Puppy Linux Discussion Forum

[Boogle]

Hi, I tracked down this information, I will look into it a bit further once I finish work for the day, but thought I'd post it now so that others can look into it.

Hopefully it is of some use:

Somewhere behind the first 32 k on the CD, a block with information about the CD is located. You can extract the information with the following

shell script:

[Lobster]

I do have a good feeling about this.

I do I do I do

Hope it works. This is excellent news. The MS Puppy (Multi-Session) is one of the innovative aspects of Puppy. It is my favourite potentials.

Now I know you said you were busy but you might like to look here . . .
http://www.goosee.com/puppy/development/developer.htm

If you scroll to the entry for June 5th
http://www.goosee.com/puppy/news.htm
you will find our Pup in Chief, Barry, has been reduced to profanity by the burden of development. . . . (he loves it really)

So Boogle, stick around. You might decide Puppy is worth adopting. Don't those big Puppy eyes and whimpering do anything for you . . . ?

Puppy - Linux - but cuter

[Boogle]

I did see the projects page a few days ago, and since I tried myself to burn a multi-session disk, but it still made a file on my HD, I decided to find out what was going on.

I to thought it is such a good idea that warranted a bit of time to find a solution.
I actually think that it should default to CD-profile, if it is mult-session, then write back to the CD, otherwise ask the user.
That would be the way I'd see it done.

But automatically choosing HD or CD is fine as long as it works!

I'll be finished up work soon, will then have to cook tea for the masses, and then I'll see if what my redhat server can tell me about the first 32k on both a closed and open CD.

In reference to Barry's June 5 entry, since Barry has got this far, I am suprised there are so few expletives around!!!...

[Boogle]

Just ran a few quick tests. 1stly, you need to ensure there is only 1 space in the array of numbers in the for loop. The script I copied had multiple spaces sometimes.

2ndly, so far the data returned just look like the following:
CD name, Info about the software that created the iso image or created the data cd. (So Nero will have a comment here in a Nero Data CD)
And then some dates.
Not very useful so far...

[Boogle]

Ok, time to figure out how a cd works.

What does "finalize" mean?

Finalizing is the process of writing the final TOC (Table of Contents), which allows disks to be played on standard players. Unfinalized CD-R disks can be played on other CD-R recorders, but cannot be played on standard CD players until they have been finalized.
Once finalized, CD-R disks cannot be used for additional recording; the recording is permanent. Unfinalized CD-RW disks can be played on other CD-RW recorders. Unlike CD-R disks, CD-RW disks can be erased. You can erase the last track or the entire disk.


What is a TOC?

It is an acronym for Table of Contents. The TOC contains track and index numbers, track start and end times, and track length information, and is read each time a disk is loaded into a CD player.




So anyway I assume that the TOC needs to be at a pre-defined place... At the start of the disk... We need to have a look at the TOC to see the differences between multisession (one session) open, multisession (more than 1 session on disk) open, multisession closed, single session closed. I will try to find exactly this.

Further information:
On a conventional CD of any flavor, the first information the reader sees is the Table Of Contents (TOC). In CD-DA, the .CDA 'file' specifying each track is a fiction that a file manager (like Explorer) uses. In a single-session, closed disc, the TOC contains information which is interpreted by a DOS extension as being a directory. The rules for converting TOC information (including the fact that everything on the disc is read-only) are embedded in the extension, such as DOS's MSCDEX. On a multisession disc, the TOC for the first session tells the system where to find the next one - or whether the current one is the last, or whether the disc is now closed. DAO is necessarily single-session (which is why one cannot write DAO tracks in Mixed or CD-Xtra formats).

[BarryK]

Very interesting!
keep going... the anwer is in there somewhere!

[Ian]

The trick is how to read the TOC. Finding out how to do this on the net is like getting the back teeth out of a Bengal tiger.
The standards govening CD burning should give some idea I think.

[Guest]

You hit the nail on the head Ian.

I have continued the research, but it's been sparse, lots to do at work.

What I have found out is that when you close a CD it writes the absolute lead-in and final TOC in a negative sector.

Which I believe is at -02:32:19 (sector: -11419)

From what I have seen, dd was written initially for disk drives, and doesn't have support for reading negative sectors.

So... What we need is something that will read that section of data, if data exits, the CD is closed.

[Boogle]

Arg, forgot to login, that was from me!

Oh, and it is a long weekend here is Australia. I'll finally have some spare time. Still a lot to do. We are having our place tiled in 2 weeks, so we have to move all the furniture...

But still relatively spare time!

For those are interested in CD writing... (This is just a FYI, doesn't help our research much... I found it interesting anyway)

What is the difference between fixation and finalization?
Fixation is the process of completing a CD-R or CD-RW disc session by writing Lead-In (table of contents) and Lead-Out information. Once a disc is fixated it can then be played back in CD and DVD-ROM drives and recorders and consumer electronics devices compatible with the particular disc type and format. It is also possible to record additional information later to create a multisession disc. Finalization, on the other hand, completely closes the disc so no further material can be added.

[Guest]

Hrm, those sectors are a dead end, they contain ATIP information, and isn't useful to our cause.

Learn more about ATIP (Pre-Groove) here:

http://knowhow.cdfreaks.com/article.php?ID=122

[Boogle]

Dang it logged me out again...

Anyway, I am looking for the "final table of contents" (TOC) at the moment.

There are enough references to it on the web, but not it's location on the disk.

[Jesse]

I also happened to stumble across a program called cdrdao which might just give you the information you're after with its disk-info command. Its hosted on source forge, cdrdao.

http://sourceforge.net/projects/cdrdao/

I found some info here, I had a bit of a look, seems like it moght contain other good lead....

http://www.epanorama.net/links/pc_storage.html

Jesse

[Boogle]

Hrm, It's been a while, so many things to do.

I had a quick look at cdrdao, not sure if it can get much further:

[Boogle]

Actually I looked further into cdrdao and there does appear to be many useful options.

EG:

[Flash]

Multisession CD Bibliography

ANSI T13 ATAPI Technical committee Home page.

BIOS Enhanced Disk Drive Services - working draft 5 Nov 2004
ATAPI Command Set

ATA-ATAPI.COM by Hale Landis

Enhanced IDE FAQ and Utilities

Enhanced IDE/Fast-ATA/ATA-2 FAQ from 2000

Excellent CDR FAQ, mostly for audio CDs but still a lot of info.

Example Subject: [4-16] My multi-session disc only has data from the last session

IML 1501 CD-R/W Encoder Decoder with ATAPI interface