Wednesday, 09 December 2015 12:34

A Year's Progress: NTVDM (Part 2)

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In A Year's Progress: NTVDM (Part 1) we talked about what NTVDM stood for and the earliest version of NTVDM that as woefully underdeveloped. In this part we will cover the new NTVDM written by [TheFlash].

When [TheFlash] joined the project, the NTVDM was still useless. But in revision 59241, a branch was given to him to begin writing a newer, better NTVDM. It progressed nicely over the time and witnessed heavy development. In revision 63177 the new NTVDM was finally ready to be merged back into trunk!

Our NTVDM

Our NTVDM is a bit different from Windows'. The Windows one sets the CPU into a 16bit mode and runs in fullscreen by default. This causes some problems: one of them is that it can only work on a 32bit CPU and won’t run at all on a 64bit and ARM processors. Also, as it runs in fullscreen by default, the computer can only be used to run one application at a time, unless you Alt-Tabbed out of the DOS game.

ReactOS' NTVDM on the other hand, is a software emulator just like DOSBox. That means it will run on 32bit and 64bit processors and even ARM processors with some work. Also, as it's not full screen by default, the user can do multiple things at once such as watch a video and play Duke Nukem at the same time. If you do want full screen mode, you can always press Alt-Enter to activate it. Cool right? :) Sure DOSBox can do this in Windows but why would you do that when you can use ReactOS! ;)

Our NTVDM "specs"

Our NTVDM implementation currently emulates a 486-compatible CPU, VGA support, MS DOS version 5 and 5.50 for NT compatibility, VGA and PC speaker sound support. VESA and Sound Blaster support are on the way.

What can the new NTVDM run

With the new NTVDM, many new DOS applications and games could be run. The progress of the development since it was merged was tremendous! At first, there were many bugs and some apps could still not run. But as time passed, new features, bugs and unimplemented code was eventually added. Now, not only apps and games can run in NTVDM, but even Windows 3.11 can be installed and run! Not even Windows XP could do this unless the user used DOSBox! ;)

As you can see, NTVDM progressed a lot. Here are some photos showing that progress:

We hope that you liked this update and we will be preparing more of the "A Year's Progress" series. Stay tuned!

Your feedback is important to us, please let us know what you think via the comments section ;)

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