Documentation
Compatibility & Current Status
DR DOS® 9.0 revision 265 focuses on core DOS functionality with stability and correctness as top priorities. This beta release executes standard .COM and .EXE programs and is compatible with most DOS file utilities.
Current limitations in this revision:
- FAT16 filesystem only (FAT32 support planned for future releases)
- Fixed disk support limited to C: and D: drives
- Wildcard characters limited in COPY command (work normally in other commands like DIR and DEL)
- FOR loops not supported in batch files
- SET command not available to modify environment variables
- Input redirection and append redirection not yet implemented
These limitations reflect our clean-room development approach, where we're building features methodically to ensure quality and stability. Check our release notes to see what's been added in each revision.
Frequently Asked Questions
Q: Why are you doing this?
A: DR DOS represents an important part of computing history and Gary Kildall's legacy. We believe this operating system deserves to live on, free from the legal complexities and proprietary code of the past. By creating a clean, open reimplementation, we're preserving the technical excellence of DR DOS for future generations of hackers, enthusiasts, and historians.
Q: Is this really DR DOS?
A: Yes. This raises a Ship of Theseus question - if we've replaced all the code, is it still DR DOS? We think so. We own the trademark, but more importantly, DR DOS was never just about the code. It was about Gary Kildall's vision: technical excellence, innovation, uncompromising quality. We're carrying forward that vision and that commitment to doing things right. This is really DR DOS - reborn for a new era, but true to its roots.
Q: What does "clean-room reimplementation" mean?
A: DR DOS 9.0 is built entirely from scratch with no code from previous versions. Unlike DR DOS 8, which faced significant legal challenges, our implementation contains no EDR-DOS code, no Caldera code, no Novell code, and no FreeDOS code. This is a completely new codebase, legally unencumbered, developed by studying documented DOS behavior and specifications. Clean-room development ensures we can distribute DR DOS without the legal baggage that plagued earlier versions.
Q: Can I use DR DOS for commercial purposes?
A: Beta builds are for non-commercial use only. For commercial licensing inquiries, contact sales@dr-dos.com.
Q: Will my favorite DOS software work?
A: Most .COM and .EXE programs should work, but compatibility testing is ongoing. Some programs may have issues due to current limitations (no batch files, FAT16 only, etc.). We encourage you to test and report your findings!
Q: Where can I find historical releases?
A: Previous beta builds are available in our releases archive.