CD Doctor Results?

[HeartBurn]

http://www.icehouse.net/jaymom/TestPage.html

Can someone take a look at this page of mine and tell me what I'm looking at please. I ran scandisk on both CD's as well as CD Doctor. Photo number 1 and 3 is of a data CD and 2 and 4 is of an audio CD. I have a LTR32123S burner. I hope this is comming out right. I'm trying to learn how to read these images. Thank you.

Heartburn

[CDRecorder]

In the pictures with CD Doctor, you are seeing a display of the C1 errors seen on the CDs you have burned. C1 errors are correctable errors. The level of C1 errors in the first photo is very good. The result in photo 2 is not quite as good, but it is still fine and won't prevent the disc from being read anywhere. In the Scandisc pictures, you are seeing a display of C2 errors. Some C2 errors are correctable and others are not, but you shouldn't be seeing any C2 errors. The green squares mean that there aren't any C2 errors. CD Doctor is also showing that there aren't any C2 errors, which it shows in red.

In any case, your disc scans look good!

[dolphinius_rex]

With all due respect to LiteONGuy, I totally disagree with his assesment of scans 1 and 3.

First of all, scans 1 and 3 are probably of the same CD, and yes, the C1 error rate *IS* good...but it appears that there are MANY unreadable sectors (shown on both scans 1 and 3). This means that the CDs are pretty much toast, especially the second half of the disc which appears to have the most unreadable blocks.

Scans 2 and 4 may be fine, although I suspect there may be problems with them as well, since Scan disc had to slow down to 0.1x when reading them, and it wouldn't do this unless it was having problems reading the disc.

I have 2 questions. What speed were you testing with? and what kind of media did you use for these tests?

[CDRecorder]

Dolphinius Rex:

I could be wrong, but I thought Scandisk usually showed red blocks for the unreadable sectors. I have seen the "missing" sectors when scanning a multisession disc. If those sectors aren't due to multisession, it would certainly mean that something is wrong with the disk.

Also, I tried using Scandisc on an audio disc, and it reported 0.0x even though it was reading the disc at full speed. My theory of the reason for this is that, when HeartBurn ran the test, he did the "file scan". As you know, Windows sees the "tracks" on the disc as tiny files. It seems to me that Scandisc reads the files so quickly that it doesn't have a chance to figure out how fast it's really reading. It doesn't seem to report speed when running the disc scan.

Please let me know if I am wrong, though!

[Inertia]

dolphinius_rex, I think that LiteOnGuy's assessment of the tests are valid.

There are no unreadable errors displayed on any of the graphs. The C1 errors, while not the best possible, are of a level for acceptable qualitiy. There are no C2 errors at all, which is good.

In CD Speed ScanDisk, if there were any C2 errors uncorrectable at that level, they would appear as yellow blocks. A red block indicates an error so severe that it is uncorrectable and unreadable by any means.

I would accept the theory of a multisession disc as a possible explanation for seemingly unused sectors in the data test. First, there is approximately 51 minutes of data space used on the CDR, which would normally consume about 448 MB of data. The graph shows only 226 MB of data on the disc, which would agree with the seemingly unused grey blocks. If a multisession disc was written overwriting files of an earlier session, the files in the earlier session would be unlinked and inaccesible to reading. This might explain the odd spotty look of the data disc contents. Whatever is causing this, it is not unreadable errors according to the graphs.

[dolphinius_rex]

I rarely run into unreadable sectors with CD Speed, so I had to assume it would appear similarily to CD Doctor. That the biggest problem with CD Doctor in my opinion actually, the unreadable sectors look a lot like REALLY good sectors.... Which I why I now use K-Probe and manually check out the .csv file with a find command.

It is possible that CD Speed isn't giving the proper speed measurement on the tests, only the the tester themselves can really answer that one though. Which is another reason why I don't like CD Speed... too many little problems like that

Perhaps Heartburn will let us know what type of format his discs are? personally, I've never seen a multisession disc look like that before. Yes, it will have some missing space, but it also has unreadable blocks usually right at the end, and sometimes even between sessions (well, that how they are interpretted at least).

[CDRecorder]

To try to clear this up, I scanned an open multisession CD-R in CD Speed 1.02e Scandisc. It looked just like HeartBurn's pics, with missing space between green blocks. It also showed no unreadable sectors. I think the "unreadable sector" thing was a bug in older versions of CD Speed which has been repaired now.

[KCK]

Does KProbe show anything interesting on your open multisession CD-R?

[CDRecorder]

KProbe 1.1.9 left a big gap (in the C1 error chart; there aren't any C2 errors) in the same place as CD Speed Scandisc (1.02e) did. I read the disc back at 40x in my LTR-32123S with firmware XS0Z.

[KCK]

Thank you, LiteOnGuy, for answering one of my questions posed in

http://www.cdrlabs.com/phpBB/viewtopic. ... 3713#63713

In a similar vein, anything interesting for TAO discs?

[dolphinius_rex]

hrm, come to think of it, when I was doing the scanning of the mutlisession CD-Rs that tested, I *WAS* using CD Speed version 1.01, since 1.02 hadn't officially released and 1.02g was a ways away yet.

Thanks for the info!

