ZNOTES.ORG UPDATED TO 2021 SYLLABUS CAIE A2 LEVEL IT (9626) SUMMARIZED NOTES ON THE THEORY SYLLABUS CAIE A2 LEVEL IT (9626) 1. Emerging Technologies 1.1. Technology and our lifestyle Smartphone and mobile device intro effects Positive: better time utilisation Negative: companies expect employees to be more available. 1.2. Three-dimensional printing Printing where an object is created based upon a blueprint made with modelling software. It works by taking thousands upon thousands of cross-section layers of the model, from the bottom to the top, to create the object. Uses heated plastic to print a single layer at a time. Takes a long time to produce object. Uses include: medicine- casts for broken bones (more flexible and don’t cover broken body part), prosthetics, replacement organs (solves organ waitlist/match problem), artificial blood vessels houses (quick rehousing if natural disaster occurs) tools, automobile parts, spare parts for space vehicles (team doesn’t need to abort mission if part damaged) Negative effects: print items like guns If ‘bio-plastic’ isn’t used, environment concerns caused. 1.3. 3 4th gen and 5th gen cellular communications Each generation development improves speed and capability of the wireless connection for data. Voice is still mostly carried using 2G technology. 3G services work by cellular based technology. The signal is passed from each cellular mast or phone tower. 4G further increased upload/download speeds and reduced latency. Reduced latency leads to a quicker response time to requests. 5G is in development; however, to provide 5G access, parts of radio network would need to be restructured. Specialist doctors can guide operation through video call. Patients receive best medical attention. Doctors are well-rested as travelling isn’t needed. Work benefits: Keep in touch with clients on the move. Video-conferencing for meetings. Navigation apps to aid travel. 1.4. Artificial Intelligence Ability of a computer to make decisions based upon stimuli, like a human. Use programming rules and are hard to create. Can be learnt from actions taken and modifying behaviour. Benefits: Voice-activated systems for the disabled. Self-driving cars for disabled. Greater entertainment in games as challenge difficulty increased. Expert systems for easy diagnosis/problem solving Issues: Input errors in voice activated systems. Programming errors cause incorrect output. Question whether company or user should pay accident cost of self-driving car 1.5. Augmented Reality Computer-generated images overlaid by technology on the real world. Working: o Camera sends real world image and signal. Software finds point where overlay is needed. Overlay image created on computer screen. Benefits: o Real-time translation of signs in other languages. AR Games like Minecraft Earth, Pokémon Go, AR cards used in Nintendo 3ds. Google Glass where glasses lens overlays information in real-time and share images. Issues: o Object recognition difficult due to camera angle and different lighting. Vision impeded with Google Glass. Security issues when streaming data using Google Glass as Bluetooth is used to connect to phone. 1.6. Biometrics Healthcare benefits: WWW.ZNOTES.ORG Use of technology that tracks user values like heart rate Measures several samples of data and stores it. A match is then determined between input and stored data to authorise. Uses: Fingerprint recognition, hand scanners for security. CAIE A2 LEVEL IT (9626) Biometric passports containing biometric data like facial or iris image scan. In fitness devices (measure heart rate). Issues: Personal details are stored in a database. This sensitive information may be exposed in a database breach. Fake biometric material may be presented by a user. Considered as an invasion of privacy by some. 1.7. Cloud Computing Servers store and process data instead of your computer. Uses: Services which allow you to upload your own files and manage them. Can be accessed from anywhere while online. Data can be uploaded from numerous devices; each device gains cloud access. Can easily share files on personal devices using this. Can be used to process data, hence not affecting console performance if there is a large amount of data to be processed. Therefore tasks beyond console performance capabilities can be conducted. Issues: Security issue as service can be hacked into and data can be stolen which may lead to identity theft if data personal. Constant internet connection needed to access service which may be an issue if provider has a power outage. Regular file syncing should therefore be done to make data accessible at all times. 1.8. Computer-assisted translation Computer is given text/document and after removal of anything not text, translation is done. Benefits: Quick real-time translations in foreign countries. Translate whole documents and websites. Issues: Direct translations given instead of meaning behind sentence. Sentence structure also kept same so grammar in translated sentence may be messy. Difficult to pick correct meaning of word with multiple meanings. Some words have no actual direct translation. 1.9. Holographic and fourth generation optical data storage Holographic data storage works by recording data throughout the volume of the medium; magnetic and optical work by storing data on surface of medium. Benefits: WWW.ZNOTES.ORG Holographic is a developing medium of high-capacity data storage. Stores bits in parallel, layer upon layer unlike magnetic and optical which store data linearly. Archive vast amounts of data for a long time as medium degrades a lot less than others. Issues: Belief that archiving ability isn’t a necessary benefit as technology advancements would make method obsolete. Drive to read data costs thousands of dollars, each medium used to store data would also cost a hundreds. Fourth gen optical media will bring about potential to hold 1TB data by using smaller pits and lands and using more layers. Third gen stores about 400GB. 1.10. Holographic imaging Known as holography; is the ability to make holograms. Hologram: free standing 3D image which doesn’t have depth. With time it may be possible to transmit holograms. 