When does 4.7=4.4?

[sam_gordon]

When you're talking about how much data you can put on a DVD.\

For work, we need to store data on a DVD. We've been trying to get one days worth of data onto one DVD. When we first started, we had 11G worth of data... obviously that won't work. So we start experimenting with compression. We get a day's worth down to 4.42G. GREAT, right? A DVD holds 4.7G (according to all the labeling). Nope. Our burning program shows only 4.38G available on a BLANK DVD.

Back for more compression.

No, going Blu Ray is not an option.
We'd REALLY want to put one day onto one disk.

Just a vent

 

[FireDancer]

There is some overhead for the file system and possibly menus but it shouldn't be 300MB. It might be the program you are using and it might be the firmware or driver of the burner. Have you tried a different software program or looked for new drivers or firmware for the drive?

 

[sam_gordon]

Tried different DVDs, different programs on the same computer and a different computer. Everything came up at 4.38 or 4.4.

The other aggravating issue is compressing the data takes 2 1/2 hours (we're exporting 24 hours of video). I think I'll have it after this attempt.

 

[jlewisinsyr]

I guess I would look at how much time your spending to manipulate this data versus the cost of upgrading. I know you said BluRay is not an option, but time equals money IMO, so I would think eventually it would pay for itself.

There is a lot of talk about 4.7GB labeling on DVD discs versus the recording standard of 4.3GB, a google search will show a ton of hits. Basically it comes down to calculations of 1,000 MB = 1GB versus reality of 1,024MB = 1 GB. A normal DVD, despite display packaging should hold about 4,490 MB or 4.38GB.

 

[FireDancer]

If your burner will do DVD +/-R DL you can get double layer discs and use the same burner.

 

[timmac]

I guess I would look at how much time your spending to manipulate this data versus the cost of upgrading. I know you said BluRay is not an option, but time equals money IMO, so I would think eventually it would pay for itself.

There is a lot of talk about 4.7GB labeling on DVD discs versus the recording standard of 4.3GB, a google search will show a ton of hits. Basically it comes down to calculations of 1,000 MB = 1GB versus reality of 1,024MB = 1 GB. A normal DVD, despite display packaging should hold about 4,490 MB or 4.38GB.

This.

Storage manufacturers label everything in terms of true GB, where 1GB = 1 billion bytes, and Giga literally mean 1 billion.

Internally, most computers use GiB, or Gigibyte, where KiB = 1024, MiB = 1024 * 1024, GiB = 1024 * 1024 * 1024. So, 4.7GB = 4.377 GiB.

Confused yet?

 

[sam_gordon]

This.

Storage manufacturers label everything in terms of true GB, where 1GB = 1 billion bytes, and Giga literally mean 1 billion.

Internally, most computers use GiB, or Gigibyte, where KiB = 1024, MiB = 1024 * 1024, GiB = 1024 * 1024 * 1024. So, 4.7GB = 4.377 GiB.

Confused yet?

Yup. Using your definition, a GiB would be 1,073,741,824. That would be MORE than 1 billion. Using the labeling convention of 4.7Gb, I'd expect 4,700,000,000 bytes to fit on a disk (forget the overhead for a moment). I don't see where you get to the 4,377,000,000. Sorry.

 

[timmac]

Yup. Using your definition, a GiB would be 1,073,741,824. That would be MORE than 1 billion. Using the labeling convention of 4.7Gb, I'd expect 4,700,000,000 bytes to fit on a disk (forget the overhead for a moment). I don't see where you get to the 4,377,000,000. Sorry.

No need to be sorry, I probably didn't explain that well, so I'll try again.

A disc does hold 4,700,000,000 bytes. Which equals 4.377 GiB.

The data you were attempting to store, which was 4.42 GiB is approximately 4,740,000,000 bytes.

 

[jlewisinsyr]

No need to be sorry, I probably didn't explain that well, so I'll try again.

A disc does hold 4,700,000,000 bytes. Which equals 4.377 GiB.

The data you were attempting to store, which was 4.42 GiB is approximately 4,740,000,000 bytes.

This is a perfect way to explain. (((4,700,000,000 Bytes/1024)/1024)/1024) = 4.377 GB

Manufacturers, be it hard drive, CD, DVD, etc take the total bytes and divide it by 1,000 for convenience of customers, thus obtaining 4.7GB number. Even the 2 TB drives I have been buying for our HTPC are that way, from a true sense they are not equal to 2TB if you do the math, but there is a sticker that explains this as well.

 

[FireDancer]

Basically what happens is the size of a kilobyte is rounded down. Because the size of a kilobyte is rounded down from 1024 to 1000 you actually can't get a kilobyte of data onto a drive labeled 1KB. When that kilobyte is multiplied to make a megabyte that difference is exaggerated and when it is multiplied out to a gigabyte it is exagerated again.

It comes down a combination of trying to express base 2 numbers in base 10 format and marketing simplification. A kilobyte is 2^10 bytes but it is easier to say a kilobyte is 1,000 bytes which is 10^3. In reality if you take an actual kilobyte file (1024 bytes) and try to put it on a drive that only holds 1000 bytes (but is sold as a kilobyte drive) it won't fit.

If the disks would actually hold 4.7GB in base 2^30 form they would have to hold 5.04GB in 10^9 form. Conversely, a disk that holds 4.7GB in 10^9 form, which is what you have, would only hold 4,377,000,000 in 2^30 form which is how the computer is interpreting it.

You spend a lot of time in entry level computer classes fumbling back and forth between the base 2 and base 10 worlds.

I completely forgot about this in my first response. It's one of those things you just don't think about until someone reminds you about it.

 

[sam_gordon]

OK. Thanks. It does make sense. Where I was getting burned was doing multiplication instead of the division. And that rounding thing got me too. I'm actually in IT support at my company and deep down knew 1Kb = 1024b, but it's easier to remember (and do the math) on 1kb=1000b.

It's only an issue on this because I was right on the edge between making the data fit and not.