CAIE IGCSE ICT (0417) ZNotes 2023-2025 PDF

lOMoARcPSD|26855763 Ict civil engineering (Sohar University) Studocu is not sponsored or endorsed by any college or university Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 ZNOTES.ORG UPDATED...

lOMoARcPSD|26855763 Ict civil engineering (Sohar University) Studocu is not sponsored or endorsed by any college or university Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 ZNOTES.ORG UPDATED TO 2023-2025 SYLLABUS CAIE IGCSE ICT (0417) SUMMARIZED NOTES ON THE THEORY SYLLABUS Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) is now called the microprocessor 1. ## 1.1. THEORY interprets and executes the commands of the computer hardware and software single integrated circuit board found on the computer Types and Components of motherboard made up of: Computer Systems Control unit: controls the input and output devices associated with the computer Arithmetic and logic unit: carries out calculations and Hardware & Software makes logical decisions Immediate access store (RAM) Hardware Internal Hard Disk Drive (HDD) or Solid State Drive Tangible physical components of a computer system (SSD) You can feel it or touch it Internal Hardware Devices: computer’s main internal storage Processor this stores the application software, operating system and Motherboard les RAM & ROM they have fast data transfer rates and data access times Video & Sound Cards large memory capacity to store data Internal Storage devices like Hard disk drive(HDD) & Solid state drive(SSD) RAM: External Hardware Devices: Random access memory (RAM) is an internal chip Monitor where data is stored temporarily Keyboard Memory can be written to and read from Mouse Stores anything that needs to be changed Printer All program and data being used are on RAM External Storage Devices Contents lost when computer is turned o Referred to as volatile memory Software ROM: Programs that control computer systems Set of instructions that make computer do something Read only memory (ROM) is memory used to store You cannot physically touch software permanent information Relates to ideas & instructions for using physical objects Used to contain con guration data for a computer etc. Chips cannot be altered, only read from Two types of software: Data not lost when computer is turned o Referred to as non-volatile memory Application software: BIOS: Programs that allow the user to do speci c task ROM contains boot le, referred to as BIOS (basic Design to carry out tasks input/output system) Can be general purpose software or custom-made Tells computers what to do when it rst starts software (specialist software) Does hardware check when computer is turned on E.g. Spread sheets, databases, word processing Then it loads operating system into RAM System Software: BIOS stores date, time and system con guration Programs that allow the hardware to run properly Control computer's hardware and application program Input & Output Devices Communicate with user E.g. Operating system, device drivers, compilers Input devices: Purpose is to provide data for processing 1.2. The Main Components of Computer Data is raw facts which alone have no meaning Examples: keyboard, mouse Systems Output devices: Displays result of processing CPU Information is processed data which has been given meaning WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Examples: monitor, printer Interface type Advantages Disadvantages -user is in direct -user has to learn communication Secondary/Backing Storage many commands with the computer for simple functions Stores data/information & programs not being used at \n -low resolution, \n -command has to current time cheap monitors can be in correct Backing store device = reader or recorder be used \n -less format, spelling (no Example: Hard disk drive expensive than GUI errors can be made Backing store media = hardware containing data Command Line \n -possible to alter or else command Example: Hard disk Interface (CLI) computer’s will not work) \n - con guration often di cult to settings \n -can change a command Basic Computer Model type commands to after it is typed in \n carry out any task -all commands on the computer need to be typed in, (not limited to icons time consuming on the screen) -expensive compared to CLI \n -user-friendly \n - -takes up more user doesn’t need computer memory to learn any \n -user is limited to commands \n -can choose from the 1.3. Operating Systems Graphical User click on icons to icons present on Interface (GUI) open applications, the screen \n - Enables users to communicate with computer systems simpler than typing requires an Controls operation of input, output & backing storage In commands \n - operating system Supervises loading, running & storage of application easy to explore the (eg. WIndows) program system which takes up Deals with error in application programs memory and is Maintains security of whole computer system expensive Maintains a computer log Two main types of interfaces: CLI & GUI 1.4. Types of Computers CLI - Command Line Interface Desktop/Personal Computers Types commands to tell the computer what to do Refers to general-purpose computers The user must know all the commands PC refers to IBM compatible computers, distinguishing Must not make typing errors them from the Macs Used by technicians Made up of separate monitor, keyboard, mouse and Can access everything on the computer system processing unit GUI users can only access places they have icons for Advantages \ Spare parts standardized results in low costs Tend to have better speci cations GUI - Graphical User Interface Less power consumption since computer is plugged into an electric socket always Uses graphics to stand for the complicated actions A large casing allows good dissipation of heat