Where are the Winamp ratings (the five star selection) for music actually stored? They appear to not be in the ID3 tags, and I loose them every time I have to re-import my MP3s. I've done much digging through the filesystem looking for the nook or cranny that they're hiding in.

How can the ratings be backed up and restored so that I can preserve them between application and OS installations or even hardware replacement or failure?

Any clues greatly appreciated.

I have done hours of searching and Googling, both at the Winamp forums and elsewhere, for any clues on the matter in total frutility.

Yay! I got a reply already:

Ratings are stored in winamp\plugins\ml\main.dat (the library database)

You can find some useful backup tips here:
http://forums.winamp.com/showthread.php?threadid=182413
http://forums.winamp.com/showthread.php?threadid=158332

Of the recommendations presented, I've gone with the option of performing a Media Library Search query for each of the five ratings, selecting the results for editing, and adding the appropriate "*" string to the Comments field:

?rating = 5 then select all results right click > edit selected items add: rating 5 in the Comment field -> Update Repeat for: ?rating = 4 etc Then once files have been moved and reimported, use search query: ?comment = "rating 5" (or: ?comment has "rating 5") select all -> rate items -> 5 and so on. You could even add: ***** to the comment tag and use query: ?comment==*****

(Find the Search field at the top of the WinAmp Media Library's right-side panel.)

This seems to be the best use of the comments field that I've seen yet anyhow.