OSDev.org

I don't think anyone is claiming that emulators should be a *replacement* for real hardware.

Emulators make progress faster by allowing the developers to debug issues much faster. When you test on real hardware in the early stages of the kernel (when there is inadequate/non-existent debugging code/traps), it is extremely time consuming to track down a bug that causes a triple-fault. In an emulator, you can freeze the virtual environment and get register dumps, memory dumps, single-stepping, and disassembly's of target areas. Also, if it works in an emulator well, then chances are it will work on real hardware, but like real hardware, they have to follow sketchy (non-)standards and such that need to be compensated for in the OS code.

bottom line: make the OS run in *all* environments.

Obviously emulators have their uses for debugging, but in addition to this, testing in an emulator / VM is just as useful as testing on an additional PC.

If it works on real hardware, but not an emulator, that tells you just as much as the other way around. Most people only have limited hardware resources to test on. An emulator / VM gives you additional variety. Emulators have bugs, but so does hardware. IMO, get your OS working on both.

Cheers,
Adam

[Edit: E got there first ]