2 ms·
If you're trying to read with a smaller block size than the media's native block size, then you'll make two or more attempts to read data from each corrupted bl
by wtallis 6y ago
If you're trying to read with a smaller block size than the media's native block size, then you'll make two or more attempts to read data from each corrupted block that's unrecoverable—making your recovery process much longer.
If you try to read with a larger block size than the media's native block size, you'll get errors for chunks of that size even when part of the data may have been recoverable.
The above is true whether or not the OS has access to the media's raw ECC data.
- compsciphd 6y agoit's not just that. Reading scratched blocks means sometimes it might work, sometimes it might not. lets say 1% of the time you get a good read. If the ECC block is 16k and you always read in 16k blocks, if you get that 1% magic time that the read succeeds, you got the whole block. If however, you read 2k blocks, you need to have the same luck 8x times. From experience of recovering bad DVDs and BRs, there were discs I had to pass through 100+ times to get a valid read on all blocks. This is also because, the underlying hardware will always do a full ecc block read (only way for it to determine that it read the block correctly, to read whole block and verify it), so any smaller reads are pointless.