build-up Uses icons Internet access is more stable because the computer Uses a mouse to select the icons is in one position Screen divided into windows allows di erent things on Disadvantages each Not portable since they are made up of separate WIMP - Windows Icons Menus Pointers components Wiring clutters up desk space Interface type Advantages Disadvantages Necessary to copy les as they aren't portable takes up a lot of desk space WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Laptop/Notebook Computers Advantages: Smallest lightest most portable Refers to computers where monitor, keyboard, pointing Integrated/virtual keyboard device and processor together in a single unit Often the least expensive device Extremely portable systems More practical for day-to-day use Low weight Disadvantages: Low power consumption Small screen may be di cult to use The processor doesn't generate too much heat Not as powerful as other devices Advantages Often has the lowest battery life Portable because monitor, pointing device, keyboard, Small size makes it easy to steal/lose processor & backing store units are together in one box Smartwatches No trailing wires Full advantage of Wi-Fi Have the same functions as a smartphone Can link into any multimedia system Uses OLED (organic light emitting diode) technology Disadvantages Can link to smartphones using Bluetooth Easy to steal features: Limited battery; need to carry charger Internet connectivity Keyboard and pointing device awkward to use Ability to message via text or video Heat dissipation is di cult due to laptop structure Weather forecasts GPS Advantages: Tablet Computer Very easy to use for monitoring health and tness Convenient as noti cations are delivered straight to These are small hand-held devices that can perform users wrist many functions that PCs & laptops do Disadvantages: Use touch screens to operate Large and bulky (heavy on the wrist as they have to On-screen virtual keyboard replaces physical keyboard accommodate the battery and screen to display apps) Often used by graphic designers to digitalize their content Usually unattractive in design with a stylus pen Can be used like a PC and/or a Smartphone Mainframe computers anti glare displays front and back facing cameras Large, very powerful computer systems longer battery life than laptops Are used to run commercial applications, such as banking light or insurance, where huge amounts of data need to be cloud storage facilities and SSD processed everyday equipped with sensors Features: Advantages: Have several CPUs Small, light & portable Fast processor speeds Built-in cameras for photos & videos Multiple operating systems Touchscreen can be used with a stylus pen Huge storage capacity Long battery life Huge internal memory (RAM) Fast to switch on Often use time sharing or batch processing No generation of heat because of SSD Disadvantages: 1.5. Impact of Emerging Technologies Less storage spaces Lacks power of laptop/PC This is technology that is being newly developed Digital keyboard can be di cult to use These can have several impacts on our society Touchscreen may be di cult to use for detailed work Arti cial Intelligence (AI) Smartphone Technology that focuses on creating a computer system Modern phones that can perform similar tasks to all the that can closely mimic or simulate human intelligence above AI can be used to: Main use of smartphones is social media & day-to-day Enhance video games and computer tactics planning Help decision making steps in expert systems Use varies from person to person Make robots to imitate human behaviour WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Understand di erent human languages Dangerous jobs such as bomb disposal Impact on everyday life: Exploring extreme environments such as volcanoes Can be used to accurately predict hazardous weather Repetitive manufacturing jobs such as welding conditions and signal warnings automatically Moving heavy objects such as large engines Take over menial tasks for humans; increasing our Examples of robotics: leisure time Drones: used by civilians in surveying the landscape Can be used for safer automated travel; cars that can with GPS, and checking weather phenomena. Drones drive and park by themselves are also used by military for reconnaissance missions Increases home safety by being able to tell the Robots in surgical procedures: allow the surgeons to di erence between owner & intruder; call authorities perform the procedures with more precision, exibility automatically and control. Improved medical care as decision making skills and Impacts on everyday life: precision can be enhanced Increased personal time since robots can take over domestic chores Increased manufacturing e ciency since robots are Biometrics much faster and less expensive than human labour Unemployment as robots replace humans in A part of a person’s body is used to identify that individual autonomous jobs Can be: Safer working environments since robots can perform Fingerprints tasks that are too dangerous for humans Retina Iris Face Quantum Cryptography Voice These are all unique to everyone thus can be used as an Technology that allows messages and data to be sent with authentication technique complete privacy; basically, advanced encryption Must be added initially to a system to use as identi cation Older encryption is based on mathematics, but this new Impacts on everyday life: tech uses physics Better security at the airport since most use at least Makes it much more complex to decrypt one form of biometric check if not more Impacts on everyday life: Increased security in certain places as only authorized Completely secure voting ensuring that votes cannot personnel can gain entry be tampered with or changed Reduced vehicle