Wasn't DOS, (which microsoft bought from a local company and pawned off to IBM) dealing with the 640k memory limitation and that is why early versions of Windows "sat a'top" the legacy operating system..no HAL bound to the GUI? Windows had no control itself over the filesystem(only by using dos execs), and filemangler, I mean winfile held strict adherence to DOS functionality? Then there was memmaker for emm386.sys and Quarterdeck (I think) that was able to overcome the 640k but it wasn't until NT w/ the new HAL that they were able to break away from 640k....and have something other than files=15, buffers=30, dos=himem, umb and emm386 to manage memory, I am no expert and do not profess to know how the widgets work with how the operating system is made.
I still partition a small part for DOS on an NT server(to boot into if necessary) and have use a DOS boot disk to start many installs of NT...so it kindasorta still all depends on DOS...wait, I'm wrong, booting off the CD-ROM overcomes that. I guess you could use all non-dos stuff for partitioning.
Also, is command.com, io.sys, msdos.sys considered DOS files, or NT files or what? These old system files are there just for DOS, or does NT now use them as well? sys c: still necessary? Sorry for rambling, I could be completely off mark too!
Something I heard that may be completely full of it: Steve jobs gave Bill Gates some jabs about still having to see the DOS bootup text when 95 debued and that a real OS didn't have such archaic aesthetics...and that's why there has been the low graphic blue screen with a wiggly bottom band since w95.
btw I had too much coffee this morning!