1.11. Quantum Cryptography Similar to normal encryption using mathematical algorithms, however key generated through photons. Transmission through fibre-optic cables. Photon key generated through polarising, i.e. creating vibrations in different directions in individual photons. To unscramble, a filter reverses polarisation. Not possible to accurately measure activity after polarisation, hence very safe. Currently successful only at short distances (60 km) 1.12. Robotics Creation of computers that perform tasks humans cannot or are less-efficient at. Requires sensors attached to robot id dependant on environment it is in. Benefits: Does mundane, repetitive tasks. Does tasks which may be dangerous to humans. Provides entertainment. Issues: Replaces human jobs. Ability scares people at times. Emotional response null unless programmed with AI. 1.13. QR codes Barcode made of black and white squares. Benefits: Provide information, saves space on packaging etc. Marketing purposes to attract users to scan for info. CAIE A2 LEVEL IT (9626) Can be used as trigger to open different app or register data within app. Issues: Need light to process image Distort when resized o need space so other stuff doesn’t interfere during recognition. Need stable internet connection to view links in code 1.14. Wearable computing Clothing or accessories involving computer-based component. Fitness devices measure activity like steps taken, calories burnt, and sleeping pattern. Smartwatches have similar functions but costly. Wearable tech like shirts can display messages/GIFs, and are fashion statements. All are subject to moisture which can cause damage. Uses Bluetooth for connectivity so not very secure. 1.15. Ultra-high-definition tv Ultra-wide screens (2560x1080) and standard desktop monitors (1920x1080) count as 2K aka HD. 4K has twice as many pixels horizontally while maintaining aspect ratios. 8K is coming with Ultra-HD. Issues: Everyday television programs aren’t made at such a high resolution. Difficult to stream Ultra-HD content as large bandwidth needed. Many also stream using online providers. 4K and 8K is expensive. To provide context, 4K is commonly used in the movie-making and cinema industry. Seizures experienced due to VR, so epileptic users need to be cautious. Injure self by walking into object in real world. 2. Role and Impact of IT in Society 2.1. What is an E-business? E-business: business that performs a majority of its operations online. 2.2. Online shopping Advantages: Receive products quickly, save travelling time Greater options and choices available. Better for the environment as less vehicles used to travel. Disadvantages: Product size and quality can’t be judged when buying. This increases product returns and people argue that the number of vehicles used to collect returns balance out the advantage of using less vehicles to travel. 2.3. Online Banking Online Banking: computerised version of the majority of services that a normal bank would offer. Setup: 1.16. Vision enhancement Normally provided in form of glasses/lens. Corrects stimulus entering eye to enhance vision. Often tailored to the person’s current vision to be effective. Enables colour-blind people to view the world normally. 1.17. Virtual Reality (VR) 3D space made by computer. User put into space using a headset which displays the space and their position in it. Uses 2 camera feeds, one for each eye, to mimic vision. Handsets or gloves monitor hand positions enabling interaction. Benefits: In games In medical, so surgery practice can be simulated. In training programs like flight simulators. Issues: Calibration not perfect so may cause motion sickness. Services: Check bank balance View bank statements Set up direct debits Apply for loans and overdrafts Paying bills Transferring money between accounts Benefits: Don’t need to leave home for everything Need to visit branch less Avoid bank queues Service available 24/7 View transactions without needing to wait for paper statements to be delivered. 2.4. Electronic funds transfer Transfer of funds electronically. WWW.ZNOTES.ORG CAIE A2 LEVEL IT (9626) Methods: Credit card. No actual money changes hand, money moved electronically by adding and subtracting amount from respective accounts. Direct debit. Person sets up agreement with a business to allow business to take a set amount of money from their account. This can be a one-time thing or regular. The person doesn’t need to remember to pay the business each time as money is automatically transferred. Safety is however an issue. Identity theft is a common form of a potential compromise in safety and the victim may lose privy to financial details, credit card number, name, address and contact, DOB, etc which can cause huge damage as purchases could be made on victims account. 2.5. Automatic stock control Control stock levels Control needed as too much stock means storage costs increase; too little stock means items might run out when needed. Easy to see how much stock present. Can be real-time or batch. Real time calculates as and when stock is added or removed from warehouse. Batch uses a transaction file to record whatever is added or removed from warehouse and is used to update the master file in database. Can be programmed to reorder when stocks reach certain level. If physical stock countless than automatic stock count, possible theft could be indicated. How it works: Product has barcode containing info on product When scanned, product ID is identified and recorded. Product level of warehouse is deducted by one. 2.6. Digital currency Internet based form of money Value fluctuates a lot Can be used instantly without the need of exchange rates. Is anonymous. This makes it more appealing to criminals too. All details are stored in an encrypted file so if the file is lost/corrupted/deleted or you lose the key, you lose the money 2.7. Data mining Involves sorting through data, finding new trends identifying patterns to establish relationships, and applying a theory to new data sets in order to try and validate the changes that are occurring. The goal is to predict changes before they occur. WWW.ZNOTES.ORG Analysis methods: o Anomaly detection - Identify unusual data that may require further investigation. Association rule - Finding relationships between variables. Cluster detection - Identifying groups and subgroups in data. Classification - classifying data into existing groups/categories. Regression - creating predictive models based on a range of variables. 