XPost: alt.comp.os.windows-11   
   From: winstonmvp@gmail.com   
      
   On 11/19/2025 2:30 PM, J. P. Gilliver wrote:   
   > On 2025/11/19 20:20:51, ...w¡ñ§±¤ñ wrote:   
   >> J. P. Gilliver wrote on 11/18/2025 5:37 PM:   
   >>> On 2025/11/18 18:18:7, ...w¡ñ§±¤ñ wrote:   
   >   
   > []   
   >   
   >>>> Movie DVD's have been available in two flavors   
   >>>>     DVD9 - dual layer which provides 8.5 GB   
   >>>>     DVD5 - single layer, 4.7GB   
   >>>>   
   >>>> Not all dual layer DVDs are DVD9; all DVD9 are dual layer   
   >>>>   
   >>>> Non-movie DVDs are also dual layer DVD+R DL or DVD-R DL   
   >>>>   
   >>>>   
   >>> Interesting that it's not 2×4.7=9.4. Why not?   
   >>>   
   >>> (Presumably the ones that are DVD5 are just movies that are short enough   
   >>> to fit in/on a single layer. What duration corresponds to that?)   
   >>>   
   >>   
   >> Physical limitations   
   >>    DVD9 single-sided with two layers on one side of the disk   
   >>     - second layer is read by focusing the laser through the   
   >> semi-transparent first layer. To reliabily accomplish the data pits(where   
   >> the data is stored)) on both layers are longer, and the track pitch(space   
   >> between the tracks storing data) wider.   
   >>    i.e. use more space for data, use more space between data = less   
   >> storage capacity   
   >   
   > Ah, understood - so to make it possible to both read through and be   
   > readable-through, they use a lower density (in both directions). that   
   > explains why only 8.5.   
   >   
   >>   
   > How long was/is the maximum for DVD5?   
   >   
   >>   
   >> Unlike DVD10 (9.4GB) Double-sided single layer on each side, 4.7GB per   
   >> side, requires flipping the disk.   
   >>   
   > Which (for that reason) presumably wasn't common; I don't think I've   
   > ever seen one. Only used for very long movies?   
   >   
   >>   
   > _Was_ (is?) there a double sided, double layer variant (DVD11 maybe)? Or   
   > were (are) that-long movies just usually supplied on two discs?   
   >   
   >>   
   > (What were DVDs 1-4 and 6-8?)   
   >   
   >>   
   All those questions can be answered via Googling or Bing or in most   
   cases, any AI web source.   
      
   The caution with web AI...AI anaylysis may contain social media   
   explanations even when inaccurate(i.e. ymmv)   
      
   Good luck.   
      
   --   
   ...w¡ñ§±¤ñ   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)