Wow. Thanks for writing it up, but that API just makes me cringe. That's what we had to deal with back in the day, but now we have abstract APIs like localStorage, Web SQL and Indexed DB [1]. At the very least, this wont gel with "Directories and System" component of the File API [2][3]. Microsoft will probably be implementing the W3C standard, but we may have to come up with a fileQuery.js library to do file-operations the same way across platforms until they see a need for it.

[1] http://www.html5rocks.com/en/tutorials/offline/storage/

[2] http://dev.w3.org/2009/dap/file-system/file-dir-sys.html

[3] http://www.html5rocks.com/en/tutorials/file/filesystem/