Binary System (traditional)
In Data storage, traditionally, when describing digital circuitry, a kilobyte is 2^{10} or 1,024 bytes. This arises from binary exponentiation common to that circuits. This is the so called BINARY system where multiple of bytes are always some exponent of two. The binary prefix kibi (old k) means 2^{10} or 1,024, therefore, a 1 kibibyte is 1,024 bytes. The units (Kib, MiB, etc) were established by the International Electrotechnical Commission (IEC) in 1998. These units are used for randomaccess memory (RAM) capacities, such as main memory and CPU cache sizes, due to the binary addressing of memory. See some examples:
 1 byte (B) = 8 bits (b)
 1 kibibyte  KiB  traditional Kilobyte  KB = 2^{10} bytes = 1,024 bytes
 1 mebibyte  MiB  traditional Megabyte  MB = 2^{20} bytes = 1,048,576 bytes
 1 gibibyte  GiB  traditional Gigabyte  GB = 2^{30} bytes = 1,073,741,824 bytes
 1 tibibyte  TiB  traditional Terabyte  TB = 2^40 bytes = 1,099,511,627,776 bytes and so on ...
The Decimal System (SI)
Recently, most hard disk manufacturers use decimal megabytes (10^{6}) which is slightly different from the decimal system for small values and considerabily different for values of the order of Terabytes and it gets confusing. This is the so called DECIMAL system where multiple of bytes are always some exponent of ten as shown below:
 1 byte (B) = 8 bits (b) (one byte is always 8 bits)
 1 kilobyte (kB) = 10^{3} bytes = 1,000 bytes
 1 megabyte (MB) = 10^{6} bytes = 1,000,000 bytes
 1 gigabyte (GB) = 10^{9} bytes = 1,000,000,000 bytes
 1 terabyte (TB) = 10^{12} bytes = 1,000,000,000,000 bytes and so on ...
Please, check the tables below for more units.
