2 5 0 0 , ▁M V / 4 0 0 0 , ▁M V / 1 0 0 0 0 , ▁M V 1 5 0 0 0 , ▁M V / 2 0 0 0 0 , ▁M V / 3 0 0 0 0 ▁and ▁M V / 4 0 0 0 0 . ▁Later ▁models ▁such ▁as ▁the ▁M V / 4 0 0 0 0 ▁were ▁S MP ▁systems ▁with ▁hot - sw app able ▁components . ▁ ▁The ▁Eclipse ▁M V ▁was ▁a ▁ 3 2 - bit ▁C IS C ▁architecture ▁with ▁a ▁ 4   GB ▁address ▁space ▁and ▁a ▁ 4 . 5 M Hz ▁clock ▁frequency . ▁The ▁ 4   GB ▁address ▁space ▁was ▁divided ▁into ▁eight ▁rings ▁of ▁ 5 1 2   MB ▁each ▁with ▁a ▁privile ge ▁mechanism ▁mapped ▁onto ▁the ▁rings . ▁The ▁outer most ▁ring , ▁ring - 7 , ▁was ▁the ▁least ▁privile ged . ▁The ▁inner - most ▁ring , ▁ring - 0 , ▁was ▁the ▁most ▁privile ged . ▁The ▁A OS / VS ▁operating ▁system ▁supported ▁the ▁notion ▁of ▁light weight ▁" tasks " ▁as ▁well ▁as ▁processes . ▁A ▁single ▁process ▁could ▁start ▁various ▁tasks ▁that ▁would ▁all ▁share ▁a ▁global ▁address ▁space ▁( similar ▁to ▁modern ▁" threads "). ▁Task s ▁were ▁very ▁easy ▁to ▁use ▁from ▁Data ▁General ' s ▁FOR TRAN ▁compiler , ▁and ▁allowed ▁faster ▁context ▁switching ▁than ▁using ▁full ▁processes . ▁One ▁could ▁also ▁start ▁sub tasks