When you pack a database, qvpack writes an entry at the start of the packed file naming the file structure of the files in the database. When you unpack a database, qvtrans reads this entry and makes any file structure conversions that are necessary.

Although qvpack and qvtrans recognize many file structures, and some systems share the same file structure, there might be times when you are working on a computer whose file structure is not known to qvpack and qvtrans. (This is most likely to happen as new computers are developed.) This does not necessarily mean that you will be unable to pack or unpack the database. Usually, you will find that the unknown file structure is the same as one that these programs recognize, but that it just has a different name. If so, you can inform qvpack and qvtrans of this relationship and they will pack and unpack the database as required.

qvpack and qvtrans recognize the following types of file structures:

If the unknown file structure is identical to one of the known file structures, you can either define an alias which links the unknown structure to the known one, or enter the name of the known file structure as part of the qvpack and qvtrans commands.