3 Forum Discussion On Sd2!



It’s all here: http://www.cdrforum.com/showthread.php?s=&postid=37302#post37302

I found this deep in the welcome.to/cloneclinic forum written by “ksch” on (5/6/01 1:00:12 pm). I know what he is talking about though! Please read his post below first, then read what I posted underneith.

SD2 - not a flaw in EFM encoding?

I don’t believe that SD2 works due to a flaw in the chipset’s EFM encoder. It is most unlikely that all manufacturers except Philips have implemented the same defect in their products. Moreover, EFM encoding is a very simple task. Each byte is converted into a 14-bit byte according to a lookup-table. There is no way to calculate this 14-bit value. Then the encoder inserts three Merging bits between each adjacent group of 14 bits. This Merging bits shall be chosen such that

  1. the number of ZEROs between consecutive ONEs is everywhere between 2 and 10,
  2. the pattern 100000000001000000000010 occurs only at the position for the Sync Header,
  3. power spectrum of the HF signal below 20 kHz must be as low as possible. (ECMA-130)

Though it is possible that Philips is using a more advanced technique to meet requirement 3, I doubt that. And it doesn’t matter. By providing a special pattern each encoder can be forced to choose “000” to fulfill number 1. These EFM encoded bits are recorded on the disc. A ONE is represented by a change of land to pit or pit to land. A ZERO is represented by no change.

So how does SD2 work? If the content of ”weak sectors” causes a high asymmetry between the amount of pit and the amount of land on the disc (if anybody knows a program, which emulates scrambling, CIRC encoding and EFM encoding, please check this), reading these sectors will result in a HF signal with a high DC bias. This bias makes it difficult to detect short effects like T3 if the contrast between pit and land is small. The higher the contrast, the better the detection. On a pressed CD with its high contrast, these sectors are readable. On a burned CDR, they are not. I assume that Philips burners, due to their combination of write strategy, burning power and optic, write not longer, but wider pits and therefore achieve higher contrast. It’s also possible to improve the detection of short effects by using a smaller laser spot for reading the disc. Some CD writers do this. The Sanyo optical pickup for CDRW writers, for example, has a numerical aperture of 0.5, whereas a typical CD reader has a NA of 0.45. And last but not least the used media and its reflectivity is also an important factor.

If this is the right explanation for “weak sectors”, than copying is up to the combination of burner, media and reader. There is no clear yes or no.


My responce:

I once used an old acer burner and a ricoh burner to burn 2 different sessions on a cd. The pits of what the ACER burner looked WAY different than what the ricoh burner. Also the ACER audio cds couldn’t be read in some audio player, because of the pits on the cd. Also firware I believe has something to do with how a cd is written to (jump on me if I’m wrong) which would explain why older firwares sometimes made drives be able to burn SD2 cds (as explained by the creator of disc dump). This would also explain why SD2 cds work in some drives and not in others. Does anyone see anything wrong with his explanation? I think it is the first explanation that explains everything.

What people can do to check is burn multiple sessions on cdr with multiple burners and look at look of the pits each burner burns? ACER users do your pits burner with the acer have higher contrast? I know the one I burnt 4 years ago did. Try a phillips to. The more sessions one the same cd with different burners the better. I am starting to believer this is the true answer, and it explains why hardware, media, and readers are all factors in the SD2 mystery. Please help figure out if this is the true answer to the mystery behind the weak sectors!

By Telstar:

EFM - codes
Well - the error in all the suppositions, hitherto made, is situated in just a simple fact…:

The recorders, which create the NOT-running SD-2 copies are writing the correct EFM-codes - and the ones like the Philips-compatibles are writing wrong codes !

This is due to the (more primitive) way Philips has solved the EFM-coding. They use solid conversion-tables within their firmware versions, while other manufacturers employ a mathematical algorithm to evaluate the correct codes…

This way of ‘using table entries’ is also the reason for the ‘strange phenomenon’ of the Philips-compatibles; they can only recognize media , which are in their built-in firmware-table of media, instead of just reading the ATIP. Thus some newer and well suitable media are just ‘omitted’…

So I conclude, there may be a cross-connection from MacroVision rather to Philips than to others like Plextor (like some fools were supposing) …

And I’m also assuming, it would be possible to ‘pre-distort’ those “weak but readable” sectors in the (read) image of a SD-2 disc in a way, that ALL writers can create “wrong” EFM-codes - but running SD-2 copies! Anyway - there’s a sufficient amount of redundant codes within EFM. So it’s the turn of software-folks like Olli (another time again!)…

BTW - as long as that ‘Xit’ is steadily trying to copy SecuROM with an CUEsheet-application like his Ddump and as long he’s stating, he’s “looking for a suitable writing-application”, which is able to write (random access) Q-codes in finalized SAO, so long I’d state my opinion:
‘Xit’ is definitely NOT the man, succeeding in this task - sorry to say…

    • Telstar - *
      Just beam.to/telstar to get more INFO and the ‘New Disc Times’…

PLZ never post WAREZ or SERIALZ to the public nor request such stuff here!

