Nero UDF & UDF/ISO confusion

On Wed, 21 Apr 2004 11:51:15 +0100, Alex Nichol
wrote:

K2 wrote:


For a few weeks I thought the same thing; multisessions seemed to work
fine. Then I noticed recent files were getting corrupted, even though
the burning seemed to go fine and they appeared intact from their size
and names. I'd give it more time if I were you. Be sure you actually
try to launch the files you've copied.

If you are using a UDF file system in Nero, you are *not* I think
using a packet written format, as in InCD (which then implements a UDF
file system on that). The terms are often confused but are not
interchangeable. So were you doing this in Nero itself - or in InCD

This is within the Nero app itself, not InCD. Per the sparse Nero Help
menu (below) it looks like UDF or UDF/ISO is probably not true packet
writing. It seems mainly optimized for DVDs.

"The UDF file system was designed at the time, when it became clear,
that the ISO9660 file system does not fit the requirements of CDRWs
and DVDs. It's optimized to handle huge data sizes and to minimize the
necessary changes if a file needs to be added or deleted."

"Nero 4 supports burning of UDF and UDF Bridge CDs that contain a UDF
and an ISO9660 file system. Windows 98, and Windows 2000 can write the
UDF file system without any special driver. Windows 98 and Windows
2000 will read the UDF file system, if both UDF and ISO file systems
are found on the media. Burning in UDF file format will be especially
useful in the future, if DVDs are to be written, because UDF is the
best file system to be written onto a DVD. Please note, that currently
Nero does not support UDF or Bridge multisession burning so you need
to burn UDF and Bridge CDs onto empty CDRs."


K2

On Wed, 21 Apr 2004 09:25:51 +0200, Pierre Duhem
wrote:

On Wed, 21 Apr 2004 01:49:25 GMT, K2 wrote:

As someone else suggested, I've tried regular ISO CD-Rs (instead of
UDF/ISO) with multisessions and have had no problems so far. I'm
wondering if there's a limit to the number of sessions you can do per
disc?


99, according to some colored book (I don't remember which one).

If so, it's not going to work too well for certain backup
applications, like a single file at a time. I've also read that space
is wasted each time you close a session. One 1997 Usenet post claims
13MB is wasted each time but that seems excessive. That was an older
technology limit, I hope (http://makeashorterlink.com/?D2C051818)

K2

On Wed, 21 Apr 2004 11:51:15 +0100, Alex Nichol
wrote:

If you are using a UDF file system in Nero, you are *not* I think
using a packet written format, as in InCD (which then implements a UDF
file system on that). The terms are often confused but are not
interchangeable. So were you doing this in Nero itself - or in InCD

I've always had UDF associated with packet writing because the term
comes up often in that context.

http://downloads-zdnet.com.com/3000-2100-9497911.html

"Adaptec's UDF Reader enables MultiRead CD-ROM drives to read
UDF-formatted CD-R and CD-RW discs (such as those written with
DirectCD)"

And there does indeed seem to be a relation:

http://www.informationheadquarters.com/DVD/UDF.shtml

"UDF means "Universal Disk Format. The UDF format is used for so
called "packet written" writable CD-ROMs that are not simply copies of
ISO 9660 CDROMs. Packet writing allows CDs to be partially written
using variable or fixed length records in multiple sessions."

K2

Answering most of my own questions below, it looks like multisession
archiving of any sort has a big price in wasted space. I think I'll
stick with perfecting InCD, or better yet, get a relatively cheap
external firewire/USB hard-drive for temp storage, then burn complete
ISO CD-Rs as needed. (K2)

from http://www.mscience.com/faq67.html

"When should multisession recording be used?

Only when you are forced to use it. Hopefully never, unless
multisession is required by a format such as Photo CD. Multisession
efficiently supported several recording sessions, enabling one session
to use only a fraction of the capacity of an expensive CD-R disc.
Media is now inexpensive, and cost savings from multisession recording
are insignificant. Packet recording methods are much more efficient,
but initially required specialized software and expensive drives.
Packet capable software and drives for CD-R and CD-RW are now readily
available and affordable.......Multisession has a high overhead.
Lead-in and lead-out of the first session occupy 28 MB that is reduced
to 13 MB for all following sessions. Twenty sessions therefore have
275 MB of overhead, and only 378 MB is available for user information.
Packet recording is highly efficient because twenty packets have only
0.28 MB of overhead."

.. --------------------------------------
Mike Richter, were you born with
"Scam Artist" emblazoned on your face?
--------------------------------------
(Mike Richter, any Material Connection w/ Roxio?)


K2 wrote:

Answering most of my own questions below, it looks like multisession
archiving of any sort has a big price in wasted space. I think I'll
stick with perfecting InCD, or better yet, get a relatively cheap
external firewire/USB hard-drive for temp storage, then burn complete
ISO CD-Rs as needed. (K2)

[2-5] What's a multisession disc?
http://www.cdrfaq.org/faq02.html#S2-5

[7-6] How much data can they hold? 650MB? 680MB?
http://www.cdrfaq.org/faq07.html#S7-6


from http://www.mscience.com/faq67.html

"When should multisession recording be used?

Only when you are forced to use it. Hopefully never, unless
multisession is required by a format such as Photo CD. Multisession
efficiently supported several recording sessions, enabling one session
to use only a fraction of the capacity of an expensive CD-R disc.
Media is now inexpensive, and cost savings from multisession recording
are insignificant. Packet recording methods are much more efficient,
but initially required specialized software and expensive drives.
Packet capable software and drives for CD-R and CD-RW are now readily
available and affordable.......Multisession has a high overhead.
Lead-in and lead-out of the first session occupy 28 MB that is reduced
to 13 MB for all following sessions. Twenty sessions therefore have
275 MB of overhead, and only 378 MB is available for user information.
Packet recording is highly efficient because twenty packets have only
0.28 MB of overhead."

In article ,
says...
I've never heard of PAR2 - I'll check it out. I had been assuming that
an app like ISOBuster could recover most data from any problem CD-R,
but I guess that's only if critical parts of a file stay intact.

ISOBuster actually works well with QuickPar. Use
ISOBuster to pull everything off the disc into an ISO
file (including damaged data). Make a copy of the ISO
file and change the extension to ".PAR2". Load both the
ISO file and the PAR2 file into QuickPar. QuickPar will
then repair any damage and write out all of the files
that were on the CD to the current directory.

Caveats:

- works best when you have all of your data in a single
folder, with a single PAR2 recovery set protecting all
of the data files (at least, until the author adds
subdirectory support), when doing backups, I put
everything into TAR/ZIP files in the root of the CD/DVD
along with the PAR2 recover files

- v0.8 requires you to make a copy of the ISO file and
rename it as PAR2, next version(?) should remove that
need

- you can only repair as much damage as you have
recovery blocks (so if 10MB of data is damaged, you'll
need at least 10MB of recovery data, maybe a bit more
depending on where the block boundaries are)

- creating the PAR2 files is an extra step and does take
time (when I create PAR2 recovery sets for my DVD
video_ts folders, usually takes 30-45 min on an AthlonXP
2600+)

- damaged ToC tracks require special drives (or
professional recovery service)... no idea who makes the
special drives or what they cost