▁functions . ▁Note , ▁System ▁has ▁changed ▁in ▁Do D AF ▁V 2 . 0 ▁from ▁Do D AF ▁V 1 . 5 : ▁System ▁is ▁not ▁just ▁computer ▁hardware ▁and ▁computer ▁software . ▁System ▁is ▁now ▁defined ▁in ▁the ▁general ▁sense ▁of ▁an ▁assemb lage ▁of ▁components ▁- ▁machine , ▁human ▁- ▁that ▁perform ▁activities ▁( since ▁they ▁are ▁sub types ▁of ▁Per former ) ▁and ▁are ▁interact ing ▁or ▁inter dependent . ▁This ▁could ▁be ▁anything , ▁i . e ., ▁anything ▁from ▁small ▁pieces ▁of ▁equipment ▁that ▁have ▁interact ing ▁or ▁inter dependent ▁elements , ▁to ▁Family ▁of ▁Systems ▁( F o S ) ▁and ▁System ▁of ▁Systems ▁( So S ). ▁Note ▁that ▁Systems ▁are ▁made ▁up ▁of ▁M ater iel ▁( e . g ., ▁equipment , ▁aircraft , ▁and ▁vessels ) ▁and ▁Person nel ▁Types . ▁ ▁The ▁architect ures ▁for ▁Do D AF ▁V 1 . 0 ▁and ▁Do D AF ▁V 1 . 5 ▁may ▁continue ▁to ▁be ▁used . ▁When ▁appropriate ▁( us ually ▁indicated ▁by ▁policy ▁or ▁by ▁the ▁decision - maker ), ▁Do D AF ▁V 1 . 0 ▁and ▁V 1 . 5 ▁architect ures ▁will ▁need ▁to ▁update ▁their ▁ ▁architecture . ▁When ▁pre - Do D AF ▁V 2 . 0 ▁architecture ▁is ▁compared ▁with ▁Do D AF ▁V 2 . 0 ▁architecture , ▁concept ▁differences ▁( such ▁as ▁Node ) ▁must ▁be ▁defined ▁or ▁explained ▁for ▁the ▁newer ▁architecture . ▁In ▁regard ▁to ▁Do D AF ▁V 1