Is the HDD interchangeable between machines?

[superwoman]

I currently have a DirectTivo R10. Can I move its HDD over to say, a Samsung SIR-S4080, and the HDD would work correctly?

[WK-Michael]

No - it won't. The HD is the same, but the OS on the hard drive is different enough to keep it from working. You can reformat the drive with the right OS and make it work, if you have a copy of the right OS.