- Released with the laptop IBM Convertible PC, 1985.
- First retail (others were all OEM) release of MS-DOS, 1986.
- Added support for 720K Low-density (LD) drives (3.5" hard-shell
- Made it more difficult to accidentally format a hard
- Expanded device driver IOCTL service to include DOS-blessed
disk formatting, etc.
- DOS function 44H extended to support Generic IOCTL and to
support logical drives with subfunctions 0dH, 0eH, and 0fH.
- Commands introduced:
- Commands enhanced: