MS DOS resulted after a request from IBM to Microsoft for an operating system. IBM had previously rejected CP/m operating system as Gary Kildall had cancelled their meeting. Bill Gates quickly responded to IBM’s request by buying QDOS from another small company. He then modified it to IBM’s specifications and renamed it, MS DOS and licensed it to IBM. This was a huge breakthrough for Microsoft as every IBM pc sold, Microsoft would receive $40, Microsoft was on its way to success. Gary Kildall realised his mistake and created an imitated version called DR-DOS.