Yes, this title does sound like the title of one of the worst movies of all time. But it is about the experiments with garbage CDs (CD-Cops in this case) I have been doing in the past weeks. In order not to waste much money for testing out disc based DRM systems, I simply bought the cheapest (and sometimes most cringeworthy) games I could find containing the various protections.
Thanks @Alexander1970 for pointing me in the right direction for getting a CD-Cops disc: Many of the ridiculous Hugo games are infected¹ with this. It is one of the earliest (or even the earliest) CD protection schemes relying on what is know as DPM (data position measurement)/CD geometry/angle based protection/RMPS. These systems do not rely on some actual data on the disc for authentication, but try to measure data density (SecuRom 4.8+) or angles between sectors by read time. The idea is quite smart as the user of a CD burner doesn’t have direct control over these parameters² (that are different for each brand and maybe even each batch of CD-R as well).
Some quotes from the Linkdata homepage.
Compared to fighting against ProtectDisc CD/DVD with the dreadful “Emulator aktiv” message stopping even the legit discs from working, CD-Cops was quite refreshing. The claims on their site are so funny! I admit that the game will probably not contain the newest iteration of their system… but it is from about the same time as my ProtectDisc samples – which gave me a major headache when pretending to be an end user wanting to have working backups (not that I even considered using this pile of useless software I've snatched up). As for the emulator part: Alcohol 120% RMPS emulation for physical media has a 100% success rate; same for the virtual drive which starts the game much faster than the legit CD in physical drive.
Now… emulation is not the point³. The point is that a geometry-based protection should be able to distinguish the legit CD-ROM from a burned copy when no emulation is used. With a simple copy in the drive, the protection module starts reading/measuring and isn’t satisfied with the results. The speed of the drive gets gradually reduced. Looks as if it wanted to say: “Well, this CD is fishy. Let me have a closer look!” (more accurate measurements with slower rotation). Ultimately the copy is rejected.
So… what does a little Sinchen answer to that? I answer: “Hmmh. So you say you can reliably detect copies on closer (slower) inspection? What if I make the drive go full speed before your check has even started?” That is what I did:
I’ve attached the result as a heavily compressed video file showing the procedure (about 4MB for 83 seconds, 720p resolution). Please be patient. All the steps take a while (CD recognition, using the PC while 4 meters away, CD Check). There is no sound – was way too quiet to hear the drive sounds, so I removed the audio to make the file smaller.
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¹ I choose blunt words now! I’m fed up with the DRM garbage!
² If you have some hours(!) to spare: https://club.myce.com/t/something-about-starforce/80056 I really have to see if I can find the tools mentioned there and maybe can create a perfect StarForce or CD-Cops backup based on this.
³ I consider CD emulation as inferior solution compared to a simple, perfectly working backup. Of course virtual drives are faster, more versatile and far more convenient. The problem is that the target computer has to have some kind of emulator installed. I wouldn’t call Daemon Tools or Alcohol 120% trustworthy. They (can) both contain adware and may upload some kind of telemetry or whatever they call their super-okay-nothingfishy-going-on-here “we collect this data for improvement”-thing at the moment. My test machine being an offline XP machine there are no such problems.
Thanks @Alexander1970 for pointing me in the right direction for getting a CD-Cops disc: Many of the ridiculous Hugo games are infected¹ with this. It is one of the earliest (or even the earliest) CD protection schemes relying on what is know as DPM (data position measurement)/CD geometry/angle based protection/RMPS. These systems do not rely on some actual data on the disc for authentication, but try to measure data density (SecuRom 4.8+) or angles between sectors by read time. The idea is quite smart as the user of a CD burner doesn’t have direct control over these parameters² (that are different for each brand and maybe even each batch of CD-R as well).
Some quotes from the Linkdata homepage.
Compared to fighting against ProtectDisc CD/DVD with the dreadful “Emulator aktiv” message stopping even the legit discs from working, CD-Cops was quite refreshing. The claims on their site are so funny! I admit that the game will probably not contain the newest iteration of their system… but it is from about the same time as my ProtectDisc samples – which gave me a major headache when pretending to be an end user wanting to have working backups (not that I even considered using this pile of useless software I've snatched up). As for the emulator part: Alcohol 120% RMPS emulation for physical media has a 100% success rate; same for the virtual drive which starts the game much faster than the legit CD in physical drive.
Now… emulation is not the point³. The point is that a geometry-based protection should be able to distinguish the legit CD-ROM from a burned copy when no emulation is used. With a simple copy in the drive, the protection module starts reading/measuring and isn’t satisfied with the results. The speed of the drive gets gradually reduced. Looks as if it wanted to say: “Well, this CD is fishy. Let me have a closer look!” (more accurate measurements with slower rotation). Ultimately the copy is rejected.
So… what does a little Sinchen answer to that? I answer: “Hmmh. So you say you can reliably detect copies on closer (slower) inspection? What if I make the drive go full speed before your check has even started?” That is what I did:
- Start copy+paste the largest file from the CD-R to the desktop → The drive goes maximum speed
- Start protected game
- As soon as the CD-Cops window appears, abort the file copy.
I’ve attached the result as a heavily compressed video file showing the procedure (about 4MB for 83 seconds, 720p resolution). Please be patient. All the steps take a while (CD recognition, using the PC while 4 meters away, CD Check). There is no sound – was way too quiet to hear the drive sounds, so I removed the audio to make the file smaller.
___________________
¹ I choose blunt words now! I’m fed up with the DRM garbage!
² If you have some hours(!) to spare: https://club.myce.com/t/something-about-starforce/80056 I really have to see if I can find the tools mentioned there and maybe can create a perfect StarForce or CD-Cops backup based on this.
³ I consider CD emulation as inferior solution compared to a simple, perfectly working backup. Of course virtual drives are faster, more versatile and far more convenient. The problem is that the target computer has to have some kind of emulator installed. I wouldn’t call Daemon Tools or Alcohol 120% trustworthy. They (can) both contain adware and may upload some kind of telemetry or whatever they call their super-okay-nothingfishy-going-on-here “we collect this data for improvement”-thing at the moment. My test machine being an offline XP machine there are no such problems.
