Measuring Network Throughput - Nomenclature

Nomenclature

The throughput of communications links is measured in bits per second (bit/s), kilobits per second (kbit/s), megabits per second (Mbit/s) and gigabits per second (Gbit/s). In this application, kilo, mega and giga are the standard S.I. prefixes indicating multiplication by 1,000 (kilo), 1,000,000 (mega), and 1,000,000,000 (giga).

File sizes are typically measured in bytes — kilobytes, megabytes, and gigabytes being usual, where a byte is eight bits. In modern textbooks one kilobyte is defined as 1,000 byte, one megabyte as 1,000,000 byte, etc., in accordance with the 1998 International Electrotechnical Commission (IEC) standard. However, when Windows systems measure file size, the old computer science definition is still used, where 1 kilobyte is defined as 1,024 (or 210) bytes, which should be denoted 1 kibibyte according to IEC terminology. Similarly, a file size of 1 megabyte is 1,024 × 1,024 byte (should be called 1 mebibyte), and 1 gigabyte 1,024 × 1,024 × 1,024 byte (should be called one gibibyte). The result of all this is that a file that according to the operational system consists of 64 kilobyte data contains 64 × 1024 bytes, or 64 × 1024 × 8 bits.