Why are Error Scans using a DVD-ROM drive unreliable?

vbimport

#1

Hi,

I read that many consider PI/PIF K-Probe or Nero CD-DVD-Speed Quality scans only as being reliable when using a BURNER for them (mainly Liteons).
It was said that when u use a ROM drive, the results won’t be “meaningful”

Why is that so ?

And does that mean that they are only inconsistent (scanning the same discs
multiple times will yield different results) or are they just complete rubbish
(way too high or low error rates) ?

Could they at least be used to get a GENERAL (if not 100% exact) idea about disc quality ?

I have a Liteon SOHD-167T and would like to use it for scanning as i don’t own a Liteon burner :frowning:

Thx.
Klaas


#2

Its has been proven that the results are often just completely meaningless wether that means too high or low im not qualified to say thats for the experts but rest assured your 167t will not do for PI PIF testing.

I have a Liteon SOHD-167T and would like to use it for scanning as i don’t own a Liteon burner

I just hope you didnt buy this for PI PIF testing, because it aint going to happen

Could they at least be used to get a GENERAL (if not 100% exact) idea about disc quality ?

Run a Nero CD Speed transfer rate test and if your drive reads it without a glitch or serious drop in read speed be happy :), or open your wallet and get a DVD-RW capable of PI PIF testing.


#3

The main problem I encountered was a lack of correlation between the scans. Those who hold they work say that the errors are wrong but that you should be able to divide by some number and get a correct rate. What I found was that sometimes the errors were too high, sometimes the errors were too low and sometimes a shift in errors was not reported. I never experimented with any very bad burns as I don’t have any. Since there was no use in a scan that was not correlated to reality it made no sense to save the $30 price difference; I went with the Liteon 812S only for scanning. As one of the ROM drives I used for testing was the 167T, I would suggest you get a burner of you want to do scans and I would suggest the BenQ 1620. Even though it seems to have a number of complaints, it would add something more than a scanning drive as the burn quality is very good when it works. The Liteons have not proven to be as good as the top of the line 16X drives, NEC, Pioneer, and the like.


#4

Thx for your answers.

But even though the errors might be too low or too high shouldn’t this at least give a general impression about disc quality in order to COMPARE discs ?

Im asking this because I now scanned 3 discs to compare them:

MCC004 16x +R burnt in my NEC-3500a -----> giving me an average of 14 PI :slight_smile:
OPTODISC 4x -R in my NEC-3500a ----> average of 200 PI
OPTODISC 4x -R burnt in a crappy burner of a friend of mine (don’t know the exact model but i know its crap), slight scratches all over the disc ------> 800 PI average :frowning:

These error rates at least roughly show what had to be expected considering the quality of the used medias - don’t they ?

Still puzzled,
Klaas


#5

I have a liteon 167T

I use it for pi/pif test (also for ripping and playing).
I cannot compare my tests with others but I can compare my own burns and it is a very good unit for this.
IMO, you can trust your findings, because they are comparison, not deviation from a standard max Pi or max Pif.

You will be able to detect what are the bad discs and what are the media to avoid with your burner. That’s good enough for me.


#6

The errors would be higher than they should be and other times lower than they should be. This makes it impossible to determine quality unless you cross check with a burner. Your 167 might be consistent; mine and others were not. You could check all your current media types on your 167 and also on someone elses scanning burner and then you could at least get a very rough idea of what your reader does but you already know that. Your NEC burns flawlessly on almost all current good and better media. But the whole point of a scan when you own an NEC is to check out new media and changing firmware. Now you have to go back to another drive to see what your 167 does. The bottom line for a 3500 is the only need for scans is for subtle changes or different media. ROM scanning just doesn’t cut it for this.

But do what works for you. I am just telling how I arrived at my decisions. Obviously the ROM will give you a gross and rough reading. If this is all you want it for it should work. I would still see if you can compare scans with a burner so you can at least get a base line that is accurate. One other thing; most often PIF errors will do you in faster than PI.


#7

Obviously the ROM will give you a gross and rough reading. If this is all you want it for it should work.

Yes, I only want it to reveal some burns that went really bad (For example, if I get another batch of bad/faulty Taiyo Yudens :a )

Thx again for your help.