theft since newer car doors come Completely secure communication eliminating the risk with a ngerprint lock on the door handle of being read/heard by the wrong eyes/ears More secure mobile devices as most now have some Completely secure bank transactions so money goes sort of biometrics integrated into them exactly where it is intended Completely secure personal information preventing hackers access to intrusive details about a person Vision Enhancement LVES: low vision enhancement systems: video projected Computer Assisted Translation (CAT) inside a headset in front of the user’s eyes. Brings the objects closer for the viewer. When human translators use computer software to help NVE: Night vision enhancement: dim light is captured and in the translation process passed through a light intensi er tube, which converts Can reduce translation time light to electrons. Electrons pass through another tube May not be 100% accurate where they are ampli ed to produce more electrons. Common CAT tools: Ampli ed electrons pass through to the end of the tube Spell checkers where they hit a screen coated in phosphor dots that glow Translation memory software when collided with. this creates an image several times Language search-engine software brighter and clearer than the original Impacts on everyday life: More accurate documents since most software can automatically detect errors Robotics More multilingual society since anyone with an internet connection can now essentially learn multiple Programmed machinery widely used to do physically languages using translators demanding tasks Quicker translations Can be automated or manually operated Used to perform several tasks: WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) 3D & Holographic Imaging Technology that makes images appear to be 3- dimensional by adding a layer of depth Holograms use 2 regular 2D images and manipulate them to produce a 3-dimensional image QWERTY- layout Di erent laser beams are used to record the 2D images Ergonomic- reduces health related problems onto a single photographic plate Uses This creates an illusion of one 3D images Keyboards are used to input data into application Impact on everyday life: software Improved security since majority of credit/ID cards & Also used to for typing commands to the computer bank notes use holograms to prevent forgery (CTRL + P) Better movie experiences since 3D viewing can Advantages provide a more immersive experience for the Enables fast entry of new text into a document audience Well-tried technology & well-known method of entry Greater data storage since holographic layers can Most people nd them easy to use potentially decrease the thickness of disc storage Easy to do veri cation check as data is entered, as it appears on the screen simultaneously Disadvantages Virtual Reality (VR) Users with limited arm/wrist use can nd keyboards hard to use When computers create an arti cial environment that Entering data is slow when compared to direct data users can virtually interact with entry (e.g. Optical mark recognition) Uses: They use up desk space as they are quite large Allow architects to walk around a virtual version of their design Training soldiers for combat by allowing them to ght Numeric Keypads against virtual enemies Training surgeons by allowing them to operate on virtual patients Playing games and enhance the level of immersion General VR equipment: Eye goggles that produce 3D images to develop the arti cial environment A numeric keypad is used to enter numbers only Special gloves or controllers to perform precise Although some have function key to allow input of actions inside the simulation alphabetical characters Headphones to control what is heard in the virtual Uses world Used in Automatic teller machines (ATMs), where customers can key in their personal identi cation Powerful computer to run the entire VR system in real number (PIN), or an amount of money time Impacts on everyday life: Used to key in phone numbers into telephones Improved medical surgeons/soldiers Electronic point of sale (EPOS) terminals have numeric keypads in case the barcode reader fails Stronger buildings Used in Chip and PIN devices to key in PIN, or amount Treatment of phobias as certain situations can be of money treated using simulations More realistic education as students can learn in a Used to enable fast entry of numeric data into a more interactive environment spread sheet Advantages Numeric keypads are faster than standard keyboards 2. ## 2.1. THEORY for entry of numeric data Since many are small devices (e.g. mobile phones), they are easy to carry around Input & Output Devices Disadvantages Can be di cult to use due to the very small keys Di cult to use for entering text Input Devices & their Uses Sometimes the order of numbers isn’t very intuitive Keyboards Mouse WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) An example of a pointing device They are more di cult when doing operations such as The ball underneath the mouse is used to detect ‘drag and drop’ movement The left button is for selecting by double on it and the right is to bring drop-down menus Tracker Ball There is usually a scroll button which speeds up the process of moving through a document Uses Used for opening, closing and minimising software Used for grouping, moving and deleting les Tracker ball is like a mouse except that it has a ball on the Useful when editing images (e.g. controlling the size top of the device and position of the image) Users control the pointer on the screen by rotating the Used for controlling the position of a pointer on the ball screen to allow: Uses Selection from a menu Have the same pointing/cursor control capability as a Selecting an icon mouse Scrolling up/down and right/left Used in applications