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darcagn

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Ah, the hot swapping is where the problem would have been. The tracks are greatly different sizes because it dumped based on the track sizes of the discs you used before swapping. So it continued dumping past the real track boundary, returning garbage data.

For dumping GD-Rs, you should insert the GD-R without a swap trick first, then dump the first two tracks. Then insert a regular GD-ROM and do a swap trick back to the GD-R for the high density.
 

PrOfUnD Darkness

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Ah, the hot swapping is where the problem would have been. The tracks are greatly different sizes because it dumped based on the track sizes of the discs you used before swapping. So it continued dumping past the real track boundary, returning garbage data.

For dumping GD-Rs, you should insert the GD-R without a swap trick first, then dump the first two tracks. Then insert a regular GD-ROM and do a swap trick back to the GD-R for the high density.

Can you elaborate a bit more? A google search brings so many different ways to dump a gd-r, hard to tell.
 

darcagn

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Can you elaborate a bit more? A google search brings so many different ways to dump a gd-r, hard to tell.

Sure.

First, if you have a System Disc 2, the method is basically to insert your dumping software, then insert a System Disc 2, wait for it to spin up and be identified, then open the disc lid and put in a GD-R and you can dump as many GD-Rs as you want as if they were standard GD-ROMs. Until you power off the console.

For those with out a System Disc 2, the GD drive will only see the standard density session (the first two tracks). So a swap trick needs to be done to fake the drive into authenticating the disc from a real GD-ROM but then swap (with lid switch held down) to a GD-R.

However the drive will cache the track listing of the original GD-ROM. So for example if you use Crazy Taxi as a GD-ROM:
Code:
[standard density]
track01 - sectors 0 - 449
[gap] - sectors 450 - 599
track02 - sectors 600 - 1126
[high density]
track03 - sectors 45000 - end

The drive will have that track layout cached whenever any dumping software requests to begin dumping.
But what if the game you're dumping on GD-R has this track layout:
(example is from Fur Fighters proto GD-R)
Code:
[standard density]
track01 - sectors 0 - 674
[gap] - sectors 675 - 824
track02 - sectors 825 - 1351
[high density]
track03 - sectors 45000 - end

The drive will have the Crazy Taxi layout cached, and when any dumping software on the Dreamcast system requests the track layout, it will receive the track layout for Crazy Taxi, even though Fur Fighters is inserted.
If you are using the SD Rip software for example, and clicked the button to dump the entire disc, this is what would happen:

  • file for track01 would be 450 sectors in size when it should be 675 sectors. So this would be a truncated track.
  • file for track02 would start at sector 600 when it should start at sector 675. Since it would be reading in audio mode at sector 600 on the GD-R which is actually still data mode from track 1, it will be a read type mismatch and your dump will be filled with sectors full of garbage data.
  • If the dumping software doesn't error out at this point then track02 would start with garbage data and then some real data then the rest of the track would be truncated.
  • file for track03 would be perfect dump, and since the entirety of the game is in track03, the dump would function 100% fine.

Also, the .GDI file saved by the dumping software would also be based off of the Crazy Taxi disc, not the Fur Fighters disc.

The game itself would be fully intact in a scenario like this, but for preservation nerds like myself, this is technically a bad dump as the whole standard density session is screwed up.

The correct way to go about doing this is to load up your dumping software and insert the GD-R. The disc will fail to authenticate so you will only get the first 2 tracks displayed, but they will be the correct track layout for those two tracks. Dump the first two tracks and save them. Then in order to get the 3rd track, do your swap tricks.

Now keep in mind, this only gets you so far dumping without a System Disc 2 because we are lucky that there's only 3 tracks in the high density session. If there are more than 3 (any Dreamcast games with CDDA), then you couldn't dump those with Crazy Taxi because it will only see one huge data track and not see any of the CDDA tracks, and it would error out with read type mismatches when trying to read audio tracks in data mode. For those games, you need to find existing GD-ROMs with audio sectors overlapping the same ranges, and dump specific sector ranges using different swap discs, and then re-assemble the sectors on your computer.

