Part 1 of ISO/IEC 80000 introduces the International System of Quantities and describes its relationship with the "International System of Units (SI). Specifically, its introduction states "The system of quantities, including the relations among the quantities used as the basis of the units of the SI, is named the International System of Quantities, denoted 'ISQ', in all languages.", and further clarifies that "ISQ is simply a convenient notation to assign to the essentially infinite and continually evolving and expanding system of quantities and equations on which all of modern science and technology rests".
The standard includes all SI units but is not limited to only SI units. Units that form part of the standard but not the SI include the units of information storage ("bit and "byte), units of entropy ("shannon, "natural unit of information and "hartley), the "erlang (a unit of traffic intensity) and units of level ("neper and "decibel). The standard includes all "SI prefixes as well as the "binary prefixes kibi-, mebi-, gibi-, etc., originally introduced by the "International Electrotechnical Commission to standardise binary multiples of byte such as "mebibyte (MiB), for 2 bytes, to distinguish them from their decimal counterparts such as megabyte (MB), for precisely one million ( 10242) bytes. In the standard, the application of the binary prefixes is not limited to units of information storage. For example, a frequency ten octaves above one hertz, i.e., 210 Hz ( 1000), is one kibihertz (1 KiHz). 1024 Hz
Historically, these "binary prefixes were standardized first in a 1999 addendum to "IEC 60027-2. The harmonized IEC 80000-13:2008 standard obsoletes and replaces subclauses 3.8 and 3.9 of IEC 60027-2:2005, which had defined the prefixes for binary multiples. The only significant change in IEC 80000 is the addition of explicit definitions for some quantities.