be shared– Communication is improved via Communication is improved via

e-mail/chat/bulletin boardse-mail/chat/bulletin boards• ManagementManagement

– Centralised back-up of filesCentralised back-up of files– Stations can be managed remotely.Stations can be managed remotely.

Describe the benefits of Describe the benefits of networksnetworksQuestions and AnswersQuestions and Answers1.1. List three advantages of a networkList three advantages of a network

SecuritySecurity– Tampering with programs and files is prevented through Tampering with programs and files is prevented through

restricted access rightsrestricted access rights– Personal work is saved in private spaces on hard disks that Personal work is saved in private spaces on hard disks that

are password protected from inadvertent or malicious are password protected from inadvertent or malicious copying and/or deletioncopying and/or deletion

• CommunicationCommunication– Data files, programs and peripheral devices can be sharedData files, programs and peripheral devices can be shared– Communication is improved via e-mail/chat/bulletin boardsCommunication is improved via e-mail/chat/bulletin boards

• ManagementManagement– Centralised back-up of filesCentralised back-up of files– Stations can be managed remotely.Stations can be managed remotely.

Describe the following features and functions of Describe the following features and functions of e-mail:e-mail:E-mail address, sending, reading, replying, setting up an E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up foldersaddress book, setting up mailing lists, setting up folders

• E-mail addressE-mail address– To send an e-mail message you must first To send an e-mail message you must first

have their e-mail address. have their e-mail address. – This is the location of the server on the This is the location of the server on the

internet where the person’s mailbox can be internet where the person’s mailbox can be found.found.•E.g. E.g. [email protected]@westlothian.org.uk

•The part before the ‘@’ symbol is the username The part before the ‘@’ symbol is the username of the person on that server and the of the person on that server and the ‘westlothian.org.uk’ part is the ‘westlothian.org.uk’ part is the domain namedomain name. . Together they make up the e-mail addres of the Together they make up the e-mail addres of the person to whom the message is being sent. person to whom the message is being sent.

mailto:[email protected]

Describe the following features and functions of e-Describe the following features and functions of e-mail:mail:E-mail address, sending, reading, replying, setting E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up an address book, setting up mailing lists, setting up foldersup folders • Sending Sending

– After entering the address of the recipient it is After entering the address of the recipient it is usual to enter a subject.usual to enter a subject.• This will appear as a short line of text telling them what This will appear as a short line of text telling them what

the massage is about.the massage is about.• It is possible to send a message without a subject but it It is possible to send a message without a subject but it

is not good etiquette.is not good etiquette.– The body of the massage is entered in the box The body of the massage is entered in the box

below the subject heading.below the subject heading.– Attachments can be added to the email in the Attachments can be added to the email in the

form of documents, files, pictures or video.form of documents, files, pictures or video.– When ready the user clicks on the send button When ready the user clicks on the send button

and the message is delivered.and the message is delivered.

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 E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up an address book, setting up mailing lists, setting up foldersfolderscont’dcont’d

• What is the domain name of the following e-What is the domain name of the following e-mail address?mail [email protected]@westlothian.org.uk

• Why do we add a subject line to our outgoing Why do we add a subject line to our outgoing e-mails?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?

mailto:[email protected]

Describe the following features and functions Describe the following features and functions of e-mail:of e-mail:E-mail address, sending, reading, replying, setting up E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up an address book, setting up mailing lists, setting up foldersfolders

• Reading Reading – In the e-mail software there is a send/receive In the e-mail software there is a send/receive

button that will send any unposted e-mails and at button that will send any unposted e-mails and at the same time download any that are waiting on the same time download any that are waiting on the server.the server.

– On web-based systems any new mail is On web-based systems any new mail is automatically made available when you log on to automatically made available when you log on to the server.the server.

• Replying Replying – The simplest way to reply to an e-mail is;The simplest way to reply to an e-mail is;

• Every e-mail client’s software has a reply button that not Every e-mail client’s software has a reply button that not only enables the recipient to reply directly without having only enables the recipient to reply directly without having to type in the e-mail address but adds the reply to the to type in the e-mail address but adds the reply to the current e-mail so that the recipient can scroll down the current e-mail so that the recipient can scroll down the message to read any previous correspondence.message to read any previous correspondence.

Describe the following features and functions Describe the following features and functions of e-mail:of e-mail:E-mail address, sending, reading, replying, setting up E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up an address book, setting up mailing lists, setting up foldersfolders

• Setting up an address book Setting up an address book – If you send e-mails regularly to the same If you send e-mails regularly to the same

people it is a good idea to set up an people it is a good idea to set up an electronic address bookelectronic address book

– The best time to add an address to your The best time to add an address to your address book is just after you have address book is just after you have received an e-amil from someone; all e-received an e-amil from someone; all e-mail software allows the option of adding a mail software allows the option of adding a sender’s e-mail address directly to the sender’s e-mail address directly to the address book without having to type it in.address book without having to type it in.

Describe the following features and functions of Describe the following features and functions of e-mail:e-mail:E-mail address, sending, reading, replying, setting up an E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up foldersaddress book, setting up mailing lists, setting up folders

• Setting up mailing lists Setting up mailing lists – A mailing lists is a pre-prepared list that A mailing lists is a pre-prepared list that

include all the addresses of the people include all the addresses of the people whom you wish to send a message towhom you wish to send a message to

– They are useful if you send messages to They are useful if you send messages to several people at the same time.several people at the same time.•You can create a list of friends or family You can create a list of friends or family

made up of a combination of addresses made up of a combination of addresses from your address book.from your address book.

– If for example you name one of the mailing If for example you name one of the mailing lists ‘friends’ then it can be selected in a lists ‘friends’ then it can be selected in a single operation.single operation.

Describe the following features and Describe the following features and functions of e-mail:functions of e-mail:E-mail address, sending, reading, replying, setting E-mail address, sending, reading, replying, setting up an address book, setting up mailing lists, setting up an address book, setting up mailing lists, setting up folders cont’dup folders cont’d

• Setting up foldersSetting up folders

– Creating folders is one way of preventing your Creating folders is one way of preventing your inbox from looking very cluttered.inbox from looking very cluttered.

– This is similar to creating folders on you computer This is similar to creating folders on you computer to store work in an organised fashion.to store work in an organised fashion.

– It is possible to create an entire hierarchy of It is possible to create an entire hierarchy of folders within foldersfolders within folders

– Once the structure of folders has been set up, Once the structure of folders has been set up, some e-mail programs allow the creation of some e-mail programs allow the creation of ‘message rules’, which automatically move mail ‘message rules’, which automatically move mail messages into the correct folder as soon as it is messages into the correct folder as soon as it is downloaded from the server.downloaded from the server.•This is a major benefit to people who receive This is a major benefit to people who receive

many e-mail messages each day.many e-mail messages each day.

Describe the following features of the World Wide Describe the following features of the World Wide Web:Web:Web pages, hyperlinks, browser, search enginesWeb pages, hyperlinks, browser, search engines• Web PagesWeb Pages

– A web page is a document that usually A web page is a document that usually contains text, images, and perhaps contains text, images, and perhaps multimedia files containing additional multimedia files containing additional information formatting information in HTMLinformation formatting information in HTML

– It is possible to create a web page in a simple It is possible to create a web page in a simple text editor or a word processing application; text editor or a word processing application; all you have to do is add the extra HTML code all you have to do is add the extra HTML code to the document so that the web browser to the document so that the web browser knows how to display the page.knows how to display the page.

Describe the following features of the World Wide Describe the following features of the World Wide Web:Web:Web pages, hyperlinks, browser, search enginesWeb pages, hyperlinks, browser, search engines• HyperlinksHyperlinks

– Hyperlink allow any page on the web to connect to Hyperlink allow any page on the web to connect to any other. any other. • If the user clicks on the link then the browser will If the user clicks on the link then the browser will

load the URL of the page it is seeking and try to load the URL of the page it is seeking and try to find it on the web.find it on the web.

