The G4 Mac Mini was slowing down. The slow down had been gradual over a period of days, but now it was becoming unusable. It wasn't one or just a handful of applications, everything was slow, including the request to shut down and restart. Eventually, it shut down and began the start up process. It got as far as showing the Apple logo, then stopped. No spinning animation, no disk drive activity, nothing. Game over, man, game over.
The Mini is one of two Macs in the house, and unofficially my wife's computer. Unofficially because she spends more time on her work laptop than her personal Mac. Still, it had important documents and files that had yet to be backed up. After several retries, it was clear that something was very wrong and that the system could not recover.
I had not had experienced a Mac emergency like this before.
I considered trying to boot from the system DVD, but instead decided to boot from a Kanguru external hard disk I had purchased earlier in the year. The Kanguru is a firewire disk I had used to back up my G4 iBook. It draws power directly from the firewire port so it doesn't clutter up your work space. It had a copy of Tiger (10.4) on it and I was able to boot to the external disk using the magic boot key sequence Cmd-Opt-Shift-Delete. I appreciate this feature -- one not as easy to achieve with other operating systems.
After booting up, I was able to make a backup copy (as root) of the Documents, Pictures, and Music folders in my wife's home directory. (note: if a home directory is encrypted with FileVault, the entire home directory will appear as a single encrypted file.)
With a safe copy of the data, I was ready to attempt a disk repair. I opened the Disk Utility, selected the Mac Mini hard disk, and tried to repair it. It didn't get very far in the process until I was notified that the disk could not be repaired due to an "invalid sibling link". Not too cool.
Googling led to a number of forums and tech support articles, leading me to believe the disk was starting to fail, or some system files were corrupted beyond repair. One blog suggested trying the fsck_hfs command line program. "Fsck" is BSD code for file system check. I followed the suggestion, manually unmounted the disk and ran fsck_hfs. Unfortuantely, it failed as well with no additional error messages.
I realized the only hope I had was to reload OS X on it from scratch. I shut down and booted from the system DVD, erased the existing partition, reformatted, and started a fresh install. No errors were displayed during the reformat or the install.
Once the system was reinstalled, I created an account for my wife, attached the firewire drive and copied the Documents, Pictures, and Music folders back to the Mini. I also changed the ownership of all files and directories I had restored (using chown) to match my wife's account.
Then, I spent a small amount of time installing a few critical third party applications.
All documents and pictures seemed to be in place and intact. That is, until I tried to open one of the restored music files with iTunes. iTunes complained that the iTunes library has been created by a newer version and refused to open.
I immediately started System Preferences and ran Software Update. A lot of patches have been released for Tiger, and it took about 45 minutes and a couple of reboots to get up to date. The time involved is not bad compared to reloading Windows or an 18 month old distribution of Linux. Both require a similar number of patches to get up to date.
With the system updated, iTunes was able to open and play everything in the music library.
With the crisis averted, I am left to wonder what went wrong. I have two hypothesis:
One, the disk lost a few critical sectors, ravaging system files and preventing it from booting. If disk damage was the cause, it wasn't bad enough to crash the entire disk. Maybe those sectors were marked bad during the reformat, and life goes on without them.
Two, my two year old son found the right combination of keystrokes and mouse clicks to rename, delete, or damage some system files. The Finder doesn't let a normal user rename or delete system files, so despite his penchant for destruction, I doubt he was able to break the system. He was able to load up about 80 (mostly calendar) widgets on the Dashboard. That incident slowed the system down, but I was able to recover cleanly.
Whatever the cause, I feel a little more Mac battle tested having resurrected the Mini.