Development of Preschool Children

Development of Preschool Children 3 and 4-year-old children are often referred to as preschoolers. Preschool children want to become more independent and do things for themselves. They are enthusiastic about learning and acquire their knowledge through experiences and playing. Their motor, social, emotional, cognitive, and language skills all developing, as they try to gain inner control. Preschoolers want to establish themselves as individuals and can more easily express their needs since they have a greater grasp of language. The preschoolers body is continuing to lose baby fat and gain muscle. Their arms and legs are becoming more slender and their upper body more narrow and tapered. Some children grow taller so much more quickly than they gain weight and muscle, that they may begin to look somewhat skinny and fragile. This doesnt mean that they are unhealthy or that anything is wrong; some children just fill out gradually as their muscles develop. Most preschoolers grow about 2 to 3 inches in height and gain about 5 pounds each year. Also boys tend to be slightly larger than girls (Berk, 2008). A childs face also will mature during this time. The length of their skull will increase a little, and the lower jaw becomes more pronounced. At the same time, the upper jaw will widen to make room for their permanent teeth. Because of this growth, their face actually will become larger and their features appear more distinct. Children are playful by nature. Their earliest experiences of exploring with their senses lead them to play, by themselves at first and then eventually with others. Usually between 4 and 5 years old, preschoolers discover that they share similar interests and seek out kids who are like themselves. They discuss, negotiate and come up with ways to create elaborate play scenes; take turns; and work together toward mutual goals. Childrens play can be divided into 4 categories, some of which overlap. Dramatic play is fantasy-directed play like dressing up in costumes, pretending to be different characters, using toys to represent characters in stories, and creating imaginary settings. Some examples of manipulative play are using small toys like blocks or Legos to build objects, putting together puzzles, and making bead necklaces. Physical play uses the whole body in activities with bikes, balls, jump ropes, hoops, and play structures. In creative play children use art materials such as paint, clay, markers, pencils, glue, etc. Preschoolers improve their mobility skills through a variety of motor activities involving the entire body. Gross-motor development includes locomotor dexterity, which requires balance and movement, and upper-body and arm skills. Examples of locomotor skills are jumping, hopping, running, and climbing. Toddlers can climb up one step at a time, but preschoolers can use alternating feet to climb stairs. Most preschoolers progress from riding a tricycle to a bicycle, and some older preschoolers are able to roller-skate. Two basic upper-body and arm skills developed during the preschool years are throwing and catching a ball. Preschool children gain more precision in fine-motor development between 3 and 5 years old. They attain more control of finger movement, which lets them become capable of using small materials that require grasping and control. According to the National network for child care some milestones in gross and motor skills in preschoolers include hopping on one foot, galloping, beginning to skip, pumping themselves on a swing, zipping, snapping and unbuttoning, cutting, lacing and making representational pictures like house, people or flowers (Malley, 1991). During the preschool years children are in the preoperational stage. Throughout this stage children think in terms of concrete materials, believe that everyone thinks as they think, are perceptually bound and make judgments based primarily on how things look (Morrison, 2009). In the preoperational stage, children are very heavily influenced by their perceptions and do not fully grasp the concept of conversation. Children who have trouble with conservation have trouble understanding that the quantity of something can stay the same regardless of physical transformations. One example of this is if a child is shown 2 identical cups filled with the same amount of beans, and then you pour the beans into 2 different size cups, a child will think that one cup has more beans, not understanding that the same number of beans is in each cup. Another characteristic of the preoperational stage is egocentrism, which is the failure to distinguish the symbolic viewpoints of others from ones own (Berk, 2008 pg325). Children also have trouble with logic and abstract thinking during this stage, because so much of their knowledge is based on their perception. Being in the preoperational stage comes with some key changes in thinking and cognitive development. In addition to acquiring language, children also start to discover fantasy and imagination. With developing language skills comes the awareness of that something can be represented even though it is not seen. For example, the word balloon describes a balloon, just like the image of a balloon does, even if the balloon itself isnt actually visible. Children also start to use their imagination by pretending that objects are other things, transforming sticks into swords, big boxes into houses, and dirt into a racetrack. Preschoolers sometimes have imaginary friends. They have a tendency to brag and can be bossy towards their peers. They have a desire to feel important and worthwhile. At times they can be aggressive but enjoy being with other children and want to make friends. They like to pretend to be important adults such as a teacher, parent, doctor, shop owner or police officer. They want and seek out praise for their achievements. Social experience, along with cognitive development, contributes to gains in emotional understanding (Berk, 2008 pg 370).Emotional understanding is a childs ability to express his or her emotions appropriately, to correctly understand other peoples emotions, and to understand the outcomes of certain emotions. Children with high levels of emotional understanding can cope with their own or other peoples emotions in a way that creates positive social interactions. Preschoolers usually start to develop self-conscious emotions as they start evaluating themselves, instead of simply reacting to peers or adults evaluations. For example, a toddler may be perfectly happy coloring all over themselves from head to toe with markers, but wont experience guilt or shame until someone expresses their displeasure at the situation. A preschooler may still enjoy drawing on themselves, but as soon as they see a parent coming, shame and guilt may surface as a result of considering their appearance. A chil d may also now experience a sense of pride when Mom or Dad says, You did a great job cleaning up your mess. Preschool is a time when children start to develop friendships with their peers and this is essential for positive social and emotional development. Preschoolers think of a friend as someone they have fun with and are willing to share their belongings with. Preschoolers give twice as much reinforcement-greeting praise and compliance-to children they identify as friendsà ¢Ã¢â€š ¬Ã‚ ¦they are more cooperative and emotionally expressive-talking, laughing, and looking at each other more than nonfriends do(Berk, 2008 pg 376).While preschoolers understand the uniqueness of friendship their concept of it is still immature. They can be best friends with a peer one day and not like them at all the next. Parents can influence their childs early peer relationships both directly and indirectly, by giving their child more frequent social experiences, discouraging teasing, being emotionally positive and demonstrating cooperative play. Social experiences are critical in the development of a preschoolers moral understanding. Disagreements with siblings or peers over toys, taking turns or ideas give children their first concepts of fairness and justice. Children also learn by observing how their parents react when then have broken a rule and the way they talk about moral issues. Children who are advanced in moral understanding usually have parents who can adapt the way they communicate with their child about honesty, arguments and sharing in a way the child can easily understand. During preschool children have a massive increase in language development. This escalation in language skills represents the development of cognitive abilities. Children become more complex thinkers and these changes are exhibited in their language. Preschoolers are curious about language and rely progressively more on language to make their wants and needs known to adults and peers. Preschoolers can learn an average of 5 new words a day increasing their vocabulary from 200 words at age 2 to 10,000 words by age 6 (Berk, 2008 pg 356). To build their vocabulary so quickly, children use the fast mapping process where they connect a new word with a primary concept shortly after being introduced to the new word. There are different theories on how children acquire their vocabulary. Some theorists believe that children are naturally predisposed to distinguish word meaning using mutual exclusivity, which is a childs assumption that words refer to entirely separate categories (Berk, 2008). These theorists also believe that syntactic bootstrapping, which is the discovery of word meanings by observation of how words are use in the structure of a sentence, plays a major part in language development (Berk, 2008). Another theory is that word learning is controlled by the same cognitive strategies that children apply to nonlinguistic information. These strategies become more e ffective as childrens information processing, communication skills, vocabulary size, knowledge of categories and mastery of syntax improve (Berk, 2008 pg 357). Generally preschoolers can use simple sentences that follow a subject-verb-object order. Once they have mastered three word sentences they start to make small additions and changes in words that allows them to express word meanings in different ways and more efficiently. As with vocabulary development there are different theories on grammatical development; from the use of semantic bootstrapping (using word meanings to figure out grammatical rules), to the belief that children master grammar through direct observation, and including the idea that they have a special language making capacity for assessing the language they hear and develops the discovery of grammatical regularities. Preschool children have typically well developed conversation skills. They use gestures and objects to assist them in conveying their meaning. By 4 years old a child can adapt their conversation to fit the age, sex, and social status of the person theyre talking to. Their conversations tend to be less mature in highly demanding situations (like while on the telephone) where they cannot see the other person or use conversational aids (Berk, 2008). There are several ways in which parents and teachers can enhance all the developmental skills of a preschooler. Some activities that enhance physical and motor skills are dancing, swinging, sandbox play, throwing, playing with play dough and finger puppets, putting puzzles together, drawing, and stringing and lacing activities. Through directed and undirected play, children are naturally able to practice and learn both gross and fine motor skills and coordination (Snuggs, 2008). Enhancing cognitive development is about strengthening and exercising a childs thinking skills, not just giving them information. Activities like hide and seek (using variations of counting), Simon Says, I Spy and board games like Memory, Connect Four and Tic Tac Toe are all beneficial ways to enhance a preschoolers cognitive development. Planning activities in which the children have to work and plan together, helps build their social skills. Providing an opportunity for different personalities to interact, plan and work together, preschool children will learn the skills of compromise and sharing, while developing their social and emotional skills. A class play is an ideal group activity for the children to participate in. The most important thing we can do to ensure healthy social and emotional development is to be a positive role model. By being trustworthy, caring, and patient role models, we can help children develop a positive attitude. By showing respect to our children we help them learn to show respect for others. In order to enhance positive language development in preschoolers it is important to be patient while they are talking and give them time to express themselves. A few activities that can help further their development are having them draw a picture and make up a story about it, singing songs and using word play and letters to build the childrens phonological awareness, alphabet knowledge and vocabulary. I believe that each preschooler is a unique individual who needs a secure, caring, and stimulating environment where they can grow and develop emotionally, intellectually, physically, and socially. Parents and teachers should adapt to the needs of each child so that they can feel capable and successful.

