[Discuss] unreadable sector

[blu at nedharvey.com (Edward Ned Harvey (blu))]

Also, at the hardware level, invisible to the OS, drives reserve a certain number of blocks for transparent remapping.  So if the number of bad blocks on your drive is higher than the number the drive can cover up...  You might find that the specific addresses of bad blocks reported to your OS might actually be unpredictable, jumping around from time to time.

You might also find that sometimes you read from a block, and no error is reported, you simply get corrupt data.