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possible boot disc

Chris - May 1, 2004

		Chris	May 1, 2004
		Is it possible to make a boot disc where you would load it up, then swap for the import disc allowing it to be played on a sega cd such as a japanese game being played on a us system? Aka along the lines of how freeloader works.

		gameboy900	May 2, 2004
		No. The SCD hard resets when the drive door is opened. And bypassing the switch wouldn't work because the new disc wouldn't have it's TOC read in.

		deadearth	May 2, 2004
		I thought Mask of Destiny was working on a boot disc? Was that before he discovered this?

		Arakon	May 2, 2004
		his bootdisk is a loader for small apps and files, I believe, which have to be on the same disk (or transferred via printerport? not sure).

		junker	May 2, 2004
		I have to say, if your in the game of wanting to play imports on your sega cd, then Arakon is the man to speak to. His multi region eeprom is absoloutly incredible, easy to fit and it beats a would be boot disc any day. I have recently recieved my eeprom from Arakon (complete with IC socket and 2 switches), and after studying his installation tutorial, I installed it into my Mega CD 1 (PAL), and before long I was playing burned imports. I'm not sure if anyone has had problems with the region converting software (conv scd, scdconv), but when I used to use it to change regions then burn a game, most of my backups wouldnt work on the real system (although they would on Gens). Therefore the only alternative was to install Arakons chip. To cut a long story short - Arakon kicks ass!

M3d10n

May 4, 2004

Originally posted by gameboy900@May 2, 2004 @ 05:02 AM

No. The SCD hard resets when the drive door is opened. And bypassing the switch wouldn't work because the new disc wouldn't have it's TOC read in.

deadearth

May 4, 2004

Originally posted by M3d10n+May 4, 2004 @ 10:15 PM--><div class='quotetop'>QUOTE(M3d10n @ May 4, 2004 @ 10:15 PM)</div><div class='quotemain'> <!--QuoteBegin-gameboy900@May 2, 2004 @ 05:02 AM

No. The SCD hard resets when the drive door is opened. And bypassing the switch wouldn't work because the new disc wouldn't have it's TOC read in.

It resets? Are you sure? I used to fuck up with my SCD all the time, by removing the CD while playing, in Sonic CD, as example, and putting an audio CD instead. Then I could play the whole level while listeting to track 1 from the audio CD.

Of course I needed to switch back to the game disc before time-traveling or completing a level, or it would hang on teh load screen. I did that with Ecco 2 too, and the CDX I bought acts the same. [/b][/quote]

That reminds me. Surely it doesn't hard reset, because then multi-disc games like night trap wouldn't work without a savegame feature. From my understanding it does work without a save feature.

Assuming that there isn't some other meaning of hard reset that i'm not aware of.

		it290	May 5, 2004
		Hmm... that might work on a SCD2, but on the first one you'd have to figure out how to eject the disc. I haven't played any of the multi-disc games, but I'm sure a game like Night Trap could create a temporary file between discs, if a reboot was necessary.

		Mask of Destiny	May 5, 2004
		The Sega CD does not do a hard reset on the opening of the CD door/tray. On Model 1 units, it can be opened by a simple BIOS call. I have done some work on a Sega CD boot disc (not to be confused with my bootloader SLO) but it is not complete.

deadearth

May 5, 2004

Originally posted by Mask of Destiny@May 5, 2004 @ 09:26 AM

The Sega CD does not do a hard reset on the opening of the CD door/tray. On Model 1 units, it can be opened by a simple BIOS call.

I have done some work on a Sega CD boot disc (not to be confused with my bootloader SLO) but it is not complete.

Like always, thanks for your wisdom, oh great one

fonzievoltonov

May 11, 2004

No, it donesnt reset, i used too to change SEGACD games during a play and the games continued to run until the next load (i always got a very cool crash effect).

I also used to:

Run a sega genesis game:

Switch (after the copyright logo of my genny2) the cartridge in sega cd mode.

Press reset.

Start to play a music disk on the segacd.

Put the cartridge in genesis mode.

Reset the console.

And play my genesis game while the segacd is playing music.

So, the sub cpu seems to continue to work but never reseted (because the genny never look at the bios, maybe?).

Bye

Fonzie

Chris

Jun 9, 2004

have done some work on a Sega CD boot disc (not to be confused with my bootloader SLO) but it is not complete.

It's great to hear your working on a boot disc for sega cd. Hopefully it will be successful.

Mask of Destiny

Jun 9, 2004

Originally posted by Chris@Jun 9, 2004 @ 05:02 AM

have done some work on a Sega CD boot disc (not to be confused with my bootloader SLO) but it is not complete.

It's great to hear your working on a boot disc for sega cd. Hopefully it will be successful.

I recently hit a bit of a snag. It would seem that either the BIOS or maybe even the CD controller itself fails to reread the TOC after a disc swap. If you try to read from a block address beyond the range of data on the first CD, the read will fail even if its a valid address for the CD you have just inserted. It could be a little while before I figure out how to get it to reread the TOC.

		M3d10n	Jun 9, 2004
		Maybe you could pad the boot disc full of data? Even if odds are very, very few games would even boot, who knows?

Mask of Destiny

Jun 9, 2004

Originally posted by M3d10n@Jun 9, 2004 @ 05:15 PM

Maybe you could pad the boot disc full of data? Even if odds are very, very few games would even boot, who knows?

I could, but that would only work for games that had no audio tracks. I'll have to dig around in the BIOS for the appropriate call to do it. The CD player program inside the BIOS seems to be able to handle disc swapping so if I look there I should be able to find it.

		WiseMan	Jun 12, 2004
		i dont c y any1 should need a bootdisc import games have always worked fine on my mcd2 providing i changed the country code with scdconv. so whats the deal here?

M3d10n

Jun 12, 2004

Originally posted by WiseMan@Jun 13, 2004 @ 12:39 AM

i dont c y any1 should need a bootdisc

import games have always worked fine on my mcd2 providing i changed the country code with scdconv.

so whats the deal here?

The "deal" is that SCD games don't have "country codes" in the likes of Saturn games. The country detection is performed by the game, not by the system.

SCDConv only works with a certain number of games that happens to use very similar and easy to locate country detection routines, so it can patch them. But I have a bunch of games it'll fail to convert, since those games use custom country deteciton schemes.

		Chris	Jun 12, 2004
		Mask of Destiny would it be possible to solve your snag by examining games on the sega cd that use two discs?

ExCyber

Jun 13, 2004

The "deal" is that SCD games don't have "country codes" in the likes of Saturn games. The country detection is performed by the game, not by the system.

No, the deal is that the country detection is performed by the system, but it's done by having completely different versions of the logo screen code rather than with flags. The codes vary in length, so you can't convert from a shorter code to a longer one without moving the game's boot code, and sometimes moving the boot code makes it not work.

		WiseMan	Jun 13, 2004
		thx for the info on the boot M3d10n and ExCyber now it makes sense to me. what are some popular games that aren't patchable?