Mac Mini drive problems but SMART verified: bad hard drive or controller?

Question

I have a 3-year-old Intel Mac Mini (EDIT: pretty sure it's the 1.66 GHz Core Duo T2300) at home. About a month ago, it stopped booting from the hard drive (internal, SATA, 80GB). I tried booting from the Install Disc to repair the filesystem but Disk Utility was unable to do so ("invalid node structure"). I was also unable to use the hard drive in the Terminal from the Install Disc nor from an Ubuntu boot CD ("DRDY err"). I could see the contents of some directories, but others would give an error and I would get failures when trying to copy files. At this point I was sure the filesystem was hosed and I'd want to reformat at least.

DiskWarrior was able to let me retrieve the data files I was interested in, which are now copied to an external hard drive, but it reported a high number of problems ("speed reduced by disk malfunction" count was over 2000) when in the process of trying to rebuild the directory for the drive. It also would not let me use the rebuilt directory to replace the one on the drive; it claimed the disk errors prevented recovery in this way.

Under normal circumstances I would now assume that the drive itself was going bad: DiskWarrior's "disk malfunction" error above is supposed to imply hardware problems. My initial plan was to buy a replacement for the internal 2.5" drive. However: Disk Utility, command-line tools and DiskWarrior had reported all along that the SMART status of the drive was okay/Verified. So I'm now worried that the drive hardware is actually fine, and that the problems were due to a disk controller that has gone "bad" somehow. If this is the case, I'll probably just replace the whole computer.

Any advice on how I can tell what is to blame? I don't have a lot of extra hardware sitting around, so I don't have the option of simply dropping the drive in another machine or popping another hard drive inside the Mini.

Answer 1

I think that Intel Mac Minis use SATA for both the hard drive and the optical drive. (Sadly I have be unable to find a clear statement that this is true. But I did find a video of someone removing the optical drive and the connector looked like SATA to me).

My speculation is that if you can use the optical drive with no problems then it is less likely to be a controller problem. If as I suspect both drives use the same SATA controller a bad controller would imply both would not work. Also as probabilities go, the hard drive is certainly more likely to fail than the controller chip.

Sadly the only way I can think of to further isolate the failure is to remove the drive and test it in a known good system.

Note that it doesn't have to be a Mac system. Any system where you can install a SATA drive would suffice. In fact, a PC would be preferred because then you could certainly boot and run the manufacturer's diagnostics against the drive.

Another approach which might work is to remove the drive and mount it in an external USB or Firewire enclosure. You could then boot from your install media and see if you still see errors accessing the drive. This is not really IMO a good alternative, but it would at least let you see how the drive behaves in a different context.

At the very least though you should try running the Apple Hardware Test diagnostics from your install disc. (ref: Intel-based Macs: Using Apple Hardware Test) As tests go, the AHT is not all the impressive or informative. But it is better than nothing. And you can do it with the hardware you have.