•Sometimes a page will not be retrieved as it has Sometimes a page will not be retrieved as it has been removed from the server by the owner; this been removed from the server by the owner; this is known as a ‘dead’ link.is known as a ‘dead’ link.

– Hyperlinks are normally identified in blue and Hyperlinks are normally identified in blue and underlined when they are text links.underlined when they are text links.

– Hyperlinks can be associated with images as well as Hyperlinks can be associated with images as well as text and normally the pointer turns into a hand with text and normally the pointer turns into a hand with a pointing finger when placed on an image that has a a pointing finger when placed on an image that has a hyperlink attached to it.hyperlink attached to it.

Describe the following features of the World Describe the following features of the World Wide Web:Wide Web:Web pages, hyperlinks, browser, search Web pages, hyperlinks, browser, search enginesenginescont’dcont’d• Browser Browser

– A browser is a program that allows a user A browser is a program that allows a user to read and navigate web pages.to read and navigate web pages.

– Two of the most common browsers are Two of the most common browsers are Internet Explorer and Netscape Navigator. Internet Explorer and Netscape Navigator. Safari is rapidly replacing Netscape, Safari is rapidly replacing Netscape, particularly on Macs.particularly on Macs.

Describe the following features of the World Wide Describe the following features of the World Wide Web:Web:Web pages, hyperlinks, browser, search enginesWeb pages, hyperlinks, browser, search enginescont’dcont’d

• Search EnginesSearch Engines– A search engine, such as Google, is a web site A search engine, such as Google, is a web site

that users can go to to search for a site or that users can go to to search for a site or information if they do not know the URL.information if they do not know the URL.

– A search engine regularly runs programs called A search engine regularly runs programs called web crawlers web crawlers to gather information about what to gather information about what pages are on the internet.pages are on the internet.

– When the web crawler comes across a document When the web crawler comes across a document it sends the URL along with extracts of the it sends the URL along with extracts of the content back to the site, where it is stored on a content back to the site, where it is stored on a database.database.

– When you enter a search you are really searching When you enter a search you are really searching the database for words that match your entry.the database for words that match your entry.

Describe the following economic factors which have led to Describe the following economic factors which have led to the development of computer networks:the development of computer networks:Falling cost of telecommunication technologies and services, shared access Falling cost of telecommunication technologies and services, shared access to expensive equipment, geographical spread of organisation, demand for to expensive equipment, geographical spread of organisation, demand for up-to-date informationup-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 officesCheaper 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. 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 This saves a great deal of money as one printer can be shared by an entire office, classroom, etc.entire office, classroom, etc.

• Geographical spread of organisationGeographical spread of organisation– Companies can use the public telecommunications infrastructure to Companies can use the public telecommunications infrastructure to

create their own WANs through a leased line and in come cases a create their own WANs through a leased line and in come cases a dedicated line.dedicated line.

– This acted as a catalyst for large organisations to expand their This acted as a catalyst for large organisations to expand their businesses on a national and global scalebusinesses 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 The growth in home computers and the demand for up-to-date

information fuelled the desire for individuals to connect to the internet; information fuelled the desire for individuals to connect to the internet; members of the public were encouraged to purchase a dial-up members of the public were encouraged to purchase a dial-up connection using their phone line.connection using their phone line.

– At the turn of the millennium the telecommunication companies began At the turn of the millennium the telecommunication companies began to offer broadband. to offer broadband.

Describe the main features of the Describe the main features of the Computer Misuse Act, the Copyright, Computer Misuse Act, the Copyright, Designs and Patents Act and the Data Designs and Patents Act and the Data Protection ActProtection Act

• Three Acts That Affect I.T.Three Acts That Affect I.T.– Computer Misuse Act (1990)Computer Misuse Act (1990)– Copyright, Design and Patents Act Copyright, Design and Patents Act

(1988)(1988)– Data Protection Act (1998)Data Protection Act (1998)

The Computer Misuse Act The Computer Misuse Act (1990)(1990)

• Created as a result of high profile Created as a result of high profile crimes where individuals had gained crimes where individuals had gained access to computers. Belonging to;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.

