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Tools part 4
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Tools part 4



tools 4 ZARKOVIC

tools 4 ZARKOVIC



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Tools part 4 Tools part 4 Presentation Transcript

  • ZARKOVIC TOOLS, Part 4Tools for Information Processes
  •  In this lesson we will concentrate on the final two information processes: – Transmitting and receiving data – Displaying data
  • Transmitting and receiving data This is an important area of study as it forms the basis of the Year 12 core unit Communications It is highly theoretical and involves the explanation of a lot of technical terms
  • Communication Concepts There are a few basic concepts in the syllabus that need to be carefully defined and explained to students
  • Parallel vs Serial data transmission Parallel – the data bits are transmitted simultaneously along multiple (‘parallel’) channels – Used extensively inside the computer system e.g. data bus, address bus, etc – Quick – Can only be used over short distances(<1m) as the signals begin to decay or channels get out of sync Serial – the data bits are transmitted one after the other (in single file) along a single channel – Slower than parallel – Good for long distances e.g. networking
  • Parallel vs Serial data transmission Parallel Serial Transmission Transmission0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 0To CPU …. To server…
  • Direction of data flow Can be classified as simplex, half duplex, full duplex Simplex – data flows in one direction only e.g. Free to air television Half Duplex – data can flow in both directions, but not simultaneously e.g. Walkie Talkie Full Duplex - data can flow simultaneously in both directions e.g. telephone
  • Synchronous vs Asynchronous Refers to the method used to transmit serial data Asynchronous – Each byte of data is sent one at a time – It is encapsulated within a ‘packet’ of 10 to 12 bits which may have 1 or 2 start bits and stop bits – A parity bit is included to aid in error checking (if used) – Most common method used outside of the computer Synchronous – A collection of data is stored as a single unit called a frame – The complete frame of data (1024 bytes or more) is transmitted to the computer – Faster, more efficient than asynchronous but expensive – Mostly restricted to use on large computer systems
  • Asynchronous Communication Parity bit Start bit(used for error checking) 11110111010 A single character of Stop bit data Every character of data is transmitted with the start bit, stop bit and parity bit
  • Synchronous Communication Groups of characters are transmitted for processing by a mainframe computer Individual Characters 11000001110111010110110000001110Frame of dataThe client and the server computer must synchronise their internalsystem clocks. When this occurs the data fame is sent as a blockto the server for processing.
  • Speed of transmission Speed of transmission is given as bits per second (bps) or baud A speed of 56000 bps means 56000 bits of data is transmitted per second Baud refers to the number of electrical signals used to transmit data i.e. timing intervals per second More than one data bit may be able to be transmitted per time interval Therefore, a transmission speed of 56000 baud would, in most circumstances, be considered faster than a speed of 56000 bps
  • Hardware Busses – these are the links used within the computer to transmit data from one part of the computer to the other The most important ones are the – Data bus – Address bus The data bus is the set of parallel links used to move data between RAM and the CPU = the ‘wider’ the bus the faster data is moved The address bus is used to send data request signals to the various memory locations in RAM The ‘width’ of the address bus is important because it determines the number of addressable memory locations (ie memory size) e.g. 16 bit address bus => 216 = 65536 (=64kb) addressable memory locations
  • Hardware There is also a control bus which is used to transmit control signals to various computer components As well, there are expansion buses, which enable peripheral devices to talk to the CPU, once the correct expansion card has been installed
  • Hardware Students need to know the general operational principles of a modem Since the standard telephone system still uses analogue signals to transmit a lot of its data, signals from the computer must be converted from digital to analogue This is done by the modem The term MODEM is derived from MOdulate / DEModulate MODulation occurs when a digital signal is converted into an analogue signal DEModulation occurs when an analogue signal is converted into a digital signal Modems can be internal (built into the system) or external Modern modems have additional capabilities e.g. used to send faxes
  • Hardware Networks are also a major part of the Year 12 topic Communications but it only has to touched on lightly here Students need to know the difference between a Wide Area Network (WAN) and a Local Area Network (LAN) If you want (and you have time) other network concepts can also be introduced e.g. ethernet, telecommunications
  • Software Basically students need to learn the following – Types of communications software  Browsers  FTP  Telnet, etc – The role of protocols in enabling communication to occur – Electronic mail (although 99% of all students I’ve taught already know it) e.g. they need to be clear about what CC: and BCC: mean and how to add an attachment to an e-mail – Compression software (like WinZip) and what it does – Encryption of data – why is this necessary?
  • Social & ethicalA lot of scope in this topic to explore social and ethical issues: How do we protect against the transmission of viruses? What is netiquette and why is it important? What copyright issues relate to using the internet? How has work changed since the explosion in communications technology?
  • Displaying
  • Displaying data…. Involves the output of data/information to meet the purpose for which the system was originally developed How data/information is displayed depends on the context e.g. data from a CAD program can be displayed on a screen in the engineers office, however, it can also be displayed using a computerised lathe in the workshop
  • Display Hardware Students need to know the basic operating principles for a number of output devices e.g. – Monitor – Printer – Speaker – Plotter Power’s book covers this fairly well, although Ware & Grover’s book does a better job outlining the operational principles of display hardware
  • Display Hardware At many schools the industrial arts faculty will have a plotter and they are usually quite keen to demonstrate its use to students Students should also be shown:  the operation of a data projector  laser printer v bubble-jet  CRT v LCD v plasma screens Investigate newer display technologies e.g. interactive whiteboards, virtual reality, touch sensitive screens, etc
  • Display Software All application software displays data in some way An application may be able to display data in more than one way e.g. In the Access database data can be displayed as a table, using a form, as a result of a query or as a report
  • Non-Computer Tools E.g. a story board is diagrammatic way of showing how data files can be linked together - a very important skill as it is of particular use when developing multimedia E.g. old v new animation techniques (jargon is still the same though)
  • Social and Ethical Issues Inclusivity issues e.g. can computer screens can be adjusted for visually impaired users? Investigate assistive technologies available for the disabled e.g. are web designers providing suitable display alternatives for disabled users? Offensive and pornographic material on the web. Should free speech be limited? Whatever happened to the ‘paperless office’?
  • end