Identifying the DBMS that uses .bt and .ov entities (files)?

Subject:	Identifying the DBMS that uses .bt and .ov entities (files)?
Date:	Mon, 8 Feb 2010 16:13:01 -0800 (PST)

I have an old database file (named *.db) that refers to what could be
a relational structure with entities that have names ending in .bt and
ov. I'm calling them entities because I don't know whether the .db
file unpacks to create a bunch of .bt and .ov files (probably key and
data files?) or if these names belong to data structures that stay in
the .db file.

Does anybody know what DBMS would have been used to read this file?
I'd love to get at the info that it holds but finding the correct DBMS
will save me days of decoding the file by hand.

I can see what I describe above by looking at the file with a binary
editor - slow and cumbersome at best.

Thank you for any insight that you can provide.