From John Wharton’s “The Origins of DOS” (Microprocessor Report: 3 October 1994):
In August of 1981, soon after Microsoft had acquired full rights to 86-DOS, Bill Gates visited Santa Clara in an effort to persuade Intel to abandon a joint development project with DRI and endorse MS-DOS instead. It was I – the Intel applications engineer then responsible for iRMX-86 and other 16-bit operating systems – who was assigned the task of performing a technical evaluation of the 86- DOS software. It was I who first informed Gates that the software he just bought was not, in fact, fully compatible with CP/M 2.2. At the time I had the distinct impression that, until then, he’d thought the entire OS had been cloned.
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The strong impression I drew 13 years ago was that Microsoft programmers were untrained, undisciplined, and content merely to replicate other people’s ideas, and that they did not seem to appreciate the importance of defining operating systems and user interfaces with an eye to the future.