1. Displaying

2. Displaying as the output from the information system to meet a purpose
It is the representation of information in the form of text, numerals, images, audio and video

3. Hardware: screens for text, numeric, images and video
A screen is a display surface that provides immediate feedback about what a computer is doing.
It can display text, numeric, images and video
All images on the screen are made up of pixels (picture elements) which are the smallest part of the screen that can be controlled by the computer.
The total number of pixels on the screen is called the resolution.
The space between the pixels is called the dot pitch.
It is also important in determining the clarity of the image. In general, the greater the number of pixels and the smaller the dot pitch, the better the resolution.

4. Hardware: Monitor
The monitor is a screen the uses cathode ray tubes (CRT) technology similar to a television.
Images are produced by firing a beam of electrons onto the inside of the screen, which contains a coating of phosphor.
The electron beam usually moves from left to right and top to bottom in a series of zigzag lines called a raster scan.
Monochrome monitors use one beam and colour monitors use three beams to strike red, blue, green phosphor.

5. Hardware: Monitor
The raster scan is repeated to maintain the images as the phosphor glows for a short time. This is called ‘refreshing’.
Interlaced monitors speed up refreshing by first scanning the odd lines from top to bottom and then the even lines. However this can cause the monitor to flicker.
Monitors come in a range of sizes. Most are 19 inches in size and have a swivel base that allows the angle of the screen to be adjusted.
The amount of colour displayed on a colour monitor depends on the amount for memory installed on the computer's video card.

6. Hardware: Flat Screen Monitor
A flat screen is a thin screen that dies not use CRT technology.
Liquid Crystal Display (LCD) consists of a layer of liquid crystal material placed between two polarising sheets.
Light is passed through the crystal material and a current is applied at particular points. This causes a pixel to be activated.
LCD are light, take up less room, produced no heat, have no glare, emit no radiation and require less power.

7. Hardware: printer for text, numeric, images and video
A printer is a device that represents data on paper.
The paper containing the data is called a hard copy or printout.
Printers are classified as impact and non-impact printers.
Impact printers make an image on the paper by using some sort of physical contact. (E.g. dot matrix printer)
Non-impact printers make an image using some other method. (E.g. laser and inkjet printers).
The quality of output of a printer is called the resolution and is measured by the number of dots per inch (dpi) it is able to print.

8. Dot Matrix printer
It has a print head that travels across the paper. In the head are a set of pins which shoot out and strike the ink ribbon against the paper as the print head moves along.
These printers produce low to medium quality black and white printing.
Not used in the home so much but still used in business for the following reasons:
The running costs are very low.
They are robust and can operate in harsh environments.
Due to the physical impact on the paper, copies can be made using self carbonating sheets - very useful in a warehouse.

9. Inkjet printer
The print head contains tiny nozzles through which ink can be selectively sprayed onto the paper to form the characters or the graphic images.
Inside the print head are tiny piezoelectric crystals. These crystals change shape when an electric current is applied across them and this forces the ink out through the print head nozzle.

10. Ink-jet printer
The printhead contains tiny nozzles through which ink can be selectively sprayed onto the paper to form the characters or the graphic images.
Inside the printhead are tiny piezoelectric crystals. These crystals change shape when an electric current is applied across them and this forces the ink out through the printhead nozzle.

11. Bubble jet printers
It is a type of ink-jet printer but instead of the ink being forced out of the printhead, it is heated rapidly. This causes the ink to boil and a bubble of ink is formed. As the bubble forms, it expands and is forced through the nozzle of the printhead and onto the paper.
Ink-jet and bubble-jet printers are relatively inexpensive and produce high quality black and white or colour printing. This makes them a popular choice for home and school use.
The printing speed is slower than a laser printer so for most businesses where a greater printed output is required, the laser printer is more suitable.

12. Laser printers They work on the same principle as photocopiers.
The toner, which is powdered ink, is transferred to the paper where it is fused by the action of heat and pressure.
Lasers are very quiet printers and give high quality print.
A mono (black and white) laser printer with a speed of eight pages per minute (ppm) can be purchased for around $250.
Can get colour laser printers.dropping to around $700.

13. Laser printers
It works by the laser drawing the image onto a negatively charged photosensitive drum.
Where the laser hits the drum, the charge is removed.
The drum then passes the toner reservoir where negatively-charged toner is attracted to these areas.
This toner is then transferred to the paper, where it is heated, and made to stick by the fuser assembly.

14. Comparison of the two major types of non-impact printers
Advantages
Disadvantages
Inkjet
Quite
High-quality display
Relatively cheep
Capable of displaying text, numbers, graphics
Slow
Jet sometimes clog
Ink cartridges are expensive and don’t last for as long as laser cartridges
Cannot produce ‘carbon copies’
Laser
Quiet
Exceptional quality display
Relatively fast
More expensive to buy
Cartridges are expensive, but last for longer than ink cartridges.

