Wednesday, October 23, 2019
How do you configure hardware and software Essay
The most common colour depths are: à 16 colours à 256 colours à ââ¬Å"High Colourâ⬠(16 bit, or 65,536 colours) à ââ¬Å"True Colourâ⬠(24 bit, or over 16 million colours) Higher resolutions are greater number of colours require more memory. At 256 colours, each pixel requires one byte of memory. There are 8 bits in a byte, so each pixel in High Colour requires two bytes, and each pixel in True Colour requires three. Because of this, some video cards may restrict you to fewer colours in higher resolutions, due to the amount of memory required. For example, a True Colour display with a resolution of 1280 x 1024 pixels would require memory of 1280 x 1024 x 3 = 3,932,160 bytes, or nearly 4Mb! Drivers Different printers have different features, such as the ability to print in different fonts, and different resolutions (i. e. numbers of dots per inch) when printing graphics. Even where there are common features, such as the ability to print in bold, the codes that the computer needs to send to switch that feature on and off can vary from model to model. What the computer requires is some software called a driver, which can translate the codes generated by the program into codes suitable for the printer. In Windows, the drivers are installed centrally in the Control Panel so that each application, e. g. Excel or Word, can use the same drivers. In the days of DOS, each program often had its own printer driver. Other hardware devices, such as video cards, modems and scanners also require drivers. These perform the same function, allowing the computer to control the device. Sometimes the same driver can be used for similar devices (e.g. you may hear about ââ¬Å"Hayes compatible modemsâ⬠, or ââ¬Å"HP LaserJet compatible printersâ⬠), but even in these cases it is often only by using the specific driver for that device that the most advanced features can be utilised. WYSIWYG and TrueType Fonts One of the problems with printing from a word processor or other application is that your text may not appear on paper as it did on the screen. With modern Graphical User Interfaces, this should be less of a problem, but with older ââ¬Å"character-basedâ⬠systems (such as DOS, or UNIX), fonts on the screen were not ââ¬Å"proportionally spacedâ⬠. Characters could only appear at fixed intervals across the screen, and so it wasnââ¬â¢t possible to insert fractions of spaces to justify the text. This meant that sometimes you could print out justified text, but not see what it was going to look like on the screen. A solution to this problem came with the arrival of WYSIWYG user interfaces. WYSIWYG stands for ââ¬Å"What You See Is What You Getâ⬠, and means that your print should appear exactly as it does on the screen. Word (in Page Layout View, at least) is a WYSIWYG word processor; you get exactly what you see as you are typing. Other word processors, such as WordPerfect 5. 1 offer a halfway house solution, with a character-based input screen, and a graphical print preview. Even with GUIs and WYSIWYG word processors, there was still the problem of the fonts being used in the printer not being exactly the same as the ones used for display on the screen. This could lead to things not quite lining up, or not appearing as expected. A solution for this came with TrueType fonts. A TrueType font is used by Windows both for display on the screen and for printing. When you select a typeface in, say, Word, the TT symbol indicates a TrueType font. If you select one of these, you can be sure that your document will appear in the same way on paper as it did on the screen. Limitations of Hardware and Software Sometimes, due to the limitations of the hardware or software being used, a system will not be able to fully exploit the features of a peripheral. You will not be able to use certain fonts that a printer may support, for example, if the word processor you are using will not let you select that font, or if you are printing from, say, Notepad. Also, there is no point in you being able to scan things in 24-bit colour (i.e. 16 million colours) if your monitor cannot display that many, or you need to save the image as a GIF (GIFs only support 256 colours; if you want more colours than that, save your picture as a jpeg). Some modern printer drivers are applications in their own right, and have minimum hardware requirements specified. The drivers for my printer at home, for example, will not run on a 386. Examination Questions When installing or configuring a particular word processing package, the documentation states that the correct printer driver must also be installed. What is a printer driver, and why is it necessary? (1997) A company sells a range of health foods at five different shops. It also sells directly to the home from a number of vehicles. There are hundreds of different items of stock and many items are seasonal, so items in stock are constantly changing. Customers purchase goods and pay by cash, cheque or credit card. The company is considering a computerised system to help manage sales and stock control. Discuss the capabilities and limitations of current à communications devices, à input devices, à output devices and à storage devices.
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