4.7G DVDs appear to have only 4.38G

With various ways of trying to burn a DVD, all the programs see to say the DVDs have only 4.38G of space. But they are 4.7G DVDs. I'm just trying to burn data. So why won't it let me use the whole space?
Thanks
Justin

The 4.7Gb is unformatted I think.

It's a pain, but the capacity is 4.3Gb in reality. If a manufacturer put 4.3Gb on the box, a rival would put 4.7Gb and gain sales. So they all put 4.7Gb on.

Its to do with they way a gig is counted (or any memory).

Manufactures counts gig as 1000mb and your computer a gig is 1024mb.

So which of the two is it that doesn't know how to count?
(Maybe I should start a media company counting a gig as 3k?)

A gig is 1024 as a computer counts in blocks of 8, hence why all memory amounts are dividable by 8. I believe.

So technically the computer companies are wrong and the computer is right. But I remeber reading this years ago.

Binary numbers consisting entirely of 1s (i.e. every bit high) are always a power of 2 minus 1. 1 byte (8 bits) is 11111111, or (2^8)-1, or 255. 2^10 is 1024 and so it's the closest you can get to 1000 using only binary 1s.

To indicate the massive disparity possible with this sort of advertising, consider a 250GB hard disk if the manufacturer use 1000s as the KB, MB and GB multipliers. 250,000,000,000 bytes! Unfortunately, if you divide it by 1024^3 (the computer's version of 1GB) it's only 232.8GB. They've nicked 16.2GB off you!

For this reason, some people like to use the abbreviations KB, MB and GB to mean 1000B, 1000KB and 1000MB respectively, and KiB, MiB and GiB to represent 1024B, 1024KB and 1024MB. I get the 'ki'lobyte and 'gi'gabyte ones, but the 'mi'gabyte one grates a little