15. Hardware:Plotter and slides for images
There are several types of plotter.
The flat-bed plotter uses precision motors controlled by the computer. Motors move an arm across the paper in the ‘x’ and ‘Y’ direction and the pen unit up and down. An electromagnet lifts and drops the pen onto the paper.
Used in science and engineering applications for drawing building plans, printed circuit boards, machines and machine parts. They are accurate to hundredths of a millimetre and can be the size of a small classroom.
However, the increase in the quality of lowpriced A2 and A3 size colour ink-jet printers has reduced the demand.

16. Hardware: Speakers and speech synthesis for audio
Spoke output can be text for the blind or music or sound for everyday use.
Speaker are the hardware to display sound.
They work with the sound card to perform this task
Current sound cards usually plug into a peripheral component interconnection (PCI) slot on the motherboard. Some computers have the chip on the motherboard.
The SoundBlaster Pro is considered the standard for sound cards.
Typically a sound card can do four things: display pre-recorded music from CD’s. DVD’s, or sound files; collect sound from external sources; synthesis sound; process existing sound.

17. Hardware: Speakers and speech synthesis for audio
To display a pre-recorded .wav file, the sound card follows these steps:
The digital data is read from the hard disk and passed on to the CPU
The CPU passes the data to the digital signal processor (DSP) on the sound card.
The DSP uncompress the digital data using a DAC chip. This creates the analogue signal that can be heard through the speakers.

18. Software for display: interface for hardware
The electronic display on the screen in referred to as the user interface.
It enables the user to interact with the hardware and the software in the system
There are two main types of user interfaces: graphical user interface and the command interface.

19. Software for display: display features in application packages
Most applications software has a range of tools to allow the user to customise a display. The page view/magnification tool allows the user to change the size of the display. This is often refereed to as a zoom function.
E.g. there are a wide range of options available in a spreadsheet to change the appearance of a display. They include showing the gridlines between rows and columns, changing the appearance of the screen and showing formulas in cells instead of values.

20. Software for display: reporting
Reporting is used to organise and display data from a database for printing. Database management systems allow complete control in the design of a report in either a tabular or column layout.
It is possible to insert headings, sort data, choose fields, switch fields, change column width, and select records.
The purpose of the report determines its content, format and style.

21. Software for display: formatting
Formatting changes the appearance of the data. Text is formatted by changing the font, alignment, tabs, indenting, bullets, numbering and style.
Additional design elements include headers and footers, colour, drop caps, text effects, callouts and borders.
Numbers in a spreadsheet are displayed using built-in formats such as currency, percentage or fixed. Page layout is the arrangement of tect and graphics on a page.
A publication that is well designed will convey its message effectively and efficiently.

22. Software for display: spacing
Spacing between lines of text is altered to improve the appearance and readability of a document, Character spacing refers to the spacing between individual letters. It is changed in a number of ways such as scale, points, position and kerning.

23. Software for display:merging
Mail merge combines a letter written on a word processor with data from another document such as a database. It saves time and makes final documents more personal.

24. Software for display: tables
Tables are rows and columns of cells that are filled with text and graphics.
Text can be displayed horizontally or vertically, and the width or heights of the rows and columns can be altered.
Tables can be stored in alphabetic, numeric or date order.

25. Software for display: charts
Charts are a graphical representation of numerical data
They convert data in rows and columns into a picture that can be read at a glance.
Charts make data easy to understand.

26. Non-computer tools – storyboard
A storyboard is a series of frames each representing a different action or screen image,
It tells the story of a presentation,
Storyboards are drawn on paper and are changed frequently.
A storyboard includes sketches and captions like a cartoon strip but in grater detail.
Storyboards can be used to outline a multimedia production. A full length movie could require several hundred sketches.
There are four types of storyboard layouts: linear, hierarchical, non-linear and combination

27. Non-computer tools – pen and paper

28. Traditional methods for displaying the different types of data.
Text and images are displayed using paper in many different forms such as reports, newsletters, books, newspapers and magazines.
They are also displayed using devices such as the blackboard, whiteboard and overhead projector.
We also see information on the form of text and images displayed when we speak or use a variety of devices such as musical instruments, radios, tape recorders or CD players.
Video and animation is displayed using television, video recorder or at the movies.

29. Social and ethical – past, present and emerging trends.
Current trends in display are changing the way people interact with computers. Fifteen years ago screens were small and unable to handle different font sizes and graphics.
Today larger monitors can display text, graphics, photographs and video.
Display technology using large flat screens is becoming more common.

30. Appropriate displays for a wide range of audiences

31. Standards for display for the visually impaired
Visually impaired people need appropriate displays.
The issue is a concern in the Internet. Webpage designers should consider how people with disabilities will be able to access their information.
All people with a disability are entitled to access technology.

32. Displays suitable for young children
Children with Internet access can potentially view inappropriate material, either deliberately or unintentionally.