As development continued and it became clear that the machine would be ready before the MS-DOS-based Microsoft Windows 1.0 was, Bill Gates became personally involved in the project to assist Mindset in emulating IBM character graphics without losing performance. Once Mindset officials determined that most of the desirable software was compatible, development was frozen and the OS burned to ROM in late 1983. The ROM did not run about 20% of the PC software base, including "Microsoft Flight Simulator". WordStar was one of the PC applications reported to run, and Mindset publicized a list of 60 applications that ran unmodified. The software base was expected to increase dramatically once a final version of Windows was released.