The surface scan itself, as performed by Drive Genius or Tech Tool Pro, should force the data block to be remapped but they still report a bad data block had been detected found in that particular scan.
Now that I think back on my out-of-control button pushing when CCC returned the error, I remember running a surface scan with "dd" and at least starting two or three TTP scans, and every scan detected the same bad blocks, so it looks like a scan does not force remapping, or at least not in the sense we're talking about.
The number of spare data blocks on a drive is a function of the total drive capacity and engineering decisions by the manufacturer, but 50 seems to me to be a very small number of available spares.
I'm pretty much positive that the four Hitachi drives (60Gb - 250Gb...best guess) I've had, whether pre-installed or purchased, had only 5 spare blocks each, and I
know that the 500Gb WD Scorpio Blue I purchased had 40, and the (failed) 500Gb Toshiba that came with my MBP had 50; the 500Gb Apple-branded HDD with which AppleCare replaced the Toshiba has only 5 spares.
And since we're on the subject, what is the difference between a spare and any other unused block, i.e. why are spares necessary on a drive that's likely got hundreds of Mbs of empty blocks?
But from the sound of things this drive might not have lasted long enough to recover the volume structure.
It most certainly didn't, and once I was fully backed up and had an AppleCare case # there was no need to attempt heroics. (The scary part was that my backup drive had just developed
new bad blocks [...tanked in short order]; I held my breath 'til the new drive was installed and I was restored. Strange that the only drives that have gone south on me did so within days of each other.)
