[mikeash]

How is that a major concern for data centers? I thought drives typically stayed in a data center machine until they died too. And even if you were swapping them around, you'd only have a requirement for a certain newer OS, not the exact same physical hardware.

[nullymcnull]

Drives ideally stay in a server machines until they die in a data center, and maybe even typically.. but MS could hardly only take into consideration what was 'typical' when it comes to things like this. And he's writing about engineering decisions made over 15 years ago here - around 1998 it certainly was more common to move hard drives around between machines. I probably did this at least 100 times just working for one company for a couple of years.

That said, it would still be one hell of a weird edge case to need to take a drive out of an x86 Win2k server, drop it into an Alpha Win2k server, and still care about its contents (vs wiping it for a newly provisioned host). But when you are writing OS filesystems, you have to care about edge cases... especially edge cases that may apply to thousands of racks worth of machines.

[rodgerd]

> it would still be one hell of a weird edge case to need to take a drive out of an x86 Win2k server, drop it into an Alpha Win2k server

I can imagine the reverse being more common though - I worked at a shop around that time where we had a handful of very expensive Alpha NT 4 (and VMS and...) boxes, and a lot of x86 NT boxes. I could imagine the magic smoke being let out of an Alpha and having to drop the drive into an x86 box for data recovery.

[mikeash]

My point is that the way drives are typically used means that the original decision doesn't have to be set in stone. A new format could be added, one which requires a recent version of Windows to read and which therefore can take advantage of recent hardware, and that would work just fine.