I've been reading some old posts and I noticed that a few folks use Test+Copy and C2 when ripping with EAC.

I bought into the opinion that C2 isn't very reliable and unchecked the "Drive is capable..." box. Instead I've been using Test+Copy with my Plextor PX-W1610A (and now my PX-708A).

Is there a case for using both methods together? Do they complement each other or can they interfere with one another? Is there any benefit to enabling C2 if I use Test+Copy?

What happens when I use T+C and C2 in secure mode? Total overkill?

What's the optimim combination of settings for secure ripping without wasting an extraordinary amount of time and/or wearing out my drive?

Test + Copy means the drive reads everything twice and the results are compared (by you, using the CRCs from the log file) - the same is done in secure mode with C2 disabled. If you enable C2, you get "best of both worlds", i.e. security by the drive (more or less reliably) reporting uncorrectable errors and re-reads.

IMHO Secure mode Test & Copy is overkill. It saves you from the effects of using wrong options (e.g. if the drive caches but EAC's cache option is unchecked), so if you start using EAC with a drive, using T&C might be a good idea for the first couple of rips, but after that it's just a waste of time (and might cause the drive to wear out earlier). Exceptions might be copy protected CDs, aging CD-Rs and aging drives.

Since you have Plextor drives, have you considered using Plextools? it seems to know ways to use C2 more reliably than EAC, so you'll get faster extraction than with EAC secure mode, C2 off but with comparable security,

I'd think the drive wears out slower if you use test+copy instead of cache disabling. Instead of seeking back and forth every few sectors, it's all done in one continuous read.

Ofcourse, if the test/copy do not match, you need another rip to 'fix' the problem spot. I use two profiles; one with C2 and no cache disabling, which I use for test/copy, and one without C2 and with cache disabled, used for finding problem spots.

And if test/copy don't match, I rip in a second drive, too...

I didn't even know PlexTools existed until recently. I didn't get a copy with either of my Plextor drives (that I'm aware of), so where do I get this mysterious utility? It seems the Plextor site has upgrades for download, but not PlexTools itself.

So let me get this straight...

Let's assume that C2 is NOT enabled for now:

-- T&C reads everything twice and I compared the CRCs in the log. Simple enough.

-- Secure Mode (SM) means EAC reads every chunk of data at least twice, more often if they don't match.

-- T&C+SM performs the SM procedure on both T&C passes for a total of at least 4 reads.

Now, let's enable C2:

-- T&C behavior doesn't change: it still means each track is read in full twice.

-- SM changes, however. SM+C2 doesn't always read the data twice like SM without C2. Instead, it relies on the drive to report C2 errors. If a C2 error is reported, EAC will perform more reads. But if the drive reports no C2 errors, then EAC might read the data only once.

So assuming C2 information isn't always reliable, using SM+C2 is not as reliable as using just plain SM without C2 because SM+C2 might be fooled into reading the data only once if C2 errors go unreported by the drive.

The Best of Both Worlds sounds like it's T&C+SM+C2. And in the event of a CRC mismatch, going to T&C+SM without C2.

It sounds like using T&C+SM without C2 all the time is overkill and harder on the drive because of all the non-sequential reads (ie, hopping around to read every chunk of data twice).

Now the only mystery is how all of the above changes when I disable/enable cache...

If your drive doesn't cache, enabling/disabling cache doesn't change reliability of extraction results, only speed slows down if cache option is checked.

If your drive caches, unchecking cache option will cause this:

- if C2 is diabled, errors won't be detected -> error correction (multiple re-reads at lowered speed) doesn't kick int. You'll get different T&C CRCs on damaged CDs (= non-perfect ectraction results) quite often

- if C2 is enabled, errors will be detected (maybe not all, depending on the drive's C2 accuracy), but error correction might fail as mulitple re-reads can return the same data from cache everytime (-> the drive assumes this data is correct). -> T&C CRCs won't match on damaged tracks.

That's why I said


@ Patsoe: You're right. I meant using T&C additionally to Secure mode (same options).

This is all true, but EAC's secure mode (=reading twice, without T&C) fails every now and then (how often depends on the drive, for good drives it is really rare).
For most drives secure + T&C can indeed be considered overkill. BTW, EAC's secure mode (atleast 2 reads) was designed to give 'perfect' results without T&C. When people still use secure + T&C (at least 4 reads), this is usually to spot when EAC fails (which is rare, except for some bad drives).

It's a good idea to do your first rips with T&C, like Tigre suggested. It is an excellent way to see if everything runs fine And with a good configuration, everything should run fine for most drives, and then you can safely think of omitting T&C, and also of enabling C2 (even if you aren't sure your C2 is reliable. Because: the weak spot of a bad C2 is that your drive might wrongly read only once instead of the safe twice. But "thanks to" T&C, you still have at least 2 reads. And as I said earlier: 2 reads is enough for most drives, EAC thanks its good reputation to that).

I'm paranoid and us T+C Without C2 on my Plextor 40x CD-ROM drive..There has been a few times it has had non matching CRC's, so my paranoia paid off

T+C are for tracks only, right? You can't do that for (single) image and cuesheet, can you?

(I'm at work right now. Don't have EAC here. But think I looked for that option not finding it...)