Computer Studies

1 GCSE Computing Revision Booklet This booklet has been created to provide an overview of each of the topics that you need to revise. Each section is broken down and guidance given on what you need to know. Use it in conjunction with your own revision techniques, e. g. mindmaps, to prepare for the exam. Name: †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 2 Fundamentals of Computer SystemsYou need to be able to: (a) define a computer system (b) describe the importance of computer systems in the modern world (c) explain the need for reliability in computer systems (d) explain the need for adherence to suitable professional standards in the development, use and maintenance of computer systems (e) explain the importance of ethical, environmental and legal considerations when creating computer systems. What is a computer sys tem? At its very basic, a computer system nothing more than an input, a processor and an output. InputProcessor Output A computer system will usually have some storage capability and more often now – a way of communicating with other devices. Computers are all around us and I’m not just talking about your desktop or laptop computer. Your â€Å"smartphone†, your games console, your ipad, even your Sky+ or freeview recorder is a computer system of sorts. 3 Computer systems are integral parts of our lives. Think about all the computer systems you or your parents use on a daily or weekly basis: Running washing programmes and sensing when clothes are dry.On-board computers to control everything from engine efficiency to voiceactivated MP3/Bluetooth hands-free system. Cashless catering system in school to add and subtract money from your account. Self-service checkouts in supermarkets that scan, weigh, take payment and give change. Contactless card payment systems whe re a small RFID (radio frequency ID) tag is embedded into the card and read when the card is near. RFID technology – often used in library books and shops to detect theft, also has future applications in â€Å"smart† clothes and food products.Imagine the RFID tag in your clothes tells the washing machine how to wash them. Or a smart fridge that knows when the milk is past it’s sell-by date and adds it to your online shopping list. Since we rely so much on technology there are huge problems when it goes wrong! If a supermarket checkout system goes down this could result in lost sales of thousands of pounds. However, if an automated system, like those onboard aircraft fails then it could end in disaster! 4 Why do we need to use the same professional standards when developing and maintaining computer systems?Without standards to adhere to we risk developing systems that are not compatible with each other. Would you be happy if your Nokia mobile could only call othe r Nokia mobiles? Standards also improve the quality of the computer system and its maintenance by ensuring that best practice is followed and people don’t cut corners. Considerations when creating computer systems: The Data Protection Act 1998 provides protection for all information stored on a computer system. It requires the person who owns the system to store the information securely and only use it for the purpose it was originally gathered for, e. . the school holds data on you for the purpose of your education; it cannot sell this data to companies who may wish to sell you things. The speed of progress means that many gadgets become old and obsolete quite quickly. This means there are potentially stockpiles of old technology which could end up in landfill. Many companies now recycle these by selling reconditioned devices to other countries or cannibalising the parts to be used again. Websites like Google use huge server-farms around the world. These buildings are full o f computers running 24/7.There is an impact on the environment from the huge amount of electricity needed to run these server-farms. Technology enables us to do many things. But are they always right? Google’s Street View caused controversy when it was launched after people said that taking photos of their houses was an invasion of privacy. Social networking sites, like Facebook, have made it easier to share information but have made it difficult to set privacy settings. You can now be tracked using GPS technology and Facebook places! Is this the â€Å"Big Brother† state? 5 Computer SoftwareYou need to be able to: (a) explain the need for the following functions of an operating system: user interface, memory management, peripheral management, multi-tasking and security (b) describe the purpose and use of common utility programs for computer security (antivirus, spyware protection and firewalls), disk organisation (formatting, file transfer, and defragmentation), and sy stem maintenance (system information and diagnosis, system cleanup tools, automatic updating) (c) discuss the relative merits of custom written, off the shelf, open source and proprietary software.Operating System functions Memory management User interface The OS manages the transfer of data between the CPU, RAM and main storage (e. g. hard drive) The OS provides the user with a way of controlling the functions of the computer without resorting to machine code. It can be graphical (GUI), e. g. Windows or text-based [no mouse] (CLI – Command Line Interface), e. g. MSDOS. The OS manages the input and output devices connected to the computer, including things like keyboard, mice and printer. The OS allows more than one program to be run at once so users can switch back and forth between applications easily.The OS provides security features to restrict access to the system or particular files. Peripheral management Multi-tasking Security When trying to remember the functions of a n Operating System – think MUMPS! Memory mgt, User interface, Multi-tasking, Peripheral mgt and Security. 6 Utility programs Type Security Purpose Detects and protects the computer against virus threats. Quarantines infected files. Spyware Detects and removes spyware (small protection programs that quietly monitor what you are doing) Firewall Restrict communication in and out of the computer from the applications that are running.Formatting Sets up a hard drive, memory stick or card into a format that the computer can use to store/retrieve data. The process of formatting erases any data that was previously on the storage medium. File Transfer Allows movement of files from one location to another, either locally or via memory stick/FTP to another computer. Defragmentation Re-organises the data on the hard drive to improve read/write access times. System info & Provides information about the diagnosis system in order to help with diagnosis of problems. System cleanup Removes te mporary files and tools compresses/archives unused files to increase free storage space.Automatic Uses the Internet to check the OS updating is up-to-date and applies software patches/fixes as necessary. Program Antivirus Security Security Disk Operations Disk Operations Disk Operations System Maintenance System Maintenance System Maintenance 7 Software development Custom written Developed specifically for a particular organisation. (a. k. a. bespoke/inAdv: custom made to meet exact purpose house) Disadv: very expensive and need technical expertise to develop. Off-the-shelf Developed by a software company to be sold to the general public. Adv: cheaper than developing it yourself and tech support available.Disadv: inflexible – might not do everything you want it to do. Open source Written by general public for everyone else to use. Source code provided so software can be tweaked. Adv: allows anyone to use/adapt the software to meet their needs, collaborative approach to develo pment which can lead to better quality software. Disadv: by making source code available to all, provide opportunity for people to â€Å"take advantage† of software installed on users’ computers compromise security. Proprietary Written by developer and allowed to be used by others but with certain restrictions, e. . can’t adapt software. Source code is hidden. Adv: can allow for different versions of same software, e. g. educational version with limited functionality or fullfunctionality version costing more. Disadv: source code cannot be inspected so may contain spyware or other malicious features within the software. 8 Computer Hardware Definition: Computer hardware refers to the physical parts of a computer and related devices. Internal hardware devices include motherboards, hard drives, and RAM. External hardware devices include monitors, keyboards, mice, printers, and scanners.The internal hardware parts of a computer are often referred to as components, wh ile external hardware devices are usually called peripherals. Source: www. techterms. com Inputs and Outputs (Peripherals) You need to be able to: understand the need for input and output devices (a) (b) describe suitable input devices for a wide range of computer controlled situations (c) describe suitable output devices for a wide range of computer controlled situations discuss input and output devices for users with specific needs. (d) Inputs and outputs are the computers way of communicating with us – the user.Without inputs or outputs our system would be quite limited. Imagine a calculator which didn’t allow you to type in numbers or display the answer on the screen! Here are some of the common input devices used: Keyboard The keyboard, along with the mouse, is one of the most used input devices. Once you get the hang of where the keys are, it allows people to enter textbased data quickly into the computer. A numerical keypad (found on most keyboards on the right) provides a fast way for accountants and people who work in finance to enter numbers. 