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UNIT 4 – INTEGRATING DATA

SUMMARY MATERIAL ______________________________________________

2008–2009

INTEGRATING DATA

Standardized ways of doing things save much time and duplication of effort; they allow components to work together smoothly. Increasingly, the trend in the computing industry has been to adopt standard formats that allow the exchange of data between different applications, leading to increased possibilities for an integrated approach to data.

Why bother with different formats?

The reason comes back to our old friend, fit-for-purpose. A composer needs a format that can be edited; a format that can be printed out and performed; a listener, a

format that produces quality sound. Different formats can also be used to provide information for a range of ages or abilities.

Marking up for style

In the past, it was the practice of an author or editor to indicate to the printer, who had to typeset by hand, which parts of the text to change into headings, lists, paragraphs, and so on. Indicating the visual style of the text in this way (a process called styling) was done through a series of marks made on the original manuscript or typescript.

The origins of using marks go back at least as far as the origins of printing with movable type, though it may originate in an even older practice of indicating to a scribe how a text should appear when copied out. Nowadays, when editors mark a document by hand, they use a pencil or pen to mark a typewritten or word-processor document called a typescript (it’s called a manuscript only if it is handwritten). The editor indicates sections of text that need to be altered by placing marks in or above a line of type in the document. These marks indicate the action that needs to be taken by the person who produces the next version of the document.

Electronic mark-up

The advantages of using computers to manipulate text became apparent in the late 1970s and early 1980s: computer programs made it easy to insert, copy, delete and move text around within a document. Most people could typewrite, even if it was only with two fingers, but preparing a professional looking typescript required considerable skill beyond most people’s ability.

As it became easier to manipulate text, and as printers were designed which used more flexible means of representing characters (e.g. by using closest pins striking an inked ribbon, jets of ink, or laser technology), it began to be possible to form letters of different sizes, to use different fonts and weights (bold or normal) and to create effects like strike-through and underlining.

Given this degree of flexibility in printing and displaying text, there needed to be a way of indicating to a computer program how parts of a text should be styled. The answer was to adopt the idea of marking up the text so that a computer program could interpret the marks and alter the appearance of the text. This resulted in the birth of the electronic mark-up language which consists of a set of marks that are recognizable by a computer

program and indicate how parts of a text should be styled.

Getting from plain to styled text

The marks of a mark-up language must be embedded within (placed into) the electronic text. But how are they to be distinguished from the text itself?

Some marks have distinct meanings and are never used in normal text. An example of a mark that possesses a meaning is ¶, which is used to indicate the start of a new paragraph. But since you can’t be sure that a computer keyboard will have a ¶ symbol, it makes sense to use an unusual abbreviation such as instead of ¶. The angle brackets (< and >) seldom appear in normal text outside mathematics, particularly in the configuration of left bracket, letter, right bracket.

There are two ways that you can style a text using a computer program:

• WYSIWYG;

• Using explicit marks.

WYSIWYG

WYSIWYG (pronounced ‘wizzy wig’) stands for ‘what you see is what you get’. WYSIWYG presentation means that the document displayed on the screen looks exactly the same as the final printed document. When using a WYSIWYG program, such as a modern word-processor application, the user types in text and chooses styles from a menu, by clicking on buttons, or by using particular sequences of key strokes (known as keyboard shortcuts).

Explicit mark-up

The second mark-up technique involves explicitly typing in marks. When I do this, I can see the marks on my computer screen, and it is only after the document passes through some software (such as a browser) that it will be displayed with the intended appearance. You’ll see how this works in the next section.

HTML – an electronic mark-up Language

It is possible to do so because web documents can bestyled using a relatively simple mark-up language called HyperText Markup Language (HTML). HTML is designed to be easy to write and understand.

It uses a small set of marks or tags, although the number of marks available has grown with the years. HTML is defined by a constantly evolving international standard governed by the World Wide Web Consortium (W3C).

While there is a standard set of HTML marks, the two major browser manufacturers (Netscape and Microsoft) have each created their own additional HTML marks which do not work in rival browsers. However, this isn’t quite the problem you might imagine.

HTML was designed to be used on any computer display but wasn’t designed to give precise styling instructions. Instead, HTML provides broad guidance on relative sizes of text, the alignment of lines of text and the placement of graphics. Thus there are variations in how different browsers render a marked-up document on the screen. Recent revisions of HTML have introduced tags that allow the user to specify particular fonts and type sizes. This is a mixed blessing because, while it gives developers the option of creating documents to the same precision possible with a word-processor or typesetting program, it introduces other problems. For example, it can reduce the flexibility of HTML. As a device-independent language, HTML allows the particular browser to arrange the display on the screen. Ideally HTML documents can be displayed on all forms of devices ranging from conventional PCs to mobile phones. However, the very small screens on mobile phones or those with restricted colour options may not be

able to display a document which contains tightly specified styling.

Beginning HTML

In HTML (and many other electronic mark-up languages) marks are called tags. Tags in HTML are always enclosed within angle brackets (< and >). HTML uses pairs of tags in most situations: one to indicate the start of the text that is to be styled and a corresponding tag to indicate the end of the styling. The end tag always includes a slash character after the left angle bracket ( ................
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