No, you can't do it for a whole CD...I usually extract the tracks on the original, and then to a Test on the copy and the CRC's should match..
Cheers

Maybe you're talking about caching issues, that make some drives return twice the same erroneous data. In this case, the problem does not lie in the drive but in EAC, that can't clear the cache properly. But there is no reason to assume this.
For a drive that doesn't cache, the secure mode failures depend on the CD. It will fail every time that a part of the data is completely damaged while the rest is intact, leaving no room for variations in different readings. This occurs on CD with very few errors. An example showed that the failure rates can be between 0.2 and 32 %.

In a case where the standard secure mode fails, chances are high that you get twice the same wrong CRC. In this case (that is likely to be if you get mismatching CRC in SM without C2, but unlikely if you get mismatching CRC with SM+C2), "goig to T&C+SM without C2" can easily return matching CRCs, not because errors not detected by C2 have been corrected, but rather because the drive read 4 times the same error. Remember that getting mismatching CRC without C2 means that an error have been consistent.

So is the bottom line that using SM+T&C+C2 the most secure mode?

It won't be much more secure, because even if C2 detects more errors, they are still corrected by rereading... So consistent errors are always thought to be corrected by EAC.

Since you have a PX-708A, I'm going to recommend using C2. Hell, I've been told I can even uncheck the "caches audio" box. The result was faster ripping, and identical checksums to a rip made without C2 and with anti-caching measures. Your mileage may vary.

This is usually ok, but still... C2-misses occur.



Ofcourse it's faster... unchecking the cache box on a caching drive means there will be only one physical read.
Identical rips with/without those settings just mean that the disc isn't substantially damaged. It doesn't tell you either setting is allright.


that's exactly why I think your suggestion isn't complete: you forget to mention that it is not truely secure.

This has all gotten me thinking about really badly scratched cds, where Secure mode without C2 returns sync errors. Will enabling C2 possibly obtain a better copy than without it? Sorry if this question makes no sense, my brain is fried right now trying to get it wrapped around the stuff in this topic. I had decided on Secure Mode w/o C2 a while back and forgot about all the details, and now this topic has gotten me to reconsider all the details again, in this case, relating only to these specific "sync error" instances.

Probably not... sync errors mean the drive can't accurately read the sector even after 32 tries or so... with C2, it will still have to read the sectors...

some drives however might perform slightly better because they perform less seeks with C2 enabled, so the laser runs over the surface in a more linear fashion. NB: this is all guessing!

Yes, and striking is that some people are closer to 32% while others are closer to 0.2%. From that I concluded that some drives are better than others (in basic error correction).
While your remark about the CD is certainly important, i think the drive matters as well (although i can't prove it, it just seems natural ). What do you think? Is anything known on this terrain?

That is no what these numbers mean. So far, in the forums history, Tigre's test is the only one ever run. The result is valid for one given rip of one given CD with one given drive. It says that about 32 % of the errors were consistent (It is the average value between the proportion compared to the first rip, and the one compared to the second rip).
Since we don't know exactly how EAC corrects errors, all we can tell is that if it have performed this rip, it would have missed at least 0.2 % of them (the ones that were completely isolated, and that couldn't have been included in any error correction reread), but maybe more... maybe it would have missed all 32 % of them.

Now, with another CD, the result can be completely different, depending of the nature of the damage (likely or not likely to produce consistent errors). We can also get results that can be slightly different if Tigre repeats the experiment with the same CD/Drive. But I don't think that a different drive would have the ability to turn some errors into a permanent state, or to make permanent errors unconsistent.
This will locally happen, of course, if a part is barely readable for one drive and not at all for another. The "grey aera" where the data is not reliably readable, but not yet completely lost (=aera of unconsistent errors) will be different, but still there.

Hi all,

FWIW, I came to the conclusion a long time ago, after a lot of reading and some observations, that EAC T&C+SM+C2 on my Plextor PX-40TW was the best possible method. It seems others [mostly] agree in this thread.

You get double reading of every sector (T&C) plus obtaining errors detected by the drive (C2) and ensure those errors are re-read multiple times (SM - until 8/16 are identical trying up to 5 times according to the EAC Extraction Technology page).

As Pio2001 mentioned is possible, I've had a few cases where T&C SM NoC2 returned Track Qaulity = 100% but mismatched CRCs. Another pass using C2 reported the errors (and went twice as fast).

The other cases I had when testing on poor quality CDs is that SM+NoC2 had higher track quality than SM+C2 but I came to the conclusion that was a result of SM+NoC2 not catching as many errors.

When I get CRC mismatches, I T&C the track again until I get a match. If the 2nd try fails I immediately set the drive speed to 1X. This usually works. If not I usually give up since my experience has been futile beyond that.

I agreee that T&C+SM+NoC2 is overkill. It's half as fast as T&C+SM+C2.

I hadn't considered the advantage of T&C if incorrectly failing to set the "Drive caches adio data".

Another advantage of T&C is that subsequent rips only need a "copy" since the results of that copy will be compare the the previous "test" stored in EAC's database. You'll see the "#" in the CRC column rather than the "OK". It's like having a baseline for the CD.

I am excited about AccurateRip now supported in EAC. I just configured it and intend to support the project.

Cheers! - Walkman

Apparently, the settings which were recommended to me for PX-708a are secure enough, and I don't feel like arguing either way. It's fast enough for me, and security should be just fine for my fairly pristine collection. Oh well, it's not like I rip more than one or two CDs every three or four months...


Just ignore me. Feel free to configure it to disable caching and ignore the C2 checking feature, and use test and copy, for the most secure reading.