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DAO or TAO


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#1 xpt

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Posted 03 December 2008 - 09:43 PM

Hi,

May .iso files come with size much less than 700M. So it would be a waste of CD spaces to burn them DAO. However, I read at many places that burning them using TAO will severely reduce the chance that they are able to boot.

I have no problem adding more files to Linux based bootable .iso images, e.g. RedHat, Debian or Slax, but I don't know if there is a sure-fire way to add more files to any generic .iso images --
http://www.boot-land...?showtopic=6370

So, what are your experiences with burning bootable .iso images using TAO, and add sessions later?

thanks

xpt

#2 cdob

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Posted 04 December 2008 - 10:11 PM

what are your experiences with burning bootable .iso images using TAO

I'm using CD TAO mode at piping data: mkisofs | cdrecord -
Well I'm lazy and don't use tsize=

CD does boot fine at different machines.
I haven't had a error caused by TAO in the last several years.

and add sessions later?

That's another question. That's a multi session disk.

According to "El Torito" Bootable CD-ROM Format Specification the last session is used.
http://en.wikipedia....D-ROM_standard)
http://www.phoenix.c.../specscdrom.pdf

This "Boot Record" must reside at sector 11 (17 decimal) in the last session on the CD.

Make the last session bootable too. Mkisofs does support this.

However there are different results:
Some BIOS boot the first session, this violates the specification.
Some BIOS boot the last session.

Adding sessions is not recommended because of different BIOS behaviour.

#3 xpt

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Posted 05 December 2008 - 04:37 AM

Thanks a lot for the knowledgeable feedback. Now I know where the caution comes from.

Thanks

#4 cdob

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Posted 05 December 2008 - 10:39 PM

Actually there is a hardware reason.
Most likely old warning refers to this, not to multi session.

Given a 2x speed CD-ROM drive from 1993:
dosn't read a CD-RW media
dosn't read multi session
dosn't read a TAO media
This drive does boot a DAO CD-R, but not a TAO CD-R.

In addition there are half broken media and half broken drives:
DAO may get better results.

As for current hardware: expect working TAO boot
contrary: DAO mode is nice for historic or half broken hardware

#5 Mikorist

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Posted 10 December 2008 - 07:35 PM

Posted Image

CD's can be burned in DAO (Disk At Once) or TAO (Track At Once) mode. The only reason to use DAO mode is when burning audio CD's. Audio CD's burned TAO will have 2 second gaps between tracks. If one is copying an entire CD, TAO mode will introduce these 2 second gaps if they do not already exist. DAO mode uses a raw CD access mode and can avoid these gaps between tracks.


Using command line and GUI interfaces to burn/rip a CD or DVD:

http://www.yolinux.c...rialCDBurn.html

:)




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