Hard Drive Problems

This blog seems to be collapsing in to a tale of hardware / software problems, but I guess that these are the things that have been on my mind the last few weeks.

I had a rather strange hard drive problem recently.   It concerned a 500GB Western Digital external USB drive (one of the basic models).  I don’t use it heavily — it isn’t really part of my normal workflow, but it contains archived material which is not particularly essential although I would be sorry to lose the contents.   It is divided into two partitions — mostly for historical reasons that it itself replaced two smaller previous disks used for the same purpose.  I noticed one evening that only one of the partitions was showing up — something which I really couldn’t understand.  If OS X can see the disk it ought to be able to see both partitions not just one.   I thought that perhaps I’d unmounted one of the partitions, but a check with Disk Utility showed that OS X was only seeing the drive as a much smaller drive containing one partition.  Furthermore, it didn’t seem to be showing the files I expected within the partition that it could see.

Having bought Disk Warrior a while ago (and found it useful from time to time), I tried applying Disk Warrior to the drive.   I guess that because of the way that Disk Warrior works, it also could only see a smaller one partition drive, but if set to work it was claiming to be able to recover a lot more files.   I decided that I really didn’t want Disk Warrior to change anything at this time, because I realised that at least part of the problem was that the partition table wasn’t being read correctly — in fact it appeared that it was being read as the wrong format.

I started researching open and closed source packages that might help with resolving the problem.   Of the commercial packages “Data Rescue 3” looked like it might be a possibility but it isn’t particularly cheap.   Open source tools such as gparted seemed to largely involve building a boot CD which I wasn’t sure would actually work on the Mac, or testdisk had not yet been recompiled for Intel Macs and so needed Rosetta (which I’ve not installed since upgrading to Snow Leopard).  It being late in the evening I abandoned trying to do anything else and put it on my list of things to do some spare weekend.

Then the strange thing happened ….

The following day (or perhaps two days later), I plugged in the hard drive again and it came up perfectly as two partitions with all of the contents intact as if nothing had happened.

Clearly, something is not quite right with the drive although there has been no repeat of the problem since.  However, I did go out and buy another external drive (this time a Lacie external drive — not that I’m any great cheerleader for Lacie as I had a network drive from Lacie that failed just outside of warranty) and backed up the contents to the (twice as large Lacie).   In fact I think I’ll try to keep using the WD drive for the moment, but each time I modify it I’ll back up to the Lacie.

One of the nice things about the Mac is that rsync is built in to the OS which is a great command line tool for backing up or cloning data files.   However, to make it easier for myself (this must be a sign of old age), I downloaded a copy of arRsync (a gui front end for rsync) which saves me remembering all of the parameters needed by rsync.


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