Home | Forums | What's new | Resources | |
this idea a had... |
AntiPasta - Jan 7, 2003 |
< Prev | 1 | 2 |
Vic Viper | Jan 9, 2003 | ||||
Only JVC MPEG cart can read Photo CDs... Mine is a Hitachi one (I own a black Hisaturn, not the car GPS model and the MPEG cart came in the bundle), which is same as SEGA one, exept for the look of the player software, which has a diferent "splash screen". For my machine I must use a CD called Photo CD operator. On the SEGA catalog there is also a E-Book operator, which I don't know anything about. |
CyberWarriorX | Jan 9, 2003 | |||
I think it might be worth our while to check out the main program of a developer's key disc. It may just give us the information we need. Cyber Warrior X |
AntiPasta | Jan 10, 2003 | |||
That might just be it indeed... anyone ISO'd it? By the way, I had this really ridiculous idea today, which I'll share with you nonetheless. The security track is on the outside of the CD, right? Well it crossed my mind to copy a Saturn game to mini-CD (8cm, will only work with smaller games like Metal Slug) and then glueing it to an original Saturn CD, a demo disc or something. |
antime | Jan 10, 2003 | |||
Yes, ISOs of the devdiscs are floating around, you'll probably find them soon enough if you start trawling the FTP section. |
Vic Viper | Jan 10, 2003 | ||||
That's how some chinese companies make their PSX and PS2 discs boot on unmoded machines ... One even took the USB naplink software and made it bootable using the inner ring and idex of DATEL's DVD region X ... lol It would be easier to dupe the saturn ring as it is on the outer side of the disc... Or maybe even cutting a original one from some demodiscs. Glueing will not owrk because the disc layer will be at a out of specification distance of the lenses, which makes the reading of the ring impossible. |
AntiPasta | Jan 11, 2003 | |||
well, the duping of the outer ring is the entire problem, isn't it? If that could be done we'd now have 100% perfect copies and no needs for modboards |
mal | Jan 11, 2003 | |||
Here we go again... The idea of reading, and then in turn reburning, the security ring gets brought up every couple of months. No one ever gets anywhere with it though. Don't let that discourage you, you'd make lots of people happy if you made any breakthrough. But whatever you do, don't mention the Yamaha burner that can burn patterns on CDRs as a potential solution. antime might just explode. |
antime | Jan 11, 2003 | |||
Yes, and I might be tempted to abuse my newly acquired moderation POWARS!!!1 So let's not do that, OK? |
AntiPasta | Jan 11, 2003 | |||
Okay I was reading sattech.txt by Charles MacDonald (get it at http://cgfm2.emuviews.com)... which states: ... 05800000-058FFFFF A-Bus CS2 [2] ... [2] The CD-ROM registers are mapped here, in 64 byte units mirrored every 64 bytes. So apparently there is something out there... If we could figure this out we could write software on cart that A. loads the executable without authentication B. patch the file loading functions to bypass the SH1 so normal games will run C. run the executable Voila! |
antime | Jan 11, 2003 | |||
The CD registers are the interface between the CD block and the rest of the Saturn, but I don't recall seeing them documented anywhere. It seems Sega didn't want people accessing them directly and only provided binary-only C libraries instead. Note that they're not the CD controller registers, but the way you can communicate with the SH1. Unless you find some good assembly-level docs on the CD communication registers, your best bet may be to disassemble those libraries in the SBL for which sources are not provided. |
Nemesis | Jan 11, 2003 | |||
I theorised a few years back that the security track was burned at a different density to the rest of the cd. Something similar used to be done on floppys in the past I heard, where they would write an abnormal number of sectors in a ring, and unless the hardware is told to read the information allowing for the different spacing, it picks them up as bad. That was just an old theory. I'm not some kind of saturn guru, so I'm probably completely off the mark. On such a low level though, where the security check commands are being issued by the chips that have direct control over the laser assembly, I don't see why it shouldn't be possible. If I'm wrong, can someone tell me why the CD slows down so much for the security check? Do we know what it stores after it reads this area either? Does it read in some kind of long string of data, or does it generate a checksum of the area or what? |
antime | Jan 11, 2003 | |||
Sega has a patent on an optical verification technology. The method described in the patent uses a special piece of hardware to compare some image on the disc (a trademarked logo, for example) to the correct image stored in the device. This gives one explanation as to how Saturn modboards work. Just as the CD subsystem is a black box to the rest of the Saturn, the verification technology is a black box to the CD subsystem. Once it has determined that the disc must be verified for further access, it asks the verification system whether the disc is valid or not. The modboard intercepts the request and returns an "OK" answer. This is where that Yamaha drive is usually brought up, but unless someone has actually bought one and solved at least some of the problems involved before even an attempt at making a disc can be made (like reading the original image) I don't want to hear anymore about that damn thing. |
ExCyber | Jan 11, 2003 | ||||||||||
If you dig deep enough in at least one of those patents, it describes using pit/land patterns to form the image such that it can be read by a standard CD laser, even going so far as to have the example of the "SEGA" image (as in 'TRADEMARK "SEGA"') laid out on its own page, though I'm pretty sure the image shown is not identical to the one actually used on Saturn discs.
This seems to be true, at least to the extent that the mainboard-bound CD system components seem to be dependent on the CD reader's H8 to tell it whether or not the signature is there. However, some recent thinking has led me to start wondering if I haven't made a faulty assumption about how these components interact...
Agreed. The entire question of whether or not we have access to a drive that can write the signature is unanswerable until the details of the signature's encoding are known in the first place. I've tried pulling a couple basic tricks to read the ring in a Dreamcast (not because of a belief in any special Sega magic; DC's architecture just made it a convenient testbed for the idea), but they failed. I fear that it would be necessary to do a bit of firmware hacking on a suitable drive in order to unlock the secrets of the ring. (urge to make smartass LotR reference suppressed) |
< Prev | 1 | 2 |