Rewritable Media

So, next go rewritable media formats.

 
Burn quality of the DVD+RW discs at 2.4x

The drive successfully burned the disc, without any slowdowns. The quality of the disc is not, however, the best possible. The PI error rate is no higher than 50 almost on the entire disc (and this is an excellent result for a rewritable medium), there are peaks of PI errors (up to 350) and PI failures (18) at the outermost tracks. This is unsatisfactory, of course. The drive evidently cannot keep the quality acceptable as it approaches the outermost tracks of a disc.

 
Beta/Jitter (left) and TA Test - Outer (right)

The Beta graph shows that the drive increased the laser power at the moment right before the error rate went up. Probably it did so to compensate for the vibration that gets stronger on the outermost tracks, but the result was poor. The Jitter rate is, on the contrary, good along the entire disc. On the other hand, the TA Test results indicate that the drive cannot keep the lengths of pits and lands as they should be when writing DVD+RWs at the min speed. The adjacent areas overlap on the diagram; Jitter is high and the average length of pits and lengths is far from perfect. So, we should acknowledge some problems with DVD+RW media at the min speed. Let’s see what happens at 4x.

 
Burn quality of the DVD+RW discs at 4x

The drive still uses a Z-CLV algorithm for processing discs at 4x speed. This increases the overall time of the burn session. Otherwise, there are no problems with burning proper.

The average rates of PI errors and failures are low, except the outermost tracks where there are surges of errors, like we have seen at 2.4x speed. The PI errors are still within the acceptable range, while the peaks of PI failures are three times above the norm and may render the disc unreadable.

 
Beta/Jitter (left) and TA Test - Outer (right)

Unlike at 2x speed, the laser power is not increased on the outermost tracks. The drive boosted the power as it transitioned to 4x speed and then the Beta graph is nearly a horizontal line. The Jitter rate is more uniform along the entire disc than in the previous tests and is smaller, although not ideal: the adjacent areas overlap rather much on the diagram. The Peak Shift is small.

Thus, the quality of the resulting disc is tangibly higher at the higher burn speed.