DOS/4G

DOS/4G is a 32-bit DOS extender developed by Rational Systems (later Tenberry Software). It allows DOS programs to eliminate the 640 KB conventional memory limit by addressing up to 64 MB of extended memory on Intel 80386 and above machines.

== Features == Functioning as a highly flexible and reusable memory extension library, DOS/4G allowed programmers to access extended memory without writing specialized code. It embeds itself in the executable file at linking time and executes before main application code, so usually DOS/4G initialization messages show up at launch. It can in principle operate within MS-DOS, PC DOS, DR-DOS and other DOS clones, the DOS boxes of OS/2, Microsoft Windows, Windows NT and Windows 95, and DOS emulators such as DOSBox. However, in practice few DOS/4G games or other applications will run on non-DOS-based versions of Windows, including Windows NT, Windows 2000 and Windows XP, since none of these allow direct access to the hardware as was used for display rendering in those days.