The Act makes the following an The Act makes the following an offence:offence:

• Unauthorised access to computer Unauthorised access to computer materialmaterial

• Unauthorised access with intent to Unauthorised access with intent to commit further offencescommit further offences

• Unauthorised modification of Unauthorised modification of computer materialcomputer material

Unauthorised access to computer Unauthorised access to computer material:material:

• Also known as ‘Hacking.’Also known as ‘Hacking.’• Hacking is the act of trying to gain Hacking is the act of trying to gain

access to another persons computer access to another persons computer files without their permission.files without their permission.

• Hacking can be done via the Hacking can be done via the telephone system and a modem.telephone system and a modem.– Hackers are hard to catch,Hackers are hard to catch,

•since they may be miles away from the since they may be miles away from the computer they access.computer they access.

ExampleExample

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

Unauthorised access with Unauthorised access with intent to commit further intent to commit further offences:offences:• For e.g. computer fraud.For e.g. computer fraud.

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

Unauthorised modification of Unauthorised modification of computer material:computer material:

• This would include the distribution of This would include the distribution of computer viruses.computer viruses.

• A computer virus is a ‘rogue’ A computer virus is a ‘rogue’ program that someone has program that someone has deliberately created and written onto deliberately created and written onto disk.disk.

• Viruses can cause a lot of damage by Viruses can cause a lot of damage by destroying and corrupting files.destroying and corrupting files.

““Love Bug” VirusLove 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 Once opened automatically forwards itself to every person in your email itself to every person in your email address books.address books.

• Deletes files, including MP3 music Deletes files, including MP3 music files and images.files and images.

How can we prevent viruses How can we prevent viruses spreading?spreading?

• Don’t share disks.Don’t share disks.

• Don’t copy software.Don’t copy software.

• Do check all your computer disks Do check all your computer disks regularly with an anti-virus program.regularly with an anti-virus program.

• FirewallFirewall

The Copyright, Design & The Copyright, Design & Patents Act (1988)Patents Act (1988)

• Note that this act covers more than Note that this act covers more than I.T.I.T.– E.g. dramatic works, sound recordings, E.g. dramatic works, sound recordings,

films, etc.films, etc.

• However, when related to IT, it often However, when related to IT, it often refers to copying software, including refers to copying software, including operating systems, games, copying operating systems, games, copying images, music, videos, etc.images, music, videos, etc.

The ActThe Act

• Companies and individuals are Companies and individuals are requiredrequired to register the data and to register the data and designs related to a product.designs related to a product.

• This in turn gives them ownership of This in turn gives them ownership of the product, making it illegal for the product, making it illegal for anyoneanyone to copy the product. to copy the product.

• The act provides a system of The act provides a system of protection for original material.protection for original material.

For Example:For Example:

• Generally software is licensed for Generally software is licensed for oneone machine only. machine only.– Unless a multiple license pack is bought.Unless a multiple license pack is bought.

• If If youyou put software onto more put software onto more computers than it is licensed for computers than it is licensed for youyou are breaking the Copyright, Design are breaking the Copyright, Design and Patents Act.and Patents Act.

Federation Against Software Federation Against Software TheftTheft

• FAST is an organization who try to FAST is an organization who try to prevent individuals and companies prevent individuals and companies breaking the law.breaking the law.

• Those that are found breaking the Those that are found breaking the law will be prosecuted.law will be prosecuted.

• FAST have the power to examine FAST have the power to examine your your computer!computer!

The Data Protection ActThe Data Protection Act• This act is concerned with information abut living This act is concerned with information abut living

individuals that is processed both manually and individuals that is processed both manually and automatically.automatically.

• It gives rights to those individuals about whom It gives rights to those individuals about whom information is recorded.information is recorded.