2.8. Social networking Features: IM – enables real time text communication Blogs/microblogs/vlogs – one-way communication channel, often personal Forums – post questions, discuss topics. Effect: Allows for different forms of expression. Find others with same interests. ‘Fandoms’/fans make you feel welcome, belonged and closer to the social media figure. Anonymous Frequent hashtags, abbreviations, acronyms difficult to decipher by people with certain disabilities. Fear that young won’t be able to recognise body language or social cues, hence won’t be able to socialise. Online bullying Data/activity tracked and sold Identity theft Criminal activities Impossible to delete data once posted. Social media figures may abuse power of large following and launch political campaigns etc. 2.9. Video Conferencing Is when computers used to provide video link between people. Equipment needed: Computer system Webcam Microphone Speakers Good broadband connection Video conferencing software ADVANTAGES DISADVANTAGES No need to pay travel expenses Video conferencing system can be costly to buy No need to travel Employees maybe in different time-zones outside working hours. People seen and heard so body language seen Not possible to see all people using camera CAIE A2 LEVEL IT (9626) ADVANTAGES DISADVANTAGES Documents can be shown and emailed Equipment breakdowns would account for missing a part of call and could be complicated and time consuming to fix Reliable and fast internet connection needed which can be costly 2.10. Web Conferencing Real-time communication where number of people are viewing same content on computer screen at same t ime. Process: Link sent to attendees Attendees download software and join room via link Enter login details Host can upload documents to room for viewing and/or downloading. Host controls content on screen and can hand over screen controls over some content to attendees to read on their own pace. Equipment needed: Computer system Webcam (optional, only needed if video required) Microphone (necessary for host, otherwise optional) Speakers Good broadband connection Web conferencing software Advantages Disadvantages Host controls content on screen Difficult to tell if person is following. Saves travelling time Time consuming for host to set up equipment and content. Saves travel costs Software can be costly Host will need training to use Pre-recorded content can be software. Attendees may also used. need training to navigate around ‘room’. Documentation can be made available for attendees to download. Needs a good stable broadband connection 2.11. Teleworking Using IT to work away from home Advantages: Freedom over hours you work, but may be restricted to office hours if employer requires it. Save on travel costs, (also benefits environment) Employers need only small building to manage and use less energy. WWW.ZNOTES.ORG Disadvantages: Distractions at home Extra electricity used by being home all day. Less control over employees Confidentiality 2.12. Technology in sports Advantages: Aid referees See if ball over line using recorded footage More accurate Players can challenge decision Disadvantages: Stops flow of game Some feel system not that accurate. 2.13. Technology in medicine Measure heart rate Analyse DNA samples Artificial limbs Nanotechnology to make drugs and target delivery which reduces damage/unnecessary treatment to healthy cells Smart devices to monitor Training Simulate procedures 2.14. Technology in manufacturing Robotics to create assembly lines of products Effects: Robots do dangerous work Greater consistency More accurate Can do repeated work Run for longer periods of time Can be operated 24/7 Results in loss of jobs Costly Competitive disadvantage if company buy machines. 2.15. Technology enhanced learning Robotics to create assembly lines of products Effects: Students provided with resources and guidance online Upload work to portal for marking Interactive whiteboard to enhance teaching, resulting in better understanding. Online learning and courses, so learn without paying at own time and pace. MOOCs are mostly free, include filmed lectures and resources and have forum to interact with other learners and educators. Also allows people in similar CAIE A2 LEVEL IT (9626) industries to learn more about their industry from other people within that industry. Demonstrations and videos online help learn visually. Might take time to find desired video or topic as there’s no governing body to oversee level of teaching. Infrared: low bandwidth, affected by sunlight, uses line of sight, cheap Fibre optics: no electric interference, great speeds, can’t be ‘tapped’, light, don’t suffer from signal degradation. Laser: can cover large distance, line of sight, can be used to connect to LANs, are secure. Wireless communication: Bluetooth: uses frequencies between 2402 and 2480 MHz, and is used for communication between short distances. Wi-Fi: operates in 2.4GHz and 5GHz. Used to connect portable devices etc. Doesn’t use line of sight. Radio: Both Bluetooth and Wi-Fi use radio waves. RFID chips use radio waves to identify the location of an object with an RFID chip. It is also used in wireless key cards and in a few secure payment methods u sing NFC. Bandwidth is important when accessing content within a time limit or in real time. Large files download quicker with greater bandwidth. When watching streams, high bitrate is generally required to keep the b uffer from emptying. Types of transmission media Cables: unshielded twisted pair (Ethernet cable) is widely used. Suitable over distances up to 100 metres. Electrical interference is also present. Shielded twisted pairs are used for high bandwidths. Wireless: less frequencies available, so lesser bandwidth than copper. Is also susceptible to interference. Optical: total bandwidth higher than copper Protocol: set of rules that ensure that data is transferred correctly. POP: defines rules for email client software to retrieve mails. Downloads all messages on client c omputer and deletes from server. Part of application layer. IMAP: alternative method for email client software. Mail is left on server and copy is downloaded. Supports multiple folders unlike POP. Is a part of application layer. TCP/IP: basic communication protocol used on the internet. FTP: part of the TCP/IP suite and defines file transfer rules. HTTP: part of the TCP/IP suite. Used by web browsers to send requests to a web server to view a web page. HTTPS is the secure version. BitTorrent protocol: specifies how multiple downloads take place from the same file concurrently. Several c lients download portions of the file and connect to send the files directly to each other. A torrent is a metadata file which identifies URLs or trackers to coordinate communication between peers. Abstraction layers: 3. Networks 3.1. Network components Switch: sends data packets to desired port Hub: sends data packets to all ports. Called a multi-port repeater. Wireless access point: connects WIFI enabled devices to a network using radio waves of 2.4GHz or 5GHz. Network interface card: needed to connect to a network or any device. Connects to the motherboard. Wireless NIC: can connect to a network without wires. Can add wireless NIC through a USB/dongle to a device which doesn’t have it enabled. Router: connects a LAN to a WAN (like internet) and determines most efficient route for data to reach destination. Repeater: Active hub which retransmits data packets to prevent signal from degrading a lot. Gateway: connects two networks of different types. Firewall: prevents external users gaining unauthorised access. Server: computer on a network which provides resources that can be used by client devices. File server: makes files available Print server: deals with