Microsoft says it is the Graphic Device Interface:
[link|http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/wingdistart_9ezp.asp|http://msdn.microsof...gdistart_9ezp.asp]

The Microsoft\ufffd Windows graphics device interface (GDI) enables applications to use graphics and formatted text on both the video display and the printer. Windows-based applications do not access the graphics hardware directly. Instead, GDI interacts with device drivers on behalf of applications.

I think what it does is makes a "what you see is what you get" image from the video to the printer, as well as control graphics and formatted text on the windows themselves. If you are using formatted fonts, or the web pages you are visiting are using customised fonts and graphics, this memory will be used.

MINI, my best guess is that it is Mini-Windows:
[link|http://support.microsoft.com/default.aspx?scid=/support/windows/tshoot/drvspace98/info/DsMn_WndwsFl.asp|http://support.micro.../DsMn_WndwsFl.asp]

Mini-Windows is a special operating mode used for sensitive operations such as DriveSpace.

When DriveSpace restarted your computer, did you see a screen with two pie charts and a message stating that your drive is being compressed?