User manual

Copying
Nero Burning ROM 45
11 Copying
Nero Burning ROM can be used for copying discs. There are two methods for this:
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On-the-fly copying
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Copy over image
Each method has advantages and disadvantages which will depend on your requirements.
11.1 On-the-fly Copying Versus Copy Over Image
11.1.1 On-the-fly Copying
LOLWhen using the on-the-fly method, insert the original disc into a drive and a blank disc
into the burner. The original disc in the drive is copied immediately without any time delay to
the blank disc in the burner. The on-the-fly method allows you to copy very fast and does not
require any additional storage space.
In order to be able to use the on-the-fly method, you will need at least two drives: one for
reading the disc and a burner for writing. The following requirements apply to the drive and
burner:
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The burner must have a function for protecting against buffer underruns or the drive must
be capable of delivering the data sufficiently fast. The read speed must be at least as
high as the write speed to ensure that a buffer underrun does not occur. It is more reliable
when the read speed is twice as fast as the write speed.
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The drive must be capable of delivering information on the number and type of sessions,
otherwise Nero Burning ROM may not be able to produce an exact copy.
On-the-fly copying can have the following disadvantages:
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If the burner does not have a function for protecting against buffer underruns, the on-the-
fly method is highly sensitive to read errors. The reason for this is as follows:
if errors occur while the disc is being read because it is scratched, it is not possible to try
to eliminate the error by reading the disc several times for example because, in contrast
to the copy-over-image method, there is not enough time (danger of buffer underrun).
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Index positions in audio files get lost. The reason for this is as follows:
Index positions only become identifiable if the corresponding position on the CD is read.
However, on-the-fly copies can only be burned using the disc-at-once method. With this
method the information on the index positions must be available before the burn process
begins. This means that Nero Burning ROM cannot copy over index positions.
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The quality of audio data read in may suffer. The reason for this is as follows: Nero
Burning ROM reads several megabytes of data at a time from the drive, Nero Burning
ROM transfers the data to the cache, and writes the data to the burner. If the data
transfer slows down because the buffer in Nero Burning ROM is full for instance, the
reading head of the drive has to jump back to a previous position. Some drives cannot
position the read head precisely for Audio CDs, which means that corrupt audio data may
be transferred sometimes.