all print jobs, maintains a ‘queue’ and allows priority users to jump the queue. Can also charge users for print using a credit system. Mail server: receives and send emails for an organisation. Application server: delivers software to clients. Proxy: deals with all requests to the internet. It sits between the LAN and the gateway. Bandwidth: measures range of frequencies on a communication channel. Bitrate: transmission rate of data Bit streaming: streaming of bits; files are sent to device for viewing without downloading. In a video, few frames are sent to fill a buffer (temporary area of storing). The buffer is emptied as the frames are viewed. Methods of transmitting Circuit switching: packet path decided before communication, one route for all packets Packet switching: each pack takes own route and is routed between nodes. Message switching: transmits whole set of data together without a predefined route. Optical communication WWW.ZNOTES.ORG CAIE A2 LEVEL IT (9626) 3.2. Network security Security issues: Hacking: act of gaining unauthorised access of a network. With access, the hacker can read, change and d estroy data. Malware: used to describe any software designed to cause damage. Types include parasitic viruses which attach themselves to files, macro viruses which attach to macros, email viruses which arrive as email attachments and worms and Trojan horses. Denial of service attack: DoS is designed to overload a server’s requests to cause disruption. They’re easy to launch and difficult to track. Security methods: Access right: The most common access rights are Create, Read, Update and Delete. To gain these rights a user has to identify themselves by a user and pass, email ids, swipe cards or NFC, or biometric m ethods. 2 factor authentication can be used at times. Users have to be careful to protect their rights access method. It is possible for companies to disable particular accounts from being used at certain times of the day to enforce better security. Biometric methods: biological characters which can be measured like fingerprints are often used to authenticate a user’s identity. Characteristics are unique. Fingerprints and retina scans are generally regarded as secure methods. However, several users feel they tend to infringe upon their privacy. Voice a nd facial recognition have never been very secure Firewalls: these control what data goes in and out of a network. It can be a part of the router or a separate software installed. They often include a proxy server and an Access Control List. Backups: Backups are required to replace original data in case if the original data is lost or damaged. However, they do not stop hackers or prevent from files getting corrupted due to malicious software if the software was present in the original data. Encryption: Process of changing data so that if it is accessed without authorisation then it will be WWW.ZNOTES.ORG nreadable. This is done by using an algorithm to u change the cipher. It however cannot stop the hacker from destroying stolen data. Malware security: anti malware software monitors the system for threats and signs of malicious files and disinfects or quarantines the malware. Physical security: Physical locks, protection against electrical surges, server locations in place where it’s protected from floods and fire are some general physical security methods. Data protection act principles: An act to protect people about whom data is stored. It outlines that data s hould be Used fairly and lawfully Used for limited, specifically stated purposes Used adequately, relevantly and not excessively Kept no longer than necessary Handled according to data protection rights Kept safe and secure Not transferred without adequate protection. Data protection laws are required to protect data subjects and the information held about them. To process data fairly, data subjects must be informed, made aware of the purpose, and be asked p ermission to collect data. 3.3. Satellite communication systems Satellites in space send microwaves down to earth. There are three different levels or orbit used by s atellites: Low earth orbit [500-1500 km from earth requiring 40-80 satellites for global coverage] Medium earth orbit [5000-12500 km from earth requiring 8-20 satellites for global coverage] Geostationary earth orbit [at fixed points 35800 km from earth requiring just 3 satellites for global coverage] Satellite broadband cannot be used by people living in areas not covered by wireless or wired broadband connection. One-way satellite broadband sends data for download from the internet to client using public switched telephone network (PSTN). Uploading can be very slow using this. Two-way satellite broadband allows client to upload/receive data directly from satellite. Television and radio broadcasting is done by radio waves, cables or satellites. As radio waves depend on frequencies, channels are limited. Satellite offers more channels as it uses microwaves. Signal is encrypted so only subscribers can watch. A set top box and a satellite dish are required to watch. Initial cost of equipment can be expensive. Global Positioning Systems use satellites to calculate their current location on earth. Trilateration is used t o locate the receiver. GPS can provide real-time location when used with satnav systems. It uses line of sight however, so finding a n exact CAIE A2 LEVEL IT (9626) position can be tricky at times. The signal can also degrade due to the atmosphere. 4. Project Management 4.1. Stages Can’t be used offline Graphic quality not as good as desktop Single user: Usually desktop systems Appropriate for small projects Personal: Typically for home users for small projects single user software Simper interface Collaborative: Several users can use at once Web based or client-server model Info stored on central server 4.3. Project Management Software Conception and initiation: Ideas identified and goals set Stakeholders identified Decisions made and requirements identified Feasibility study made Planning and design: Budget and time scale formulated Milestones set Gantt chart made Personnel coordinated Execution: Project manager communicates roles and responsibilities to team. Interim targets there for each member Monitoring and control: Project manager ensures tasks complete on time. Also monitors performance and progress. Monitors and tracks budget and spending. Holds meetings with stakeholders. Closure: Handover project from team to client. Termination of contract. Resources released; employees deployed. Evaluation and success review done. 4.2. Types of project management software Desktop: One project manager Sophisticated software more responsive better graphics License costs incurred Collaboration limited Web-based: Can be accessed through browser Multiple users can access at once