I've just realised that my Nero burns CD's in TAO (Track At Once) mode... I remember reading a FAQ in this forum earlier strongly advising against using TAO... does this leave DAO (Disc At Once) as the only alternative?

Which mode is better and why? (I only burn data CD's, never audio)

Thnx in advance..

I prefer DAO because it's faster.

It doesn't matter which mode you use while burning compiled data cds. DAO is required/preferred when burning audio cds or protected data cds.

When using TAO, you'll have 2 bad sectors at the end.

I've seen the very end sectors show up as bad on Nero's CD surface scan check even while using DAO, even though this doesn't affect the readability of the CD.

From what I've seen on my CD MP3 player, DOA provides better compatibility and takes less time to read the Table of contents. Otherwise on a PC, I cannot see any difference other than the way it writes the CD and the fact that TAO supports multisession.

@Seanburn: I have seen this too (last time: in the liteon 52x review...), and this is part of the LiteOn-SAO bug. If you encounter this, then upgrade to the latest Nero and use DAO/96.

Thanks for the helpful responses...

Three questions further:

1- what is DAO/96? I noticed this too in the latest Nero version

2- "When using TAO, you'll have 2 bad sectors at the end." Why is this? Does it make a big difference?

3- what makes DAO faster in recording/reading terms in comparison to TAO -- what is the purpose of TAO (just multi-sessioning?)

thanks once again

write modes

DAO is faster because the drive doesn't interrupt the recording process

With standard recording modes such as DAO & TAO, the recorder adds all the extra information such as forward error correction, CRC checksums, etc. while recording to the CD. DAO/96 writing sets the CD recorder to raw writing and leaves it up to the recording software to add all the extra error checking information and CRC information to the data as it's being written to the CD. DAO/96 is also used by Clone CD, Blindwrite, etc. to copy some protected CDs as the software can replicate bad sectors (often used as copy protection) by simply putting in invalid CRC checksums while writing the sectors to mark as bad.

I'm not quite sure why the very end of a TAO session is unreadble, but I think it's due to the CD Recorder turning off the laser at the end of a session to prepare for the lead in/out. Either that or Nero's surface scan tries reading too many sectors and goes a little ahead of the end of the session.

With DAO, the laser stays on throughout the entire disc, this means that there is no loss in recording time between when it records the session and the lead in/out tracks. In DAO, it starts with the leadin, then the track and finally the leadout without switching off the laser the whole way through. With SAO, it starts writing the track, moves the laser back to the center of the disc and starts writing the lead in and lead out.

The advantage of multisession use to be useful back in the early days of CD recording for archival purposes. With multisession, you can write a session to a CD and at a later stage, add another session to a CD and so on until the capacity of the CD has reached. When you add another session to a CD using Nero for example, it will show you in the left panel what's already on the CD in a different shade of colour than you drag into that column. This way you can tell what's already on the CD and about to add. When a second or further session is added, another track is written to the CD. A marker is then added to the previous table of contents to mark that there is a new session on the CD. The marker points to the new table of contents. Another lead in/lead out is also written. This extra overhead takes about 30MB, so when adding sessions to a CD, I'd recommend a reasonable session size such as 100MB or more. Multisession CDs can be read by just about every CD-ROM drive out there from the days of 8x onwards. Once CD-RWs bacame popular, multisession CD-Rs died.

fantastic explanation, thank you dearly seanbyrne

TAO: When you backup multiple documents, photos, mp3. Why? 'Cause damn Nero will change the damn file names to all CAPS and underscores when DAO's selected.

DAO: DivX, or any single file backups.

Man, I tell you, before I knew DAO would change everything to CAPS, I was backing up my photos and animes, and when I saw what it did, I was like, you POS, I'm gonna kill you. Spent days changing the file names back to Cap Title format.

Stoner: This has nothing to do with DAO/TAO, but with which file system you use (ISO, UDF, ISO/UDF, 8.3 vs 31, Joliet yes/no...)

Hmm... you think it's the Joliet? Well, the thing is I've tried all that, but to have nero not alter the file names, TAO had to be selected. I'll go home tonight and try again w/ the settings... wait, my monitor is in for service. It'll be a few days.

If DAO/TAO influences this, then this is the most weird bug i've ever seen

i've had a lot more success burning CDs in TAO mode so i tend to stick to it!

If you write a CD in ISO mode, whether 8.3 or 31 characters, the file names will be written in uppercase with underscores in place of the spaces. Joliet supports up to 64 character file names and supports spaces, uppercase & lowercase, so the filenames should still be the same after writing.

There is a small bug in Nero I encountered and I'm not sure if they fixed it in their latest release. If I record a Video CD, the next time I write a data CD, 'Joliet' will become unchecked. That means if the box is not ticked again before recording the next CD, all file names will be converted into ISO mode and they look ugly on the CD after recording (Caps with underscores replacing the spaces) I've had a few CD-Rs recorded in ISO mode as a result of recording a video CD previously and forgetting to retick this box As I generally write CDs using DAO, I'm not sure if this affects SAO also, but as a precaution now, I always make sure 'Joliet' is ticked before finally clicking 'Record'.