4GB SD not quite 4GB

[Guest ddieter]

I've just purchased an Adata 4GB SD card.

I plugged it in and noticed that I don't quite get all 4 GB. It's more like 3.8GB

Is this a normal occurance? I can understand it losing a bit of space, but 200MB? That's a fair number of songs!

Has anyone had better luck with their 4GB SD cards?

[Guest funkychicken9000]

I've just purchased an Adata 4GB SD card.

I plugged it in and noticed that I don't quite get all 4 GB.  It's more like 3.8GB

Is this a normal occurance?  I can understand it losing a bit of space, but 200MB?  That's a fair number of songs!

Has anyone had better luck with their 4GB SD cards?

<{POST_SNAPBACK}>

"metric gigabytes" ;)

Manufacturers like calling 4,000,000B 4GB. Doing the maths:

4,000,000 / 1024 / 1024 = 3.81 So really you only get 3.81 "proper" gigabytes, less a bit for filesystem etc.

[Guest Tech]

yes this is normal as the rest of the space that appears to be "lost" is used for the FAT system - File Allocation Table

just like your computer harddisk - you buy a 200GB and format/partition it - you will have around 196GB or slightly more available

[Guest shadamehr]

How big is your COMPUTER hard drive, as opposed to how big it is MEANT to be?

My 300GB is a fair old whack short of that.

It's exactly the same thing with memory cards, but its only when you start getting into the big realms like your 4GB card that you really start to notice the shortfall.

Explanation:

Q: Why is my hard drive size smaller than advertised?

A: Hard drive manufacturers define 1 gigabyte as exactly 1,000,000,000 bytes. By their definition, a 45BG hard drive is exactly 45,000,000,000 bytes. The true definition of 1 gigabyte is actually 1,073,741,824 bytes:

1024 bytes = 1 kilobyte

1024 kilobytes = 1 megabyte

1024 megabytes = 1 gigabyte

To obtain the true size in gigabytes of a 45BG hard drive you must divide the manufacturer's size in bytes by the number of bytes in a gigabyte:

45,000,000,000/1,073,741,824 = 41.9

As such, the actual reported size in gigabytes will always be smaller than the manufacturer's advertised size.

So in your case:

4,000,000,000 / 1,073,741,824 =

3.7253 GB

Is that what your card says? If so, it's absolutely spot on!

Alternatively, for another answer:

Q: Why is my hard drive smaller than its advertised size?

A: There is probably nothing wrong. Imagine a world where a "foot" was 12 inches to one person and 11 to another. The only thing common to the two people with yard sticks would be the size of the inch. Their yard sticks placed side to side would be different. There are two gigabytes, two megabytes, and two kilobytes, each meaning something slightly different then its counterpart. It so happens that 2 ^10th power is almost 1000 (it's 1024) and 2 ^20th power is almost 1 million (it's 1,048,576) and 2 ^30th power is almost 1 billion ( it's 1,073,741,824). A kilobyte is 1000 bytes to person counting in decimal and 1024 bytes to a person using the binary representations. The only thing common to the two measurement systems is the size of a byte.

Your operating system uses both binary and decimal representations of hard drive space depending on where you look. The hard drive manufacturers use the decimal representation. I've seen people complain that HD manufacturers are using the most beneficial numbers to rate their products, but I don't agree with this. If you use the decimal system you know exactly how many bytes your hard drive will hold without having to think about it. If you use the binary representation, you have to do a calculation to figure the exact number of bytes your hard drive will hold.

Let’s use the example of an 80 gigabyte hard drive. A typical 80 gig will have 80,048,390,144, but Windows will report that as 74.5GB in some places. If we calculate 80,048,390,144/1,048,576 we get roughly 74.55, (binary) gigabytes. A 160 GB drive would be 160,000,000,000/1,073,741,824 or 149.0116119 (binary) gigabytes. To get the values in (binary) megabytes simply divide by 1,048,576.

[Guest shadamehr]

yes this is normal as the rest of the space that appears to be "lost" is used for the FAT system - File Allocation Table

just like your computer harddisk - you buy a 200GB and format/partition it - you will have around 196GB or slightly more available

<{POST_SNAPBACK}>

Tech - see either answer above or below yours for the correct answer why this is happening.

Just to put you at rest, it's NOT because of something hidden using it - it's becuase its simply NOT THERE at all - as it is due to how you measure...

[Guest ddieter]

Hey fellas,

Thanks for the explanation.

I guess from my question you can tell I'm a bit of a noob. :oops:

I was just wondering if I had to tweak anything to free up that remaining space. But now I know it was never there in the first place, and my SD card is working just fine.

Cheers,

D