Usually, in MSDOS, the primary hard disk drives has the drive letter _______.
Usually, in MSDOS, the primary hard disk drives has the drive letter C.
Why 'C' is the Default Hard Drive Letter in So Many Computers. For nearly as long as hard disk drives have been placed in personal computers running certain popular operating systems (notably MS-DOS/Windows), the primary hard disk has been designated with the letter “C”.
On IBM compatible computers (PCs) running a Microsoft operating system, such as Windows or MS-DOS, the hard drive is the C: drive because it is the first available drive letter for hard drives. The computer assigns the A: and B: drives to floppy disks and sometimes other removable media, such as tape drives.
If you bought an ultraportable, you likely had a solid-state drive (SSD) as the primary drive (C: on Windows, Macintosh HD on a Mac). Every other desktop or laptop form factor had a hard disk drive (HDD). Now, you can configure most systems with either an HDD or an SSD, or in some cases both.