As far as we know, Microsoft Windows no longer supports 16-bit MS-DOS application and they removed NTVDM, since virtual 8086 mode is not available under amd64 extended mode. This project aimed at building a virtual dos machine for 64-bit Windows.
The idea of this project is to emulate a 16-bit CPU and provide BIOS/DOS interrupt services to MS-DOS applications. In NTVDM64, 16-bit applications runs as before in 32-bit Windows. We want to create a compatible environment for 16-bit applications, for example, applications can access disk files on host machine using legacy DOS interrupts instead of using network sharing.
Now we already have a PC emulator which could run in Win32 console and it supports all 8086 instructions - MS-DOS 6.22 runs well inside this PC emulator. The only work left for this project is to combine the emulator with Windows Shell.
Please visit the homepage for NXVM and NKVDM at https://github.com/cshaxu/. Here you can find all the demo/manuals about it.