Unix System Laboratories Europe – formerly the Unix Software Operation – says that Unix System V/386 Release 4 has now been stamped as XPG3-compliant by X/Open Co Ltd, claiming it to be the only source code product that has received such a brand: System V/386 is the reference version of V.4 for computers built around Intel 80386 and 80486 microprocessors; other Unix System software getting the brand for the Intel chips are XWIN – its implementation of the X Window System, its C programming language tools, System V Release 4 commands and utilities, internationalised system calls, terminal interface and interprocess communication routines.