▁ 9 0 0 0 ▁Series ▁ 2 0 0 , ▁ 3 0 0 , ▁and ▁ 4 0 0 ▁computer ▁systems ▁based ▁on ▁the ▁Motor ola ▁ 6 8 0 0 0 ▁series ▁of ▁process ors , ▁as ▁well ▁as ▁the ▁H P ▁ 9 0 0 0 ▁Series ▁ 5 0 0 ▁computers ▁based ▁on ▁H P ' s ▁propriet ary ▁FO C US ▁architecture . ▁ ▁H P - U X ▁was ▁the ▁first ▁Unix ▁to ▁offer ▁access ▁control ▁lists ▁for ▁file ▁access ▁permissions ▁as ▁an ▁alternative ▁to ▁the ▁standard ▁Unix ▁permissions ▁system . ▁H P - U X ▁was ▁also ▁among ▁the ▁first ▁Unix ▁systems ▁to ▁include ▁a ▁built - in ▁logical ▁volume ▁manager . ▁H P ▁has ▁had ▁a ▁long ▁partners hip ▁with ▁Ver itas ▁Software , ▁and ▁uses ▁V x FS ▁as ▁the ▁primary ▁file ▁system . ▁ ▁It ▁is ▁one ▁of ▁five ▁commercial ▁operating ▁systems ▁that ▁have ▁versions ▁cert ified ▁to ▁The ▁Open ▁Group ' s ▁UN IX   0 3 ▁standard . ▁ ▁( The ▁others ▁are ▁mac OS , ▁Sol aris , ▁A IX ▁and ▁H ua wei ' s ▁E uler OS .) ▁ ▁Character istics ▁ ▁H P - U X ▁ 1 1 i ▁offers ▁a ▁common ▁shared ▁dis ks ▁for ▁its ▁cluster ed ▁file ▁system . ▁H P ▁Serv ic egu ard ▁is ▁the ▁cluster ▁solution ▁for ▁H P - U X . ▁H P ▁Global ▁Work load ▁Management ▁adjust s ▁work loads ▁to ▁optimize ▁performance , ▁and ▁integr