where the user has a disability Advantages (RSI) Faster to select an option by a mouse than a keyboard Used in a control room environment, where it is faster Enables rapid navigation through applications and the than a mouse to navigate through process screens internet and more robust than a mouse Mice are small and don’t take much area Advantages Disadvantages Tracker balls don’t need the same ne control as a People with restricted hand/wrist movement can nd it mouse hard to operate a mouse People with limited hand/wrist movement nd easier Easily damaged and can easily be clogged up with dirt to use than a mouse They are hard to use if there is no at surface The pointer can be positioned more accurately on the available screen than with a mouse They take less desk space than mice since they are stationary Touchpad Disadvantages Touchpads are used in many laptop computers as a Tracker balls are not supplied with the computer as standard, so they are more expensive pointing device The pointer is controlled by the user moving their nger User may need training since they are not standard on the touchpad equipment Uses Used for opening, closing and minimising software Remote Control Used for grouping, moving and deleting les Useful when editing images (e.g. controlling the size A remote control is used to control the operation of other and position of the image) devices remotely by using infra-red signals Used for controlling the position of a pointer on the Uses screen to allow: In home entertainment devices such as Televisions, Selection from a menu DVD player/recorder and satellite system Selecting an icon Used to control multimedia systems Advantages Used in industrial applications to remotely control Faster to select an option by a touchpad than a processes, stop and start machinery keyboard Advantages Enables rapid navigation through applications and the Enable devices to be operated from any distance, internet which is useful for people with disabilities Since the touchpad is integrated into laptop computer, Some chemical processes are hazardous, so it is safer there is no separate mouse, aiding portability to operate equipment from a distance They can be used when no at surfaces are available Disadvantages Disadvantages People with limited hand/wrist movement can nd People with limited hand/wrist movement can nd them hard to use touchpads hard to use The signal between the control and the device can be It can be more di cult to control the pointer when easily blocked compared to a mouse WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Joystick Non-digital photographs can be scanned for storing on a computer Advantages Images can be stored for editing later Scanners are much faster and more accurate than typing in documents again It is possible to recover damaged documents and By gripping the stick, a pointer on the screen can be photographs by scanning them and then using controlled appropriate software to produce an acceptable copy Buttons are used to make selections Disadvantages Uses The quality can be limited depending on how good the Video/computer games are often controlled by scanner resolution is joysticks They are used in simulators to mimic actual controls Advantages Digital Cameras Easier to navigate round a screen compared to a keyboard Control is in three dimensions Disadvantages More di cult to control the on-screen pointer with a joystick than with other devices such as mice Photographs are stored in memory They can be easily transferred to a computer using a USB Touch Screen Uses Digital cameras can produce photographs for direct User can choose an option by simply touching a transfer to a computer or to print out button/icon on the screen Digital cameras allow short video clips to be produced The selection is automatically made without the need for Photographs can be uploaded directly into application any pointing device software such as word processor Use Advantages Used for service tills e.g. petrol stations Easier to produce better quality photographs than with Used where selections are made on a screen e.g. a tradition camera ATMs, public information systems, airports and Easier and faster to upload photographs to a railway stations computer Used in PDA’s There is no need to develop lm and print out Used in Interactive white boards photographs (saves paper and no longer needs the Used in computer-based training (CBT) chemicals to produce photographs from lms) Advantages Easy to delete an image from the memory if it’s not Enable faster entry of options than a keyboard/mouse satisfactory Very easy to choose options The memory card can store several hundred User friendly method for inputting data photographs They are tamperproof, preventing people from Disadvantages keying in information (which could corrupt the The camera user needs to be computer literate to use system) the camera properly Disadvantages There is some artistry lost since clever software There is a limited number of options available corrects errors in the photographs Using touchscreens often can lead to health problems The resolution is not yet as good as traditional e.g. (straining of arm muscles and RSI) cameras The screen can get very dirty with constant touching Images often need to be compressed to reduce the amount of memory used It is possible to ll up computer memory very quickly Scanners with several photos of the same subject (to nd the perfect snap shot) Used to input information on hardcopy e.g. text document Uses Used to scan in documents and convert them into a Video Camera format for use in various software packages Old and valuable documents and books can be DV (digital video) camera store compressed photo frames scanned, protecting the original copies from damage at 25 MB/s – motion