General question about CDR's

Okay, I've been wondering this for sometime now, and I feel like an idiot..

The CD's I buy say they're "700MB".

However, I'm only able to burn about 670 MB to the disc before it tells me it's full. And if I click on my CD drive, and it shows the little pie chart of how much space is taken up, it says the max is 670 and not 700.

So what is up with this? Does it have to do with my CD drive?
What burner do you have? Does the manual say it can burn 700MB (i.e., 80 minute) CD-Rs? Also, what recording software are you using?

As for it saying the max is 670, that's because that is how much has been burned onto the CD-R. Think of it as only 670MB of space has been formatted on the CD-R.
just a thought, are you using direct cd or something similar to put files onto the cd like you would do a hard disk?

if so, then the way direct cd works if i remember correctly, is to format the cdr in someway before you use it to store data on

that would account for the missing 30mb of space
Yeah I am using that... I figured it would format it in some way, but then I also thought that if it did, it'd still say "700MB" when I highlighted my D Drive, instead of the formatted 670.