GB vs GiB
5:15 AM
Recently my friend bought a USB Flash Drive of 16 GB capacity and complained that it doesn't even have a storage capacity of 15 GB. Of course, no USB Flash Drive will have exactly the same capacity as advertised but a difference of 1 GB is not acceptable. Then I realized that she was using a Windows system and the problem arose due to the popular notion that 1 GB equals 230 bytes.
We have been taught that 1 GB(gigabyte) equals 1024 MB(megabyte), which in turn is equal to 1024 kB(kilobyte), which is again equal to 1024 B(bytes). In metric prefix we use the term kilo to represent 103 . But in binary system everything is represented in powers of 2. This lead to the introduction of kibi, which is a combination of kilo and binary. It solve the ambiguity raised with the usage of the prefix kilo to represent 1024 and 1000. So, 1 KiB(kibibyte) represents 1024 bytes and 1 kB (kilobyte) represents 1000 bytes. Similarly 1 MiB(mebibyte) equals 1024 KiB & 1 GiB(gibibyte) equals 1024 MiB.
Hardware manufactures and scientific applications sticks to this standard. Some non- scientific applications, JEDEC memory standards and Microsoft Windows use the term kilo to represent 1024 Bytes. So, coming to our problem the 16 GB USB Flash Drive should have a memory equal to 16 x 109 bytes which is equal to 16 GB but will be shown as 14.90 GB(rounded) in Windows (which is actually 14.90 GiB).
A table covering these differences could be found at http://en.wikipedia.org/wiki/Orders_of_magnitude_(data)
We have been taught that 1 GB(gigabyte) equals 1024 MB(megabyte), which in turn is equal to 1024 kB(kilobyte), which is again equal to 1024 B(bytes). In metric prefix we use the term kilo to represent 103 . But in binary system everything is represented in powers of 2. This lead to the introduction of kibi, which is a combination of kilo and binary. It solve the ambiguity raised with the usage of the prefix kilo to represent 1024 and 1000. So, 1 KiB(kibibyte) represents 1024 bytes and 1 kB (kilobyte) represents 1000 bytes. Similarly 1 MiB(mebibyte) equals 1024 KiB & 1 GiB(gibibyte) equals 1024 MiB.
| 1000 B | 1 kB | kilobyte |
| 1000 kB | 1 MB | megabyte |
| 1000 MB | 1 GB | gigabyte |
| 1024 B | 1 KiB | kibibyte |
| 1024 KiB | 1 MiB | mebibyte |
| 1024 MiB | 1 GiB | gibibyte |
Hardware manufactures and scientific applications sticks to this standard. Some non- scientific applications, JEDEC memory standards and Microsoft Windows use the term kilo to represent 1024 Bytes. So, coming to our problem the 16 GB USB Flash Drive should have a memory equal to 16 x 109 bytes which is equal to 16 GB but will be shown as 14.90 GB(rounded) in Windows (which is actually 14.90 GiB).
A table covering these differences could be found at http://en.wikipedia.org/wiki/Orders_of_magnitude_(data)
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