On 06/27/11 1:40 PM, Lamar Owen wrote: > On Sunday, June 26, 2011 06:53:48 AM Robert Heller wrote: >> It is also possible that the drives got 'wiped' somehow, eg they were >> on the bottom shelf when the cleaning crew came by with the floor waxing >> machine... > That would wipe more than the data; it would also wipe the embedded servo information and render the drive completely useless until someone with a servowriter for that drive rescues them..... and even then, since many drives load portions of their firmware from the disk surfaces (from reserved tracks that cannot normally be overwritten), the drive may be bricked. I might be wrong about this, but I was led to believe that the servo data is written with special heads onto the platters before the disks are even assembled. If you somehow managed to magnetically bulk erase the drive it would indeed be bricked, it wouldn't pass the initial spinnup and seek calibration tests, and would simply report 'NOT READY' and/or 'FATAL ERROR'. if the magnetic erasure was partial and just weakened a small part of the disk, you'd get servo errors attempting to go anywhere near that part of the disk. -- john r pierce N 37, W 122 santa cruz ca mid-left coast