GD-ROM/GDI and last data track reading

[Berion]

Hello everyone,
I hope I'm writing in the proper forum section. If not, I'm sorry but I cannot find it more fit than in general discussion.

Since version of IsoBuster 4.7, VMU, GDI and MIL-CD images support was added (it is not advertisement! :P). However, crawling through GDI I see that always if disc image have more than three tracks, 4th is audio and last is data (i.e if there is more audio tracks than 4th, like i.e 20th, then 21 is data track). And here is my question: did we know how games accessing data there? There is two TOCs, one for "low density area", and second for "hi-density area" but there is not third for last track or I don't see anything which would organize view of it. Does games access to last track via LBA or hh:mm:ss so there is not really any filesystem but raw data (disc track used as some kind of VFS) or maybe there is something which I missing? All homebrew readers also doesn't parsing "last track", so this means that no one knows that or access is just via i.e LBA? Some games stores there PVR textures/3D models, some other data. So, well I don't know. Also I'm not familiar with Dreamcast scene as I'm mainly Sony scene guy. ;p

PS: I hope my English is good enough to understand.

[megavolt85]

the last track with data is the continuation of track03
the list of files and their LBA is stored in track03