Last edited by Telstar on 25th May 2001 at 16:08

My reply:

Just so you know, I just do tests, read and spread the best info I can find around and get lots of people’s info. I would have never guessed at this new SD2 theory. As for your info, let me try to put it into english and then say any questions I may have about :

when the information is sent to the burners either:

A. solid conversion-tables within their firmware versions are used to evaluate the efm codes on phillips based hardware drives.

B. while other manufacturers employ a mathematical algorithm to evaluate the correct codes on other burners

In which case:

A. The solid conversion-tables in the firmware don’t use math to figure out the correct codes to send to the EFM encoder and write it perfectly.

B. The mathimatical algorithm in the firmware of other burners, used to calculate the efm codes, screws up the info it sends to the EFM encoder when encoding the weak sector data. Because while the mathimatical algorithm thinks it is fixing messed up data, by correcting the data it is sending to the EFM encoder, this is what makes unperfect SD2 copies.

Olli quote:
“The sectors I have mentioned above try in fact to overload the EFM encoder of the CD-Writer, because AFTER passing the scrambler the poor device has to write REGULAR BIT PATTERNS - something it really doesn’t like.”

That about as english as it is going to get, here are questions:

  1. Does this mean the Plextor 8/20 and 8/2/20 TLA #01xx have solid state conversion tables in their firmware for those specific drives because mabey they don’t have math things in them to calculate the mathamatical algorithms? This would mean firmware would have figure out what TLA # your drive was and then update it correct? There are other things this would mean, but before I go off lets answer the first question first.

  2. “I’m also assuming, it would be possible to ‘pre-distort’ those “weak but readable” sectors in the (read) image of a SD-2 disc in a way, that ALL writers can create “wrong” EFM-codes - but running SD-2 copies!” If the mathematical algorithims in each firmware are all different and each drive has a different algorithim how could this be possible without having to make software very very very specific on firmware and hardware?

  3. Why would some SD2 copies work in some drives and not in others and like some work in the plextor drives that made them?

Thanks for your info. Could the original post have something to do with the protection too?

LocutusofBorg posted this http://www.daemon-tools.com/ikonboard/topic.pl?forum=8&topic=39 in the Daemon-tools support forum and he is part of the Daemon-tools test team!

That’s exact the theory I posted for a long long time ago.
Nothing new. Increase the laserpower is after all a difficult thing but we tried this and the result was a significant decrease in unreadable areas (weak ones). But we never reached our goal, instead we destroyed the burner, and after all you don’t need a burner able to burn nearly everything. In future the copyprotections maybe prevent the real 1:1 copys, but we have daemontools, right?


Turak said:

You are dancing around the root cause of the probem…
There are basically 2 different Chipsets used in 95% of all the burners made, the Sanyo and the Phillips. There are a few others, but they are not really worth mentioning.

The Phillips chipset is the chipset that is able to make working backups of SD2 protected disks that will work in any Writer or CDROM. This chipset is used in the following drives; Acer’s, Artec’s, Fujitsu’s, Seimen’s, HP 8250i, Iomega ZipCD’s, Lifetec’s, Medion’s, Tevion’s, Phillips, TraxData’s, & Waitec’s.

The Sanyo chipset is the chipset that seems to allow many burners to make copies that will work in the burner that made it, many times in other writers, and rarely in other CDROMS. This chipset is used almost all the other drives except those mentioned above(including Plextors, Creative Labs, HP’s, Imations, Ricoh’s, Yamaha’s, etc).

Now one interesting fact is that Sanyo changed the version of their chipsets roughly midpoint of the Plextor 1210a run. The older chipset seemed to be able to make working backups of the SD2 discs a little more often than the newer chipset does. Thus the reason why many people with certain Plextor 1210a’s seem to be able to make working copies of the SD2 discs more often.

But neither Sanyo chipset CAN NOT make working backups of SD2 discs that will reliably work on ANY other CDROM drive 100% of the time, where the drives using the Phillips chipsets can.

