Not 100% sure on this, but it's probably a standard Mac OS error code. Lists are here:
The second link indicates -84 means "track failed to verify". So I'm guessing it writes the track, then reads it to check that it wrote successfully, and reads back something different from what it wrote. My guess is that it means a bad disk, but if you're seeing a ton of them, maybe a bad drive?
I noticed -84 also means "firstDskErr", but it appears that's just an identifier they used to show the range of error numbers that apply to disks (-64 is lastDskErr) so I would ignore that one.
Can't locate what -2 means...it doesn't appear in any lists I can find.
Edit: Found a header file that indicates -2 means "invalid queue element" -- no idea on that one. It doesn't appear to specifically relate to disks.
The second link indicates -84 means "track failed to verify". So I'm guessing it writes the track, then reads it to check that it wrote successfully, and reads back something different from what it wrote. My guess is that it means a bad disk, but if you're seeing a ton of them, maybe a bad drive?
I noticed -84 also means "firstDskErr", but it appears that's just an identifier they used to show the range of error numbers that apply to disks (-64 is lastDskErr) so I would ignore that one.
Can't locate what -2 means...it doesn't appear in any lists I can find.
Edit: Found a header file that indicates -2 means "invalid queue element" -- no idea on that one. It doesn't appear to specifically relate to disks.