Sony owns the Blu-Ray technology, and licenses it to a consortium of manufacturers.
One of the conditions Sony imposes on the licensees is that they cannot manufacture equipment for the competing HD-DVD technology.
I don't think the restriction applies to content providers (i.e., movie studios), who can sell discs in both formats if they choose to do so.
Blu-Ray is the better format, but I'm concerned that Sony's restrictions are anti-competitive. A dual-mode player would be a good thing.
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Another caution from the EE article stated that current RICOH mechanism would only read BluRay, to write a BluRay would require a stronger laser beam than manufactures are currently using....so lots of issues yet...including the legal entanglements.....