Shoe size "Footwear - Sizing - Vocabulary and terminology"; currently in development are companion standards ISO/TS 19409 "Footwear - Sizing - Measurement of last dimensions" and ISO/TS 19410 "Footwear - Sizing - Inshoe measurement". The adult shoe sizes are calculated from typical last length, which is converted from foot length in mm by adding an allowance of two shoe sizes: where formula_13 is foot length in mm. Direct conversion between adult UK, European and Mondopoint shoe size systems is derived as follows: Exact foot lengths may contain repeating decimals because the formulas include division by 3; in practice, approximate interval steps of
ISO 9660 well when reading optical discs. Several disc authoring tools (such as Nero Burning ROM, mkisofs and ImgBurn) support a so-called "ISO 9660:1999" mode (sometimes called "ISO 9660 v2" or "ISO 9660 Level 4" mode) that removes restrictions following the guidelines in the ISO 9660:1999 draft. ISO 9660 file system images (ISO images) are a common way to electronically transfer the contents of CD-ROMs. They often have the filename extension codice_1 (codice_2 is less common, but also in use) and are commonly referred to as "ISOs". Most operating systems support reading of ISO 9660 formatted discs, and most new versions support