Revision Topics For I

I.T. Revision Notes Input, Output and Storage devices Input • • • • • • • • • • • • • • • • •

Keyboard Mouse Tracker Ball Touchpad Joystick Touch Screen Graphics Tablet Magnetic Stripe Reader Barcode Reader OCR (Optical Character Reader) MICR (Magnetic Ink Character Reader) OMR (Optical Mark Reader) Microphone EPOS (Electronic Point Of Sale or Cash Register) Scanner Camera Sensor

Output • VDU (Visual Display Unit or Screen) • LCD Screen (Liquid Crystal Display • Laser Printer • Ink-jet Printer • Dot-Matrix Printer • Graph Plotter • Robots • Speakers • Headphones Storage Devices • ROM (Read-Only Memory) – Usually holds the boot program • RAM (Random Access Memory) – Usually holds data and programs while they are running • Magnetic Media o Floppy Disk o Hard Drives o Magnetic Tape • Optical Disks o Compact Disks o Digital Versatile Disks • Back up Devices o Flash Devices o External Hard Drives

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E-mail Sending a text message, which can include attachments, over a communication network such as the internet Advantages o Arrives faster than post o Free to post o Less chance of being lost o Can be sent to multiple people o Can be received anywhere, not at a set location o No need to leave the house Disadvantages o Sender and Receiver both need devices capable of network connections o Cannot send physical objects o Possibility of the spread of viruses System Lifecycle Analysis o Requirement Specification o Feasibility Study  Technical  Economical Design o Test Plans Implementation o Creating the system o User Guides o Change-over methods  Parallel (Run both systems until the new system is 100% running)  Pilot (Run the system in a small part of the company and then move to the rest when satisfied)  Direct (The old system is immediately scrapped and removed) Testing Evaluation

Testing Normal Data – Data within certain validation boundaries (E.G. 50 if the boundaries are 1100) Extreme Data – Data on the border of certain boundaries (E.G. 100 if the boundaries are 1100) Erroneous Data – Data outside of the border of certain boundaries (E.G. 110 if the boundaries are 1-100)

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Spreadsheets Cell Referencing (Letter THEN Number e.g. “A1”, “H67”, “F12”) Cell Formats o Text o Number o Date o Currency o Formula Creating and Identifying Formula o Adding two cells “=A1+A2” o Subtracting two cells “=A1-A2” o Dividing two cells “=A1/A2” o Multiplying two cells “=A1*A2” o Adding multiple cells “=SUM(A1:A2)” Advantages of using spreadsheets over manual methods o Quicker to calculate information o Information can be changed easily o Less Errors are likely to occur in calculation Spreadsheet Modelling o Changing a variable or variables within the model o Analysing the results of these changes o Make decisions and predictions as a result of the analysis o The process is often cyclic Data Logging

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Data logging is the collection of data over time from preset inputs known as sensors. Most logging is automated by computer control Sensors are the input of the system. Sensors can be thermal, sound, pressure, light, acidity or humidity sensitive Calibration must occur when the sensors are set to a certain scale so the data produced is understandable Advantages of Data Logging o Highly Accurate o A system can be left unattended by humans o Can be used when safety risks are involved o Can be used over long periods of time o Can take multiple readings over a short period of time Disadvantages of Data Logging o The correct equipment is required o Equipment can cost a lot of money o If the machinery is left unattended and breaks, all data is lost

Operating Systems What do they do? • Provide a way for applications software to communicate with hardware for example printing data of a package by clicking the printer icon. • Manage system resources and manage CPU and memory usage. • Manage the transfer of data from the peripherals to the applications. • Manage system security such a logon password and firewalls (if built in OS). Examples of Operating Systems • Windows XP • Windows Vista • Windows 7 • Mac OS X • Ubuntu Linux Types of Operating system • Multitasking – Ability to run 2 or more programs at once • Multi-user - Allows two or more users to access a document at once User Interface This is what you see when you turn on the computer; consisting on the icons, prompts, menus and cursor, etc. allowing you to control the computer; this should be as easy to use as possible. There are three types of User interfaces: 1. Command-Driven 2. Menu-Driven 3. GUI Command-Driven With a command-driven system, you type in instructions and the order is sent to the computer. These commands are usually abbreviated such as typing ‘cmd’ in a Windows Operating Systems ‘Run’ box will open up the command prompt. They are not easy to use and you need to learn many commands, commands for different software are often different so often people get mixed up. Menu-Driven This is a type of interface that produces a list of options that the user can select for the program. Windows and Macintosh Programs are menu-driven. Graphical User Interface

