What does the Rewrite speed in CDRW mean?

[whoami2000au]

when you say rewrite speed for a CD-RW is 8x, what does that mean?
Is that the speed I would get when i write on a cd second time whether the surface was written before or not?
Or is that the speed I get when I try to write on a surface where it was written before?

For example...
If i write about 10 MB on a cd, then write about additional 20 MB later, what speed do I get for the second write?
Sorry for the dumb question..
Please help~~

 

[EvilDonnyboy]

The ReWrite speed means the speed to write to a Cd-RW. It doens't matter if ur erasing, writing 1st time, writing 2nd time.

 

[Noriaki]

There are two different types of media.
CDR Discs and CDRW Discs.

CDR Discs are write once (though you can do sessions and add more later, once data is there it's there forever) and use the first number.

CDRW Discs can be erased and use the second number, regardless of whether it's the 1st write or a later one.