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Sega Saturn - Cross Products Mirage CD Emulator - preservation / file formats

Radar

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I'm currently working on backing up the contents of a Sega Saturn Mirage CD Emulator HDD and need some help with the best way of testing the files I've found on it.
There is a WIP project on the drive (very small and early - from the file names in the compiled log it may be an unreleased Football game, so nothing super exciting)

The compiled code on the Mirage is in the .DSK format which while a Mirage can read and load, (And my CardDev/Saturn setup isn't complete to test that) I've had no luck finding any tools that can open/run or emulate Saturn games in this format. The Mirage manual mentions using its CPBUILD tools to convert the .SCR into an .RTI file for writing to CDr. There is a .TOC and other headers in the Project directory as well)

Does anyone have any experience in working with files of these formats? Is the Mirage software publicly available?
 

HI_RICKY

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on Mirage CD Emu , it direct link to CD burner to burn master. some dev house have ISO tool
convert .VCD / RTI to ISO , but no one have it

btw , if you got all file , should be normal burn /build to image should be work
 

Radar

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on Mirage CD Emu , it direct link to CD burner to burn master. some dev house have ISO tool
convert .VCD / RTI to ISO , but no one have it
btw , if you got all file , should be normal burn /build to image should be work

Thanks, it looks like all the files are present, the small size of the .DSK gives me concerns about how complete / early this is.
Confirmed as a Football/Soccer title

All of the IP. files reference one of the developers previous (released) games.
The .SCR build files is a nice snapshot of the dev environments with the references back to the SourceFile host, filenames and folders with the very UK c:\footy\ appearing frequently.

1596174603758.png
 

HI_RICKY

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it not hard recover back file from .DSK , open the .RTI , it easy read which file and name in DSK location by byte to byte
Screen Shot 2020-07-31 at 6.09.24 PM.png


SCR also easy read :)
Screen Shot 2020-07-31 at 6.05.06 PM.png




here is how Mirage CD EMU take the index work
 
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Druid II

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I can convert it for you, if you send the DSK+RTI files over. I have a converter somewhere.

It's been a while since I last checked so I don't remember the specifics, but iirc the DSK format is a very basic CD image file designed for streaming directly, it's very similar to bin/cue except that it includes the pregap and there's a few bytes of 00s between... I don't remember if it was all tracks or just audio sectors, but basically the data is laid out like that on the CD so the format mimics it so it can just stream data without any cpu processing.

If you just manually rebuild it using the files listed in the RTI, you may or may not get everything right, it's more accurate to convert the DSK+RTI altogether. If there are no audio tracks you can probably just copy the DSK, renamed it to BIN, manually delete the pregap from the start, and write a dummy cue for it. However you will lose audio tracks that way - the audio tracks do specifically need their layouts converted, from what I remember.
Hmm, if you have the audio source files (not just the DSK+RTI), then it is also possible and probably easier to just hack out the first track from the DSK based on the size/layout written in the RTI, and then dummy up a cue sheet that adds the audio source files as separate tracks, again using the layout listed in the RTI. But if you only have the DSK+RTI then this is more difficult.
 
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Druid II

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oh, I think I remember now. In the DSK files, one audio track sector has the 2048 bytes of audio data, then 2 empty bytes (synchronization patterns SYNC0 and SYNC1, look it up in the Red Book if you need to know more) and then 96 bytes of empty/dummy subcode data.

Modern CD images omit the sync patterns (they are always empty?) and store subcode in separate files, but in the DSK data they are interleaved with the audio tracks because that's how the CD drive expects the data to be laid out.

And of course all index00/pregap data is also stored (the RTI file lists them) and the DSK file also has the lead-in (150 sectors) and probably the lead-out too, but I'm writing most of this from memory..
 

Radar

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Thanks Hi_Ricky and Druid II for assistance, I've made some more progress on getting this running.

The STRIPVCD tool available here can convert the .RTI file into a .BIN / .CUE

I've used this to create something that loads in both an emulator and when burnt (with a pile of errors) runs on real hardware.
Game looks pretty early/glitchy and there are no music tracks but it at least partially works.

I'm short the right SCSI cable but once that arrives I'll test it running on the full cartdev/mirage setup and see if it runs better and if some of the issues are caused by the conversion process.

I'll look to release the full HDD dump along with more background around the games development, why it was cancelled etc. so people with more experience can play with it in more detail.
 
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