DOS 20

DOS 20 may refer to IBM OS/2 versions:


 * OS/2 2.0 ("DOS" version 20.00)
 * OS/2 2.1 ("DOS" version 20.10)
 * OS/2 Warp 3 ("DOS" version 20.30)
 * OS/2 Warp 4 ("DOS" version 20.40)
 * OS/2 Warp 4.5 ("DOS" version 20.45)