XPost: alt.comp.os.windows-11   
   From: nospam@needed.invalid   
      
   On Fri, 2/21/2025 5:35 AM, Jasen Betts wrote:   
   > On 2025-02-16, Daniel70  wrote:   
   >> I've got a PVR who's HD is getting pretty full (90%+) with programs I'll   
   >> want to watch some day ... so I was thinking about coping some of the   
   >> 'Keeper' programs onto DVD which meant buying a spool of DVD's.... but   
   >> then needed to check if I needed DVD-R or DVD+R disks. (It is DVD-R)   
   >>   
   >> Which got me thinking ...... What's the difference between DVD-R and DVD+R??   
   >   
   > Different chemical process.   
   >   
   >> Back in the day (70's/80's), I used to do some Digital work where 'they'   
   >> talked about Positive Logic (Ones = +5V, Zeros = Zero volts) and   
   >> Negative Logic (Ones = Zero Volts and Zeros = +5V or even Ones = -5V and   
   >> Zeros = Zero Volts), so I can understand/accept that there are   
   >> differences ..... but with DVDs??   
   >   
   > Different strength of laser pulses I think.   
   >   
   >> On a +R DVD, are the 'Ones' high points on the disk whilst on a -R DVD   
   >> are the 'ones' the low points on the disk?? (Or, rather than 'highs' and   
   >> 'lows', is it a case of the orientations of the 'North Poles' and 'South   
   >> Poles' of the Domains??)   
   >   
   > The sifference between + and - is one bit in ASCII.  in DVD R  "+" is   
   > a newer technology, and older DVD-R drives can't write it.   
   >   
   >   
   > A spool of DVDs say 50 pieces,  that's like 250GB.   
   >   
   > Why do this? USB flash is cheaper, SSDs are cheaper.  Hard drives are much   
   > cheaper.   
   >   
      
   The lasers have programmable strength.   
      
   read is different than write is different than erase strength.   
      
   The media tag indicates the strength, and as well there is   
   a burn experiment the drive can do to determine the strength.   
   But the instructions in the media tag would generally give a   
   better result.   
      
   And the chemistry and appearance are interesting, even if   
   they don't match the colors you see at home right now :-)   
      
      https://ccssinc.net/index.php?main_page=cdr_dye_explained   
      
   At least we see why the gold-colored media is archival.   
   The PhthaloCyanine is transparent.   
      
      Paul   
      
      
      Paul   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)