Often referred to as GUI, they provide a way for the user to communicate through icons and pull down menus. Windows and Macintoshes are examples of GUI. Windows provides a common way of controlling programs which makes it easier for the user to learn. It also controls devices such as disk drives and printers making them easier use. WIMP W.I.M.P. stands for windows, icons, menus and pointing devices typical to a GUI which makes it easier to get work done. Designing a User Interface To make an interface as user friendly as possible it is necessary to be careful in designing it. This includes: • • • • •

Consistency- Each part of the software should work in the same way making it easier to learn. Positioning – The placing of the icons and menus should all be consistent throughout the software. Colour – Some colours are easier to see that others so they should be chosen carefully. Sound – Sounds can be annoying so the should not be common and irritating and must include the ability tot be turned off. Help – Most software has online help and a built in help in case the user doesn’t understand a function/topic. Databases

Validation • Range Check • Presence Check • Format Check • Check Digit (Barcodes) • Lookup Table • Spell Check Verification • It is a check to see the data entered exactly meets the original source • Double Entry Check – The data is entered twice to ensured no errors were made while entering it • Proofreading Check – Data is entered and then checked over by a different user Key fields • A key field is usually a unique identification code to a record, so that it is different to every other records

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Coding Advantages of using coding o Quicker to type o Reduce file sizes o Increase process speed o Unique – quicker to search for Disadvantages of using coding

o Codes must be the same length o Codes have to be remembered by the user o Codes have to be a certain length or codes will run out

Online Shopping Advantages of Online Shopping • Cheaper as money is saved for petrol • No need to leave the house • Can order outside supermarket opening times • Home delivery • Wider choice • Faster to search online • Repeat orders can save time Disadvantages of Online Shopping • Cannot choose own groceries • Virus Issues • Fear of buying due to credit card fraud • Not everyone has access to a computer and a network • Arrives late Networks LAN and WAN • Local Area Network – A linking of multiple computers in a small area such as a school network • Wide Area Network – A linking of multiple networks over a much larger area such as the internet Advantages of Networking • Peripherals such as laser printers may be linked to multiple computers • Messages can be sent to anyone within the LAN or WAN • All users can access the same files without the need for duplicates • Network software can be purchased which is cheaper that buying software individually for each PC. • It is possible to access data from all terminals and workstations • Data can be stored centrally, making it easier to access and back-up. • Users can easily be prevented from accessing files that they are not allowed to which is useful in environments such as schools. Disadvantages of Networking • Sophisticated equipment is often needed for a WAN making it extremely expensive

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If the network fails temporarily, a lot of work has to be done manually and will hinder everyone on the network. When all computers are linked, file security is very important because of the ability to access any computer, anywhere Wiring is expensive to buy and install If a file server network fails, all of the files become inaccessible A network needs to be managed by a network manager because they are temperamental.

Flowcharts Look at page 5 on http://store.aqa.org.uk/qual/gcse/qp-ms/AQA-3521H-W-MS-JUN07.PDF Features of Desktop Publishing Software • Numbered points / bullet points • Increase text size/Text size made bigger • Text made bold/italics/underline/ Changed font style/effects e.g. shadowing • Coloured text / coloured background / colour • Alignment - Centre text/ Text right/fully justify/rotate text • Import company logo/picture • Move, rotate, edit images, drawing tools/auto shape • Tables • Text boxes • Borders/Border Art • Columns/Tab/margins • Shaded/pattern/watermark/transparency • Text wrapping • Page size / orientation • Word art • Master page/header/footer/page numbers Interviews and Questionnaires • • • •

Interviews give immediate feedback of information Questionnaires are often uncompleted Can see what is happening in an interview Interviews are not exaggerative

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Rights for Data subjects o Subject Access o Correction o Prevent Distress o Prevent Direct Marketing o Complain to Information Officer o Prevent Automated Decisions o To Compensation due to data Responsibilities of Data Users o Collected and Used fairly within the Law o Must only be held for the reasons given by the data commissioner o Can only be used for registered purposes o Adequate, Relevant and Not Excessive o Mustn’t be held longer than required o Information must be kept safe and secure o Must not be transferred out of the European Economic Area Role of the information commissioner

Health and Safety Health issues Back/Neck pain/problems Headaches Eye strain Wrist problems/Carpel Tunnel Syndrome/RSI(finger problems) Possible radiation from monitor Possible epilepsy from monitor Overheating of the room Safety issues Trailing wires Electrical faults Overload sockets/supply

Health solutions Regular breaks/walk around/relaxation techniques/fresh air Correctly adjusted chair/back support correct in chair/footrest Adjust monitor distance/brightness Visit doctor/eye test Use wrist support/ergonomically designed keyboard Check radiation level/change type of monitor/possible .screen shield. Use of air conditioning/ventilation Safety solutions Make sure all leads are secure/out of reach Repair faults/report faults Regular service and checks/PAT tests Use of blinds/fluorescent diffusers Install additional sockets