Definition(en): Archiver Format (.ar) is a non-compressed archive format associated with the archiver utility for Unix-style operating systems. It has largely been replaced by .tar for general archiving use, but persists in use for specialized applications involving statically-linked libraries for development. The format has never been standardised with modern archives based on a common format with two main variants - BSD and System V (previously known as COFF). There are other known past variants such as V6, V7, AIX (small), AIX (big) and Coherent.