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Only 4.5 gigs on a TDK 4.7 Gb DVD+R ... ?!


Only 4.5 gigs on a TDK 4.7 Gb DVD+R ... ?!

Postby sebmex on Fri Sep 30, 2005 5:12 am


how comes Nero tells me that less than 4.5 gigs are available for burning ?

thanks for the help

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Postby Wesociety on Fri Sep 30, 2005 12:05 pm

Q: What is the capacity of a DVD disc? Is it 4.7 GB or is it 4.38 GB?
A: Technically, a blank single-layer DVD disc is 4.7 GB in size, which is equal to 4.38 GiB. GB and GiB are actually different units of measurement, and the confusion comes from the fact that "GiB" is very often mislabeled as "GB". This page explains what the difference is.
- For single-layer discs, it is 4,700,372,992 - 4,707,319,808 bytes (about 4,482 - 4,489 MiB or 4.38 GiB).
- For double-layer discs, it is 8,547,991,552 bytes (about 8,152 MiB or 7.96 GiB).
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Postby burninfool on Fri Sep 30, 2005 9:40 pm

That's the first time I've seen MiB or GiB.
In the computer world 1 KB data = 1024 bytes so 4 700 000 000 bytes / 1024 = 4 589 843KB / 1024 = 4482MB / 1024 = 4.37GB.
DVD+R/DVD+RW/DVD+R DL and DVD-R/DVD-RW exact sizes:
DVD-R/DVD-RW = 4 706 074 624 bytes ( 4488 MB or 4.38GB )
DVD+R/DVD+RW = 4 700 372 992 bytes ( 4482 MB or 4.37GB)
DVD+R DL = 8 547 993 600 bytes ( 8152 MB or 7.96GB)

It's a marketing trick just as a "120GB" HDD(120,000,000,000 bytes) is actually 111GB.
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Postby dodecahedron on Sat Oct 01, 2005 12:03 am

this has been discussed/argued many times.
"in the computer world" is an amorphous description.

to an Assembler programmer 1K=1024, 1M=1024^2 etc.
beyond that, nothings is clear. 1K is sometimes 1024 sometimes 1000.
too bad, that's just the way it is.
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them
In the land of Mordor, where the Shadows lie
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Postby MediumRare on Sat Oct 01, 2005 9:38 am

I'm with wesociety on this one!
burninfool wrote:That's the first time I've seen MiB or GiB.

Well I've been using them since I became aware that binary mulitpliers exist.

Frankly, this is something I feel very strongly about.

Although I now live in Germany, I grew up with feet, inches and miles etc. so non-decimal conversion factors are a nuisance, but "normal".

What bugs me more is the use of one name for different quantities. Example: nautical and statutory miles; various kinds of ounces; US vs. Imperial gallon; long, short and metric tons (and an english "horsepower" is not quite the same as a german "Pferdestärke"). Even more insidious- in the US a "billion" is 1000 million (10^9); in Europe it's a million million (10^12).

It's for this sort of thing that the SI multipiliers were specified. These are decimal multipliers and use for binary quantities may be "customary" for some parts of the computer worls, e.g. storage capacity, but is not standard. It gets worse- the computer world isn't all binary either. You certainly don't specify frequncies with binary multipliers, nor bandwidth or transfer rates. GBit ethernet means 10^9 bit/s, not 2^30.

Maybe there was a reason to tolerate this in the past, but now we have the binary multipliers and we can use them to avoid the confusion. I certainly hope that they will be taught to engineers and computer scientists in the future.

Just because the marketroids use the decimal multipliers doesn't make them wrong: a "120GB" HDD(120,000,000,000 bytes) is not "actually 111GB"- it's actually 111GiB.

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Postby burninfool on Sat Oct 01, 2005 12:13 pm

Mental note to self:
When using binary multipliers think of Girls in Black and Men in Black. :wink:
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