Anybody know a SEGA Saturn Hardware Dev?

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Ceph
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Post by Ceph »

Dreamcast could play CD+G, that's how the exploit works.
Saturn can also play CD+G. However, if Saturn could execute code from a CD-R without bios modification wouldn't someone have discovered this by now?
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Ex-Cyber
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Post by Ex-Cyber »

I'm more interested in this because it would allow publishing new Saturn games. Warez and homebrew aren't that hard if you actually want to play with them.

It seems possible in principle, but I'm not aware of anyone who has actually burned a working disc. The signature does consist of normal data in the CD channel (unlike PS1) and has been dumped, but there are enough little gotchas that it's not a straightforward process to get an acceptable disc. Relevant info is here. If CD-ROM structure in general is a mystery to you, you could try reading this.

In any case, don't get your hopes up too much; the most likely outcome is a pile of coasters.

Another option, which is noninvasive but still requires additional hardware, is a cartridge firmware containing a loader for patched discs. As far as I know, the only reason that this doesn't exist is that nobody has gotten around to writing it.
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jonny5
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Post by jonny5 »

you can actually run backups on a saturn without modding with a chip using the swap method...

you just have to tape down the sensor that tells the saturn that the lid is open and then just use a retail disc for the swap...

you can see videos of it on youtube

although if you want to play backups of imports you have to patch the region on the iso....

but ya....it is doable....just more work than on a DC
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antron
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Post by antron »

How does the saturn modchip even work? what does it do?
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Ceph
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Post by Ceph »

It modifies the the signal coming from the laser and tells the Saturn that every disc you insert contains the Saturn copy protection ring near the disc's edge (which is what the consoles checks before booting a game).
Last edited by Ceph on Fri Jun 27, 2008 1:25 pm, edited 1 time in total.
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antron
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Post by antron »

does anyone know if this ring is actually on a part of the disc that is burnable on a cdr?
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D
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Post by D »

Just release your game with swap disc instructions. :lol: Or make a game that will allow more time and on-screen instruction of how to swap, like the action replay for instance. I will keep following this thread as I am now curious!
trivial
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Post by trivial »

antron: with rail / firmware mods to a burner, I would think the issue would be blank media. Love to be proven wrong on that score.

But I don't think Saturn has much to offer a homebrew dev, sadly. The quantity of chips in the "iron" is probably not good compensation for each chip's low speed by modern standards.
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antron
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Post by antron »

here is a thread like this one but with some information about the ring and its data:

http://club.cdfreaks.com/f80/sega-satur ... on-132193/

it's on the outer edge. can't a cd be over-burned all the way out?
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Ceph
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Post by Ceph »

Correction, it wasn't CD+G that allowed hackers to hack Dreamcast, it was Mil CD. http://en.wikipedia.org/wiki/Mil-CD
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trivial
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Post by trivial »

well shit you sure wouldn't need to mod a burner's rail to write the outer edge of a disc. I dunno, mang
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antron
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Post by antron »

trivial wrote:well shit you sure wouldn't need to mod a burner's rail to write the outer edge of a disc. I dunno, mang
and 90 min cd-rs exist. one guy at cdfreaks burned 93 min of audio to one. this looks doable
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Ceph
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Post by Ceph »

As you can see, they couldn't get it to work in over 5 years and have seemingly given up. I wouldn't expect anything to come out of this. It may simply be physically impossible for CD writers to write to the position of the protection ring. The PS1 protection can't be duplicated with CD-Rs, either.
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antron
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Post by antron »

Ceph wrote:As you can see, they couldn't get it to work in over 5 years and have seemingly given up. I wouldn't expect anything to come out of this. It may simply be physically impossible for CD writers to write to the position of the protection ring. The PS1 protection can't be duplicated with CD-Rs, either.
damn Ceph, why do you have to be so f*cking realistic?
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antron
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Post by antron »

I have a better idea, if Action Replay can run code on a saturn from a cart in the memory expantion slot, why can't someone load an entire homebrew or game? imagine if the AR had a USB slot for flashdrives
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Post by Udderdude »

Step 1. Obtain Saturn
Step 2. ???
Step 3. LOL HOMEBREW COMMUNITY!

