An Introduction to Blu-Ray

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Until recently, optical disc technologies such as DVD, DVD±R, DVD±RW and DVD-RAM relied on a red laser to read and write data, the Blu-Ray format uses a blue-violet laser, which explains the name Blu-ray.

A blue-violet laser (405nm) has a shorter wavelength than a red laser (650nm); this makes it possible to focus the laser with even greater accuracy. This allows data to be packed more tightly, so it’s possible to squeeze more data on the disc even though it’s the same physical size as a CD/DVD. This together with the change of numerical aperture to 0.85 enables Blu-ray discs to hold 25GB/50GB.

Blu-ray drives can also be made backwards compatible with CDs and DVDs through the use of a BD/DVD/CD compatible optical pickup unit.

Now let’s take a look at the track pitch and compare them with that of DVD

As we can see in the above screenshots, the storage density of Blu-ray is much higher than DVD. The Blu-ray laser beam spot is also much narrower than that of DVD.

Blu-Ray Error specification:

In the above table we present some of the specifications for reported errors on Blu-ray media. At present we have no equipment or software available for measuring these errors.

BD-R writing tests

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The specifications of the eHBU212 state that the drive is able to write BD-R at 12x. Let us find out how the drive really performs.

Reviewers note: We had no media that was supported at 12x on theeHBU212, and also we weren’t able to burn faster than the rated speed of the media. All disc quality tests were done at maximum speed.

BD-R 25GB

For this test we used Nero Disc Speed to create our test disc.

Not a great result to start. The selected burn speed was 6x but it slowed down to 4x, and quality scan of the disc was average. The only positive is the perfect TRT. Anyway I am left with mixed feelings, firstly because of the quality of the burn and secondly by the speed of the burn.

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BD-R LTH Type 2x

With the LTH disc everything looks much better, and again the TRT is perfect.

BD-RE 2x

 

With the RE media the results are even better from the LTH disc. Everything looks okay and there is also a perfect TRT.

TDK BD-RE 2x

Finishing my BD tests with this TDK –RE media I can say that the result is good, and there is also a perfect TRT to finish my tests.

Summary

Mixed feelings again, this time I won’t just say that it’s the media to blame. I believe that the software has a role in all this, ODC hasn’t been updated for quite some time, and nero CD-DVD speed is too old. For the moment I have to say that the overall performance is good.

Now let’s do some real world tests …

• Write dual layer performance
• Real world tests