Interval of approximately one year, where the public interest will be the product of IBM PC, Microsoft is making improvements to MSDOS, and appeared DOS version 1.1. Actually, this is caused by IBM to launch new products for the floppy disk drive floppy double-side measures 5 ½ inches with a capacity of 320K. Use double-side for the floppy disk is very influential, because storage media can store two times more compared with single-side floppy diskette. Do not laugh to see capacity of floppy disks that are supported by MS-DOS 1.1. You will not get the capacity of tens of megabytes or gigabytes. Even the hard disk it is still rarely encountered in the microcomputer, and only the Apple III, which have them.
After that, Microsoft appeared to sell MS-DOS to IBM's competitors are making such a 5150 IBM PC clones. Microsoft gave her version of 1:25. Because so designed using the philosophy of open-architecture, unlike Apple and Commodore then the clones of the IBM PC can be done. And that's why the IBM PC and clone the IBM PC compatible with IBM PC is very successful in the market. This is the success of three companies: IBM, Intel, and of course Microsoft. It's just that the market was undermined by the time IBM, Compaq, Hewlett-Packard, and Dell Computer Corporation, which makes IBM PC clones.