DVD-Disc size?

[DVD]

Why can i only put 4,37GB on a DVD instead of 7,4GB?

[RJ]

Hi,

it's because the DVD manufacturers use the same wrong number for advertisement as the hard drive manufacturers do.
They calculate with 1000 instead of 1024. The result is:

4,7 GB -> 4700 MB -> 4700000 KB -> 4700000000 Bytes

Now, using 1024 you can calculate the real capacity:

4700000000 Bytes = 4589843,75 KB = 4482,269 MB = 4,377216 GB.

So 4,377 GB is the real capacity of a recordable DVD. Also look at the MB size: 4482. If you ever burned a data DVD using Nero, you will notice that the capacity mark is a few pixels right of 4480 MB.

The same calculation works for hard drive, if you wonder why for example a 120 GB drive shows up with 115 GB in Windows (Windows always displayes the correct size).

RJ

[Nuclear Krusader]

:mad:

Now I know why my Barracuda 80 GB is displayed as a 76 GB drive!

[RJ]

And my IBM Deskstar 120GXP "121,5GB" is displayed as 115 GB (that'd be 5 to 6 GB already).

Hopefully they will some day change it, as the difference between correct size and advertised size increases with even bigger hard drives.

RJ