TAO vs DAO question

vbimport

#1

Suppose I burn some files (avi, jpeg,…) to a CD-R with, for example, Nero. Would there be a difference if I used DAO (disc-at-once) instead of TAO (track-at-once)?

I’m curious. :slight_smile:


#2

Nope no difference, TAO is just fine for burning data files as far as quality is concerned.


#3

So, just to be sure, no physical difference on the disc, for example lead-in/out position or something else?


#4

No what i meant is that there’s no concern as far as the data quality is concerned. In TAO mode there’s a lead in/out at every track session if memory serves me right.


#5

Damn! This goes back a long way … for a moment, i thought someone had bumped an ancient thread!

Generally people use DAO, especially if there is only going to be a single Data track. Opens and closes the disc in one go. There’s no reason you can’t select TAO though. The burner will just use SAO or DAO anyway :stuck_out_tongue:

Generally TAO was traditionally used for Audio, but DAO was the preferred method, as you can specify the audio gaps between tracks, and I vaguely remember that long gaps between audio tracks was compulsory on TAO, which caused (annoying) pauses between tracks when playing them in audio cd players.


#6

Damn! This goes back a long way … for a moment, i thought someone had bumped an ancient thread!
It does doesnt it :slight_smile:

So yes if you want the audio tracks to be continuous/mixed with no gaps you have to use DAO, but when it comes to just data storage as hitokiri mentioned there’s no reason why one should not use TAO, that was my initial point.


#7

So, for a normal data CD like I described, you wouldn’t be able to tell if it was written in TAO or DAO? :slight_smile:


#8

you could by maybe looking on the back surface for each track’s session, but other than that no.


#9

If there is multiple data tracks on a TAO disc, then only the first data track is accessible, except by special software.

But as I replied before, burners won’t write your Data disc in TAO, they will write it as SAO or DAO.


#10

TAO can only be written in SAO anyways, if memory serves me right.


#11

I know for a fact (sort of) there is some difference in the writing proces of a normal data disc between TAO and DAO in Nero. That’s what got me wondering in the first place. If memory serves me, with DAO the lead-in/out are written in one go at the very start, as opposed to TAO which burns lead-in at the start and lead-out at the end.

According to this link, SAO also writes lead-in/out in one go.

So…I’m confused. :doh:

I’ve been using TAO for every data disc burned in Nero over the last 8 or so years, just because it was the default option in Nero. Just so you know why I’m being persistant. :slight_smile:

edit: Well, when selecting TAO in NERO the option “Finalize disc” is available, so I suppose I am actually writing in SAO then? Ehh, I’m gonna burn some TAO and DAO discs to compare today…


#12

It’s just the other way around…


#13

Something along the lines of …

Tao = Disc Leadin -> Session Leadin -> Track ->Track -> track ->Track -> Close Session -> (if closing disc) Disc Leadout.

Sao = Disc LeadIn -> Session Leadin -> Track -> Close session -> (if closing disc) Disc Leadout.

Dao = Disc LeadIn -> Session Leadin -> Track -> Close session Disc leadout.

TAO turns the laser of between tracks, causing unreadable areas between tracks, which doesn’t conform to the redbook standard (Commercial Audio CD’s are not written in TAO either).

I’m not even sure why TAO was even ever offered :stuck_out_tongue:
If you are using Adaptec/Roxio EZCD, they’ve offered TAO, when it was actually SAO :stuck_out_tongue:


#14

Okay, after reading the whole thread again and going through some websites and the Nero manual…I still don’t get it. Sorry guys. :o

I think I know what tracks and sessions are, sort of. DAO writes all tracks in 1 go, TAO turns off the laser with each track…okay. But what happens with data discs with only one track? What is the difference THEN?

Here’s what Nero does:

  1. when selecting TAO: burn track -> burn lead-in/lead-out (at this point the drive first spins fast for a while, then slow for a while…so I think it burns something at the start AND end of the disc)
  2. when selecting DAO: burn lead-in -> burn track -> burn lead-out

Does DAO turn off the laser between the leads and the track? I spent a dozen of discs (of 30MB) trying to figure it out… It seems TAO does, but I’m not sure about DAO.
Is there a difference in the sequence of leads, track, session openings/closures…you know in this case of a one-track data disc?

Btw, 1) doesn’t seem to fit in your diagram debro?

Sorry for the long-winded discussion, but I’d really like to understand. :slight_smile:


#15

No.

Burning software is intelligent enough to close the session for you, otherwise the data track will be inaccessible.
It’s using SAO/DAO to write the data track, depending on whether you close the disc or not :wink:

Read above.


#16

Okay I’m starting to understand it better…

SAO = DAO without finalization. TAO doesn’t necessarily mean closing the session but in this case it’s done automatically to create a session for a possible multisession disc. So, essentialy it’s not really TAO but SAO. Right?

But I think TAO here is just writing a SAO disc that gets finalized in the end, not really DAO because the laser is turned off after writing the track to go to the beginning of the disc for the lead-in, and then the end for the lead-out. Could that be correct?


#17

Track At Once is useful for multi session and DIsc at Once is useful for single session, or cd audio single session and the laser writes the entire disc without shutting off between every track.