Also, I'm a bit confused.. the 'logo' area, is it the same area that is visible at the end of the disc when you hold it in the light? It has the same Sega logo written on there.
when console boots up saturn will drive laser to this area and do few readings and if it's a backup - will fail.
so this final protection, it's very likely to be somewhere there.
i'm now very sure it's actually this logo, like RPS and few other people said (years ago ). because it's in CAV, this area is unlike the rest of cd.
every track consists of the same amount of frames (tracks do not get longer, closer to outer edge)
FPT=2058 (2058/98=21 sec.) <|Frames Per Track
FPT=1078 (1078/98=11 sec.)
so on backup this logo will never show up. it washes along the tracks and becomes garbage.
so i guess it doesn't matter how you pad it - to get logo, whole data would have to be recreated anyway, based on cd geometry.
would that work? - i don't know, it's unlikely, original is very precise (as can be seen in microscope,
i don't belive anyone could do that without proper hardaware)
maybe offset affects this whole process as well - i'm not sure. if it does, ther's 6 possible ways to pass data to circ
(one is correct, on four other ring will shuffle, like in those images i posted earlier).
and probably contrast on recorded media is too low to see anythig, anyway.
and maybe protection is something else after all...
also what's strange, sector count per track seems very low, compared to what i estimated from empty area. but maybe i made a mistake there.
i only had one DC ring, from European ChuChu Rocket. and it looks to be 1sample off. so you must remove 4bytes from the start of data
to get correct logo. but likely it's also my fault could be a bad dump.
Vigi, could you, please, check your DC rings?
i've uploaded the program here that will do circ delay lines and output ring to ASCII.
ring2ascii.bat s 2058 10 RING_data.raw >SSRing
ring2ascii.bat s 1078 10 RING_data.raw >DCRing
i'll try to write something to reconfigure this data depending on cd in next few days,
maybe something shows up, some blured franken-image...
also, maybe new burners could write this logo easy, if you could specify CAV mode and speed,
i think, that's pretty much all there is.