Bill's mother also paid for the computer time at the high school Bill went to with his other friends who formed Microsoft with him. Since this was before the Mi

Bill's mother also paid for the computer time at the high school Bill went to with his other friends who formed Microsoft with him. Since this was before the Microcomputer, time sharing on a minicomputer or mainframe was very expensive. So Bill and his friends had knowledge of programming a computer before anyone else did. IBM claimed DRI charged too much for CP/M, and since Microsoft made BASIC IBM thought they could get a better deal on a DOS from Microsoft. 86-DOS became PC-DOS/MS-DOS and the DOS interrupts emulated the CP/M interrupts or API as it was later called. Back then, it was legal to reverse engineer stuff and make a copy of it using new source code. But the claim of Paterson and others was that they didn't pirate/steal CP/M they made an API in DOS that could run CP/M programs and then had a program that could convert a program to DOS from CP/M because the executable file format was different in DOS. Microsoft did undercut CP/M in OS price, which was a big factor in getting paid by IBM and other OEMS for their DOS. Microsoft Windows came out in 1985 and over the years it took more and more features from the Apple Macintosh. It did not have the source code of a Mac, but it was designed to use some of the look and feel from a Mac. Enough for trade dress lawsuits. Microsoft and Apple settled their differences out of court in the late 1990's. CP/M was a good operating system, my father bought me and my siblings a Commodore 128 after the Commodore 64 died. By that time the Z80 coprocessor on the 128 ran CP/M80 for cheap, but it was too late, DOS had killed CP/M.