Most people only know about KB, MB, GB, TB, etc., but have not heard of KiB, MiB, etc. The difference lies in whether calculations are based on 1000 bytes or 1024 bytes.
This is why the capacity of hard drives or USB drives we buy differs from the actual usable capacity. For example, a commercial 8GB USB drive actually has 8,304,717,824 bytes, but it only shows 7.73GB. Why? Because computers calculate using 1024 bytes, so dividing 8304717824 by 3 times 1024 (Byte>KiB>MiB>GiB) gives a result of 7.73 (to two decimal places), which is the actual capacity shown by the computer, i.e., 7.73GiB (displayed as 7.73GB).
If calculated using 1000 bytes, 8304717824 divided by 3 times 1000 (Byte>KB>MB>GB) yields a result of 8.30 (to two decimal places), which manufacturers label as 8.3GB in specifications.
For a 200GB hard drive, the computer shows 200,047,325,184 bytes, which calculates to 186.30GiB (displayed as 186GB) using the 1024 byte method, while the calculation using 1000 bytes gives 200.04GB, which aligns with the manufacturer's marketed specification of 200GB.
Thus, the byte counts provided by different manufacturers for hard drives can vary, but they are all within their specification standards. Simply put, you can approximately calculate the usable capacity by multiplying the purchased hard drive capacity by 0.93 (e.g., 500GB x 0.93 = approximately 465GB usable capacity).
Conversions:
Additionally, Kilobyte often refers to Kibibyte, with conversions as follows:
Understanding Bytes:
| Name | Abbreviation | Power |
|---|---|---|
| Kilobyte | KB | 10^3 |
| Megabyte | MB | 10^6 |
| Gigabyte | GB | 10^9 |
| Terabyte | TB | 10^12 |
| Petabyte | PB | 10^15 |
| Exabyte | EB | 10^18 |
| Zettabyte | ZB | 10^21 |
| Yottabyte | YB | 10^24 |
| Name | Abbreviation | Power |
|---|---|---|
| Kibibyte | KiB | 2^10 |
| Mebibyte | MiB | 2^20 |
| Gibibyte | GiB | 2^30 |
| Tebibyte | TiB | 2^40 |
| Pebibyte | PiB | 2^50 |
| Exbibyte | EiB | 2^60 |
| Zebibyte | ZiB | 2^70 |
| Yobibyte | YiB | 2^80 |
蘊藏許多助人的知識與智慧。