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Welcome to FreeDOS

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FreeDOS is an open source DOS-compatible operating system that you can use to play classic DOS games, run legacy business software, or develop embedded systems. Any program that works on MS-DOS should also run on FreeDOS.
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You can play your favorite DOS games on FreeDOS. And there are a lot of great classic games to play: Wolfenstein 3D, Doom, Commander Keen, Rise of the Triad, Jill of the Jungle, Duke Nukem, and many others!
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Need to recover data from an old business program? Or maybe you need to run a report from your old finance system? Just install your legacy software under FreeDOS, and you’ll be good to go!
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Many embedded systems run on DOS, although modern systems may instead run on Linux. If you support an older embedded system, you might be running DOS. And FreeDOS can fit in very well.

FreeDOS is open source software! It doesn’t cost anything to download and use FreeDOS. You can also share FreeDOS for others to enjoy! And you can view and edit our source code, because all FreeDOS programs are distributed under the GNU General Public License or a similar open source software license.

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Latest Updates

Blocek v1.7

Blocek is a text editor for DOS with Unicode support. That means unlike other DOS editors, you are not limited to your current code page. Laaca writes: "After many years I finally managed to adapt my text editor Blocek to new generation of my GUI system, Wokna32. So finaly the version 1.7 is here!" A few highlights from the changelog: + many improvements in the graphical user interface (GUI) + slovak keyboard layout + blocks of text can be selected by dragging the mouse with pressed left button + the scope of the Search or Search and Replace functions can be limited to text block only + many powerful conversion routines handling the code pages and Unicode + and more. More info and downloads at the updated Blocek website.

UPX 4.0.0 released

UPX is a free, secure, portable, extendable, high-performance executable packer for several executable formats. Programs and libraries compressed by UPX are completely self-contained and run exactly as before, with no runtime or memory penalty for most of the supported formats. UPX 4.0.0 is a bugfix release. Read the UPX 4.0.0 announcement, or download from the UPX releases page.

DOjS v1.9.0

DOjS is a JavaScript programming environment for systems running FreeDOS or any other DOS. It features an integrated editor, graphics & sound output, mouse/keyboard/joystick input and more. New in this release: + includes the source for 2 games (SpaceButton and NumGam) + added a plugin to render PDFs + can load 3DFX textures from a zip archive + updated zlib, OpenSSL, and curl + reworked file, socket, and zip API + bugfixes. Find it at DOjS on GitHub.

64-bit math on 16-bit DOS

If you've wondered how the FreeDOS VMATH program can do math operations on 64-bit numbers, using a 16-bit CPU, you'll want to read Jerome's article about Doing 64-bit math on a 16-bit system. With a little basic understanding of assembly, these functions could be scaled to do math on integers of any bit size.

Semware has released TSE as Freeware

If any of you remember Qedit, or its big brother TSE (The Semware Editor), you may be interested to know that Semware released TSE as freeware! You can download a copy at Semware's website. Note that this is the version from 1997, so it hasn’t been updated in a while. That's why the license in the readme file differs from the version displayed from inside the program. Source code is not available, but it's still great to see classic DOS software released for free so people can use it.

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