The (never-was) DOS 4 was a preemptive real-mode multitasking operating system for the 8086 family of processors. It had a boatload of cool features, including movable and discardable code segments, movable data segments (the Windows memory manager was a version of the DOS 4 memory manager). It had the ability to switch screens dynamically Ė it would capture the foreground screen contents, save it away and switch to a new window.
posted by Eugenia Loli on Tue 23rd Mar 2004 03:09 UTC
Most people donít know about Microsoft's other multitasking operating system, MS-DOS 4.0 which was actually a version of MS-DOS 2.0 that was written in parallel with MS-DOS 3.x (DOS 3.x shipped while DOS 4 was under development, which is why it skipped a version). The MS-DOS 4 version described here was never shipped and instead a beefed-up version of 3.x was labeled 4.0 and shipped instead.