• If someone holds data electronically about an If someone holds data electronically about an individual, then that individual has the following individual, then that individual has the following rights:rights:

1.1. To view a copy of the data being held on themTo view a copy of the data being held on them2.2. To have any inaccurate data correctedTo have any inaccurate data corrected3.3. To prevent junk mail: by registering with the mailing To prevent junk mail: by registering with the mailing

preferences services you should be exempt from receiving preferences services you should be exempt from receiving junk mailjunk mail

• The data controller who is in charge of managing The data controller who is in charge of managing the data that is held must:the data that is held must:

1.1. Ensure that the data is accurate, up-to-date and relevantEnsure that the data is accurate, up-to-date and relevant2.2. Allow access to the data if requested by a data subjectAllow access to the data if requested by a data subject3.3. Change in formation that is incorrectChange in formation that is incorrect4.4. Store data securelyStore data securely

Computer SoftwareComputer Software• Distinguish between an operating system and an Distinguish between an operating system and an

application program with examples of eachapplication 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 Describe the following standard file formats for text

files:files:– Text, ASCII, rich text fileText, ASCII, rich text file

• Identify data objects and operations in the context of Identify data objects and operations in the context of word processing, databases, spreadsheets, and graphic word processing, databases, spreadsheets, and graphic packagespackages

• Define a virusDefine a virus• Describe how a virus operatesDescribe how a virus operates• Describe the following common symptoms of virus Describe the following common symptoms of virus

infection:infection:– Displaying unwanted messages, unusual visual/sound Displaying unwanted messages, unusual visual/sound

effects, computers rebooting unexpectedly, unwanted effects, computers rebooting unexpectedly, unwanted generation of e-mailsgeneration of e-mails

• Describe how viruses are spread via floppy disk, Describe how viruses are spread via floppy disk, homemade CDs, ‘fun’ websites and e-mail attachmentshomemade CDs, ‘fun’ websites and e-mail attachments

• Explain the need for anti-virus softwareExplain the need for anti-virus software

Distinguish between an operating Distinguish between an operating system and an application program system and an application program with examples of each.with examples of each.•The software used on a computer is The software used on a computer is

stored in one of two types of file. We stored in one of two types of file. We are going to look at one of these are going to look at one of these types, the program files closertypes, the program files closer– Program files fit into two general types, Program files fit into two general types,

system software and application software system software and application software

• System software: the programs which System software: the programs which manage the computer and let us control manage the computer and let us control its functionsits functions

• The most important program of this type The most important program of this type is the operating system.is the operating system.

Distinguish between an operating system and an Distinguish between an operating system and an application program with examples of each.application program with examples of each.Cont’dCont’d• The OS is a group of programs that The OS is a group of programs that

automatically load from your hard disk when you automatically load from your hard disk when you turn on your computer. turn on your computer. – These programs remain in RAM until you turn your These programs remain in RAM until you turn your

computer off.computer off.– they control the hardware and software running on they control the hardware and software running on

the computer, allowing the user to communicate with the computer, allowing the user to communicate with application programs and peripheral devices.application programs and peripheral devices.

•Whether you load or save a file, access the Whether you load or save a file, access the internet, print a hard copy or just type on the internet, print a hard copy or just type on the keyboard, the OS is involved working in the keyboard, the OS is involved working in the background.background.

– There are four main types of OS in popular use today:There are four main types of OS in popular use today:

•MS-DOS, Windows, UNIX and MacOSMS-DOS, Windows, UNIX and MacOS

Distinguish between an operating Distinguish between an operating system and an application program system and an application program with examples of each.with examples of each.• Application software: the programs that we run on Application software: the programs that we run on

the computer when we have a tsk to do. There are the computer when we have a tsk to do. There are an enormous number of different application an enormous number of different application programs.programs.– E.g. E.g. word processingword processing is used to create, edit, format and is used to create, edit, format and

save documents, e.g. WordPerfect and Microsoft Wordsave documents, e.g. WordPerfect and Microsoft Word– SpreadsheetsSpreadsheets are used to perform numerical calculations are used to perform numerical calculations

and accounting tasks. E.g. Excel and Quattro Proand accounting tasks. E.g. Excel and Quattro Pro– Database managementDatabase management is used to organise a set of related is used to organise a set of related

information. E.g. dBase and Accessinformation. E.g. dBase and Access– Desktop PublishingDesktop Publishing is used to produce documents with is used to produce documents with

sophisticated formatting that includes text and graphics. sophisticated formatting that includes text and graphics. E.G. Quark, CorelDraw and PageMakerE.G. Quark, CorelDraw and PageMaker

