A major DOS upgrade in 1991 that included an enhanced user interface (DOS Shell) with task swapping, undelete commands, a full-screen text editor, online help and an improved memory manager. Support for 2GB hard disks and 2.88MB floppies was added. DOS 5 included QBasic, which superseded GW-BASIC in the MS-DOS version and accompanied BASICA in the IBM version. Significant new features were:

           DOS Dos
           DOS Doskey
           DOS Editor
           DOS EMM386.EXE
           DOS Loadhigh
           DOS Mirror
           DOS online help
           DOS Setver
           DOS Task Swapper
           DOS Undelete
           DOS Unformat