CD-MRW → working name for a CD-RW storage format developed by the Mount Rainier Working Group.
This standard is being promoted by Compaq, Microsoft, Philips, and Sony. The web site claims support by "over 40 industry leaders", including OS vendors and PC OEMs.
500+MB of reasonably fast storage that doesn't require long formatting delays or the installation of special software.
Discs created with Mount Rainier appear to organize the data slightly differently from other UDF solutions, so some compatibility problems exist.