Help with identifying good drives

[SeanRamey]

Hi. So, I've been trying to make some back up discs of my PC games, as much a 1:1 copy as possible. I've run into some issues with 1503 AD which seems to use SafeDisc 2.80, and I've been using cdrdao on Linux to do my backing up. I opened an issue with cdrdao and me and another guy have been learning that the problem is certain drives can't seem to write all data properly. I run across this project in my research (redump) and I was thinking maybe you could help me identify drives that can write these copy protections properly. Here is the link to the cdrdao issue.

Thanks!

[superg]

http://redump.org/disc/64375/

SafeDisc protection intentionally corrupts some files so standard drive reads slowdown/error on a disc copy. To dump such games you need a drive that reads data tracks as audio (scrambled mode) and you need software that recognizes the protection and treats it appropriately (redumper).

Compatible drives: http://wiki.redump.org/index.php?title=Optical_Disc_Drive_Compatibility

TL;DR: get good plextor or asus and use redumper.

[SeanRamey]

http://redump.org/disc/64375/

SafeDisc protection intentionally corrupts some files so standard drive reads slowdown/error on a disc copy. To dump such games you need a drive that reads data tracks as audio (scrambled mode) and you need software that recognizes the protection and treats it appropriately (redumper).

Compatible drives: http://wiki.redump.org/index.php?title=Optical_Disc_Drive_Compatibility

TL;DR: get good plextor or asus and use redumper.

Yes, I know how to get a good dump/read, but my question was about which drives are good for writing . See the cdrdao github issue I linked for the details on what we've done so far.

The same drives that are fine for reading are not necessarily good for writing, and the backup use case for disc image files is incomplete if they can't be properly burned back to a disc.

[superg]

There are a lot of issues with writing. One thing is that you will not be able to write back SafeDisc errors because there is no way to simulate C2 errors with consumer optical drive. Second, when you burn image, your write offset will be different, TOC and subchannel will be regenerated. Writing is complex and is definitely out of redumper scope.

[SeanRamey]

There are a lot of issues with writing. One thing is that you will not be able to write back SafeDisc errors because there is no way to simulate C2 errors with consumer optical drive.

What is a C2 error, what is a SafeDisc error, and what is the difference between them? Thus far I have been able to seemingly make 1:1 working copies of some earlier SafeDisc games, so it seems to me that what you say is not true unless I misunderstand.

Second, when you burn image, your write offset will be different, TOC and subchannel will be regenerated. Writing is complex and is definitely out of redumper scope.

I do realize that writing seems to be out of redumper's scope. I'm just looking for information and help from people who seem to have the most knowledge about these topics and I do appreciate your time.

[superg]

What is a C2 error, what is a SafeDisc error, and what is the difference between them? Thus far I have been able to seemingly make 1:1 working copies of some earlier SafeDisc games, so it seems to me that what you say is not true unless I misunderstand. C2 error is a notification from a drive that data is corrupted (there are checksums on a lowest level to know that).

1. C2 errors from the scratched disc / disc degradation are what I refer to as genuine errors.
2. SafeDisc protection intentionally masters disc with C2 errors so you cannot easily dump the disc, let's call them fake errors.

The distinction between (1) and (2) is important because (1) is often repairable (constant re-reads might eventually get the correct data), but (2) was mastered that way and drive will not be able to fix it. In the worst case, when you dump scratched SafeDisc, you have a mix of both (1) and (2) and you need to be able to tell what is what, because it's pointless to re-read (2).

Thus far I have been able to seemingly make 1:1 working copies of some earlier SafeDisc games, so it seems to me that what you say is not true unless I misunderstand.

You can make a copy of SafeDisc game but it will not be 1:1 because of mentioned (2). 1:1 doesn't mean playability, 1:1 means the exact disc copy (dump), minus of course the mastering errors. I suggest to go to redump.org wiki and read the dumping guides. There is plenty of information that will be relevant.

[SeanRamey]

I suggest to go to redump.org wiki and read the dumping guides. There is plenty of information that will be relevant.

Firstly, I didn't really find anything useful in any of the dumping guides or the wiki in general. Maybe you could direct me to the specific ones you think I should read?

You can make a copy of SafeDisc game but it will not be 1:1 because of mentioned (2). 1:1 doesn't mean playability, 1:1 means the exact disc copy (dump), minus of course the mastering errors.

I was under the impression that a SafeDisc protected game wouldn't be playable if it wasn't a 1:1 copy. It's just my understanding that creating a 1:1 copy got harder and harder as the SafeDisc versions go higher. Why are mastering errors not included in a 1:1 copy? Wouldn't this by definition no longer be a 1:1 copy?

2. SafeDisc protection intentionally masters disc with C2 errors so you cannot easily dump the disc, let's call them fake errors.

Ok, yes these errors I know of. I'm thinking of the "weak sectors" that were used in SafeDisc v2.0+. From my understanding so far, they have intentionally written data to the disc that screws up the vast majority of CD-ROM writers (but not readers) because of hardware (or sometimes firmware) limitations. This can be illustrated by performing the test here where you write certain combinations of known screwy data to a CD-ROM, then attempt reading the data back. If you can successfully read the data back, then your drive has an accurate "EFM capability" because it wrote the data properly. If you can't read it back, then the data was corrupted in the writing process. This particularity is the main thing I was originally asking about.

Do you know of any modern drives that have "accurate EFM capability"?