Sadly it doesn't work like that. The Saturn is too much of a pain to develop for in the first place.
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Ceph
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Post by Ceph »

Why don't you simply use a Dreamcast for homebrew? There's really nothing a Saturn can do that a DC can't.
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Post by Ex-Cyber »

antron wrote:How does the saturn modchip even work? what does it do?
My understanding of it is: It sits between the drive itself and the motherboard, so it can control the low-level communication to/from the reader unit. It watches for a command to seek into the ring area, and then takes over the command stream, nullifying that seek command by corrupting the checksum byte for the command packet (if it didn't do this, the reader would try to seek beyond the recorded area and freak out). Then it generates fake sectors containing the small portion of the ring data that the CD controller is actually looking for (from the patent, this most likely corresponds to part of the Sega logo visible on the disc), also generating some fake status data to make it look like the drive is actually reading. When the CD controller is satisfied, it asks to seek back to the beginning of the disc, and seeing that, the modchip releases control of the interface. Gory details, and even VHDL for those who can read it, are somewhere on the page I linked in my previous post (not my page, if you're wondering).
antron wrote:I have a better idea, if Action Replay can run code on a saturn from a cart in the memory expantion slot, why can't someone load an entire homebrew or game?
Someone hasn't written AR firmware that actually does that. No other reason that I know of.
D wrote:Or make a game that will allow more time and on-screen instruction of how to swap
That would mean that you already have your code running, which is more or less the goal of swapping. If you have some other means to load code, then you may as well write a custom bootloader and use a disc without a Saturn header.
Ceph wrote:I wouldn't expect anything to come out of this.
I wouldn't either; I'm not sure that it's possible with standard burner firmware.
Ceph wrote:It may simply be physically impossible for CD writers to write to the position of the protection ring.
That's not the problem; AFAIK the problem is that it's tricky to write the data where it's supposed to be without tripping up some other secondary consistency check (IIRC, I've been told that the TOC cannot claim that leadout starts after where the ring is supposed to be and that the disc can't be multisession, and I suspect that the offsets in the sector headers have to be consistent with Q subcodes at the same locations).
Ceph wrote:The PS1 protection can't be duplicated with CD-Rs, either.
The PS1 signature is much more cleverly hidden; normal readers lose it before the raw laser signal is even digitized. The Saturn signature is merely beyond what the TOC claims to be the end of the disc. Judging from the patent, Sega expected discs with this protection to be copied; that is the reason for incorporating a visible Sega logo in the ring (to invoke trademark law against makers/sellers of unauthorized discs).
Ceph wrote:Why don't you simply use a Dreamcast for homebrew? There's really nothing a Saturn can do that a DC can't.
There's really nothing a Dreamcast can do that a 5-year-old PC can't. People generally code for non-current consoles because they like the challenge and/or because they like the particular console, not out of practical considerations (another reason that this wouldn't magically supercharge the Saturn homebrew scene). To put it another way, people typically don't think "I have this cool idea for a homebrew game/app; which console should I put it on?", they think "I should write something cool for this console; what would be interesting and feasible given its limitations?"
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iatneH
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Post by iatneH »

I know there are ISOs of the two Saturn development discs floating around the net.

I wonder if you can "make" a boot disc out of these by burning the ISO to a mini-CD, and gluing it to the bottom of some cheap-ass EA Sports game so you get the outer ring... now there would be problems of altered weight, thickness, and focal depth of the outer ring. But wondering if there is a remote chance for it to work.
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ED-057
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Post by ED-057 »

Saturn is the console ever. I would do some homebrew on it if I could ever find one of those "PC Comm Card" (an old ISA jobby that has a port on it to connect to the DB25 on the Action Replay). I saw a page once where someone made their own interface but it ran at some pitiful speed like 20KB/s.

It would be cool if there was a way to run CD-Rs without a mod chip or the swap trick (or other complicated hardware mods). Since it hasn't yet been done, I'm betting that it isn't possible. Probably there is no way to run custom code on the drive CPU, and no way to access the drive from the main CPU, other than by sending a request to the drive CPU which will always verify the disk copyright string first.
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Post by Ex-Cyber »

ED-057 wrote:It would be cool if there was a way to run CD-Rs without a mod chip or the swap trick (or other complicated hardware mods).
AFAIK there is a way, with an AR running custom firmware. However, it wouldn't be able to load unmodified Saturn copies; the header would need to be altered.
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