9 There are some interesting variations on the keyboard:Roll-up keyboard (portable – can be rolled up and stuffed in laptop bag) Wireless keyboard (no need for messy wires, frees up user needing to be near computer) Laser Projection (projects a keyboard layout on to any surface; sensors detect which â€Å"keys† have been pressed) Mouse The computer mouse is another common input device. It allows the user to interact with the software on screen. The mouse is quite versatile, with at least two buttons and the ability to move in any direction. However, it can be difficult to be precise – e. g. drawing using the mouse is quite hard! Mice have also undergone a few changes over the years as well:Laptop touchpad (touch-sensitive pads that allow the mouse to be controlled by just a finger) Trackball (the user moves the pointer on-screen by moving rolling the ball; the unit doesnâ€℠¢t move around like the mouse) Optical Mouse (old mice used balls which used to get clogged with dirt and grease – new mice use small cameras to detect movement instead). 10 Other Input Devices Scanner Scanners convert physical documents and photos into digital format. They can be used in conjunction with special software to automatically read handwriting and convert it into computer text. This is called Optical Character Recognition.Some tickbox forms are scanned in, like the Census form or your multiple choice Science exams; this is called Optical Mark Recognition. Touchscreen Touchscreens have been around for years in one form or another. The latest versions, like the Apple ipad interface use multi-touch technology to allow greater control. Microphone Microphones convert analogue sounds into a digital format that the computer can understand and playback. Sounds are usually recorded as . wav or . mp3 files (the latter uses compression to make the file size smaller and is mo re likely to be used to store music tracks).Digital Camera Digital cameras convert live images into digital format. Photos are usually stored as JPEG files. The quality and size of the picture is determined by the number of megapixels the camera is capable of detecting, e. g. photos taken with an 8 megapixel camera are made up of 8 million pixels. 11 Webcam Webcams capture live video feeds and using appropriate software can then transmit those across a network. Sensors Sensors measure the physical world and translate that into a digital format that a computer can understand. There are various sensors that detect ll manner of things: movement, light, heat, moisture, gases (e. g. carbon monoxide levels), location (GPS), etc. For example, the iPhone has an accelerometer so it knows which way round it is to ensure the screen is rotated the correct way. Output Devices Printer Printers produce physical documents and photos from digital files. Most photo printing is done by inkjet printers which can be expensive to run. Laser printers use toner cartridges which are more expensive initially but can print more pages before being replaced. 12 Monitor/screen Monitors/screens provide the visual output from the computer system.Most computer monitors and mobile phones use colour LCD (liquid crystal display). Speakers Working the opposite way to the microphone input, the speaker converts digital sound into analogue waves. 3D Printer A 3D printer uses lasers and a special kind of plastic to build physical 3D shapes from drawings made using CAD software (computer aided design). The object is built up layer by layer. The whole process can take many hours before the final product is finished. They are often used for creating prototypes in manufacturing, e. g. Dyson uses them to create prototype parts for their products.They are still very expensive but the price is coming down. Motor A motor can be driven with precision by a computer system. Often used in manufacturing, e. g. bu ilding cars, motors are used to control robotic arms. 13 Input and output devices for specific needs Keyboards have been adapted for users with limited movement in their arms/hands. A keyboard designed to minimise the movement of your hands. Trackballs have also been used where users only have limited motor ability. They can be used by hands or feet, like the one below: A foot-operated mouse, ideal for people with limited/no mobility in their arms.For quadriplegic users, there are two alternatives to using the mouse or keyboard. The first is voice-recognition; this involves the user reading a passage of text from the screen so the computer â€Å"learns† their voice pattern. They can then use special software to control the computer using voice commands. The technology is getting better but can still make mistakes. The second is eye-tracking which uses small cameras mounted on the monitor to detect eye movement and move the cursor to the point where the user is gazing. A mouse click is made by blinking slowly.Stephen Hawking uses a special device to allow him to communicate. An infra-red sensor detects twitches in the cheek muscle below his eyes in order to enter words and then his device generates a computer synthesised voice to read them out loud. 14 Internal Hardware Devices (Components) Central Processing Unit (CPU) You need to be able to: (a) state the purpose of the CPU (b) describe the function of the CPU as fetching and executing instructions stored in memory (c) explain how common characteristics of CPUs such as clock speed, cache size and number of cores affect their performance.The purpose of the CPU is to Fetch and Execute instructions stored in memory. It acts as the brain of the computer and controls the rest of the system. INPUTS and OUTPUTS CPU RAM 15 Fetch Execute Cycle (using Little Man Computer) Download the software: http://www. cs. ru. nl/~erikpoll/III/lmc. Allows you to quit out of the current program and go back to the Start This d isplays which phase of the fetch/execute cycle we are currently in. The program that is currently being carried out. The current instruction is the one in line with the phase display. Provides the name of the current instruction, along with it's op code and operand.This explains what the little man is doing at each stage as he follows the program. Fetch phase Before the little man can carry out an instruction, he needs to find out which instruction he has to carry out. He does this by first getting the value from the program counter (The thing that looks like a green mushroom in a block of wood), and then fetching the value from the corresponding address in memory. The Program Counter The little man uses the value in the program counter to decide which address in memory he should get the next instruction from.After getting the value, but before going and getting that instruction, he increments the program counter, so that it has the correct value in it when he visits it next time. M emory Memory can be used to store programs, and data. In the fetch phase of the fetch execute cycle we are only interested in the fact that we can get instructions from the memory. 16 Execute phase Once the little man knows which instruction he is going to perform, he has to set about actually doing it. This is the ‘Execute' phase of the fetch execute cycle. For each instruction the little man will perform a series of tasks.For instance, for an input instruction, the little man will go to the input tray, take the value he finds there, and go and put it into the calculator. For an add instruction, he will take a value from memory, and add it to the value presently in the calculator. Once the execute phase is complete, the little man will start the cycle again, and head to the program counter to get the value of the next instruction he has to fetch. The Input and Output trays These are what we (the user) use to communicate with the little man. We provide him with data via the in put tray, and when he's ready, he provides us with data via the output tray.Calculator (Arithmetic Logic Unit – ALU) On a ‘real' computer, this would be the Arithmetic Logic Unit (ALU). It’s basically a calculator that will carry out arithmetic operations. Memory Memory is accessed during the execute phase when we need to store or access data. It is possible to overwrite your programs when putting data into memory though, so be careful where you put it. Following a program (Decoding instructions) The program is a series of instructions made up of an op code and operand (either data or the address where data is stored).For example: Op code Operand 1 2 3 4 5 6 7 800 801 802 9 Load Store Add Subtract Input Output Halt Skip If Negative Skip If Zero Skip If Positive Jump 2 means â€Å"Store† 2 99 99 refers to the memory address where little man should store the data. These can be stored as binary bit patterns, e. g. 10 could refer to the op code (2) above and 1 1000011 could refer to the memory address (99). Remember 2 in binary is 10 and 99 is 11000011. This would give the bit pattern for the above instruction as 1011000011 Q. How does little man (CPU) know the difference between data or an instruction?It all depends on which phase of the cycle the CPU is in, e. g. in the Fetch phase the CPU knows it is an instruction. In the Execute phase the CPU knows it is data. Op codes understood by LMC 17 Characteristics which affect performance Clock Speed This is the number of cycles that the CPU can complete in one second (measured in Hertz or Hz) A faster clock speed means the CPU can process more instructions per second. For example a 1MHz processor can process 1 million instructions a second; whereas a 1GHz processor can do 1000 million instructions in the same time.This is the A larger cache size means holding area for more data can be held and data from the it’s less likely that any cycles are wasted. A RAM. It ensures the CPU smaller cache size and is always busy fast clock speed may with data. result in a bottleneck between the RAM and CPU. A dual-core processor or This is the quad-core processor is 2 number of processing cores to 4 times faster than a conventional chip as they the CPU has. A can process simultaneous dual-core has instructions. two and is able to process two instructions simultaneously in the same cycle. Cache sizeNumber of Cores It is important to balance all of the above to avoid â€Å"over-speccing† one area and creating bottlenecks elsewhere. 