difference between dvd media

[donniejoy]

can anyone explain the difference between dvd disc
dvd-r
dvd-rw
dvd+r
dvd+rw
we have a philips dvd+rw/cdr burner in our new dell
it burns cdr fine and it burns dvd+rw but not dvd-r discs
I understand the difference of write once and rewritable but not the disc that are labeled
dvd_ram
dvd-rw
dvd+rw

what the minus and the plus does this mean something

[donniejoy]

:D hi this site is great , as soon as i posted this message i found the answer here thankyou