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CD Recording FAQ
2. The CD Recorder
2.6. Buffer underrun
During its recording operation, the cd recorder receives data and transfers them on the cd surface at a constant and strictly defined rate. If this flow is for some reason disturbed, the laser beam loses its proper location on the cd and the blank is destroyed. If the cd is written in DAO mode, you have to throw it away, but if the cd is written in multisession mode you can disregard the session and continue using the cd. Whatever the case, the result is not pleasant.
2.6.1. Buffer memory
The cd recorder has some memory built in, called buffer memory. Buffer memory has the role of stabilizing the data flow and is constantly filled during the writing operation, and is also used by the recorder for internal operations. Due to its important role, its size has to be sufficient.
On the other hand, many programs add a second layer of buffer memory, using a part of RAM, thus strengthening the overal process. But, whatever the case, between two recorders of the same speed, the one with the largest buffer memory has a significant advantage. For a number of reasons, the computer may be unable for some seconds to provide the appropriate data flow towards the cd recorder. This can happens due to a number of reasons, for example heavy multitasking during the process of recording. When this happens, the buffer memory tries to maintain the data rate needed till it empties its content, resulting to a "buffer underrun" error.
2.6.2. BURN Proof - JustLink - Seamless Link
Technollogies like BURN PROOF and JustLink have minimized the role played by buffer memory by allowing the laser beam to continue the recording process when the data flow is restored. This means that, when, for some reason, the buffer memory is emptied, the recorder waits till it starts receiving data again, leaving a tiny gap on the cd surface which certainly lowers the quality of the final written cd.
The BURN PROOF technology is mostly intended for high speed recorders using IDE or similar low speed connection. Furthermore, it is patented by SANYO, which means that only licensed manufacturers are allowed to use it (basically the manufacturers building their products around SANYO mechanisms). It also requires software supporting BURN PROOF.
So, if the question is whether a BURN PROOF enabled drive is a better one, the answer is no. Not only are you restricted to a SANYO mechanism, but also modern computers combined with SCSI recorders don't need BURN PROOF anyway. BURN PROOF came too late to be really useful.
JustLink is a technology similar to BURN PROOF, but independently developed by Ricoh. The main difference is that it is more precise, resulting in smaller micro-gaps on the cd surface, which makes it a superior choice.
Seamless Link is another similar technology, independently developed
by Philips and Acer. The difference with BURN PROOF and JustLink is that
it doesn't rely on software support, but instead it is controlled by the
firmware, so that you won't have a buffer underrun no matter what software
or even operating system you are using.