[HeartBurn]

First let me thank everybody for their inputs, its much appreciated.

The media used is CMC Magnetics Phthalocyanine CD-R in both cases. The two cd's are from two different stacks of 100. I didn't mention this before because I didn't want it to become a factor in your evaluations.

I should have numbered all 4 images though. The top image, number 1 and number 3 are of a multisession FILE disc . I started gathering all my programs, little and small and added them all to one disc and have been doing so for over a year. That disc has been burned at every speed my LTR32123S is capable of burning at. (Firmware XSOZ)

Numbers 2 and 4 are of a disc that I bought approximately 6 months ago. Totally different stack than from the first disc. I burn just about every AUDIO disc (which is what this one is) at 16x DAO from songs that I have compiled in My Music folder.

I have never found an instance when I have suspected the multi session disc to be anything but totally reliable. I have used it to install programs on many computers belonging to friends and relatives as well as my own. I don't know how many times I have added files to it but it has earned its money believe me. The audio cd is played at least once a week and has been for approximately 6 months. It sounds great.

Not having anyone close by to ask questions to has caused me to rely on forums like CDRLabs and I surely do appreciate the opportunity to pick brains as the ole saying goes. Many thanks.

Heartburn

[dolphinius_rex]

that's very interesting! I'd never considered using 1 multisession CD-R with different speeds for each session!

Of course you'd never hit the higher speeds, probably not anything past 24x unless you were using a majority of the disc for one session, but it is still an interesting idea!

[HeartBurn]

LiteOnGuy....You say that C1 errors are correctable. How do I go about correcting them? By making changes to the settings the next time I burn something? How do you know what to change? Won't it report different C1 errors when it see's a different disc? Thank You.

Heartburn

[HeartBurn]

dolphinius_rex... The vast majority of all entries on the multisession data disc is short and sweet. Small programs such as JASC Image Robot, PrintKey18, TweakUI, Winzip, Atomica, a whole slew of BMP's I use for backgrounds, etc. The list goes on and on. Makes installing an OS an awful lot easier and faster. I almost always leave the speed just the way I found it, whatever speed it was set on the last time I burned something. I always burn music at 16x although there is no music on this multisession CD. I have read that the newer burners show better results at full throttle though.

What I would like to know right now though is what causes one "spike" to reach 5 cps and the next one 10 cps as in my image number 1. And what do I do about C1 and C2 errors.

Heartburn

[cfitz]

What I would like to know right now though is what causes one "spike" to reach 5 cps and the next one 10 cps as in my image number 1.

Just random happenstance. Don't worry about it.

And what do I do about C1 and C2 errors.

I would say don't worry about that too much either. You don't show any C2 errors, so that isn't an issue at all. And your C1 error rates, while not as low as they can go, still aren't terribly bad. If you want to do better, your best bet at this point is to try new media. CMC isn't the best of quality, although people do get serviceable results from it. Taiyo Yuden (e.g. Fuji in North America) is always tops in LiteOn burners, and I have had good success with the 48x Verbatim DataLife Plus (SuperAZO) discs on my LTR-48246S and even 40x and 48x TDK and Maxell branded Ritek discs.

By the way, every session of a multisession disc eats up around 14 MBytes of space in overhead, with the first session using up almost twice that. So, if you have a choice, it is better to group a bunch of small files together rather than writing them one per session. There is nothing inherently wrong with writing a very small amount of data per session, it just isn't very efficient.

cfitz

[CDRecorder]

KCK: That multisession disc I posted earlier was a TAO multisession disc (I think). Was there anything else you were wondering about TAO discs? I'd be happy to run a few tests if you want. BTW, you're welcome in regard to my answer!

HeartBurn: When I said that C1 errors are correctable, what I meant was that the drive (any drive in which you read the disc) can correct these errors when it reads them; this is normal and happens on every CD. You have nothing to worry about unless your C1 error rate is very high.

[CDRecorder]

One other thing you might find interesting HeartBurn: You may have had more C1 errors on the audio CD because you burned it slower than the data one. As long as the media is up to the task of high-speed burning, it seems that burning at the highest possible speed actually makes a higher-quality burn.

[dolphinius_rex]

One other thing you might find interesting HeartBurn: You may have had more C1 errors on the audio CD because you burned it slower than the data one. As long as the media is up to the task of high-speed burning, it seems that burning at the highest possible speed actually makes a higher-quality burn.

umm...not quite. Yes, burning the CD-R slowly DOES tend to create a larger amount of C1/C2 errors, but this is generall a problem with burning speeds of 10x or less. If the media is good, the C1/C2 errors should remain farily constant between 12x and 52x or whatever the top speed of the media is. However, speed affects more then just C1/C2 errors, it also affects jitter rates. Jitter doesn't normally cause problems, however, it can affect the sound quality of an audio CD, or the general quality of a(n) (S)VCD. If you plan to burn an audio CD or (S)VCD, then I would suggest sticking between 12x and 24x speeds, and only go as high as 24x if REALLY neccessary. Chances are even at 24x there won't be any problems, but that is when most drives and media start having jitter rates higher then officially allowed by the standards set for the formats...I don't remember which colour book that would be.

[CDRecorder]

Oh, OK. I'll have to do some more tests; thank goodness for rebates on media!