So, you copied from A: to a the virtual drive B: and the OS prompted you to swap disks as necessary.
Floppy drives got cheaper, and it became common to have two. This was very common as up to and including MS-DOS 3.3, DOS only supported partitions of up to 32 MB.
Alternate drive letters for the primary hard disk is something that almost no one tests for, and so you'll end up finding subtle breakage in lots of places.
I'm not saying that you shouldn't be able to do it (heck, Windows works just fine if you install to a primary other than C:), but you don't have a Windows computer just to run Windows, you'll want to put on other software.
The convention may be outdated but guys who write the apps are still pretty "dated" for lack of a better word :) My recommendation?
Keep the C:\ While the idea of drive letters is becoming deprecated, keeping a hard drive available on drive c: is still a good idea.Use drive letters C through Z for hard disk drives.Drive letters A and B are reserved for floppy disk drives.The way that CP/M and MS-DOS originally assigned drive letters was simple.The drive you booted from was the first, so it was called A. But floppy drives were expensive and hard drives were very expensive, so in the late 1970s when this stuff was standardized, most machines only had a floppy drive or 2.So many answers, so much guesswork, so little valid information. The way IBM PC-compatibles assign disk drives is copied from the way the IBM PC running PC DOS assigned them. DOS copies its disk assignment methods from Digital Research CP/M, because DOS started out as a copy of CP/M.You didn’t need the virtual drive thing any more; to copy from one floppy to another, you copy from floppy to hard disk, then swap floppies, then copy back. However, having drives change letter depending on which you booted from was confusing — again, see the Apricot comment — so later firmware started changing this. And the rest of the machine’s RAM aside from the 64 k B that CP/M used was made into a RAMdisk called drive M: “M” for Memory. A lot of software still assumes that drive c:\ is present and persistent.It may be an archaic standard but drives A: and B: are reserved for removable disks.