Hi I'm using a Pioneer Blu-ray PC writer and just wanted to point out a few things which I didn't appreciate until I started burning disks that might be useful to others to know. Recordable Blu-ray supports defect management within the drive, this defect management is handled entirely by the writer and the computer/player has no part in handling defects, they just see a big lump of free-space which is all defect free. Defect management also takes place when creating a Blu-ray video disc and this is a big change from DVDs. DVDs for video do not support defect management as video data must be in a continuous stream, and for data, DVD needs the host to deal with defect management (except for DVD-RAM). This defect management is not just used on BD-RE, but also write once BD-R. This should mean more reliable burns to Blu-ray media as any defects while burning can be remapped to a spare sector, and the Blu-ray player will be able to play this back without a problem, a good job considering the price of blanks at the moment. It also makes Blu-ray great for storing data. Because of defect management, burning speeds can be less than half of the advertised speed (just like DVD-RAM) as everything written is read back and verified and if necessary sectors are remapped by the drive. Software packages can let you disable defect management to get the full burn speed, but this might mean a coaster which could have been avoided. Also when defect management is in use free space is slightly reduced in order to reserve space for defects. Another change that can look like a fault when recording to BD-RE, is that BD-RE is a truly random access format. Where CD-RW/DVD-RW/+RW always records sequentially from the last point recorded, so on a new blank disk you can see the recording sequentially grow from the centre outwards with no gaps, Blu-ray BD-RE can record anywhere to the disk (like a hard-drive) and so isn't constrained to always recording from the very last point written to. This means on a clean blank Blu-ray BD-RE disk, as you add and remove recordings, you can see concentric rings with gaps where no data has been recorded. On a DVD/CD this would show something had gone terribly wrong, but is quite normal on BD-RE and is not a problem. (See attached picture). Best Regards Phil
Thanks for that info Phil. I think we may have discussed this sometime ago. [ Welcome back ] When recordable Bluray first emerged, I had concerns about burn reliability because of the much more critically intense technical parameters and requirements... particularly given that it was clear , and to an extent remains so, that DVD burning can be a bit of a lottery- one of the causes being the one you mention. I'm pleased to say that over the period I have presided here, during which recordable bluray has become increasingly established, the reports of coaster manufacture, that I feared with this format, have not apparently emerged. Off the top of my head I can only recall one such report ...which may have had its causes elsewhere. So on the face of it it appears this technology is doing it's job.
Hi Another big plus for Blu-ray recording is that unlike CD and DVD, the spec's for Blu-ray were designed around it being recordable. With CD and DVD, recordable disks came sometime after and was always a bit of a hack. So hopefully Blu-ray will prove much more reliable and all hardware out there should work fine with BD-R and BD-RE media. Regards Phil
