mameinfo.dat vs. history.dat

[jimj]

-Should you use one or both of these files?
-Is history.dat simply a subset of the info in mameinfo.dat?
-Since they are both accessed via the same "Game History" menu option, what does Mame do when you have both files present (for example only use mameinfo.dat, or merge the info together somehow)?
-Should your version of mameinfo.dat match the version of Mame you're running?  I run Mame 0.88, but I can't find an archive of old versions at http://www.mameworld.net/mameinfo/ or google.  If the versions should match, where can I download the 0.88 version of mameinfo.dat?  I know some rom names changed since 0.88 (like sf1 is now sf), so I would guess that the version matters.

TIA,
Jim

Sorry for the stupid questions, I found almost all the answers myself.  Just in case anyone else was as clueless as me, mameinfo.dat and history.dat are complementary files.  Their contents are described here http://www.mameworld.net/easyemu/mameguide/mamefiles.htm and in the mame docs.  The contents of mameinfo.dat are appended to history.dat when viewed from within a game.

The only reason the version matters is that the rom filename must match what's listed in the history.dat and mameinfo.dat files.  Since rom names sometimes change between versions of mame, it's best to use the same version of these files.  For me I know that the only rom names that changed since 0.88 and 0.90 are sf1 and vf1, so it was easy to manually update the files.  If someone knows of an archive of these files I'd still like to know about it though.