Yes, depending on the chipsets capabilities some of the problems with the SD2 discs may be able to be compensated for in the firmware. But it truly comes down to the chipsets physical capabilities when reading the various protection types. You can only do so much with software and are always limited by the hardwares capabilities.

Try to get Sanyo or Phillips to release the technical specifications of their chipsets, or even better yet the internal design schematics, or even the FULL undisclosed command sets. Never happen…been there, done that.

People talk about Plextor being in bed with Cdilla (creators of SD2 protection). It would be far more likely that Sanyo may be doing a little collaborating with Cdilla, since EVERY drive that uses the Sanyo chipsets are unable to produce reliable, working backups that will run on ANY CDROM, not just Plextor’s.

Now on the other hand, why can the Sanyo chipsets read/write sub-channel data and the Phillips chipsets can’t? Lookout another conspiracy theory here, hmmm? Is someone in bed with the makers of SecurRom protection (hehe). No, I doubt it, again it comes down to the physical characteristics of the chipset design along with the internal command set.

I replied:

When you say:

"There are a few others, but they are not really worth mentioning. "

But if what you say is true, the chipset in the plextor 8/20 and 8/2/20 TLA #0100 must be in the other category to be able to have the following capabilities:

Perfect SD2 copies

Firmware comment:

Best Supported Write Mode:

Best supported Read Mode for Data:

Best supported Read Mode for Audio:

And they’d also have to have solid conversion-tables within their firmware versions specifically for these special “other” chipsets? If this is true then the Plextor 8/2/20 #TLA 0100 is amazingly unique. Thanks for your info, please follow up.

Blindwrite’s Comments
I found this in the Blindwrite F.A.Q.:

Safedisc 2 is very hardware orientated CD copy protection. In addition to all the safedisc 1 tricks, SD 2 uses a mathematical suite of data which requires, for reading, a very well contrasted CD. the explanation is far beyond the scope of this FAQ, the result is that only a few CD readers can read the backup of these mathematical sectors. Both a good reader and a good cd writer are required to produce a working backup, and a SAO RAW writing mode shall be preferred, as SAO writing offer more contrast than DAO on the backup CD.

I guess he is into the contrast theory too.

new info:

LocutusofBorg brings more info…
This is all from http://www.daemon-tools.com/ikonboard/topic.pl?forum=8&topic=39 written by LocutusofBorg:

I’ve posted this under the name “LocutusofBorg2K” in CloneClinic in December 2000. I’m started a “Firmware Project” with some teammembers, but we never reached the goals, instead we invest tons of money.
DOTC (one member) figuered out, that it is all sync-related.
It has nothing to do with the EFM, cause the datapattern is intact. The difference between f.e. Plextors and drives that can’t READ the “bad burns” is that plextor implement additional circuits to position the laserpickup exactly.
You can proof this by yourself: Plextordrives can position even on audio-cd’s exact due to additional circuits.
They don’t need (in lower read-speeds) the syncsignature.
But try to read this discs with f.e. clonecd: this program use special commands, so it’s unable to read the “bad burned” cd’s exact. Start a sectorscanner and try to read the weak sectors. surprise, surprise: no problem. Some TEAC drives use the same technology so they are able to read the “bad burns” from plextor, too.
After increase of laserpower it seems that some of our “testburns” turned to audio-cd’s ?!?! No idea why this happens we concluded it’s better to stop the further development, cause noone think it’s funny to destroy other devices and additional to that we got mail from “friends” that developing and manipulating firmwares is illegal, they are copyrighted. You surely can imagine what “friends” I mean.
I’ve then send email to Olli Kastl to ask about the possibilities of a copyright lawsuit against us, but he never answered.
But the point is: NO ONE! and I mean NO ONE, knows for sure!!! what causes the “badburns” on most cd-recorders.
There’s also rumour that “Philips” burners write “raw” other than most burners. We’ve a philips-employee (from r&d), he’s a good friend of mine but he’s sure that there is nothing “special” about the philips/acer burners except 2 things. Our team now develop more “constructive” software and it’s real funny.

before I forget:
We never found indices (but after all we never take a look at Plextor 8/20 firmware cause nobody own’s one) that there’s a “mathematical” algorithm for the efm encoding
And besides this Olli K. posted that there is a overflow! of the scrambler device. If you’re interested in the exact function of this efm-device, write a mail. (My Opinion on that: Quote from Olli K: “The sectors I have mentioned above try in fact to overload the EFM encoder of the CD-Writer, because AFTER passing the scrambler the poor device has to write REGULAR BIT PATTERNS - something it really doesn’t like.”
Just my 2c

PS: The EFM is Chipset related, not Firmware-related