DVD+R and 4.7GB

[Hurin]

Why can't I burn a dvd+r with 4.7GB of data, no dvd I buy can hold more than a few megs less than 4.5GB is this a problem with my software, burner or is it just the discs?

 

[BlueWeasel]

It's not a problem with anything you've got. There is a confusion of units to make DVD-R/+R discs appear to hold more data.

A single-sided DVD disc can hold 4.7 billion bytes.

1,000,000,000 x 4.7 = 4,700,000,000 bytes

But since a gigabyte consists of 1024^3 bytes, a GB is actually 1024^3 = 1,073,741,824 bytes, not 1,000,000,000 bytes.

Therefore, a DVD with a capacity of 4.7 billion bytes actually has a capacity in GB of:

4,700,000,000 / 1,073,741,824 = 4.37 GB

Marketing just assumes that one GB = 1,000,000,000 for simplicity. Using that number, the capacity of the DVD comes out to 4.7GB, which you know isn't valid.

Confusion about capacity @ the DVD FAQ

 

[Hurin]

Ah what the computer refers to as a GB is actually a GiB... darn

 

[VirtualLarry]

I've been a bit confused about this as well. I have burned several data ISO backup DVDs, using Nero 5.5.x.x (newest), and it shows both a yellow and red dashed line at the bottom, showing the "capacity limit" of the media, at "4500". And yet, when I fill it to nearly that mark, and pop it back in a DVD-ROM under Windows, it shows up as something like 4.23GB burned, and using DVDInfoPro, it shows as 4.23GB/4.5GB or something like that, meaning, that I've wasted a bunch of the blank space on the disk. I've been unable to adjust the position of the yellow/red limit bars in Nero, but am wondering "how high can I go" in terms of stacking data on a DVD ISO before I run out of room.

I guess that another way of saying that is, I'm going to go read up on the capacity limits, because I'm a bit confused over whether Nero, Windows, and DVDInfoPro are speaking in terms of GB or GiB, and what units the size limit is, as written on the DVD media packaging itself.

(Sigh. Why don't they just show capacity in "available LBA sectors", in all cases, maybe even in hexidecimal even. Would make life so much easier for us technical types.)

 

[NightCrawler]

4.70 Gigabytes metric ( marketing hype )

4.38 Gigabytes binary ( The Real Deal )


PS: I really hate the use of the metric system in the computer world.