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08 Mar 2008 12:27:47 | John McGrath
What is it? It is known by many names, "BURN-Proof", "SafeBurn",
and "lossless linking" to name but a few. Regardless of the
name, they are all buffer under-run prevention strategies. In
the dark days of CD-R recording, before we had BURN-Proof and
the like, if a drive's on-board buffer became empty, the write
would fail leaving an incomplete and unusable disc. The on-board
buffer of the drive is analogous to the fuel tank on a military
aircraft, which relies on periodic in-flight refuelings. If the
jet's fuel runs out, the plane will crash. The host computer, or
duplication controller, is the refueling aircraft. If it cannot
supply DATA as fast as the drive consumes it, the write process
will fail. Essentially, what buffer under-run prevention gives
you is a means to pause while the host catches up. Why do I need
it for my PC? Buffer under-run prevention was really a response
from drive manufacturers to overcome limiting factors that were
preventing drives from going to higher write speeds. Many PCs
were, and still are, simply not up to the task of writing at
these higher speeds. The burden of handling so many technical
support calls was more than anyone was willing to deal with. The
answer was simply to design the drives in a way whereby if the
computer could not deliver the data as fast as the CD-R drive
required, it would simply pause and wait for the PC to catch up.
No coasters, no tech calls. Why does it not make sense on a high
performance duplication system? A better analogy for CD-R
writing when using buffer under-run prevention is that of a car.
If a car runs out of fuel, you can simply fill up a gas can, add
fuel, and continue on your way. No plane crashes here. Using the
car analogy, what would be the down side if your tank was very
small and you were embarking on a long drive whereby the
distance between gas stations was greater than the fuel capacity
allowed? Well, you would run out of gas frequently and find
yourself walking along the road to fill your gas can only to
walk back to your car, refill, and continue on your way,
repeating this step as often as necessary. So in effect, if the
host PC or duplication controller cannot provide data as fast as
the CD-R drive writes, the drive will pause, wait for the buffer
to refill, and then begin the write process again. The downside
here is performance. This can take from one to several seconds
per actuation of buffer under-run prevention. A one-drive 32x
copier from one company might easily out-perform a 52x unit
relying on buffer under-run prevention. The MF Digital
difference MF Digital designs its duplication and publishing
systems so that buffer under-run prevention strategies are not
needed. This is achieved through MF Digital's own precision
duplication controllers and software, and the use of high-speed
hard drives, fast processors, and plenty of memory. When using
MF Digital's PC based systems such as the Scribe, be sure to
adhere to the minimum system requirements.
About Author :
If you have any questions that might make an interesting
TechNOTE or white paper, please do not hesitate to send them in.
Please forward your questions or suggestions to John McGrath c/o
MF Digital. 121 Carolyn Blvd., Farmingdale, NY. 11735, or email
technotes@mfdigital.com, or http://www.mfdigital.com/
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