– Presentation softwarePresentation software is used to produce slide shows. E.g. is used to produce slide shows. E.g. PowerPoint, Harvard Graphics and Lotus Freelance GraphicsPowerPoint, Harvard Graphics and Lotus Freelance Graphics

– E-mail programsE-mail programs are used to compose and send e-mails. are used to compose and send e-mails. E.g. Outlook, Eudora Pro and Pegasus Mail.E.g. Outlook, Eudora Pro and Pegasus Mail.

Explain the need for standard file Explain the need for standard file formatsformats• Before standard file formats were produces Before standard file formats were produces

one of the main problems was that a file one of the main problems was that a file produced in one application packages could produced in one application packages could not be opened in another. not be opened in another.

• To solve this problem standard file formats To solve this problem standard file formats were produced, e.g. ASCII, plain text and were produced, e.g. ASCII, plain text and RTF.RTF.

• Standard file formats make documents more Standard file formats make documents more portable, e.g. if you save a MS Word portable, e.g. if you save a MS Word document in ASCII file format you will be able document in ASCII file format you will be able to open it in a Claris Works word processor or to open it in a Claris Works word processor or Wordperfect, etc.Wordperfect, etc.

Explain the need for standard file Explain the need for standard file formatsformatsCont’dCont’d• However there was still a problem!However there was still a problem!

– Documents saved as ASCII or plain text do Documents saved as ASCII or plain text do not include the formatting information of the not include the formatting information of the original document (font, bold, italic, etc.)original document (font, bold, italic, etc.)

• So to solve this problem rich text format So to solve this problem rich text format (RTF) was developed.(RTF) was developed.– RTF includes formatting codes.RTF includes formatting codes.

Describe the following standard Describe the following standard file formats for text files:file formats for text files:Text, ASCII, rich text fileText, ASCII, rich text file• Text and ACSIIText and ACSII

– Documents saved as .txt or .ASCII are known as Documents saved as .txt or .ASCII are known as plain text documentsplain text documents

– Text and ASCII are standard file format for text Text and ASCII are standard file format for text documentsdocuments

– They do not save any of the formatting of the They do not save any of the formatting of the original documentoriginal document

• Rich Text Format (RTF)Rich Text Format (RTF)– RTF is a standard file format for text documentsRTF is a standard file format for text documents– It does save the formatting of the original It does save the formatting of the original

documentdocument– It is still in popular use today.It is still in popular use today.

Identify data objects and operations in the Identify data objects and operations in the context of word processing, databases, context of word processing, databases, spreadsheets, and graphic packagesspreadsheets, and graphic packagesPackagePackage ObjectsObjects OperationsOperations

Word Word ProcessorProcessor

CharacteCharacterr

WordWord

SentencSentencee

ParagrapParagraphh

TableTable

DrawingDrawing

Enter, insert, edit, delete, copy, paste, format, spell Enter, insert, edit, delete, copy, paste, format, spell check, search and replacecheck, search and replace

Import/exportImport/export

Add row, ass column, Split cell, merge cellAdd row, ass column, Split cell, merge cell

Group, scale, move forward/backGroup, scale, move forward/back

DatabaseDatabase FieldField

RecordRecord

FileFile

LayoutLayout

Enter, insert, edit, delete, copy, paste, format, Enter, insert, edit, delete, copy, paste, format, search, sort, calculate, querysearch, sort, calculate, query

Import/exportImport/export

ReportReport

PackagePackage ObjectObjectss

OperationsOperations

SpreadsheSpreadsheetet

CellsCells

RowRow

ColumnColumn

NumberNumber

TextText

FormulFormulaa

ChartChart

Enter, insert, edit, delete, copy, paste, set Enter, insert, edit, delete, copy, paste, set attributesattributes