Documents stored centrally One version maintained WWW.ZNOTES.ORG Planning: Milestones identified. Templates help to set up software plan. Company standards, House Style is set. Scheduling of tasks: Gantt charts can be created. Tasks are assigned, dependencies identified. Allocation of resources: Costs can be assigned to resources. Resources can be assigned to tasks. Resource conflicts avoided. Costings: Records expenses. Custom analysis of expenditure and comparison to budget possible. Information can be exported. Communications: Synchronised calendars with tasks and deadlines. IM/Video chat/Video conferencing possible to communicate in real time. Shared documents stored in central repository. Document changes can be tracked. Discussions/Forums for tasks and milestones. Useful if a member can’t communicate in real-time. Progress tracker can inform members when a milestone is achieved or task is completed. Decision making: Communications logged and tracked. Graphs, charts and reports used to analyse budget, scheduling and task progress. Critical path for project shown. 4.4. Disaster recovery management Risk assessment carried out to identify potential risks. Risks quantified using business impact analysis (BIA). Potential hazards: Power cut Fire Flood Denial of access to premise CAIE A2 LEVEL IT (9626) Malware Unauthorised access to data Theft of data Corruption of data Loss of key personnel Impacts: Loss of revenue. Damage to organisation’s image. Effect on other business activities. Risk = likelihood x impact Recovery management: Restoration of backups. Replacement of hardware Reinstallation of software. Emergency replacement of key personnel. Emergency office accommodation. Resources needed to recover must be planned for. Recovery point objective (RPO) must be identified. It’s the estimated max amount of time that the business activity has to recover systems and resume operations. Know how long recovery would take. Maximum tolerable downtime (MTD) should be considered. It’s the max time a business activity could tolerate not having essential system functionality. Backed up data should be tested regularly to ensure the backup process has succeeded and data is a ccessible. Full systems restorations should be tested periodically by attempting to restore whole server backups onto a clean server and testing them. 4.5. Prototyping Is a ‘mock-up’ of a software or manufactured solution in a primitive form. Used to demonstrate how product will look and work. Usually focussed on UI for the feel. Evolutionary/Incremental prototyping: Iterative approach Initial prototype developed, reviewed, and refined according to requirements and feedback. Throwaway/rapid prototyping: Prototype is discarded and doesn’t become part of the final product. Requirements fine-tuned early in development. More cost-effective. Advantages Disadvantages Problems identified early in Requirement analysis may be process.Cheaper to make rushed so prototypes aren’t changes in early stages than reflection of expectations. later. Users get new ideas when seeing prototypes and can Requirements can be clarified lead to disappointment when and refined. the features can’t be funded. (Called feature creep) End users more involved in process, so more valuable feedback. Initial costs of developing prototype is high compared to traditional designs. In rapid prototyping, the Developers have better prototype can become understanding of expectation rushed and may have design flaws or errors carried to end due to feedback. solution. In throwaway, when users see a working interface, they In evolutionary prototyping, don’t realise effort and time users can get used to using needed to make that into a parts of system before whole, working solution. In iterative, so need for bulk-training is the feedback process can last reduced. too long if regular changes are wanted by user. Rapid application development: Uses prototyping to develop a system in a short time frame. Requirements gathered through a focus group. This type of user involvement is known as Joint application development (JAD). Less time spent on planning and design and more emphasis put on development stage. Strict deadlines there throughout development. Advantages WWW.ZNOTES.ORG Disadvantages CAIE A2 LEVEL IT (9626) Advantages Disadvantages Requirements not clearly High level of user specified so final solution involvement so end solution may not meet needs of entire more suitable for end users organisation. Users often not sure of the Users required throughout requirements so evolutionary the project which may lead to approach allows for work overload for users or requirements to evolve. need for temporary staff. System structure may be Over ambitious requirements compromised leading to quickly realised and instability as focus is on User simplified. Interface and getting system developed quickly. Strict deadlines prevent feature creep Strict deadlines may cause parts to be rushed and compromise on quality. Less time spent on design, more on development. Existing software modules may not be made for the same requirements so won’t be sufficient. Software application Software application frameworks allow users to be frameworks don’t produce involved in configuring efficient code so end solution layouts. won’t run as quickly. Users who were not involved in the JAD may be disappointed. Waterfall method: 4.6. CAD and CAM Computer-aided design (CAD) involves use of computers to design physical products. Computer-aided manufacturing (CAM) involves use of computers to manufacture physical products. Benefits Drawbacks Expensive prototypes not Lead to loss of jobs and need necessary as stress testing for employee reskilling. can be carried out on models CAD drawings can be modified and enhanced without manufacturing. Testing using model doesn’t provide same results as testing using product so at least one prototype needed. List of required materials automatically produced by CAD drawings. User can experience 3D model but it isn’t same as experiencing real thing. CAD models can be viewed from many angles and elements can be zoomed into. CAD software is complex so highly trained staff needed. Components once designed High initial costs of software. can be reused. Fewer designers required so is cheaper. Designs developed by CAD will include errors made by designer. CAM enables products to be mass produced consistently. Designs limited to vector objects. CAM more precise than manufacturing by hand. Manufacturers drawings can be created seamlessly. CAM removes need for manual labour so reduces costs. 5. System Life Cycle 5.1. Analysis User requirements gathered at beginning. Interface and structure designed during design stage. System programmed in implementation stage. Verification confirms if user-requirements are met. Problems discovered are corrected in maintenance stage. Waterfall method fundamentally flawed as it relies on the requirements being clearly defined. WWW.ZNOTES.ORG Involves finding out working of current system and requirements for new system. Questionnaires Used when large number of users present. Users remain anonymous, so more honest answers received. Doesn’t allow elaboration of answers. Shouldn’t be too long. Closed questions should be asked Interviews Direct conversation possible Interviewee can expand upon answers CAIE A2 LEVEL IT (9626) Questions and logistics of interview need to be carefully planned. Interviewee may not be honest. Analyst needed to be involved in every interview. This is time consuming and costlier. Observation Analyst watches processes. Gives a good understanding of current processes and methods used. Users may do things differently under observation though. Users may not like to be observed. Method takes a lot of time. Document analysis Analyst sees examples of current documents to understand what data is collected or output, and identify p rocesses. Method is not to be used on its own. Documents only show output, doesn’t show additional data needed. Three types of specifications are used in the system life cycle. Requirements specification: Contract between developer and client specifying system requirements so the developer can produce a system matching needs. Created by the analyst. It includes- Purpose of system Main objectives of system Data to be output Data to be input Validation and verification Processes that convert inputs to outputs or store data Functional requirements Deadlines for milestones System specification: specifies all hardware and software required for the system. Software needs to be identified and hardware depends on the software. The analyst also needs to consider how much storage the data would require. Design specification: Illustration of how system will look, what data structures will be and how system will work. Specification will include- Flowcharts Data flow diagrams (DFD) Data collection forms Screen layouts Validation routines Data dictionary House style (logos, colours, fonts, styles, sizes) Screen sizes Connectivity diagrams Purpose of calculations 5.2. Design DFD shows how data moves in a system. Element Purpose WWW.ZNOTES.ORG Symbol Element Purpose Data flow Data that flows through system Processes Action that uses/manipulates data Data store Place where data is stored External entity Where data originates or is destined Symbol System flowchart shows processes that take place within the system and decisions that are made. Element Purpose Terminator Start and end of flowchart Arrow Direction of flow Process Activity within system Decision Decision with different outputs based on result Input/Output Input data or output data for system Symbol Data collection form principles: Avoid colour as it may be printed without colour Include instructions on how to complete form Include instructions about where form should be returned Indicate compulsory and optional questions Give enough space to answer Use tick boxes for MCQ questions Indicate how many options allowed from a multiplechoice list Ensure fonts used consistently and legibly Avoid clutter Explain what scale indicates if there is a question about a scale When designing screen: Use colour sparingly Ensure fonts used consistently and legibly Avoid clutter Include instructions on how to complete form Indicate compulsory and optional questions Give enough space to answer Use tick boxes for MCQ questions Use drop-down boxes or option boxes for MCQ questions with only one response. CAIE A2 LEVEL IT (9626) Validation routines should be used wherever possible and be appropriate in order to reduce number of possible input errors. Error messages should be positive and guide users as to what to do to correct error. 5.3. Development and testing When a system is developed, data needs to be created for the purpose of testing, called test data. Alpha testing is carried out by the developers or a special team before a system is delivered to users. Beta testing is used when software is being made available to a large number of users. Beta testers would be selected users who test an early release of an application after alpha testing. Black box testing involves selecting input data and checking that expected output matches actual output. Involves testing the whole system or user testing. No knowledge of the way the system works is required. White box testing involves the same process but the internal structure and logic of the program are known to the tester. Usually takes place with small program modules. 5.4. Installation Parallel is when a new and old system is run at the same time. Advantages: It’s less risky because if the new system fails, the old is always there. Accuracies of both systems can be compared. Disadvantages: it’s more expensive as more staff is required to duplicate data and different hardware may be needed. Data might be input differently in both. Direct or plunge changeover is when all the data is moved to the new system. Advantages: This is a cheap method, the data used will be consistent and the new system doesn’t have to be compatible with the old Disadvantages: it’s very risky and users would need to be trained in advance. Phased is when parts of new system are installed one at a time. Advantages: Errors would only affect one part and users can easily be trained. Disadvantages: using 2 systems might be confusing and there might be delays waiting for the phase to be successful. Both systems will also need to be compatible. Pilot takes place when one part of an organisation starts to use the new system and the rest continue with old. Advantages: Errors will only affect pilot group and the pilot group can train other users. Disadvantages: the method is very slow, and users might not like to use the new system. Both systems will need to be compatible. WWW.ZNOTES.ORG 5.5. Documentation Technical documentation is an overview of the structure of the system, how it was put together, and how it works. It will include a data dictionary to show how data has been structured within the system. It will also include an installation guide, results of testing and detailed backup routines. It’s needed for people carrying out future maintenance so they can understand how the system is c onfigured. User documentation is user guide giving instructions to the user. It includes details about how to use the system, alphabetical list of technical terms, a troubleshooting section and an index. Its needed so the user can learn how to use the system and easily troubleshoot. 