by Andrey Kuznetcov
07/19/2005 | 01:51 PM
I bet many of you have faced the situation at least once when you borrow a CD disc from a friend of yours and it turns out badly scratched. Or even worse, you get a valuable CD back and your system simply refuses to read it. Well, touch wood if you haven’t, but I am definitely not the lucky one here.
Usually if there is a problem with the system being unable to read the disc, you usually should blame the wearing out of the disc surface, which is inevitable if you are using it a lot. Some surface damage may also result from careless disc handling or simply from bad luck. The optical media manufacturers do their best to find a panacea against these problems by creating special types of optical discs, which should be robust to work surface damages like that.
Today we decided to pay special attention to the new TDK products: DVD+R/DVD-R discs. To make the overall picture complete we also added a few DVD-RW solutions from TDK and Verbatim that are certified for 4x write speed. Since we haven’t yet tested these discs for writing quality and performance characteristics, we decided it would be a good idea to combine the regular DVD media testing with the indepth disc quality investigation.
For DVD burning quality tests we used Sony DW-Q28A drive (KYS1 version), which proved pretty successful in our previous test session, and LiteOn SHOW-1653S (CS09 version).
During our test session we burned MPEG4 movies and individual files onto the discs, so that we could fill them almost up to the maximum of their supported capacity.
The tests were run in the following system:
The optical drives were connected as Master devices to the second IDE channel.
During our tests we used the following benchmarking software:
The discs were burned at the maximum supported speed claimed by the manufacturer. The burning quality was estimated by the drives themselves. The discs were scanned at the constant speed of 4x.
Before getting to the actual tests, we would like to say a few words about the criteria we are going to use for burning quality evaluation and analysis. We will base our statements on the ECMA standards for DVD-R/RW and DVD+R/RW media, which say that the total number of PI errors in 8 subsequent ECC blocks should not exceed 280. This is the first limiting parameter that we will take into account. Besides, any ECC block should not contain more than four irrecoverable PI errors (an irrecoverable PI error is referred to as PI failure by CD-DVD Speed utility, which we will also take into consideration).
Thus, we consider those DVD discs as quality media from the formal standpoint that have no more than 280 PI errors per each 8 ECC blocks and no more than 4 PI failures per a single ECC block. Besides the purely formal approach to DVD running quality evaluation, it also makes a lot of sense to pay due attention to the surface-scan graphs showing at the distribution and type of errors discovered on the disc surface. If the maximum number of errors per disk is equal, then we should regard those cases as the most dangerous when the maximum number of errors exceeds the limits over the entire disc surface rather than in one individual case.
We haven’t yet paid that much attention to different way of reaching higher mechanical stability and sturdiness of the disc work surface against external influences. Once TDK started offering their media promising over 100 times better anti-scratch protection, we decided to take a closer look at these solutions and find out, how they managed to achieve that and what the other benefits of this technology are.
So, let’s start with the data we managed to retrieve from TDK’s corporate web-site. As for the technological side of the story, they didn’t offer that much of the detail there, unfortunately. We can only assume that the above mentioned effect is achieved due to special disk surfacing, which chemical contents is TDK’s corporate secret. Of course, the manufacturer paid special attention to the physical scratches, to be more exact, to the external factor provoking these potential scratches. These types of damage are the primary cause for concern for the majority of users, unlike dust and fingerprints. The latter can be removed from the disc surface with special sprays and cloths, while the mechanical damages can hardly be eliminated.
Every scratch on the disc surface is potentially hazardous for the entire medium, because it may result into its complete inoperativeness. Sometimes, even if only one single file from the game or software package cannot be read, the entire disc appears useless and the money yo9u spent on it gets simply wasted. The scratches going along the track lines are usually the most dangerous. In other words, there is always a possibility that the hardware error correction mechanism will fail to help.
The DVD-R and DVD+R media from TDK with ScratchProof DVD technology support promise to reduce the possibility of scratching significantly due to special hard surface coating. As we have already mentioned above, the manufacturer claims that their discs are 100 times more resistant against physical scratches compared with the standard DVD discs.