jpeg. WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Light turned into electronic signal through light sensitive Type of sensor Applications sensors and automatically converted to a digital le Automatic greenhouse, chemical format. pH processes, environmental monitoring Advantages Easy to edit footage in a video editing. Advantages High quality video captured, therefore Readings by sensors are more accurate than taken by Disadvantages humans Storage medium (Memory cards) more expensive to Readings are continuous, there is no break in buy than lms. monitoring Because it is a continuous process any necessary action or warning will be initiated immediately Microphone The system can be automatic, removing the need for human intervention, this is particularly important if the process is hazardous Disadvantages Faulty sensors can give spurious results Graphic Tablet Can be connected directly to a computer Sounds can be inputted and manipulated Uses Microphones are used to input speech/sounds to be used in various applications They are used in voice recognition software- for A graphic tablet is used with a stylus to produce freehand conversion of speech into text, and recognition of drawings commands Uses AdvantagesFaster to read in text than to type it using a Graphics tablets are used to produce drawings, keyboard computer graphics Possible to manipulate sound in real time using In countries where characters are complex e.g. japan, special software they are used as a form of input If used in a voice activation system, this has the They are used in computer aided design (CAD) work advantage of improving safety Advantages Disadvantages It is possible to modify drawings before they are input Sound les can use up a lot of computer memory They o er an accurate method of drawing Voice recognition software isn’t as accurate as typing Disadvantages in manually They are more expensive than other pointing devices Sensors Web Cam Type of sensor Applications Automatic washing machines, central Temperature heating systems, automatic green houses, ovens Burglar alarm systems, robotics, Connected directly to a computer via a USB port Pressure environmental monitoring, Automatic Uses washing machines While chatting online webcams can be used to have Automatic doors, street lighting conversations Light control, Burglar alarm systems, Used to enable video conferencing to take place automatic greenhouses Advantages Burglar alarm systems, monitoring Can be left on constantly and activated when required Sound liquid and powder ow in pipes Allow people to keep in contact with each other Automatic greenhouses, without the need to travel, particularly useful for Humidity/moisture environmental monitoring, factories disabled or elderly people where moisture levels are crucial Disadvantages WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Webcams have limited features and the picture is Provide a more secure payment system than requiring often of poor quality a signature or using magnetic stripe, since the PIN They need to be connected to a computer typed in must match up with the PIN stored on the chip Provide a more robust system than magnetic stripe 2.2. Direct Data Entry & Associated since the chip does not need to be in contact with the reader Devices Disadvantages Customer needs to be careful when typing in the PIN, Magnetic Stripe readers so nobody reads it giving an opportunity for Fraud Radio Frequency Identi cation (RFID) Readers RFID readers work in similar ways to a bar code reader Used to read information on the magnetic stripe An RFID tag is attached to/inside a surface The stripe contains useful information such as start and The reader reads the data held on the tag which is then expiry date input into the computer system for processing Uses Radio waves are used to transmit data thus can be used Credit and debit cards have magnetic stripes that are through most materials used by ATMS or EFTPOS (electronic funds transfer Uses point of sale) terminal Used in retail or supermarkets as barcode Security cards for entering building e.g. hotel rooms alternatives Travel systems e.g. train and underground tickets Used to identify pets Advantages Used in passports Data entry is fast compared with keying in using a Advantages keyboard or keypad Can hold a lot of data System is error free, no typing involved Can be read from long distances Information is secure since there is no typing and the Does not require direct line of sight information can’t be read directly by a person Information can be read faster than barcodes Can prevent access to restricted/secure areas Can alter information Magnetic stripes are una ected by oil water and Disadvantages moisture Thieves can steal information easily No moving parts therefore physically robust RFID tags are expensive Disadvantages Radio waves can experience interference If the magnetic stripe is damaged the data is lost \ Card needs to be in close contact with the reader Since the information is not human readable, they Magnetic Ink Character Reader (MICR) need to nd a way to show the information to the customer (e.g. hotel room number not printed on cards) Chip & PIN readers Magnetic ink character recognition is a system which can read characters printed in a special ink Uses Used to process cheques in banking operations – cheque is read using a batch processing method Advantages The device has a slot where the card is placed, and the MICR o ers great security than OCR since the oriented chip is read characters cannot be altered A small screen is part of the reader which gives There is no manual input, thus errors are reduced instructions to the operator If somebody writes over the magnetic ink characters, Uses it can still be read Chip and PIN readers are used where