18 Memory You need to be able to: (a) describe the difference between RAM and ROM (b) explain the need for ROM in a computer system (c) describe the purpose of RAM in a computer system (d) explain how the amount of RAM in a personal computer affects the performance of the computer (e) explain the need for virtual memory (f) describe cache memory (g) describe flash memory (h) discuss how changes in memory technologies are leading to innovative c omputer designs.RAM and ROM Both are needed in a computer system but for different reasons. In a computer computer, ROM (Read Only Memory) is used to store all the instructions (the BIOS – Basic Input/Output System) to get the computer up and running. It seeks out the amount of memory, input and outputs available to it and then loads up the operating system. In some computer systems, like your washing machine, the ROM stores the software to control the hardware, as well as data such as cooking/washing times etc.RAM (Random Access Memory) is used as temporary storage for instructions and data between the inputs, outputs, secondary storage (e. g. hard drive) and CPU. The larger the RAM, the more instructions/data can be held in quick access memory without needing to use Virtual memory; this can improve performance. Random Access Memory Read Only Memory Volatile (forgets everything when power switched off) Non-volatile (remembers content even if power switched off) Can be writte n to and read from Can only be read from (not written to) Usually measured in Gigabytes (Gb) For the BIOS, usually measured in Kilobytes (Kb) 9 Virtual Memory Depending on the size of the RAM, it is not always possible to store all the running programs in the RAM at once and the computer will start running low on memory and slow down. This is where virtual memory comes in. It stores the data that the RAM isn’t actively using on the hard drive to free up the RAM. Then, when the CPU needs the data it pulls it back from the virtual memory on the hard drive. As far as the CPU is concerned, all the programs are running from the RAM. The operating system sets up a page file on the hard drive to be used for virtual memory.This is usually set at twice the size of the amount of RAM, e. g. 1GB of RAM should have a 2GB page file. Cache Memory This has been explained in the CPU section on page 17. Flash Memory Flash Memory is often referred to as solid-state storage, which means that the re are no moving parts. It’s similar to RAM but is non-volatile which means when the power is cut off, it still remembers the content). Flash memory is used in USB memory sticks and memory cards for digital cameras and some games consoles, e. g. Sony PSP.Future developments in Memory technologies Physical Size & Capacity Costs Speed Power Memory chips have become more compact (storing more bits per chip) which has lead to smaller computing devices and larger capacities. The cost of memory has fallen which means it is now affordable to have large amounts of RAM available. Read/write times are improving which mean faster access and better performance. Memory chips are more power-efficient meaning portable devices work for longer between charges and batteries can be smaller and lighter. 20 Secondary StorageYou need to be able to: (a) explain the need for secondary storage (b) describe common storage technologies such as optical, magnetic and solid state (c) select suitable stora ge devices and storage media for a given application and justify their choice using characteristics such as capacity, speed, portability, durability and reliability. Secondary storage is needed for when we want to store files permanently or semi-permanently. We might want to transfer files between computers by using portable secondary storage media. Storage TechnologiesCodes data using microscopic dips on the surface of the disc. Units Optical Codes data using small changes in magnetic fields. Magnetic Uses non-volatile memory chips to store bits of data Solid State Candidates should be able to: (a) define the terms bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte Bit 1 Nibble 4 bits Byte 8 bits Kilobyte (Kb) 1,024 bytes Megabyte (Mb) 1,024 kilobytes Gigabyte (Gb) 1,024 megabytes Terabyte (Tb) 1,024 gigabytes 21 Storage Media Comparison Storage Medium CD Method Optical Capacity Medium 650-700Mb Small 1. 4Mb Large 1Gb to 2+ Tb Speed Fast access Portability Lightweight and fl at Lightweight and flat Heavy and not designed to be carried around. Requires integrating into computer system. Medium-weight. Plugs into computer USB or Firewire port. Lightweight and small. Durability and Reliability Easily scratched and will then not work. Can only be written to once. Can be snapped. Can be damaged by strong magnets or heat. Quite reliable but can crash – when the read/write head crashes into the platter. Sometimes happens on laptops when dropped. Can be damaged by magnets.Same concerns as internal hard drive. Floppy Disk Magnetic Slow access Internal Hard Disk Magnetic Fast access (dependent on speed of motor RPM – rotations per minute) Portable Hard Disk Magnetic Large 40Gb to 640Gb Medium-fast access (dependent on connection method, e. g. USB cable) Flash drive (USB stick or memory card) Blu-ray disc DVD (Digital Versatile Disc) Solidstate Optical Optical Medium/Larg Medium-fast access e (dependent on connection 1Gb to 64Gb method, e. g. USB cabl e or card reader) Large Fast access 50Gb Large Fast access 4. 7Gb Not affected by magnets.Quite hardy. Can be dropped without damaging contents. Easily scratched and will then not work. Easily scratched and will then not work. Lightweight and flat. Lightweight and flat. 22 Binary Logic You need to be able to: (a) explain why data is represented in computer systems in binary form (b) understand and produce simple logic diagrams using the operations NOT, AND and OR (c) produce a truth table from a given logic diagram. Computers use binary as it's a lot simpler. Each CPU is made up of millions of transistors which can only have two states (ON/OFF).Anything can be converted into a binary number so a computer can understand, process and store it. NOT Gate NOT Truth Table Input Output 0 1 1 0 Flips the input, e. g. 0 becomes 1 and 1 becomes 0. AND Gate a b Waits for 1 on both inputs before outputting a 1. AND Truth Table Input Input Output a b 0 0 0 0 1 0 1 0 0 1 1 1 OR Gate a b Wait for 1 on either input before outputting a 1. OR Truth Table Input Input Output a b 0 0 0 0 1 1 1 0 1 1 1 1 You can practice with NOT, AND and OR gates using the following website: http://logic. ly/demo/ 23 Representation of data in computer systemsNumbers You need to be able to: (a) convert positive denary whole numbers (0-255) into 8-bit binary numbers and vice versa (b) add two 8-bit binary integers and explain overflow errors which may occur (c) convert positive denary whole numbers (0-255) into 2-digit hexadecimal numbers and vice versa (d) convert between binary and hexadecimal equivalents of the same number (e) explain the use of hexadecimal numbers to represent binary numbers. Denary and Binary conversions Numbers greater than 1 can be represented in binary by using more bits. e. g. 129 can be represented in 8 bit (byte) binary as 10000001.Denary Binary 128 1 64 0 32 0 16 0 8 0 4 0 2 0 1 1 This means that if you put a 1 on each increased by double bit (i. e. 11111111) the highest denary for each new bit added to the left. number 8 bits (a byte) can store is 255; 128+64+32+16+8+4+2+1 = 255. Notice how the number To convert binary into denary, just add together the denary numbers above each bit that has 1 in it, e. g. 10000001 = 128 + 1 = 129. To convert a denary number into binary, find the highest value that will go into it and then continue down the number of bits with the remainder until there is nothing remaining. 4 For example, to convert 44 into binary 8-bit format: 44 is smaller than 128 and 64 so we place 0s in those bits: Denary Binary 128 0 64 0 32 does go into 44 with remainder of 12, so we place a 1 in that bit: Denary Binary 128 0 64 0 32 1 The remainder of 12 is smaller than 16 so we place a 0 in that bit: Denary Binary 128 0 64 0 32 1 16 0 8 does go into 12 with remainder of 4, so we place a 1 in that bit: Denary Binary 128 0 64 0 32 1 16 0 8 1 4 does go into 4 with with nothing remaining, so we place a 1 in that bit: Denary Binary 128 0 64 0 32 1 16 0 8 1 4 1 nd 0s in all the remaining bits: Denary Binary 128 0 64 0 32 1 16 0 8 1 4 1 2 0 1 0 Therefore 44 as an 8-bit binary number is: 00101100. 