1981 MS-DOS 1.0 was released August, 1981.
1982 MS-DOS 1.25 was released August, 1982.
1983 MS-DOS 2.0 was released March, 1983.
1984 Microsoft introduces MS-DOS 3.0 for the IBM PC AT and MS-DOS 3.1 for networks.
1986 MS-DOS 3.2 was released April, 1986.
1987 MS-DOS 3.3 was released April, 1987.
1988 MS-DOS 4.0 was released July, 1988.
1988 MS-DOS 4.01 was released November, 1988.
1991 MS-DOS 5.0 was released June, 1991.
1993 MS-DOS 6.0 was released August, 1993.
1993 MS-DOS 6.2 was released November, 1993
1994 MS-DOS 6.21 was released March, 1994
1994 MS-DOS 6.22 was released April, 1994

补充：

1995 MS-DOS 7.0 was released Augest, 1995
1997 MS-DOS 7.10 was released June, 1997
1999 MS-DOS 7.10a was released May, 1999
2000 MS-DOS 8.0 was released July, 2000

么有DECEMBER出来的？