payments are Disadvantages made using cards e.g. travel agents Only certain characters can be read, and the number Advantages of di erent characters is very limited WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) It is a more expensive method than other methods used for direct data entry Optical Mark Reader Used to read information in the form of a barcode Handheld scanners or wands are very common for reading barcodes Uses Optical mark recognition is a system which can read Used in supermarkets and other shops where the marks written in pen or pencil goods are marked with a barcode Uses Used in libraries to scan user’s library card and OMR devices are used to read questionnaires, barcodes on books (to keep track of books on loan) multiple choice examinations papers and other types Used as a safety function in many companies to of forms in the form of lines or shaded areas ensure that electrical equipment is checked on a Advantages regular basis A very fast way of inputting results of a survey Advantages Since there is no typing, it is more accurate than Faster than keying in information, and fewer mistakes keying in data are made OMR is more accurate than OCR Used as a way of recording data, can improve safety Disadvantages Barcodes enable automatic stock control Forms need to be carefully designed to make sure that Barcode scanning is a tried and trusted technology the marks/shadings are correctly positioned to gather When an item price is changed, only the central accurate information database needs to be updated, there is no need to There can be problems if forms aren’t lled correctly, change the prices individually on each item sometimes they must be checked manually before Disadvantages being read by an OMR, this is both time consuming Barcode scanning is an expensive system to and expensive administer since every item in the shops needs a barcode and every barcode needs to be entered on the system Optical Character Reader Also, there is a need to invest in the computer technology together with sta training, which can all be expensive The system is not fool proof- barcode can be swapped around on items Optical Character recognition is a software that takes scanned text and converts it into a computer readable 2.3. Output Devices & their Uses form Uses CRT Monitor Processing of passports and Identity cards Cathode Ray Tube monitors OCR is used when scanning documents to modify them using a suitable software Least expensive type of monitor, becoming rarer as TFT Advantages monitors take over Much faster data entry system than manually keying Come in various sizes in data Picture created is made up of tiny dots (red green or blue), the intensity of the colour of the dot determines the Since there is no manual data entry, the number of colour perceived by the eye errors is reduced Disadvantages Uses The system has di culty reading handwriting Primary output device for computers, user can immediately see what they are typing in It is still not a very accurate technique Used with light pens to allow designs to be created on screen Advantages Produce higher quality images than TFT monitors Barcode readers Angle of viewing is better than a TFT monitor They work with light pens in CAD and CAM applications (Computer Aided Design/Manufacturing) Disadvantages WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Tend to be heavy, weight hazard if not supported High power consumption properly Slow response time Run very hot, can cause res if left unattended – Note: Old LCD monitors used CCFL (cold cathode especially if they are old uorescent lamp) technology to light up the screen. Consume more power than TFT monitors They can icker, this leads to headaches and eyesight problems with prolonged use LED Monitor: Front layer made from liquid crystal diodes; grouped TFT Monitor together to form pixels (RGB or RGBY-more vivid colours) For the image to show up on-screen a light source of LED backlight is used. Advantages (over LCD monitors): Lighter and thinner Longer life Lower power consumption Greater contrast and more vivid colour Relatively more robust Thin Film Transistor monitors Disadvantages Taking over from CRT monitors as the main output device Glare gives viewers headaches The progress in TFT technology is one of the reasons for Images too sharp, so can cause eye strain the rapid development of laptop computers The screen is made up of thousands of tiny pixels which are made up of transistors controlled by a Touch Screen microprocessor Each pixel has three transistors-red, green or blue; the Automatic selection without a pointing device intensity of each determines the colour of the pixel seen. Uses Uses Automatic teller machines Primary output device for computers, user can EFTPOS (electronic fund transfer point of sales) immediately see what they are typing in PDA Integral part of laptop computers Smartphones Advantages Public information points Lightweight, so no weight hazards like CRT monitors Advantages Less glare produced than in CRT monitors; also emit Faster data entry less radiation Easy to choose options Consume much less power and generate less heat User-friendly and intuitive than CRT monitors Disadvantages Disadvantages Limited options Angle of viewing is critical; image appears unclear if Frequent usage can lead to RSI, etc. viewed slightly from the side Constant usage results in the screen getting dirty; This is an issue if several people are looking at the visibility and sensitivity decreases screen at the same time They cannot yet be used with light pens, Multimedia Projector IPS/LCD Monitor Front layer made from liquid crystal diodes; grouped together to form pixels (RGB or RGBY-more vivid colours) Receive analogue and digital signals, although most Receive analogue and