Wednesday, January 26, 2011

Blu Ray Media: Failure Modes

Blu Ray blank media guide : Introduction to Blu Ray blank media 
Introduction to Blu Ray Blank Media Part 3: Media Failure Modes

Read-only DVD media, such as those used in movie and audio distribution have excellent compatibility and very low failure rate. On the other hand, recordable DVD media (used for data storage and home or office media duplication) only have a 90-95% compatibility rate (in the best cases) and significant failure rate. The same is true with Blu Ray media: read only Blu Ray is highly compatible, while recordable Blue Ray suffers from lower compatibility (equivalent to recordable DVD media) and higher failure rates. What can of failures can be expected?

Mature industry
While a list of all possible failure modes can be frightening, it is important to remember that Blu Ray storage is no more faulty or difficult than the mature DVD storage industry. If you are burning DVDs today, you will have no more trouble burning BD-Rs (Blu Ray recordable media) tomorrow. In the same way as for DVDs, you want to choose a good burner and good media.

Because of the nature of the Blue Ray standard (similarly to the DVD standard), inherent compatibility between media, player and burner is approximately 90-95% for the better brands. It is possible to buy media that will not be compatible with your player or burner. Some players and burners, such as the PS3 game station, or LR burners, are more subject to compatibility issues than others, while others, such as Pioneer burners, are less subject to the same issues. Better brands of media will also have less compatibility issues. Because compatibility issues are inherent to the standard, having media that is not compatible with your player does not automatically mean that the media is poor.
As a note, compatibility can be different for the burner and the player. If it burns in your burner, it may not play in your player... On the other hand, it may happen that a media will burn and not play, but that, if it is duplicated on a media of a different brand, the new media will work (i.e. the burn was successful, but the

Coasters/ Frisbees
Beyond compatibility, the most common issue is a high percentage of "coasters", i.e. a burn that did not complete or verify properly, or that does not play in any player. Low end products should be expected to produce a higher percentage of coasters. Convenience and cost analysis are necessary to evaluate whether a lower cost brand is still worth purchasing despite a higher percentage of coasters. Given the value of time in the modern professional family, we would expect that a low coaster percentage is a requirement.
Compatibility can masquerade as high coaster production, as some media is recognized by a burner but will show as non-recordable, yet the burner will still try to burn it if the operator does not notice the lack of recordability.

Archival failure: media writes but will not read
The worst of all failure modes is short archival: the media burns, and verifies (a truly necessary step), but will not read when tested 3, 6, or 12 months later. It is already possible to find this problem in some brands. This failure mode is particularly treacherous, as it cannot be diagnosed at write time, and may result in data loss, while the others can be diagnosed at write time, and will not result in data loss. Archival failures after longer durations cannot yet be found from existing reviews.

Lack of performance in some attributes
Other causes can result in a negative user review, such as low write speed, appearance of the media, etc. These causes can be the cause of a downgrade, but are not true failure modes.

Archival failure: the most dangerous failure
Of all failure modes, short archival duration is the most dangerous. In an industry focused on data storage, data loss, the consequence of short archival, is the most drastic penalty. While we will look at all failure modes, we will give short archival the highest factor when comparing brands.

Next we start our review of the best Blu Ray media brands, and discuss brands and manufacturers for Blu Ray media... So come back soon!

To understand Blu Ray lingo, check our lexicon of Blu Ray vocabulary. Our Blu Ray brand predictive quality rating process is explained here. Our statistical analysis practices are described here, which is also where we discuss's predictive quality rating.

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