IBM Personal Computer Technical Reference
  Software
    Operating Systems
      DOS
	Compairison
	  Version 1.0  (PC-DOS)
	  Version 1.1
	  Version 2.0
	  Version 2.1
	  Version 3.0
	  Version 3.1
	  Version 3.2
	  Version 3.3  (MS-DOS)
	  Version 4.0  (PC-DOS)
	  Version 4.01 (PC-DOS)
	  Version 5.0  (MS-DOS)
	  Version 6.0  (DR-DOS)