5.6. Evaluation and maintenance When a system has been installed, it will be evaluated. Users will be asked about the system and r equirements would be checked to see if they’re fulfilled. Maintenance takes place after a system has been delivered to a customer and is being used. Reasons for requirement: Perfective maintenance aims to always look to improve the system even if there aren’t any errors. Adaptive maintenance aims to adapt to changes such as new laws, new organisation etc. Preventative maintenance aims to prevent problems arising in system. Regular checks like hardware c hecks are conducted for this. Corrective maintenance is to correct errors or bugs discovered in the system. 6. Graphics Creation 6.1. Fundamentals Node: An editable point on a line or vector which can be selected, transformed and moved. Meta-graphics: images containing a combination of bitmap and vector data. Tracing: Conversion of a bitmap graphic into a vector graphic. Rasterization: Conversion of a vector graphic to a bitmap graphic (at the native resolution of the display device) so that the vector can be viewed on a display. Pixel: Single unit / picture element of a bitmap graphic – a single coloured dot. Short for ‘picture element’. Pixilation: When a bitmap image is enlarged so much that you can start to make out the individual pixels f rom which it is made. Edges and details lose their sharpness and the whole image can appear blurry or b locky. Resolution: The amount of detail in an image, which is dependent on how many pixels it contains. Measured in CAIE A2 LEVEL IT (9626) Megapixels, dpi, ppi, or pixel dimensions. Resolution independent: Graphics which are redrawn, when moved or scaled, at the native resolution of t he display or output device (this applies to vector graphics). Compression: The re-encoding of data into a format which uses fewer bits of information than the o riginal. This can speed up loading and transferring the file, and reduce the amount of memory it takes up on your computer. Lossless compression: Compression of a bitmap graphic which removes repeating patterns of data, but a llows the original data to be exactly reconstructed from the compressed data. Lossy compression: Compression of a bitmap graphic which uses approximations to remove and discard data within a graphic that is unlikely to be noticed. Run length encoding: A data compression algorithm, that is supported by most bitmap file formats, which reduces the physical size of a file by encoding a run of repeating characters in the file into two bytes. The fi rst byte is the run length - the number of repeating characters. The second byte is the repeating c haracter or value. 6.2. Vector vs Bitmap Vector: created using shapes and coordinates, and mathematical formulae and calculation are used to draw and fill areas. Doesn’t pixelate as image is recalculated and redrawn when size is changed. Instructions to create image are saves, not the image itself. Don’t work as efficiently when an image contains a lot of data. Can look ‘blocky as screen is bitmap display device (uses pixels). On a lower resolution screen, you can see the dots. A vector image drawn on the screen is at the resolution of that screen. On a lower r esolution screen, you will see dots in the rasterised vector graphic. Bitmap: created using pixels. Each pixel has one colour. Pixelates as squares(pixels) are enlarged when size is changed. Image itself is saved and goes blurry when resized. Image quality measured by resolution which is number of pixels per measurement (like dpi) 6.3. Extras Duotone: duotone is a reproduction of an image, but only using two colours to represent a photograph as a vector, a pixel would need to be represented as one line, because of the image’s complexity. This is considerably more data per pixel than just the RGB value, making it much less efficient. It is possible to convert a bitmap image to a vector (known as ‘tracing’). This converts each p ixel into vector data by WWW.ZNOTES.ORG using a threshold to choose how close the RGB values of adjoining pixels need to b e in order for the computer to view them as ‘the same’ and therefore create a shape rather than trying to create a single line per pixel. The threshold value set when the trace is performed will affect how good t he trace is in terms of image detail. File types: BMP (Bitmap): range of bmp formats like four-bit (16 colours), eight-bit (256 colours). GIF (Graphic Interchange Format): Compressed format which allows transparency (as long as not created u sing alpha option). Restricted to 256 colours. JPEG (Joint Photographic Expert Group): Image compressed when saves, decompressed when opened. Does not allow transparency, transparent areas stored as white or black. PNG (Portable Network Graphics): lossless compression, keeps transparency. TIFF (Tagged Image File Format): adjusts number of colours to reduce file size. File type can save effects such as use of layers if saving and opening in same software. Use of vectors and bitmaps in webpages: Vectors Bitmaps Scalable Photo-realistic Complex data so can delay loading of site Can be compressed so loads faster. Might pixelate if zoomed Effect of editing: Enhances image Bring elements into focus which can help emphasise purpose behind image. Can set the mood of the scene in an advertisement. Can create a false sense of reality, like airbrushing models to be more ‘beautiful’ can set standards of beauty which are not naturally possible. Editing images of celebrities and famous figures can create impression that product or campaign being advertised is favoured by the celeb. 7. Animation 7.1. Fundamentals Object: image(s) on screen manipulated as one item Layer: object given its own timeline.Animation: series of images played one after the other to stimulate movement. Frame: one screen or page where an image is placed. Key frame: frame that has a change in animation. Will have a dot • on the frame in timeline. Frame rate: number of frames per second. (fps) CAIE A2 LEVEL IT (9626) Opacity: lack of transparency Tween: animation where start and end points are set and the computer generates the images in the m iddle. Morphing: shape tweening. Allows a shape to transform into another shape and also includes movement so location can be changed too. Onion skinning: The term given to showing several of the previous frames when working on a new frame. Persistence of vision: Is an optical illusion where the human eye is fooled into thinking a series of still images represent one image which is moving. Stage: area in an animation software where you create the animation Rendering: the process the animation software uses to show an animated scene with all it components. Rotoscoping: animation technique where the animator will trace over footage of something frame by f rame, often a subject of real life which has a complex movement pattern. 