Brasero, multisession CD and visibility of the burned files [Archive]

Alberto1

06-25-2009, 03:57 PM

Hello,
I'm using Ubuntu 9.04 and by means of Brasero I burned a multisession data CD writing on it several files.
A few days later I wanted to add to it other ones obtaining this message, that I'm translating from italian into english: "It's not advisable adding new files to a multisession disc. The already burned files won't be visible (but will be still readable).
As I haven't clearly understood its meaning I'll be grateful to you if you give me a plain explananation of it.
Best Regards

i845_

06-26-2009, 05:35 AM

Shamelessly pulled off the CD-R FAQ (http://www.cdrfaq.org/) by Andy McFadden (with *slight* edits...)

A session is a recorded segment that may contain one or more tracks of any type. The CD recorder doesn't have to write the entire session at once - you can write a single track, and come back later and write another - but the session must be "closed" before a standard audio CD or CD-ROM player will be able to use it. Additional sessions can be added until the *disc* is closed or there's no space left.

When you put a data CD into your CD-ROM drive, the OS finds the last closed session on the disc and reads the directory from it.

Most of the popular CD creation programs allow you to "link" one or more earlier sessions to the session currently being burned. This allows the files from the previous sessions to appear in the last session without taking up any additional space on the CD (except for the directory entry). You can also "remove" or "replace" files, by putting a newer version into the last session, and by not including a link to the older version.

However, in certain cases, (if you happen to use different CD-burning apps to burn different sessions, try burning too many of them*, or maybe forget to do so manually), the files from the previous session(s), may fail to get linked into the current one. This results in a CD-ROM where you can see the new files but none of the old, unless you have a program that lets you choose which session you look at.

Most recording applications these days will ask you if you want to preserve the data from the earlier sessions, or will default to keeping it. Earlier versions of the software either defaulted to throwing it away or didn't support the feature at all.

The files themselves aren't really lost. Some programs are available that will let you access the "lost" data, including IsoBuster and CD-R Diagnostic. Some CD recording software will allow you to extract the data track from a specific session, which you can then access with IsoBuster or WinImage.

A more transparent solution is to use a "session selector", such as the one that ships with Roxio software. This lets you choose which session you see in Windows explorer.

* Some older CD-ROM drives had a "feature" that caused them to stop looking for sessions after a certain point, so if you wrote too many of them you'd "lose" the data from the last session rather than the next-to-last. This is also curable with the above solutions, though you may have to use a more recent drive.Hope this helps.