25 Adding two binary numbers together Adding two binary numbers together is not as scary as it sounds or looks. It uses the same principles at the denary number system (Hundreds, Tens, Units). For example: Work from right to left, like you do when adding denary numbers using HTUs. 00010010 + 00010100 0+0=0 0+0=0 0+0+1 1+1=0 0+0=0 0 0 11 0 0 1 1 0 0+0=0 1+0=1 0+1=1 (carried over) = 1 (carry 1)Let’s convert it back into denary to check it is correct: Denary 128 Binary 0 16 + 2 = 18 Denary 128 Binary 0 16 + 4 = 20 Denary 128 Binary 0 32 + 4 + 2 = 38 64 0 32 0 16 1 8 0 4 0 2 1 1 0 64 0 32 0 16 1 8 0 4 1 2 0 1 0 64 0 32 1 16 0 8 0 4 1 2 1 1 0 So as 18 + 20 are 38. Then we know the binary calculation is correct! 26 Hexadecimal Numbers Programmers started to use hexadecimal to reduce mistakes and make it easier for them to underst and than using lots of 0s and 1s. Denary and hexadecimal conversions Hexadecimal uses a base 16 system = 0-9 and then A-F.That means that the denary number 15 is equal to F in hexadecimal. The denary number 16 is equal to 10 in hexadecimal (which means 1 lot of 16) The highest denary number represented in 8-bit (byte) binary is 255 and was represented by 11111111. In hexadecimal this would be represented as FF (15 lots of 16 + 15). Confused?! Remember, F in hexadecimal represents 15. Therefore F0 would be 15*15=240. The second F is 15, therefore FF = 240+15 = 255. To convert denary to hexadecimal you can divide the number by 16. For example, to convert 141 into hexadecimal do the following: 141 / 16 = 8 remainder 13. /16 = 0 remainder 8. Therefore, working from right to left, the hexadecimal number is 8 13 (and 13 is represented as D in hex) so it would be 8D. Alternatively, convert the denary number into binary and then binary to hexadecimal. 27 Binary to hexadecimal conversions To convert binary to hexadecimal you need to break it down into nibbles (blocks of 4 bits). For example, 141 as a binary number is: 10001101. The two nibbles are 1000 and 1101. Converting each nibble into denary we can see that 1000 = 8 and 1101 = 13.Remembering that 13 = D in hexadecimal then 141 would be represented as 8D. To convert hexadecimal to binary you just reverse the process. Convert each part of the hexadecimal number into nibbles of binary numbers. For example: Hex Denary Binary 8 8 1 4 0 nibble D 2 0 1 0 8 1 4 1 nibble 2 0 1 1 HELP! This conversion chart below may help to make sense of it all! Denary 0 1 2 3 4 5 6 7 Binary 0000 0001 0010 0011 0100 0101 0110 0111 Hexadecimal 0 1 2 3 4 5 6 7 Denary 8 9 10 11 12 13 14 15 Binary 1000 1001 1010 1011 1100 1101 1110 1111 Hexadecimal 8 9 A B C D E F 8 Using binary to represent characters You need to be able to: (a) explain the use of binary codes to represent characters (b) explain the term character set (c) describe with exampl es (for example ASCII and Unicode) the relationship between the number of bits per character in a character set and the number of characters which can be represented. Computers use the ASCII (American Standard Code for Information Interchange) format to use binary codes to represent numbers, letters and special characters. It uses 8-bits (byte) to represent each character, so every character has it’s own unique 8-bit ASCII code.Using the ASCII character set on the next page we can convert characters into binary numbers. For example, Isambard would be represented in binary as: I s a m b a r d = = = = = = = = 73 115 97 109 98 97 114 100 = = = = = = = = 0100 1001 0111 0011 0110 0001 0110 1101 0110 0010 0110 0001 0111 0010 0110 0100 Notice how the capital I is different from the lowercase i in the ASCII format. An upper and lower case version of each letter is present in the chart to enable the computer to tell the difference between them. If you remember what we said about binar y numbers back on page 23 then you know that 8-bits (a byte) can store up to 255 in denary.This means that the ASCII format can have up to 255 characters represented in a character set. 29 American Standard Code for Information Interchange character set Note: You don’t need to remember these codes for your exam but just be aware of how it works. 30 Using binary to represent images You need to be able to: (a) explain the representation of an image as a series of pixels represented in binary (b) explain the need for metadata to be included in the file such as height, width and colour depth (c) discuss the effect of colour depth and resolution n the size of an image file. Images on the computer are made up of lots of individual pixels (small squares of colour). If you zoom into any image enough times you will see these little blocks of colour. We can use binary numbers to represent each pixel. In a simple image, where there are only two colours (colour depth of 1) then we can si mply use a 1 for one colour, and 0 for another. For example, look at this small 3 x 3 pixel image below. The 1s represent the black colour and the 0s represent the white. 0 0 0 1 0 0 0 1 31 That is the principle behind storing images as binary. However, we also need to know a few other things about the image in order to display it correctly, i. e. its height, width and colour depth. Image Metadata Height Width Colour depth Resolution The height of the image in pixels The width of the image in pixels The number of bits available to represent each pixel The pixels per inch (PPI) – if the pixels per inch is high, then the resolution and image quality is also high.Without this metadata the computer would not be able to reconstruct the image properly. Colour Depth In a simple 1-bit colour depth image, we can only display two colours. However, in an 8-bit colour depth image (like the gif format), we can display 256 colours (one for each binary number from 00000000 to 11111111). In a 24-bit colour depth image (like the jpeg format), we can display just over 16 million colours! If we use more bits to store each pixel, then the file size will be larger. That is why . gif images are often smaller in file size than . peg images. Resolution If the image has a higher resolution, it has more pixels to store data about and is therefore larger in size. If the image is lower resolution, this means that there are less pixels per inch, which means less pixels to store data about and is therefore smaller in size. 32 Using binary to represent sound You need to be able to: (a) explain how sound can be sampled and stored in digital form (b) explain how sampling intervals and other considerations affect the size of a sound file and the quality of its playback.Sound is stored in the computer by taking samples of the sound wave at regular intervals and converting those into binary numbers (using an analogue-to-digital convertor). The computer can then re-create the sound by reve rsing the process. The file size and quality of the sound recording is affected by the sample rate and bit rate. The sample rate refers to the number of samples taken each second. It is measured in Hertz (like the CPU clock speed). If the sound wave is not sampled at a higher enough rate, this can lower the quality of the sound recording, but the file size would be smaller.If the sound wave is sampled at a higher sampling rate, this will increase the quality of the recording, but the file size will be much larger. The bit rate refers to the amount of bits used to store the different levels of sound at each sampling interval. The more bits, the greater range of levels that can be distinguished. This also has the affect of increasing the file size if the bit rate is high (e,g. 16-bit instead of 8-bit). 33 Computer Communications and NetworksNetworks You need to be able to: (a) explain the advantages of networking stand-alone computers into a local area network (b) describe the hardwar e needed to connect stand-alone computers into a local area network, including hub/switches, wireless access points (c) explain the different roles of computers in a client-server and a peer-to-peer network (d) describe, using diagrams or otherwise, the ring, bus and star network topologies (e) describe the differences between a local area network and a wide area network such as the Internet explain the terms IP addressing, MAC addressing, packet and (f) protocols (g) explain the need for security measures in networks, such as user access levels, suitable passwords and encryption techniques (h) describe and justify network policies such as acceptable use, disaster recovery, failover, back up, archiving. Why network? Allows computers to communicate with each other and share resources, e. g. peripherals (printers, scanners), storage, internet access. Data Packets Information is sent around a network in data packets. Data is broken down into packets to be sent over the network and ofte n may take different routes to get there. It contains info on where it needs to go (the address) and the packet number and an error-checking facility to ensure the packet arrives intact and can be put back together in the right order. 