Inconsistent result for ScanDisc

vbimport

#1

Hi,

I have a question which i couldnt google for an answer.
Really appreciate if anyone can help me out on this.

I burned a BD-R and perform mulitple ScanDisc using same and different version of Nero DiscSpeed on my LG GGW-H20L.
Every scan would end up with a few Damaged (Yellow) squares.
But the square do vary in position.
According to the manual, Yellow means Damage sector that can still be read using the drive’s error correction.

Question is, are the Yellow sectors really damaged ?
I dont think so because if the sector is really damaged,
the same square should always show up rite ?
If not damaged, then what is causing this false alarm ?

Observe this on made-in-Taiwan Verbatim BD-R,
while the made-in-japan TDK BD-R scan looks fine. (all green)

Thanks.


#2

Damaged (yellow) sectors in a ScanDisc Read Test (not the ScanDisc C1/C2 - PI/PO Test) usually(*) means that the drive had to re-read a sector because the first attempt failed.

This means that the sector can sometimes be read, and it also means that the drive can sometimes read the sector on the first attempt, which will show as a green sector.

For this reason you can expect that (some) yellow sectors will move around, appear, or disappear between scans.

Bad (red) sectors are much more likely to stay in the same place, since they indicate that the drive was unable to read the sector after multiple attempts.

(*) For some drives and when reading CD media I believe it can also mean that a C2 error was flagged.


#3

Hi DragMester,

Thanks for the response.
That makes sense.

In that case, generally speaking,
Is this result consider as a Good Burn ?
Or will this result increase the chance of the disc becoming unreadable after sometime?

I manage to copy the data back to my hdd without problem.
But it took 3hrs.
Is this normal considering it contain 30,000 small files?

Thanks


#4

[QUOTE=albetan;2470811]In that case, generally speaking,
Is this result consider as a Good Burn ?[/QUOTE] Not really, there shouldn’t be any damaged sectors in a good burn (provided that the drive is working and scanning in a reliable way).

Or will this result increase the chance of the disc becoming unreadable after sometime?
That’s impossible to predict, but the disc won’t become more easily readable than it is right now.

I manage to copy the data back to my hdd without problem.
But it took 3hrs.
Is this normal considering it contain 30,000 small files?
Copying a lot of small files off an optical disc in non-sequential order can be a very slow process; you can estimate the time as at least the time it takes to read the whole disc sequentially plus the number of files (30,000) times the average access/seek time (let’s say 0.15 seconds) which is about 75 minutes plus the time to read the disc sequentially.

So 3 hours sounds a bit on the high side but it’s not out of the question, that this is what it would normally take on your drive.

When you want to extract an optical disc full of small files to your harddrive, it’s faster to use a program that reads the disc sequentially instead of in folder/file alphanumeric order; this avoids unnecessary seeks. You can use e.g. IsoBuster for such a sequential extraction.


#5

Hi DrageMester, appreciate the reply. :clap: