Norton Commander for DOS is the original line of Orthodox file managers that exists in five major versions: 1.0, 2.0, 3.0, 4.0 and 5.0. Only the last one has an additional sub-version (nc 5.5). All versions are still used (mostly by DOS enthusiasts) and are often posted on the abandonware sites. […] It was probably one of the most popular file manager of the DOS era, which along with Xtree remains one of the few programs which managed to transcend their DOS roots and Norton Commander descendants (OFM managers) now exist on all popular OSes. The first version of NC (1.0) was designed and written by John Socha in 1984-1989. We provide a short biographical notes about him later in this chapter.
http://www.softpanorama.org/OFM/Paradigm/Ch03/norton_commander.shtml#Timeline