size of a dvd+rw

[dpkkk]

i just bought a dvd+rw thats supposed to have 4.7 gigs of space on it. however, when i check the properties it only holds 4.37GB of data.

why does it have just 4.37 and not 4.7??

[photolady]

The reason is, that the way they (manufacturers) total drives or disks. It's not 1000 kilobytes, but actually 1024 Kilobytes. So, the answer is:

Keep in mind that manufacturers quote the capacity of a writable DVD disc in decimal (base 10) rather than binary (base 2)

4,700,000 KB ÷ 1000 = 4,700 MB ÷ 1000 = 4.7 GB] but actually it's this instead.

4:700,000,000 bytes ÷ 1024 = 4,589,844 KB ÷ 1024 = 4,482.27 MB ÷ 1024 = 4.38 GB

Of course this is the same as any harddrive marked 80gb won't actually show in windows as 80gb it's 74gb.