KProbe Scans vary - same disc?

vbimport

#1

why is it that the 2nd, 3rd, 4th … kprobe scan on the same DvD will differ, radically in many cases, from the 1st scan ? surely they shoud be the same, no ?


#2

no

the disc will scan differently every time you mount although the total pif should be about the same.

also you live in aus(hot hot hot), if you scan the disc directly after burning and it is still hot, then if you rescan it later when its cooled down then this can make a big difference.


#3

that’s interesting stuff. thanx for that.


#4

The heat of the drive can also affect the scans (for instance, if the PC has been on for a while).


#5

In general the average and total PIF should be no more than two times (max) from scan to scan. If it is more, suspect the drive for being unreliable or partially faulty.

However, some drives just read that way by default (i.e. the number of errors they make in reading can vary an order of magnitude or more).

IMHO, such drives are not very useful for digital error rate scanning.

regards,
halcyon


#6

Ok, you said that it would make a difference, but you did not mention which one would be the preferred difference… I take it scanning a ‘cooler’ disk is preferable to scanning a warm one?

I always scan my disks immediately after a burn, and yes, they are still warm. I’ve often wondered wether or not this would have a negative impact as to the outcome of the scans.

I’d be interested in hearing from those who have an opinion on this.

Thanks,

-Behr


#7

if first noticed it last summer, i had just burned then scanned a disc and the scan wasen`t to plesent, when i removed the disc it was quite hot (not warm but a lot hotter than usual, well it is the uk) after an hour or so i rescanned the disc and got a far better scan more like what i was getting from that batch of media.


#8

so if i place a disc in the freezer for an hour, then scan it, the scan will be near to the best scan possible for that particular disc ?


#9

You may prefer to put your burner in the freezer. :wink:

Actually, if you always scan after burning- continue to do so and you’ll have comparable results (without the extra variable of repeated scans). I’ve found rather divergent results- on one disk, the PI Sum 8 value went up by a factor of 5 after 3 scans - but normally it doesn’t vary much.

G


#10

5 to 8 ! dude, my PI max results are going from 24 to 345 !


#11

Some discs will consistantly give inconsistant scan results. These discs are of a marginal quality and should be considered failures. A good disc should always scan well, baring other issues like extreme heat or faulty drive.

Discs, especially cheap ones, can have a range of issues that cause inconsistant reading problems, and not all the causes are directly related to “burn quality”. On such media, lowering burn speed may resolve issues, or may not.