However, the higher surface robustness is not the only positive effect from the new work surface coating. It is also highly anti-static. The superficial charge of the new DVD media drops down much faster than that of their predecessors. And it means that the discs will accumulate less dust and will be better read by the optical drives. Moreover, all ScratchProof DVD discs allow reducing the negative effect from fingerprints, because the physical peculiarities of the protective surface coating prevent it from taking on most of the oil from your fingers once you touch the disk. And this definitely reduces the amount of dust and dirt sticking to these spots.
Note that DVD-R and DVD+R from TDK that we are going to take about today, they also offer DVD-RW 2x discs with ScratchProof technology.
Sony DW-Q28A
Now that we have already talked about the major advantages of the ScratchProof DVD discs family in general, let’s move on to discussing their burning quality. We will start with the DVD-R discs. The diagram with the DVD disc burning quality results created for the Sony DW-Q28A drive looks impeccable. Very moderate amount of errors of both types as well as their even distribution over the surface of the disc indicate that this is an excellent medium.
LiteOn SHOW-1653S
In case of a different optical drive the situation changes completely. The results here suggest that this is hardly a high-quality disc, because the maximum amount of PIE and PIF errors exceeded the allowed maximum set by the ECMA standards. Although, if we take a closer look at the diagram, we will notice that these unacceptable results exist only in one single spot of the disc, while everywhere else, the error rates are within the allowed limits. In other words, it may all be not that bad in the long run.
Sony DW-Q28A
Now let’s take a look at the results obtained for the other ScratchProof solution from the DVD+R standard. The screenshot taken for the disc burnt with the Sony DW-Q28A drive we see almost an ideal picture. Very low level of both types of errors, very small number of them overall and very even distribution of these errors over the disc surface. This is where our positive evaluation comes from.
LiteOn SHOW-1653S
In case of the DVD+R disc burnt with the second drive from LiteOn, the situation is again far from beautiful. We can see that the maximum level of PI failures has been exceeded in two surface areas, while the rest of disc looks quite OK from this point of view. To tell the truth, we get the impression that these issues are most likely coming from the drive itself, namely from its firmware version.
Sony DW-Q28A
The surface scan screenshot taken from the DVD-RW disc burnt with a Sony DW-Q28A drive leaves us no doubts about the excellent disc quality. The only issue worth pointing out here is the increasing number of errors in the end of the disc. However, even despite this increase the rates are still within the allowed ECMA limits.
LiteOn SHOW-1653S
The results obtained with the LiteOn SHOW-1653S drive are definitely not so appealing. The number of errors of both types has been exceeded noticeably. Again, we tend to blame the drive’s firmware for that.
Sony DW-Q28A
This is going to be the last disc we will discuss today.
As in all the previous cases the results obtained with the Sony drive do not leave us any causes for concern. The PIE and PIF error rates are much lower than the allowed maximums, as to ECMA. All the errors are spread evenly over the disc surface, with a little bit higher error density in the end of the disc.
LiteOn SHOW-1653S
The disc surface scans are really impressive and indicate excellent disc quality. The maximum number of 9 PI Failures was recorded only once, and hence should be regarded as an exception, rather than a rule.
The release of TDK ScratchProof DVD media is great news for those users who need DVD discs capable of standing high workloads and better protected against accidental physical damages in case of careless or improper usage. Actually, it is still pretty hard to check how true the manufacturer’s statement about “100 times better anti-scratch protection” of the new discs is, but believe that TDK would hardly make a statement like that without really good grounds. As far as quality of these discs is concerned, there is nothing we can complain about: all the error rates are within the allowed limits. If you feel comfortable with the 8x writing speed, then these discs may be a pretty good choice for you.
The DVD-RW 4x discs from TDK and Verbatim (MCC) also showed quite acceptable results. It is especially true for the latter. The less impressive DVD burning quality results were obtained on the older LiteOn SHOW-1653S drive, and are most likely to result from the drive’s firmware version. Therefore, we assume that the new firmware for this drive may help improve the situation. The side by side comparison of the results obtained on the two different drives, Sony and LiteOn, gives us the right to hope so.
Of course, the best results can only be obtained if you have the most optimal combination of the hardware components, so we wish you good luck in achieving that. The new TDK discs should definitely make this task a lot easier now.