oun cement ▁of ▁virtual ▁memory ▁added ▁to ▁System / 3 7 0 ▁series . ▁ ▁VM / 3 7 0 ▁announced ▁– ▁and ▁running ▁on ▁announ cement ▁date . ▁VM / 3 7 0 ▁includes ▁the ▁ability ▁to ▁run ▁VM ▁under ▁VM ▁( pre viously ▁implemented ▁both ▁at ▁IBM ▁and ▁at ▁user ▁sites ▁under ▁CP / C MS , ▁but ▁not ▁made ▁part ▁of ▁standard ▁releases ). ▁▁ 1 9 7 3 ▁ ▁First ▁ship ment ▁of ▁announced ▁virtual ▁memory ▁S / 3 7 0 ▁models ▁( A pril : ▁- 1 5 8 , ▁May : ▁- 1 6 8 ). ▁▁ 1 9 7 4 - 1 9 9 8 ▁ ▁[ ongo ing ▁history ▁of ▁VM ▁family ▁and ▁V P / CSS .] ▁▁ 1 9 7 7 ▁ ▁Initial ▁commercial ▁release ▁of ▁V AX / V MS , ▁later ▁renamed ▁Open V MS . ▁▁ 1 9 8 5 ▁ ▁October ▁ 9 , ▁ 1 9 8 5 : ▁Ann oun cement ▁of ▁the ▁Intel ▁ 8 0 2 8 6 - based ▁AT & T ▁ 6 3 0 0 + ▁with ▁Sim ult ask , ▁a ▁virtual ▁machine ▁monitor ▁developed ▁by ▁L ocus ▁Comput ing ▁Corporation ▁in ▁collaboration ▁with ▁AT & T , ▁that ▁enabled ▁the ▁direct ▁execution ▁of ▁an ▁Intel ▁ 8 0 8 6 ▁guest ▁operating ▁system ▁under ▁a ▁host ▁Unix ▁System ▁V ▁Release ▁ 2 ▁OS . ▁ ▁Although ▁the ▁product ▁was ▁market ed ▁with ▁Microsoft ▁MS - D OS ▁as ▁the ▁guest