digital signals, although most modern projectors only work with digital inputs modern projectors only work with digital inputs IPS (In-plane switching) is the technology used in LCD The signal source is usually from a computer, television, monitors. or DVD player Advantages The image from the source is magni ed and projected Colour can be seen accurately from di erent viewing onto a large screen angles The devices usually work with a remote control, but can No lightening on touching also use virtual mouse technology – cordless PC mouse Disadvantages (has a laser pointer) Expensive WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) It is then possible to direct the presentation without These have been linked to health hazards in the o ce being tied to the computer Most multimedia projectors take input from various types of video format e.g. PAL, NTSC or SECAM Inkjet Printer Uses Used for training presentations (allows the whole audience to see the images from a computer) Also used for advertising presentations (shown at exhibitions, shopping malls etc.) Home cinema systems (projecting the images from a DVD or television) use multimedia projectors Used to produce good quality hard copies – the quality is Advantages not as good as in laser printers but much better than that Enables many people to see a presentation rather of dot matrix printers than all of them crowded around a small computer Do not have large bu ers like laser printers, so printing is screen done a bit at a time Avoids the need for several networked computers Therefore, printing is sometimes paused – the whole page e.g. when looking at a video clip on the internet, can’t be stored in the bu er, it must wait for the computer everybody can see the video on the large screen to send more data rather than logging on to several computers Uses Disadvantages Used where low volume outputs are needed Images can sometimes be fuzzy Ideal for high quality printing for small print jobs or Expensive to buy single pages e.g. for photo quality printouts Setting up projectors can be a little di cult Advantages High quality output Laser Printer Cheaper to buy than laser printers Very lightweight and take up little space (small footprint) Do not produce ozone and volatile organic compounds, unlike laser printers Disadvantages Output is slow if several copies needed – there is little bu er capacity to store the pages Produce very high-quality hard copy output The ink cartridges run out too quickly to be used for Print rate per page is fast if many pages are being printed large print jobs Rely on large bu er memories – the data for the whole Printing can smudge if the user is not careful document is stored before pages can be printed out Can be expensive to run if they are used a lot – Uses original ink cartridges are expensive Used where noise levels need to be kept low e.g. in an o ce The best option for fast, high quality, high volume Dot Matrix Printer printing Advantages Printing is fast for high volumes, slightly faster than inkjet if only a few pages are to be printed Can handle very large print jobs Quality is consistently high Toner cartridges last for a long time; laser printers A type of impact printer can be a cost-e ective option if colour outputs are not A print head made up of a matrix of pins presses against an inked ribbon required Disadvantages Uses Expensive to buy Can be used in noisy environments e.g. garage workshops Only fast if several copies are being made Colour laser printers tend to be expensive to run since Can be used in applications were the print quality is not very important four cartridges are needed as well as di user kits, etc. Advantages Produce ozone and volatile organic compounds Can be used in environments which would be a because of their printing method and type of toner/ink used problem for laser and inkjet printers – dusty, dirty or moist atmospheres WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) Carbon copies or multi-part outputs can be produced Used to produce prototypes which work from CAD Very cheap to run and maintain packages, photograph images, stored drawings etc. Easy to use if continuous stationary is required e.g. Scale models are produced in colour before the real long print jobs such as wage slips thing is manufactured Disadvantages The ultimate objective is to produce organic objects Very noisy – not good in an o ce environment using this layering technology (such as replacement Cost more than an inkjet printer to buy human organs) Very slow Advantages Printing is of poor quality Save a lot of money, other methods of making prototypes are very time consuming and expensive The powders used can often be ground up and reused Wide Format Printer Physical scale models are produced with working parts, which gives a better idea of how the product will look Disadvantages Expensive to buy Slow at producing their output Product is sometimes a little rough, often further work Devices that produce hard copies but operate in a needs to be done di erent way to printers Not limited to normal printer paper size and can produce Speakers highly accurate, very large drawings and posters The most common types are pen plotters, electrostatic (similar method to laser printers) and inkjet plotters With pen plotters, coloured pens are controlled by a computer and the paper can move backwards and forwards to allow accurate shapes to be drawn Uses Used to produce large drawings e.g. blueprints of buildings; are often used with CAD applications Can be connected directly to a computer or are built into Used to produce large pictures for use on billboards the monitor or casing (as in laptop computers) or giant posters Uses a digital to analogue converter (DAC) to convert They can also print on plastic coated