A company called Whitehorn Ltd. has quietly been rebuilding DR-DOS from the ground up, and the project is now public enough for users to download test versions. The long-dormant DR-DOS.com website is alive again, and DR-DOS 9.0 is in development, with six preliminary releases so far this year and the current work-in-progress version at 9.0.291.
But this is not a return to the original DR-DOS that Gary Kildall's Digital Research developed in 1988 as a disk operating system for IBM PC compatibles that was the first DOS to attempt to be compatible with IBM PC DOS and MS-DOS. Instead, the person driving the revival, who posts on Reddit under the name CheeseWeezel and claims to own the trademark, has chosen something far more radical: a complete rewrite with no connection to any previous version's code.
According to the developer, they have been working on a complete clean-room reimplementation of DR DOS from scratch with no EDR-DOS code, no FreeDOS code, no Caldera code, building a totally new codebase to honour Gary Kildall's vision. This approach sidesteps the messy ownership history that has dogged DR-DOS for decades. The rationale is that DR DOS deserves to exist without the legal baggage that has plagued every version since Digital Research, making this legally unencumbered real DR DOS.
Early testing suggests the rewrite works. The developer has tested classic games including DOOM, Warcraft, SimCity, Stronghold, Commander Keen, and Oregon Trail, with most working, though there are still gaps. The new kernel is 386 code, so it won't run on any 1980s PCs such as 8086 or 80286 machines.
The decision to build from scratch rather than restore the original codebase reflects a bitter truth about DR-DOS history. EDR-DOS is the modernised kernel based on code Caldera released 30 years ago, and today it forms the core of the open source SvarDOS DOS-compatible OS. That fragmentation happened because Lineo was bought out in 2002, and some of its former managers purchased the name and formed a new company, DRDOS Inc. dba DeviceLogics, which continued to sell DR-DOS for use in embedded systems.
What makes this moment significant is that the new DR-DOS is deliberately closed source. Development of DR-DOS is happening in private, so there is no way to say whether the project may eventually open-source the code. The developer has been open about using artificial intelligence for documentation and unit testing, which marks a notable departure from how retro software projects typically operate.
The original DR-DOS was, by all accounts, genuinely good. DR DOS 5.0 was released in 1990 as the first to be sold in retail and was critically acclaimed, becoming the main rival to Microsoft's MS-DOS, which responded with MS-DOS 5.0 but released over a year later. Yet in one beta release of Windows 3.1, Microsoft included hidden code (later called the AARD code) that detected DR DOS and displayed a cryptic error message, a reminder of how Microsoft used its dominance to suppress competition.
For retro computing enthusiasts, the return of DR-DOS matters mostly as a piece of history. Compatible systems other than MS-DOS include DR-DOS from 1988, ROM-DOS from 1989, PTS-DOS from 1993, and FreeDOS from 1994, yet MS-DOS dominated the IBM PC compatible market between 1981 and 1995. As of 2026, available compatible systems are FreeDOS, ROM-DOS, PTS-DOS, RxDOS and REAL/32, with some computer manufacturers including Dell and HP selling computers with FreeDOS as an OEM operating system.
Whether Whitehorn's approach succeeds depends on what happens next. If the developer eventually open-sources the code under a genuine free licence, DR-DOS could finally escape the legal tangle that has defined it since Gary Kildall's company fell into the Microsoft shadow. If it remains proprietary, it will be an interesting curiosity but little more. For now, the project sits in that uncertain middle ground: publicly visible but privately developed, legally clean but not open. The vision is clear. The execution remains to be seen.