Thanks for your reply Agustin. To answer your questions: (sorry, don't know how to include your message in my reply)...

1. This is SBT accounting software and they do delete all the tags, then reindex from a dictionary containing the tag names and index definitions.

2. Logical index meaning there is a field in the data file called POSTED, which is a logical (.t./.f.) field. They are indexing on this field, probably for speed of posting to the GL. VFP 5.0, but it's running from SBT's SBTW.EXE compiled "trunk" program.