Quote Originally Posted by Ao1 View Post
Factory shipped defects in NAND are perfectly normal and are not an issue as long as they are within certain parameters. With IMF NAND I believe an invalid block is one that contains one or more bad bits. Out of 4,096 blocks at least 3,936 must be available throughout the endurance life of the product. [Speculation; maybe that is why the MWI appears so conservative] Invalid blocks are identified following worst case condition testing in the factory and are marked 00h, which enables a bad block table to be created so that the controller can avoid using them.
I understand that it's normal, which is why I'm wondering whether Intel and Micron (possibly others) either have 1) some process to zero out factory identified bad blocks in SMART data OR 2) really good NAND processes that just generate 100% good blocks (or a process to effectively bin NAND). Only my Indilinx drives have bad blocks now, and that's because they came from the factory like that, and so I have to wonder which scenario it is.