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Thread: Difference between DVD-R/RW and DVD+R/+RW?

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    Default Difference between DVD-R/RW and DVD+R/+RW?

    Can anyone tell me what the + means? Thanks.

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    The Differences

    There is very little difference between DVD-R and DVD+R, both of which can only be written once. They are used in exactly the same way. But you have to be careful with DVD-R because there are two standards for blank disks. The one to use is marked "DVD-R for General Use." The other is marked "DVD-R for Authoring," and it only works for mastering DVD video or data because its composition is different. This sort of DVD-R is not usually available to the general public.

    Things get a bit more complicated with DVD-RW and DVD+RW. DVD-RW technology is very similar to that of the CD-RW. For DVD+RW, the Alliance wanted to make video recording easier, especially for home use. So they implemented a technology called Lossless Linking. In DVD+RW video format, a video can be encoded in VBR (variable bit rate). The process of writing at a constant rate takes up a lot of room, so it has to be stopped and started again. This is likely to cause link loss, which makes the disk incompatible with read-only devices like DVD video players. With DVD+RW, the process can be stopped and started again without any link loss. This characteristic makes the format efficient and suitable for random data writing and video applications. With lossless linking, it is also possible to replace any individual block of 32 KB (write unit) with another, without losing compatibility.

    For a lossless link, each block of data must be written in the right place with precision (on 1 micron). For this, the groove is controlled by a high-frequency wobble (817 kHz at n=1) to ensure that writing stops and starts in an exact position. The writing clock resulting from the groove is very precise. At the same time, addressing information is stored in the spiral groove by locally inverting the radial wobble mark. There are four addresses per ECC block of 32 KB, so the address format is reliable with wide margins of detection.
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    I'm still not clear on the whole +R -R thing. The main difference is that there are two formats with -R and only one with +R?

    What's this about general use and for authoring? Why is for authorign not usually available to the general public and why would you want it? You say the "for authoring" disk is only good for video or data but I'm wondering what else could you conceivably put on a DVD-R besides video or data? Thanks.

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