Where the TOC is stored on a drive

vbimport

#1

The short question I have, do you know of any code example on reading the FAT/TOC table directly on the DVD?

My theory is that you can read disk that has some damage, by implanting a new TOC into the drive controller. (I assume the FAT is kept in drive memory, not on the PC?) or by bypassing it, since most Movies keep the data at roughly the same points.

My goals:

Read a FAT Table. (just because I’ve always wanted to learn more about them)

See if I could read a disk without using it.
See if I could swap the FAT table, with a different (good) on.

While I know a fair bit about coding, and interacting with hardware. I don’t know allot about drive controllers, and was hoping someone here could point me to an example, or a nudge in the right direction.

Thank you.


#2

I don’t think drives ever store the FAT since they are OS/platform independent. It is the OS that has to read sectors from the disc and parse the file system. Some discs do not even have a file system.

The TOC is stored in the leadin of the disc and that is what the drive will read. There’s no file information in the TOC though. Only info like number of layers, ROM, -/+R RW, leadout address, etc…

RM


#3

[QUOTE=RichMan;2157226]I don’t think drives ever store the FAT since they are OS/platform independent. It is the OS that has to read sectors from the disc and parse the file system. Some discs do not even have a file system.

The TOC is stored in the leadin of the disc and that is what the drive will read. There’s no file information in the TOC though. Only info like number of layers, ROM, -/+R RW, leadout address, etc…

RM[/QUOTE]

Thank you for your responce.

Is it the driver keeps a translation between file name and TOC offset?


#4

It’s not really the driver. The data on the disc is just raw bytes that only mean something to the OS or software that gets this data and then parses it to find what it contains. The file names and directory names are just raw data on the disc.

If the OS finds a file system when it starts looking at the data, it continues to read the sectors from the disc. Each sector will tell it what directory names and file names are and also where the files can be found on the disc. When you ask to open or copy a file from the disc, it goes to the correct location and reads how ever many sectors that are needed to make the entire file.

Hope this helps. It’s a bit tough to put in easy terms.

RM