This weekend I had a scare concerning my iPhoto libraries, spanning over a decade of photos, which I use in many of my projects. I had purchased a new PC over the weekend to help with some of the more CPU intensive projects (mostly related to videos) and used this as an opportunity to rearrange my computing space. This lead to an arrangement which was not fail safe, and failed in the following way.
I had a power strip which relied on an uninterrupted power being drawn from the first outlet in order to power the other outlets. A PC tower should draw enough current to keep the rest of the outlets active, so this arrangement saves energy when I’m using the PC. I had the PC hooked up, and connected my external hard drives to my macbook to browse some photos. One of the iPhoto libraries needed to be upgraded, and just as the upgrade started the PC went into sleep mode, reducing the current and cutting power to the external hard drive. At this point the macbook complained and when the power returned to the external hard drive, the macbook could not mount it. I had already mounted the hard drive on the PC without any problems, so I decided to use the PC to save the hard drive. The drive mounted successfully, so I swapped it back to the macbook, which still refused to mount. Connecting it to the PC again, I ran the check disk feature and had a quick look. The iPhoto libraries seemed to be missing, but the remaining disk space hadn’t changed, so I assumed that the files were still there, just not readable by Windows. So I hook up the hard drive once more to the macbook and try to mount the drive. It fails, but this time I can repair the disk. The disk is repaired and all the files are there. Except for the iPhoto libraries. To make matters worse the free disk space is now about 1.1TB larger, roughly the same size as all my photos. Between them, the PC and macbook had managed to delete all my iPhoto libraries, and all because the setup I had arranged was not fail safe.
I think what happened was the following: The macbook uses “special” directories to store the iPhoto libraries, which Windows can browse, but doesn’t recognise fully. When the check disk feature was used in Windows is remade the partition and no knowing what to do with these directories, put them in some kind of trash area. Then the macbook decided to repair the partition to be readable by OSX and finding this strange directory that it couldn’t read but saw was marked as trash, deleted it and freed up 1TB of space.
In principle those files are all recoverable, but that’s not necessary. I made a complete backup of everything two days previously (partly in anticipation of buying a new PC) so nothing was lost and no harm was done. It was an interesting problem and the system failed in a rather perverse manner. It’s good to have scares like these every now and then, to remind us of our single points of failure. Tom Scott has something interesting to say on that subject:
It was his video that reminded me that it’s worth spending about 24 hours of CPU time to back up our files.