34Basic components of a local area network (LAN) Client/ Computer Hub, Switch or Router See next page for explanation of each. Server In a Client-Server network, the server handles the logins, applications and file storage. Modem Interfaces between the Internet and the network. Shared Peripherals Networks allow peripherals like this printer to be shared by all the computers on the network. Internet 35 Hub, Switch or Router? These are not the same. You need to know the difference between them. Hub A hub receives all data sent over the network and sends it to all the other devices on the network. Only the device who the data packet is for will acknowledge it; the other devices will ignore it.A switch is bit more intelligent than a hub and it learns which devices are on the network (and their port number/address) and only sends the data packet to the computer who is the intended recipient. This is more efficient than a hub as it doesn’t result in lots of unnecessary network traffic. A router is cleverer still than both hubs and switches. It can re-direct network traffic and deal with different packets in different ways. It can protect the computers on the network by hiding them from the outside world (i. e. a firewall). Some routers have a modem built-in and wireless capabilities. Most homes have a 4-port wireless broadband router to access the Internet. This combines the router and modem functions. Switch RouterWireless access points don't require a physical connection and therefore are suited for a variety of different devices and provide access to network over an area, e. g. iPad or smartphone. IP address The IP address (Internet Protocol) is a computer's unique address on the network, e. g. 192. 168. 0. 1 is usually your home router's address. On the Internet, each website has its own or several IP addresses. 36 MAC address The MAC address (Media Access Control) is a hexadecimal number that is unique to that particular device. Hey! Did you know that there are 281,474,976,710,656 possible MAC addresses in the world? That’s a lot of MACs baby†¦ huh huh! Network Protocols Protocols are a set of standards and guidelines that tell computers how they should handle the sending and receiving of data over the network.TCP/IP (Transmission Control Protocol and Internet Protocol) Used to exchanged data between computers on a network and route packets between networks and over the Internet. Used on WWW to transfer webpages and web content from the website host server to the computer requesting the page. Used to transfer files between computers over a network. Used to transport emails. HTTP (HyperText transfer Protocol) FTP (File Transfer protocol) SMTP (Simple Mail Transport Protocol) LAN or WAN? A L AN is a Local Area Network which is usually set-up within a certain area, e. g. a building or group of buildings – hence the term â€Å"local†. A WAN is a Wide Area Network which is usually on a nationwide or worldwide scale. The Internet is an example of a WAN – a series of interconnected LANs. 7 Network Topologies A network can be set up in three main ways: Ring 4 3 5 1 2 All the computers are linked together in a ring and data packets are sent one way round. For example in the diagram above to get from PC 1 to PC 5 the data needs to go through PCs 2, 3 and 4. It can’t go anti-clockwise back to PC 5. Drawbacks: If there is one break in the ring then the network breaks down. Also not very efficient as a lot of network traffic doesn’t take the most direct route. Bus All the computers are connected to a central bus. You can add and take away computers easily in a bus network as the computers are connected to the central bus, rather than between one another.Drawbacks: Only one computer can use the bus at once which means only one computer can communicate at a time – the others have to wait until the bus is free before sending their data; this makes it slow. If a computer connected to the bus breaks down, then the network still runs but if the central bus breaks down then so does the whole network. 38 Star 4 3 5 1 2 All the computers are connected to central server. The server can handle multiple communications at once and re-directs traffic over the network. More computers can be added or taken away without affecting the network. Drawbacks: If the main server fails then the network goes down. Client-server and peer-to-peer networks In a Client-server network, the server acts as the main computer handling login requests, user storage, etc.The client could be any computer. The user can log on to any client and still access their stuff on the server. In a Peer-to-peer network, each computer shares information equally and pl ays an equal role in the network. Network Security Part of Data Protection Act 1998 requires companies who store data electronically to keep it safe and secure. Without security then anyone could hack into the network and intercept data packets. Confidential data packets should be encrypted so if they are intercepted they are unreadable. There may be a need to prevent unauthorised access to particular areas of the system; this could be controlled by passwords and different user levels, e. g. n the school a student can only access the student shared drive, whereas teachers can access both the student shared drive and the staff shared drive. 39 Network Management Policies Disaster recovery In the event of the system failing there needs to be plans in place to get the network up and running again as quickly as possible. Many organisations, such as banks, have a disaster recovery plan which may mean relocating to a different location (if the building is no longer accessible). Failover a nd backups If there is a power cut, many networks have UPS (uninterrupted power supplies) which are large batteries with enough charge to keep the network going long enough to shut it down correctly. If a hard drive fails, there is usually a backup which can take the strain.Networks are often backed up at least daily and these backups are stored off-site or in a fire-proof safe so in the event of a disaster in the building, the data is still intact. Maintenance Sometimes data needs to be kept but is not accessed regularly. This data can be archived off onto tape to help free up space on the network. Acceptable Use It is important for the network to have an acceptable usage policy to provide users with guidelines about what they can and can’t do using it. For example, it would use up vital network bandwidth if some users decided to play a network game or download the latest torrent from the Internet. If users start file sharing copyrighted materials, like music, using the netw ork then there is a legal issue to consider as well. 40 The InternetYou need to be able to: (a) describe the nature of the Internet as a worldwide collection of computer networks (b) describe the hardware needed to connect to the Internet including modems, routers etc (c) explain the need for IP addressing of resources on the Internet and how this can be facilitated by the role of DNS servers (d) explain the importance of HTML and its derivatives as a standard for the creation of web pages (e) describe common file standards associated with the Internet such as JPG, GIF, PDF, MP3, MPEG (f) explain the importance of compressing files that are transmitted via the Internet (g) describe the differences between lossy and lossless compression. What happens when you type in a web address in your browser? When you enter a web address in your browser, it heads off via your modem to your ISP’s (Internet Service Provider) domain name servers (DNS).These computers store the IP address(es) for each website and directs your request to the relevant server hosting the webpage you want to view. The information is then sent back to your ISP and then back to your computer. Why HTML? HTML (HyperText Markup Language) provides a standard format which any computer with web browser can interpret and display the pages. It allowed the World Wide Web to get going as there was a universal standard that everyone could now use to share information. 41 Common file formats used on the Internet . html . jpg HTML Web page JPEG image Used to store webpages Used to store photos as can show up to 16. 7 million colours. Used for simple graphics and short animations – can show up to 256 colours.Used to store noneditable documents for viewing on the Internet using the free Adobe viewer software. Used to store music tracks. Compressed to make downloading faster. Used to store videos. Compressed to make downloading faster. Used for Adobe Flash files to add interaction and/or animations to websites. Used to store video files playable using free Apple viewer software. .gif Graphic Interchange format image .pdf Adobe Portable Document format .mp3 MP3 Music format .mpg MPEG video format .swf Shockwave Flash format .mov Apple Quicktime format Why compress on the Internet? The Internet can be slow at times, especially in it’s early days relying on early 56Kbps modems as opposed to the 3-4 Mbps average.Therefore if you could compress the files that were being sent on the Internet, then you sent smaller files, and smaller file sizes meant faster downloads. It also frees up the network and avoids clogging up the bandwidth. 42 Lossless versus Lossy Compression Lossless compression Compression used means the original file stays completely intact and unchanged. Used for text documents, data files and executable programs where it would not be desirable for parts to be lost. Used for multimedia files, i. e. sound, images, video. Lossy compression Compression which involves discarding parts of the file which won’t be noticed if they are not present.For example, it is possible to remove some data within an image and your brain fills in the gaps. Take a look at the images of the dog below: Source: wikipedia. org The image has more compression applied to it as you go from left to right. Even though the image on the right in heavily compressed, we can still see it is a dog. Our brain fills in the gaps. 43 Databases What is a database? A database is a persistent organised store of data which can be easily and quickly searched. They are most commonly used for Marketing, e. g. loyalty cards. Huge databases are searched for patterns in customer’s buying habits and then targeted coupons are mail shot to customers.The school has several databases to store everything from your behaviour logs and Brunels, to your address, date of birth and even how much money you have on your lunch card! Data handling software, such as Microsoft Access, allow users to: add tables, define fields and validation (create) add/edit/delete data (maintain) run queries to extract information from the database (interrogate) DBMS (Database Management System) Many large databases use a database management system (DBMS). This system separates the data stored from the data handling applications used to maintain and interrogate the database. Feature Concurrent usage Security Recovery & Backup Data integrity Why is this good? Allows multiple users to use the database at the same time Provides bility to allow/restrict data access to individuals or applications Provides backup solution and recovery tools to ensure data is not lost in event of failure Enforcing data integrity by ensuring data is consistent and adheres to the rules Relational databases A flat-file database is when all of the data and fields are stored in one table, e. g. an excel spreadsheet full of names and addresses – see below: 44 A relational database is when that data is separated i nto individual tables (entities) that are linked by a primary key (which appears in each table). Student Student ID First name Surname Class Class ID Student ID Teacher ID Teacher Teacher ID Name SubjectIn the example above, the STUDENT, CLASS and TEACHER are all tables (entities) in the database. The id is the unique piece of information (the primary key) that identifies each instance of a student, class or teacher. We couldn’t use First Name as the primary key in STUDENT as many people share the same first name – it isn’t unique enough! The advantage of separating the data into different entities is to avoid data redundancy – when the same data is stored in several places in the database. Let’s imagine if we stored the information above in a flat-file database (all in one table) – it would look something like this: Duplicated data Can you see the duplicated information?Not only does this use up space but it is easier to make a mistake (and lose data integrity) if we only update one of the records. E. g. if Miss Parsons gets married and her name changes to Mrs Smith then we need to make this change for every record in the database. If are using a relational database, because the Teacher’s name is stored in a separate table and linked to the rest of the entities, we only need to update it in the TEACHER table once. In the CLASS entity, both Teacher ID and Student ID are foreign keys (primary keys that when linked to another table become foreign keys in that table). Components of a relational database Tables Represents the entity in the database. Fields and primary keys are defined and data stored in the table. Create) Forms Provide a customisable user interface to add/edit and delete data (Maintain) Queries Allow data that meets specific criteria to be extracted and displayed (Interrogate) Reports Displays the results of queries in a customised format designed to be printed Querying a database 45 When interrogat ing a database, you need to specify the fields you wish to display and the criterion you will use to search. E. g. if you were searching for a car on a car supermarket website you might search using the make of the car you wanted: Make = â€Å"Ford† You could also use logical operators such as (NOT equal to), < (less than), > (greater than), = (greater than or equal to). E. g. Mileage

Effects of Roman Architecture

It was an art of shaping space around ritual, it sought identity and fulfillment in the performance and creation, it was their way of reducing chaos, it was used to show their newly developed building skills, it was to â€Å"romanize† their country and set it apart from others. What was the reasoning for making such extraordinary structures? From the beginning of the use of â€Å"the arch† to the construction of huge public places such as the Roman arena. There’s a reason why thousands of people visit these places every year, something so amazing that keep’s our attention. It’s the beauty, or the concept of building these, or maybe the idea of designing such complex structures. The detail is tremendously in depth also, they truly cared about what they were doing. We here the quote said by John Heywood when being lectured about hard work, â€Å"Rome was not built in a day. †7 And it’s so very true. We today are amazed in how and why they would do it. The effects on today are tremendous. If you were to look down your street you would see so many uses of Roman Architecture. Columns? So simple but still so elegant. Domes? Such an amazing architectural design. Arches? Gave a whole new meaning to an open-looking building. Before Roman style came we had other styles including; Prehistoric which did not inspire much besides stone circles and Ancient Egypt which gave us the beautiful pyramids. Besides that, the Romans were the first to really break through. Which is what they wanted, wanting to be known by all. Roman Architecture effected the future’s idea on structure, design and the ability to obtain power by it’s beauty, it’s structure, and it’s uses. So what was the reasoning of making these structures? To show all the power they had, to show what they could do themselves. The English author Goethe once said, â€Å"Dream no small dreams for they have no power to move the hearts of men. †2 Proving that they were the ones that were smart enough to come up with this. Not only did they make them to show everyone, they used them. They were used daily and stayed intact. They’re still intact today! 4 So many designs that helped the future come up with more and more complex ideas. Producing such massive, creative, and beautiful designs made people come and sit in ah. The year is 2009 and guess who is still coming and sitting in ah, we are. The poet Friedrich von Schelling once said, â€Å"Architecture in general is rozen music. †1 And music in general is a beautiful thing. Beauty is a big factor in attracting attention. If something is that beautiful, people will take the effort to take a double look. Romans took this into account and used it to their advantage. Take the Pantheon for example, simply amazing. It’s thought by many to be almost perfect in interior design. The light pours through the aperture in the coffered dome, and creates a mystical atmosphere in the windowless building. From afar you see the massive dome, the octastyle porch and a rectangular feature connecting the two. There are also eight granite columns, six of them being original. 4 The two replacement columns were made of a reddish granite, almost identical. The inside is what is really amazing, you first walk up to the porch which is made of all marble and granite. The two stones were arranged in a pattern of circles and rectangles. You then enter the â€Å"entranceway† where you see that it is framed by pilasters of white marble. To get into the rotunda you enter through huge doors made of bronze that are connected by wooden planks, attached again by bronze nails. When first stepping into the rotunda your eye goes directly to â€Å"the eye†. â€Å"The eye†, or the all-powerful eye, is a round piece of glass on the direct top of the dome. It gives off a fair amount of light and in the Roman’s perspective, keeps an eye on all visitors. 7 Thomas Fuller a British author once said â€Å"Light, God's eldest daughter, is a principal beauty in a building. †2 The Rotunda also has an unbelievable amount of statues, columns, and detailed stoned etchings. The ground their is also arranged with alternating circles and squares of colored marbles and granites. What’s amazing is the craftsmanship that was put into every piece of art the Roman’s produced, and the time it took to make them. William Sutton once said, â€Å"Success in any endeavor requires single-minded attention to detail and total concentration. †9 Like the Colosseum’s hundreds of beautiful arches and the detail involved in each square. Or the beautiful rounded look they created for their theaters. Or the amazing etchings in the Monumental Arch. And who could forget about the baths! The creative, soothing paintings and the marble lined utilities were enough to ease the mind. Beauty, if used wisely, can lead to power. Power is what the Romans craved for and power is what was perceived from the outsider, they won. The structure of every building they ever erected was just amazing. Without their help the idea of theatre seating may not have even happened. The theatre has always meant so much throughout history, Oscar Wilde once said, â€Å"I regard the theatre as the greatest of all forms, the most immediate way in which a human being can share with another the sense of what is is to be a human being. †3 Take the Theatre of Marcellus for example. The theatre is 111 m. n diameter and could originally hold 11,000 spectators. 