Not a DOS command but a program that M$ included with some versions of DOS. It is MSD.exe. The info it gives may or may not be accurate. It should be run from a DOS prompt outside Windows to get the DOS information. From a DOS prompt inside windows it will display the info that is passed to it by windows. Do not use it on 2k or XP systems unless you know they are FAT32 format. If it is not on your HD and you are using W98x, you can find it on the windows CD in a directory named olddos.