The SD Rip software doesn't let you dump by specifying sectors, though. Only the Broadband Adapter software (httpd-ack) supports sector range dumping, so you will need a Broadband Adapter to dump CDDA GD-Rs (unless someone wants to write new SD ripping software). httpd-ack also lets you view the proper track layout of a swapped disc (by reading the track layout from the disc IP.BIN manually instead of drive's cache) and allows you to save the proper version of the .GDI with that info. But it is still bound to the limitations of the drive when dealing with read type mismatches (so basically 1. use httpd-ack to dump first two tracks, 2. do a swap trick and read track layout via IP.BIN mode, 3. write down the track layout it gives for the CDDA tracks, 4. browse the TOSEC archive of GDIs and find a game (or games) that have overlap in audio sectors in common, 5. obtain said GD-ROMs, dump all the audio sectors by manually inputting their ranges into httpd-ack 6. on a computer, use a hex editor or whatever to cute and paste/reconstruct the ranges of audio data into individual track files).

Because this is such a complicated process it's much better to just have a System Disc 2 if you're dealing with a GD-R that has CDDA in the high density session. And that is why I offer my services for free for anyone who needs a proper GD-R dump done. I am happy to just do the dump myself and ship it back, or walk anyone through if they're willing to get the Broadband Adapter. I've done several with damaged GD-Rs that needed manual repair as well. I am just a data hoarder/preservationist nerd so that's my motivation. Most people are doing Redump these days for GD-ROM dumping (esp. since TOSEC GDI set is pretty much complete) but Redump methods can't do GD-Rs so I feel there's not many people who are well versed in the complexities of getting a perfect dump from GD-Rs using the real Dreamcast methods. And I really don't want to see GD-Rs get dumped incorrectly and disappear into some private collection forever.
 

darcagn

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@thedoctor45 revisiting the two dumps again and analyzing them in a hex editor, the original release of the files in ISO format is a correct and proper dump as far as I can tell. So for everyone who downloaded it originally, that's good enough. However for the raw dump, track 01 is cut very short, and track 02 contains data which should be in track 1 with a bunch of read type mismatch garbage data. If you open the .GDI from the original ISO release in notepad and compare the track listing to the one from the raw dump you will see that the tracks aren't at the same position or size.
 

PrOfUnD Darkness

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Sure.

First, if you have a System Disc 2, the method is basically to insert your dumping software, then insert a System Disc 2, wait for it to spin up and be identified, then open the disc lid and put in a GD-R and you can dump as many GD-Rs as you want as if they were standard GD-ROMs. Until you power off the console.

For those with out a System Disc 2, the GD drive will only see the standard density session (the first two tracks). So a swap trick needs to be done to fake the drive into authenticating the disc from a real GD-ROM but then swap (with lid switch held down) to a GD-R.

However the drive will cache the track listing of the original GD-ROM. So for example if you use Crazy Taxi as a GD-ROM:
Code:
[standard density]
track01 - sectors 0 - 449
[gap] - sectors 450 - 599
track02 - sectors 600 - 1126
[high density]
track03 - sectors 45000 - end

The drive will have that track layout cached whenever any dumping software requests to begin dumping.
But what if the game you're dumping on GD-R has this track layout:
(example is from Fur Fighters proto GD-R)
Code:
[standard density]
track01 - sectors 0 - 674
[gap] - sectors 675 - 824
track02 - sectors 825 - 1351
[high density]
track03 - sectors 45000 - end

The drive will have the Crazy Taxi layout cached, and when any dumping software on the Dreamcast system requests the track layout, it will receive the track layout for Crazy Taxi, even though Fur Fighters is inserted.
If you are using the SD Rip software for example, and clicked the button to dump the entire disc, this is what would happen:

  • file for track01 would be 450 sectors in size when it should be 675 sectors. So this would be a truncated track.
  • file for track02 would start at sector 600 when it should start at sector 675. Since it would be reading in audio mode at sector 600 on the GD-R which is actually still data mode from track 1, it will be a read type mismatch and your dump will be filled with sectors full of garbage data.
  • If the dumping software doesn't error out at this point then track02 would start with garbage data and then some real data then the rest of the track would be truncated.
  • file for track03 would be perfect dump, and since the entirety of the game is in track03, the dump would function 100% fine.

