Many thanks for your attention, and I like your frankness. Now some meaningful discussions are possible.

I did not say that the authors are young kids, which mean people under 20 in my definition. In my country “young people” includes those in their thirties. I have read many of Spath’s posts at this forum and elsewhere, so I know that he is more knowledgeable than I in many aspects. IMO, however, he is somewhat biased in certain viewpoints; I know that no person is completely unbiased. In this article the conclusions stretch too far from the data, being not acceptable in scientific papers. I know that the target audience of the article is not professionals, but it is not so difficult for the article to be scientifically sound.

To my knowledge suitability of consumer drives for writing quality testing is not as simple as yes or no. I shall elaborate on this point in some detail later.

When you talk PI-Sum 8 only, even a Million-$-CATS system with a calibrated Pulsetec drive isn't suited for general or universal determination of the thing called 'writing quality' (which is far more complex than just counting PI errors).

The problem is the missing absolute reference when 'scanning' for casual errors so IMO, the real advantage of a calibrated measuring system like CATS is the fact that you are able to assess mechanical and geometrical characteristics of any blank disc ... additionally, jitter measurements are very useful, too (especially when it comes to high-speed readability).

By using K-Probe, PTP and/or CD/DVD Speed, one can achieve one goal only ... these programs will tell you how your drive reads the disc ... nothing more, nothing less. BTW, CATS PIE results will tell you how a Pulsetec drive reads the discs which is somewhat pointless since there are no Pulsetec drives available for the Joe-Average customer.

I think home scanning is a suitable real-life test since most people will use their writing device for reading back anyway (especially for data discs).

Additionally, most reasonably-priced standalone DVD players are equipped with a standard ATAPI DVD-ROM these days (or with a drive that is based on a standard unit), so you can, to a certain degree, extend your home-made scans to assess playability of video DVD's as well (regarding the fact that differences in reading capabilities between different DVD-ROM drives used in standalone players are not that huge - a totally substandard disc will be a totally substandard disc on almost any drive).

But if you question the validity of home scanning, feel free to send every burned disc to Audiodev, Malmö ...

I agree with most of what you said above, but let me inform you the followings:

According to CDRInfo, PIE/PIF error scan profiles and values given by LiteOn 167T and by Plextor 712 at max or 8X speed are quite close to those by CATS for MCC and CMC discs. But since few if any PIE/PIF scan data by CATS are available to the public, they are of use to only very few people.

Usually DVD-ROM drives are pickier than most DVD recorders, so a disc considered to be good by scanning with such a recorder sometimes will not play flawlessly by these DVD players .

I am not sure about what you intended to convey. Have I said that home scanning is totally unreliable?

I do own a 712A and a 167T and these drives did never ever produce comparable results (in both numbers and trends) at all (using PTP and CD/DVD Speed, that is) at any speed.

167T error numbers are way off and the mediatek chipset 'bug' makes this drive a very unreliable scanner IMO.

I did notice that there are often similarities in trends between a CATS system and a PTP/PXScan test, though ...

Your observations are very valuable. I do not own a Plextor 712, but I shall get a 716 soon, for I am interested in its unique TA test. Would you talk more about your study of the comparisons between Plextor 712 and CATS, since CDRInfo used discs from only two makers in its investigations?
I did not talk about my experience with LiteOn 167T, because I had intended to do so later. Among the 6 discs from 5 makers I have tested, PIF trends and rates reported by CATS and by LiteOn are quite close. As to PIE, the trends are similar at least to my satisfaction; the rates are close for Verbatim (MCC 002) discs, but are higher by LiteOn for discs from TY (YUDEN T02), Optodisc (R02), Mitsubishi (MKM A02) and Philips (041), and lower for Ricoh (RICOHJPN 02). Although I do not have discs from many makers, these data have provided evidence to indicate that CDRInfo's results are grossly valid, but too simplified. Sometimes the singular spike by LiteOn drives is annoying, but I can tolerate it or remove it by KProbe if desired.

One should keep using 167T and Plextor 712/716 if they work well for scanning. I don't have any of them so I'll keep working with BenQ and Lite-On DVD writers.

As long as those CATS and other high-name devices cost so professionally, BenQ DW1620 and DW1640 are my best recommendations.

The jitter detected with BENQ drives is generally higher than that with CATS by ca. 2% or less, so I consider jitter returned by BENQ is indicative of the disc writing quality, despite that the curves sometimes differ in trends. On the other hand, I observed that there is no correlation between PIE/PIF and jitter when the latter reported by BENQ 822A is <24%. It is probable that BENQ 1620 and 1640 behave similarly. Therefore I have reservation about the PIE/PIF measured with BENQ drives. IMO, at least values other than 280 SUM8/4 SUM1 for PIE/PIF should be used as index. It is also possible that some errors will be missed, so file test needs to be done to check data readability.

Although jitter cannot be determined with LiteOn DVD writers, the 16xx models may behave similar to BENQ drives to some degree.

On my 1620, PIE/PIF will rise sky-high @ 8x scanning speed once the displayed jitter values exceed 13-14 % ...

As I do not own a BENQ 1620, my observations below are based on scans in the cyberspace I have spent some time to read before writing this post:

No correlation between PIE/PIF and jitter can be found when jitter increases transiently, though sometimes there are concurrent changes.

When jitters fluctuate more smoothly and are below 15%, the relation between PIE/PIF rate and jitter level is variable. The drive often aborts scanning when jitter is around 15%, so it is difficult to define the correlation clearly. On the basis of such data, I would say that the jitter tolerance of BENQ 1620 is about 15%. I was incorrect in assuming that BENQ 1620 behaves similar to 822A in this aspect.

The jitter tolerance of CATS is about 11% according to my estimation. Hence different criterion still ought to be used when interpreting PIE/PIF rates given by BENQ drives, and it is better to use jitter as the indicator for writing quality.

I was talking gliding average jitter, not small jitter peaks ... just to clarify

Did you think that I talked only about brief jitter peaks in my post above? Maybe I should have written “When jitter levels do not change rapidly and are below 15%, the relation between PIE/PIF rate and jitter level is variable.” instead of “When jitters fluctuate more smoothly and are below 15%, the relation between PIE/PIF rate and jitter level is variable.” I am annoyed that BENQ 1620 often aborts scanning when jitter approaches 15%, similar to the cases of disc #5 and 6 in the article we have been discussing. Although I do not own a BENQ 1620, I have a Nu 061, which also uses chipset from Philips. With a jitter tolerance of 15% according to C’t, the PIE rate measured with Nu 061 increases roughly proportional to jitter when the latter exceeds 15%, and the PIF rate reaches 1664 for Sum8 when jitter is close to 18%. So it is likely that BENQ 1620 would behave similarly if it can handle high jitter levels.

The following statement on the page related to disc #5...

"there are only 1664 columns in 8 ECC blocks"

Seemingly should read 'there are only 1664 rows in 8 ECC blocks'... so as not to confuse the ECMA standards use of the words 'rows' and 'columns' when they speak of ECC blocks.

Not quite on topic.

Some of you maybe already read it, but cdrinfo.com published new tests with DaTARIUS analyzer equipment on DVD media burned by some of the most common burners.

(Posted this here because I don't see any reason to create a new thread.)