How can I check whether there are any bad sectors on a USB Hard Disk Drive?
It's sometimes inappropriate to use the automatic sector relocation capabilities of a drive, so the question raised by ohho becomes distinctive:
If there's a defective sector, then you'll either:
– consider this before performing any action that may cause relocation (or remapping or sparing, or whatever you call it).
Whilst SpinRite 6 is not for Macs, a 2003 page for version 5 is enlightening:
Note the section about auto-relocation and the associated risk of dataloss.
SpinRite aside, fast forward a decade from 2003 to 2013:
To the question here …
How to check whether there is bad sector on a USB harddisk on OS X?
For Mac – for OS X – I don't know of anything as capable and careful as SpinRite (nothing to disable auto-relocation).
So, as things stand: to verify the sectors of a disk on USB with OS X, we're probably limited to using utilities that may cause relocation. I can't estimate the degree of risk of associated dataloss, but if that risk is acceptable then I should steer first towards:
Hint: what's under related question (1) is more immediately user-friendly.
The OS alone can not use S.M.A.R.T. technologies on drives that are external on buses such as USB 2.0 and FireWire.
Elsewhere there's a wealth of information ( and misunderstanding ;) so I'll focus this part of the answer on just one point:
OS X SAT SMART Driver
kasbert / OS-X-SAT-SMART-Driver on GitHub:
If you try this KEXT with Lion then – as with any third party kernel extension – proceed with caution.
Only way to really know is to write to each sector and read it back to see if you get the same thing back, checking for errors on the way.
Under Windows, I believe if you invoke
This Superuser answer suggests that SpinRite 6 may also do the same thing but I haven't tested.
Depending on the filesystem on the drive you could run
This would check an FAT FS. Maybe that's what you want? Possible commands are: