Large-scale training simulation systems have historically required a real-time operating system to function deterministically. First generation operating systems were no more than a program loader. Second generation systems, which are the bulk of the existing production simulators in existence today, have proprietary operating systems written by computer companies focused on real-time. Third generation systems, which have been in existence for about ten years, took the standard Unix kernel and modified it to have all of the real-time characteristics of the proprietary operating systems with a look and feel that was recognizable by anyone with a Unix background.

Running flight simulators under Microsoft's Windows NT would be the next evolutionary step. The main driving factors for this are the low-cost COTS hardware platforms and COTS software solutions. For Windows NT to be effective as a flight simulator operating system, it must have the ability to handle IEEE Posix. 4 components such as Synchronous and Asynchronous I/O, Semaphores, Processor memory locking, shared memory, priority scheduling, fast interrupt response times and interprocess communications. Not only must NT support these functions, but also it must be modified to make these features the most time-critical functions of NT. This paper examines the problems associated with porting flight simulation applications to NT.

This will include the real-time support issues as well as GUI conversion problems associated with X-Windows to Microsoft Windows.