paper digital data from the computer to analogue from so the If the pens are replaced by cutting tools, it is possible to speakers can process it; the signal is then ampli ed make large signs through the speakers. Advantages Uses Can produce huge printouts Used to output sound from multimedia presentations Print quality is extremely high Used in home entertainment centres Disadvantages They can help blind people through audio output of Slow in operation text on the screen (together with speech generation Expensive to buy and maintain software) Used to play downloaded sound les Advantages 3D Printer Usually long lasting and durable (if operated within their intended power levels) Often provided with the computer/laptop although these may not be the best quality Disadvantages Can take up a lot of desk space, compared to headphones A new type of printer that produces solid 3D models using Can distract people around you, everyone can hear modi ed inkjet technology called tomography what you are playing Very thin layers of ne powder (plaster, resin, starch) are May not be able to hear the full sound spectrum, this bonded together as a 3D model is slowly built up requires multiple speakers Items produced are known as prototypes Uses Actuators WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) 3. ## 3.1. THEORY A type of controlling device Transducers that are used to take signals from a computer and convert them into some form of motion e.g. Storage devices and media operating motors, pumps, switches and valves Digital signals are sent from the computer to an actuator to operate a device Conversion of the digital signal to analogue is required What is backing up of data? rst (using a DAC) Backing up refers to the copying of les or data into a di erent medium Motors Examples of di erent mediums les can be copied to are: disk tape ash drive Turned on or o by the actuator Why do we back up data? Uses Used in many domestic appliances To safeguard against loss of data when the original Automatic washing machines (to make the drum secondary storage device fails. The secondary storage rotate) device can fail due to hardware failure, problems caused Cookers (to switch on fans) by les being overwritten or by corruption of les. Water pumps in central heating systems To safeguard against damage caused by hackers. Even if Automatic greenhouses to open windows and switch the hacker’s primary intention wasn’t to hack the data in a on fans computer, the very act of hacking into les could lead to Used to control robot arms in the industry the possible corruption of data or data loss. Operate fans, disk drives and DVD drives in computers When les need to be used elsewhere, the data can be copied into a medium and transferred to another medium. Buzzers 3.2. There are 2 methods of accessing Switched on or o by the actuator Uses data: Used in cookers and microwave ovens to tell the operator when the cooking process is complete Serial access: Used in burglar alarm systems to warn if intruders are present This involves starting from the beginning of the le and accessing each record to get to the le required It is a very slow form of data access Heaters It is used in systems where the speed of accessing data is not important Actuators are connected to switches which turn the It is used in magnetic tape systems heater on or o examples where serial access is used: Uses utility billing Used in automatic washing machines, cookers and clearing of bank cheques central heating systems producing pay slips Used in automatic greenhouses to control the temperature Direct access: This is used to access data stored in any record by typing Lights in the required key eld Typing in a key eld will allow the user to access a The actuator is connected to the switch that turns the particular record directly from the calculated position lights on or o It is used in optical storage media, magnetic disks and Uses solid state media Security lights Accessing data is much faster Used in greenhouses to control the lighting conditions Storage Devices & Media WWW.ZNOTES.ORG Downloaded by hpk gondwe ([email protected])  lOMoARcPSD|26855763 CAIE IGCSE ICT (0417) 3.3. Magnetic Backing Storage Media Used as a backup media Long term archiving of data due to the large memory capacity of Magnetic tapes Depend on the magnetic properties of certain materials. Advantages Magnetic material is coated on the surface of a disk which Less expensive compared to hard disk of equivalent can be magnetised to represent a 1 or 0 and data is read memory capacity accordingly. Very robust technology Fixed Hard Disks/Drives Data transfer rate is fast Disadvantages Available on all computers and is the main method used Access time is very slow (need to go through all for data storage previous les to reach the one required) Uses a read/write head to write and read data from it When updating another tape is needed Disk surface coated in magnetic lm, storage is done by A ected by magnetic elds altering binary codes to 1s or 0s These hard disks are used to store the Disk Operating 3.4. Optical Backing Storage Media System (DOS), application software and les Uses CD-ROM/DVD-ROM Used to store operating systems and working data Used for storing application software Laser light is used to read data stored on CDs or DVDs Real time systems and online systems used xed hard Use a thin layer of metal allow or light-sensitive organic drives dye to read the data Used in le servers for computer networks Spiral track included Advantages Read only memory – cannot be overwritten Very fast data transfer rate Data is stored as a series of pits and lands formed by a Fast access times to data laser beam etching the surface at manufacturing stage Have very large memory capacities Uses Disadvantages