2 The theatre was built mainly of tuff and concrete faced with stones in the pattern known as opus reticulatum, then completely plastered in white travertine. 5 It also consisted of three levels supported by columns. Each level had a different architectural style: the first level had arches supported by columns in the Doric Order, the second featured arches with Ionic columns and the third one consisted of a wall with pilasters in the Corinthian Order. 8 Only parts of the first two levels are still visible today but their design withstood years and years of usage. The Roman’s also used the idea of the arch and developed into the vault. The simplest kind of vault is a barrel vault, it’s generally semicircle in shape and has a continuous arch, the length being greater than its diameter. 4 Rings are placed in position one at a time while the timber supports are taken out. With a barrel vault, the temporary support is then shifted on to support the next rings. 6 You had to take so many steps to get the final structure. And did they know it was going to work? They’re the Roman’s, they can do anything. Maybe they took a few test trials though. Two kids received identical play houses. One kid brought fake pots and little plastic food to play with. The other kid brought a toy gun and plastic tools to play with. Which kid would you assume has power of the other? The kid with the toy gun of course! The Roman’s not only had amazing, massive structures, they also used them to the max. The Roman’s are known for their spectacular public baths. The most famous being Diocletian and the Bath of Caracalla. 3 During this period of time many people did not care much about their hygiene. What they did was create elegant baths for the Roman public. This was never before done, so those looking from the outside would think that pretty important people must live there. The Roman’s also had many temples and tombs to honor certain people. The temples and tombs always looked so exquisite too. So did that mean so many great and powerful people lived in Rome? That’s what they wanted you to think. Josh Billings a humor writer once said, â€Å"You pretty it up, they’ll believe anything you’ll say. †9 The Colosseum is a great example of how the Roman’s used their masterpieces. The Colosseum was used to host gladiatorial shows as well as a variety of other events. Another popular type of show was the animal hunt. This utilized a great variety of wild beasts, mainly imported from Africa and the Middle East and included creatures such as rhinoceros, hippopotamus, elephants, giraffes and ostriches. 1 Such events were occasionally on a huge scale; Some contests involving 11,000 animals and 10,000 gladiators over the course of 123 days. 7 There are also accounts of a â€Å"sea battle†, described as being filled with water for a show of specially trained swimming horses and bulls. The way they did things in the Colosseum was very gruesome. They occasionally used condemned people for â€Å"plays† where executions in which the hero of the story was killed in various gruesome but mythologically authentic ways, such as being mauled by beasts or burned to death. 6 The poet Anatole Broyard once said, â€Å"Rome was a poem pressed into service as a city. †3 If the Colosseum singly would be a poem it’d be the gruesome, horrid type of poem. Bringing wild animals and having men try to kill them was just a game to watch. What is the rest of the world going to think about Rome when they here what they do for fun? I would be scared. The Colosseum is the pride and joy of the Roman’s. It is the greatest work of Roman Architecture and Roman Engineering. It put together everything they worked for, everything they were good at. It’s the distinct building that everyone knows and remembers. Byron, a historian once said, â€Å"While stands the Colosseum, Rome shall stand; When falls the Colosseum, Rome shall fall; And when Rome falls, the world. †2 Its beauty, design and usage made everyone believe the Roman’s had the power. The Colosseum is about 620Ãâ€"513 ft. in length and about 165 ft. in height. The internal arena was 287Ãâ€"180 ft. It’s estimated that it could seat 45 to 50,000 spectators and on special occasions the numbers could be as high as 70,000! 4 The skeletal framework consisted of concentric piers and arches and was built of Travertine limestone, these rings were linked with walls. There were also four stories all together, all surrounded with a total of 80 arches. 2 The floor of the arena was made of wood and then covered with sand. Under the arena there was an 18 ft. high basement which stood on cement foundations some 18 ft. thick. The basement is an architectural masterpiece in itself, about as big as the arena itself too. The rooms of the basement were specially constructed to support the show on the stage above but were used for a number of purposes such as keeping animals, medics, gladiators, general supplies and so on. It is known that there was an elevator type device to elevate animals and fighters into the arena from the floors underneath so that they could join in the action when it was their turn. 7 Besides the structural wonderment of the Colosseum, it held so much allure from all points of view. Matthew Arnold is quoted saying, â€Å"I gazed upon the scene with intense and mingled feeling. The world could show nothing greater. â€Å"2 From the thoroughness of every individual arch to the hand crafted statues. There was a definite appeal in this building. Only the great and powerful can do great and powerful things. This is something the Romans believed, and heavily. Being able to build such grand and ravishing buildings proved that they could do great and powerful things. The late Spanish writer, Miguel de Cervantes Saavedra once said, â€Å"When thou art at Rome, do as they do at Rome†. 2 Obviously Rome’s â€Å"scare factor† was known to many. Some may think that Roman and Greek architecture are the same concept, but the Roman’s put so much more into their skill. The way they meshed together their artistic abilities and architectural abilities created such a great and powerful bond. Their unbelievable leaps in the architecture ladder should be remembered for a long time, it is very much deserved. Roman Architecture effected the future’s idea on structure, design and the ability to obtain power by it’s beauty, it’s structure, and it’s uses. They wanted to be know, they literally killed for it! The year is 2009 and we remember, congratulations Rome.

A Review of the Iphone 5 - 1002 Words

A Review of the iPhone 5 Abstract Apple’s iPhone 5 had been under development for over a year until its release a few weeks ago. With so much time dedicated to its development, one could expect nothing short of perfection. This and the fact that Apple is a well established brand in the market of technological gadgets accounts for the elevated expectations placed by consumers on iPhone 5. Features of this phone are innumerable, but consumers agree that they make it stand out among leading brands in market. It seems to make a striking impression to general users, business users and students alike. Having been a loyal user of android smart phones for almost three years, it has experienced great features that these mobile gadgets offer. A†¦show more content†¦It is exactly what I expected for in the phone (Grothaus, amp; Sande, 2011). Computing Capabilities Apart from ordinary call features, extended battery life and up to 64 GB of internal memory, iPhone 5 comes with several build in features that provide strong computing capabilities comparable to some extent with those of low-end desktop computers. This includes social networking apps including facebook and twitter, iCloud – an app to integrate you phone to Apple’s cloud platform; build in maps, among many others. Consequently, the phone generally has appreciably excellent programming capabilities just as I expected. Augmented Reality As a student, it would benefit greatly from an app that recognises my handwriting and transforms it into standard computer text. Although this feature is not build in to iPhone 5, it is available through a jailbreak tweak. I expected this feature to be built in like it is Samsung Galaxy S III, one of the competitors of iPhone 5. However to some extent the feature may still be implemented in iPhone 5 albeit at an extra cost and poor quality. Conclusion Unlike android smart phones that have been used previously, most third party applications for iPhone are not free, contrary to my expectations. Moreover, promotion advertisements of iPhone 5 display rather unrealistic but very appealing features of the phone that are actually not there. However, since most of what was expected in the phone was actuallyShow MoreRelatedApple s Iphone 5 Expert Reviews Vs Consumers Reviews874 Words   |  4 PagesApple’s iPhone 5 Expert Reviews vs Consumers Reviews Reviews are excellent resources to discover pertinent information about a product that consumers wish to purchase. In addition, Reviews come from multiple sources, whether it comes from expert or consumers, both play an important role of the consumer and are thought to be valued resources. 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