Re: Dreamcast 2 once and for all!
[quote author=Saoshyant link=board=news;num=1088473728;start=30#33 date=07/04/04 at 07:14:01]What? GD-ROMs are not high quality CDs! They are double layered CDs, which can take the double amount of a normal CD. It's not a new thng since some DVDs have this feature too. It has a great drawback, in where a small scratch can do a lot more damage (i.e. corrupt data) than in a normal CD.[/quote]That is specific to DVDs. GD-ROMs are *not* dual-layered. Where the heck did you hear that? It has data seperated into two REGIONS, not two layers. The one low-density region is on the inside of the disc (near the center in other words), and can be read by regular CD drives. The outside section is the part where they put the game, the high-density part. Dual Layer discs are completely different, and involve a translucent data layer physically on top of an opaque data layer. That's a lot more complicated, which is why we are only recently seeing DVD burners capable of writing to new DL DVD+R/RW discs.
http://mc.pp.se/dc/gdrom.html
[quote author=Saoshyant link=board=news;num=1088473728;start=0#13 date=06/29/04 at 15:57:06]The SH5-100 is the latest SuperH chip. It's clocked at 900 MHz and it's back-compatible with the SH-4. You put 2 PowerVRs and maybe a Geometry Engine and it rocks![/quote]I don't know if a standard SH-5 has the extra instructions specific to the SH-4 in the DC. Not like it really matters with that kind of power. Also, you wouldn't use two outdated PVR cores and a seperate geometry chip. You've got "Naomi 3" (or whatever they'll end up calling it) technology to play with. That means instead of using 2 Series 2 and a T&L unit, you use a Series 5 PVR chip.
Re: Dreamcast 2 once and for all!
You are quite right about the GD-Roms, thank you for clearing out. However, you are wrong about the rest. Putting two powerVRs is stupid yes, it was kind of a idea I got while examining Naomi 2 hardware, but the geometry engine would be really cool. Moreover, the SH5 does is backwards-compatible with SH4 instructions, meaning you could play Dreamcast 1 games easialy with some optimization. No extra CPUs nor anything else needed.
Re: Dreamcast 2 once and for all!
[quote author=Saoshyant link=board=news;num=1088473728;start=30#41 date=09/22/04 at 20:30:43]You are quite right about the GD-Roms, thank you for clearing out. However, you are wrong about the rest. Putting two powerVRs is stupid yes, it was kind of a idea I got while examining Naomi 2 hardware, but the geometry engine would be really cool. Moreover, the SH5 does is backwards-compatible with SH4 instructions, meaning you could play Dreamcast 1 games easialy with some optimization. No extra CPUs nor anything else needed.[/quote]
The SH4 in the DC was a special chip made for sega, based on SH4s. It may (or may not) have instructions in it which are not included in the standard SH5s because of this.
Re: Dreamcast 2 once and for all!
On the SH5, I'm afraid it is as Quzar said. You can't assume it has those specific instructions unless you see it on paper. Although I said it didn't really matter with that kind of power. After all, you could probably build a software layer to handle those instructions.
Also, I don't think you understand what the geometry chip in the Naomi 2 was for. The Series 2 chips do not have hardware T&L, meaning that work has to be done on the SH4. So when they added a second PVR chip they used a dedicated chip (codenamed "Elan" I believe). It takes the burden off the SH4, which is good because 1) It frees up the SH4 for other things and 2) The second PVR would push more polys than the single SH4 can handle.
Now that you understand that Elan was a way of adding dedicated T&L, I'll tell you why they don't need it anymore. You see, Series 5 already HAS T&L in its core, and in fact it is a lot more modern. It is probably DX9 compatible, programmable T&L, much like the newest Geforce cards in functionality.
Re: Dreamcast 2 once and for all!
Oh for God's sake, I know that Alex. I also read the segatech.com pages, but maybe it was my fault that I did not make myself very clear, sorry for that. Though I really do not know anything about the Series5, can you give me one or two links for it please? Quzar I believe there are no special instructions on the SEGA custom SH-4, but if there are you only need to consider that if SEGA was to make a new system they would not use a standard SH-5. Now about the idea of the Geometry Engine, I did not mean just a Elan (T&L) chip like the Videologic one in the Naomi 2. I wanted to say a different hardware that instead of coming from the makers of PowerVR like the GE on the N2, would complement the GPU with new technology like let's say Truform. So, what I mean with this is that the GE could for instance be created by ATi. The idea was to complement anything a PowerVR would lack not just T&L (which apparently the Series5 has and I did not know). Hope I make my point clear this time, sorry. Maybe it is not a good idea, but I do think it could work, though possibly making the system more expensive, I don't know.... Comments please (and don't forget to post a link to info on the Series5 please).
Re: Dreamcast 2 once and for all!
The custom SH4 in the DC most certainly has extra instructions. You could probably just emulate them for backwards compatibility mode, as I tried to say.
You don't want to go throwing extra chips in for no reason. The Series 5 chip could do all of that, just like any other modern programmable GPU. If it's not fast enough for you, you integrate more units into the GPU core. You don't need to go off an use extra chips unless you have to. I mean at that point wouldn't it be better to include a second SH5, since it could help with anything, being a powerful general purpose chip?
Series 5 is what is going into Sega's next arcade system. http://www.xbitlabs.com/news/video/d...522053649.html
