Overview

There are quite a lot of different electronic document formats, and to make it easier to describe their common properties they can be divided into three groups, as shown in Figure 1

  

Figure 1: The three groups of document formats and their relationship

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Target formats are the ones which existing documents are converted to and which are used in keeping documents for reading and other usage. Existing documents are produced in one of several source formats, usually by the author of a book, using some text processor. Some of these source formats can be brought into the desired target format either directly or via some intermediate format that can then be converted into the final (target) format in a second step.

I will explain the formats addressed in Figure 1 from bottom up. Starting with the target formats, via some intermediate document formats to the formats in which the document source is most often available today. The next section will go and describe the converters used to transform the various formats in greater detail.

For every single document format, I will discuss the following attributes:

• General description
• Type of standardisation: Proprietary, vendor dependent or open (independent) standard?
• Advantages / Disadvantages: Given under the special aspect of document conversion
• Structure: Are the contents of the document human readable or is special software required for handling it? For documents of the first type it's usually easier to manipulate them if some tool breaks something. Does the document format support structured text so that parts of it can be extracted easily? Is the document self-contained, or does it require any additional data not contained it itself, e.g. for fonts?
• Tools: A list of programs which can read, write and manipulate this document format.