Format, import/exportFormat, import/export

Calculate (sum, average, max, min, if)Calculate (sum, average, max, min, if)

Chart scaleChart scale

GraphicsGraphics PixelPixel

LineLine

CircleCircle

RectanRectanglegle

PolygonPolygon

Enter, insert, edit, delete, copy, paste, format, Enter, insert, edit, delete, copy, paste, format, scale, rotate, layer, group, ungroup, cropscale, rotate, layer, group, ungroup, crop

Define a virusDefine a virus

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

Describe how a virus operatesDescribe how a virus operates

• Viruses enter your computer via e-mail, Viruses enter your computer via e-mail, downloads form the internet, infected floppy downloads form the internet, infected floppy disks, homemade CDs and ‘fun’ websites.disks, homemade CDs and ‘fun’ websites.

• When a virus program is executed it tends to When a virus program is executed it tends to perform four actions:perform four actions:

1.1. Replication: copies itself to other files, particularly Replication: copies itself to other files, particularly to to .com.com and and .exe.exe files and the boot sector record files and the boot sector record

2.2. Camouflage: attempts to disguise itself to avoid Camouflage: attempts to disguise itself to avoid detection from anti-virus softwaredetection from anti-virus software

3.3. Event watching: whenever the virus runs it checks for Event watching: whenever the virus runs it checks for certain events, e.g. a specific date, when the virus will certain events, e.g. a specific date, when the virus will activateactivate

4.4. Delivery: this is the purpose of the virus or what it Delivery: this is the purpose of the virus or what it does. This may be simple jumbling up of letters or does. This may be simple jumbling up of letters or wiping an entire hard drive. wiping an entire hard drive.

Describe the following common symptoms of Describe the following common symptoms of virus infection:virus infection:Displaying unwanted messages, unusual visual/sound Displaying unwanted messages, unusual visual/sound effects, computers rebooting unexpectedly, unwanted effects, computers rebooting unexpectedly, unwanted generation of e-mailsgeneration of e-mails

• There are a number of tell tale signs There are a number of tell tale signs that can indicate that your computer that can indicate that your computer has been infected with a virus.has been infected with a virus.

• They include;They include;– Displaying unwanted messagesDisplaying unwanted messages– Unusual visual/sound effectsUnusual visual/sound effects– Computers rebooting unexpectedlyComputers rebooting unexpectedly– A flood of unexpected e-mailsA flood of unexpected e-mails

Describe how viruses are spread via Describe how viruses are spread via floppy disk, homemade CDs, ‘fun’ floppy disk, homemade CDs, ‘fun’ websites and e-mail attachmentswebsites and e-mail attachments

• Floppy DisksFloppy Disks– The disk acts as a carries spreading the virus into The disk acts as a carries spreading the virus into

each machine when it is placed into the drive.each machine when it is placed into the drive.• Homemade CDsHomemade CDs

– CDs spread viruses in a asimilar fashion when the CDs spread viruses in a asimilar fashion when the original CD has been infected during its compilationoriginal CD has been infected during its compilation

• ‘‘fun’ websitesfun’ websites– Programs such as Napster or Kazaa allow users to Programs such as Napster or Kazaa allow users to

share files on each others hard drives via the share files on each others hard drives via the internetinternet

– There are concerns that this is being used as a There are concerns that this is being used as a means of spreading virusesmeans of spreading viruses

– According to an articles in the UK-based IT site, The According to an articles in the UK-based IT site, The Register, 6% of all the music downloaded from Kazaa Register, 6% of all the music downloaded from Kazaa is virus-ladenis virus-laden

Explain the need for anti-virus Explain the need for anti-virus softwaresoftware

• Having learnt what we have about Having learnt what we have about how destructive a virus can be the how destructive a virus can be the need for anti-virus software is need for anti-virus software is obviousobvious– It can prevent the spread of virusesIt can prevent the spread of viruses

THE ENDTHE END