Also, the .GDI file saved by the dumping software would also be based off of the Crazy Taxi disc, not the Fur Fighters disc.

The game itself would be fully intact in a scenario like this, but for preservation nerds like myself, this is technically a bad dump as the whole standard density session is screwed up.

The correct way to go about doing this is to load up your dumping software and insert the GD-R. The disc will fail to authenticate so you will only get the first 2 tracks displayed, but they will be the correct track layout for those two tracks. Dump the first two tracks and save them. Then in order to get the 3rd track, do your swap tricks.

Now keep in mind, this only gets you so far dumping without a System Disc 2 because we are lucky that there's only 3 tracks in the high density session. If there are more than 3 (any Dreamcast games with CDDA), then you couldn't dump those with Crazy Taxi because it will only see one huge data track and not see any of the CDDA tracks, and it would error out with read type mismatches when trying to read audio tracks in data mode. For those games, you need to find existing GD-ROMs with audio sectors overlapping the same ranges, and dump specific sector ranges using different swap discs, and then re-assemble the sectors on your computer.

The SD Rip software doesn't let you dump by specifying sectors, though. Only the Broadband Adapter software (httpd-ack) supports sector range dumping, so you will need a Broadband Adapter to dump CDDA GD-Rs (unless someone wants to write new SD ripping software). httpd-ack also lets you view the proper track layout of a swapped disc (by reading the track layout from the disc IP.BIN manually instead of drive's cache) and allows you to save the proper version of the .GDI with that info. But it is still bound to the limitations of the drive when dealing with read type mismatches (so basically 1. use httpd-ack to dump first two tracks, 2. do a swap trick and read track layout via IP.BIN mode, 3. write down the track layout it gives for the CDDA tracks, 4. browse the TOSEC archive of GDIs and find a game (or games) that have overlap in audio sectors in common, 5. obtain said GD-ROMs, dump all the audio sectors by manually inputting their ranges into httpd-ack 6. on a computer, use a hex editor or whatever to cute and paste/reconstruct the ranges of audio data into individual track files).

Because this is such a complicated process it's much better to just have a System Disc 2 if you're dealing with a GD-R that has CDDA in the high density session. And that is why I offer my services for free for anyone who needs a proper GD-R dump done. I am happy to just do the dump myself and ship it back, or walk anyone through if they're willing to get the Broadband Adapter. I've done several with damaged GD-Rs that needed manual repair as well. I am just a data hoarder/preservationist nerd so that's my motivation. Most people are doing Redump these days for GD-ROM dumping (esp. since TOSEC GDI set is pretty much complete) but Redump methods can't do GD-Rs so I feel there's not many people who are well versed in the complexities of getting a perfect dump from GD-Rs using the real Dreamcast methods. And I really don't want to see GD-Rs get dumped incorrectly and disappear into some private collection forever.

Thank you for the explanation. I can probably use your help, I have the BBA and a few GD-R I'd like to dump, nothing really exiting but worth preserving for sure.
 

darcagn

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Thank you for the explanation. I can probably use your help, I have the BBA and a few GD-R I'd like to dump, nothing really exiting but worth preserving for sure.

Sure, feel free to PM me anytime and we can work together on them.
You'll just need to set up your Dreamcast with a static IP (using XDP or Broadband Passport or something) -- can't use a dynamic IP/DHCP.
Then boot the httpd-ack disc and access the disc from a web browser on your LAN.
All of the ones with 3 tracks will be pretty straightforward for me to help you get going, but CDDA ones might require me helping you find swap GD-ROMs and piecing together tracks. You can hit me up on here, DCEmulation, IRC, Discord, etc.
 
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