DOS or Disk Operating System; is related to different operating systems. Earlier IBM was on the top of the list during 1981 to 1995 and then came Windows which included Open DOS, MS DOS, PC DOS and some more. The main attraction which these operators had was that only a single user can use this and it can perform only one task at one time. One out of the list was MS DOS which was from Microsoft originally, was used in a huge manner. The compatibility of this operating system differs, as they can be operated on IBM PC hardware and having different configurations.