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In addition to these categories, a division can also be made into compulsory and non compulsory. The compulsory keywords are given in Table 2. These keywords form the file tracing and file descriptive categories. The compulsory keywords are the minimum requirement concerning the occurrence of keywords with which a GEF file must comply. There are also non compulsory keywords or conditionally compulsory keywords.
Anchor
Conditionally compulsory keywords are sometimes compulsory, depending on the occurrence of another keyword. If, for example, binary data are recorded, not only must the fact that binary data are recorded be stated, but also the size in bytes of each measurement and in which sequence the bytes are written. This information is not necessary for ASCII values.
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Parts of the information following keywords which can be omitted are given between [] in the typescript. Abbreviations are used to characterise the information, as given in Table 4. E.g. 4Value represents a value of 4 bytes in size, sUnit states a string which describes the unit.
Data types.Anchor Datatype Datatype
Table 4: Types of variables and their abbreviations.
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