7.2. Extras Types of animation: Traditional 2D hand drawn animation. Animator draws each frame separately and then they are photographed and played back to the viewer in sequence at higher speed. Stop motion Animation. This is where physical objects are photographed one frame at a time. The o bject is then moved and the next frame is recorded. A variation on this is known as “Claymation” which involves the use of objects made from modelling clay or similar. Key frame animation. The animator will set two key frames and the software will generate all the f rames in between the two key frames over period of time designated by the animator. Shape tweening a nd motion tweening are common methods used within this type of animation. 3D animation. powerful computers are used to create objects that can be easily manipulated in a 3D environment. Motion capture is now often used to record the movement of real people or objects. This real-life movement is then processed and applied to a digital version where it can be manipulated and rendered with different attributes. 3D animation and motion capture have now replaced, in many cases, the traditional method of rotoscoping. Lesser key frames mean the animation isn’t smooth. However too many key frames mean more work for t he animator. Animation speed can set the mood. A higher fps can be used for action-oriented animations, lower for a c alm, soothing mood. 8. Mail Merge WWW.ZNOTES.ORG 8.1. Mail Merge Mail merge: process of merging data from a source file into a master document. Master document: created using pixels. Each pixel has one colour. Source file: contains the data that will be included in each mail merged document. Formats include: Database table Database query Spreadsheet Word processed table Variable length text file Fixed length text file Email contacts Prompts: asks user what data should be. Used for items which change as per occasion and are not in data s ource but needed in the master document. 8.2. Error-free accuracy Checks to carry out before finishing mail merge: Run spell checker and grammar checker on master document. Visually check for errors on master document. Visually check for any errors on previewed or merged documents. Check that correct records have been included in the filter. Errors may be there even after spell checker as it won’t detect errors in words which sound same but are s pelt different. It also won’t identify extra spaces, field codes, or errors in names. 8.3. Why use mail merge? Mail merge saves time and increases accuracy as: Source data may already exist. So time isn’t wasted reentering data for each document. Accuracy improved as source data usually validated and verified. Letters are personalised rather than being generic easily. Quicker to proof-read on master document than several individual documents. Master documents can be reused in future. Filters applied so documents only made for a select category. 9. Programming for the Web 9.1. JavaScript Programming language that can be used to add interactivity to web pages. Can also be integrated with other programming languages. CAIE A2 LEVEL IT (9626) To print/output Operator Function <= Less than or equal to == Equal to === Equal to and same data type != Not equal to !=== Not equal to or not of same data type Logical operators Or to add in set location Operator Function Explanation && AND TRUE if both conditions true || OR TRUE if either true ! NOT TRUE if false String manipulation Operator Description word = “Hello World”; Variable is a space in memory given a name where data can be stored and changed. substring*(startLetter, endLetter);* Return letters from position of startLetter to *endLetter**subword = word.substring(7,11);*subwor d holds “World” substr*(start,noOf);* Starting at start letter, return letter numbers.*Subword = word.substr(2,4);*Subword will hold “llo” replace*(“string”, “string”);* Replaces first string with second*newW = word.replace(“Hello”, “Ok”);*newW will hold “Ok World” Data types: Type Description Number Numeric value String Letters, characters, and numbers. Use “…” / ‘…’ to surround text string. Boolean True or False Array Series of values of same data type Object Series of named values of variable Arithmetic operators Operator Description + Addition - Subtraction * Multiplication / Division ++ Increment (increase by 1) -- Decrement (decrease by 1) % Modulus (return whole part of quotient) Comparative operators Operator Function > Greater than < Less than >= Greater than or equal to WWW.ZNOTES.ORG Joins stringsword1 = “h”; *word2 = “world”**final = concat*(“string1”, “string2”);* word1.concat(word1, “ ”, or String1 + String2 word2);*or final = word1 + “ ” + word2; \n final stores “h world” toUpperCase(); Converts string to uppercase*final = word.toUppercase();*final stores “HELLO WORLD” toLowerCase(); Converts string to lowercase*final = word.toLowercase();*final stores “hello world” charAt(number); Returns the character in the string at number given*letter = word.charAt(2);*letter will now store ‘e’ Comments: text in code which interpreter does not run. Used to make notes about how your code works s o other CAIE A2 LEVEL IT (9626) developers can understand. Add // before and after text you want to mark as comment. Arrays: Data structure that allows you to store multiple values under one name. an array value can be e xtracted and stored as variable, be replaced or even added. length of array can be found too. Conditional statements: IF checks a condition. If true, first block of code is run. ELSE gives an option to run code when condition false ELSE IF allows multiple conditions with different outcomes. SWITCH used instead of combining multiple if statements as that can get difficult. Loops: FOR – need to know number of times loop is to run FOR/IN – used when there’s an object to loop through each element WHILE – runs code when condition true DO/WHILE – condition checked at end of loop. Functions: set of instructions that perform a specific task. It has a given name and can take values (parameters) Iterative methods: function (or task) that is repeated. Every: checks every element in an array against a condition. WWW.ZNOTES.ORG SOME: checks if at least one item meets the conditions FILTER: returns any array with all elements that meet the criteria FOR EACH: runs task on every element within the array MAP: runs task on every element within the array and returns the new/edited array Trap errors: detect errors. Try and catch code is used. HTML forms and control events: Lets you combine multiple objects and receive input from user. BUTTON TEXT BOX DROP-DOWN BOX RADIO BUTTON 9.2. Pop-up boxes Pop-up box can be used to display text or info. There are three types of them: ALERT: only displays text CONFIRM: has two options, ok and cancel. PROMPT: allows user to enter some text and gives them options of ok and cancel. 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