GB 和 GiB 的區別

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Gibibyte (GiB) is one of the standard units used in the field of data processing and data transmission (along with mebibyte (MiB), kibibyte (KiB), etc.). Gibibyte, mebibyte, and kibibyte are defined as powers of 2.

1 GiB equals 2³⁰ bytes or 1,073,741,824 bytes. Gibibyte is closely related to gigabyte (GB), which can be a synonym of gibibyte or can refer to 10⁹ bytes or 1,000,000,000 bytes in accordance with International System of Units (SI).

Gigabyte (GB) can have different meanings in different contexts. When referring to computer memory, gigabyte is allways a “power of two” - 1,073,741,824 bytes, but when measuring hard drive capacity it is often defined as 1,000,000,000 bytes. Generally, operating systems calculate disk and file sizes using binary numbers, so a new 500 GB drive you've just purchased would be reported by the OS as "465.66 GB" (meaning 465.66 GiB).

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=============== TB GB  MB KB =================

1 TB = 10¹² bytes = 1000 x 1000 x 1000 x 1000 bytes

1 GB = 10⁹ bytes = 1000 x 1000 x 1000 bytes

1 MB = 10⁶ bytes = 1000 x 1000 bytes

1 KB = 10³ bytes = 1000  bytes

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=============== TiB GiB  MiB KiB ===============

1 TiB = 2⁴⁰ bytes = 1024 x 1024 x 1024 x 1024 bytes

1 GiB = 2³⁰ bytes = 1024 x 1024 x 1024 bytes

1 MiB = 2²⁰ bytes = 1024 x 1024 bytes

1 KiB = 2¹⁰ bytes = 1024  bytes

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1 GiB = 1.073741824 GB

465.66 GiB ≈ 500 GB

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總結

GB 是 十進制 的，GiB 才是 二進制 的。

但是現在經常在寫法上，習慣用 GB 代替 GiB，導致有些應用場景下，會產生概念上的混淆。

就會導致一個商業誤導，商家宣稱一個 500 GB 的硬盤，其實只有 465 GB（其實這里的單位應該是GiB） 左右。

 

有興趣深入了解的，可以參考如下資料：

https://www.wintelguy.com/gb2gib.html