. ▁ ▁Thread s ▁were ▁processed ▁from ▁top ▁to ▁bottom ▁for ▁each ▁file . ▁A ▁developer ▁thread ▁might ▁have ▁" res erved " ▁at ▁the ▁top , ▁followed ▁by ▁a ▁l abeled ▁version . ▁For ▁a ▁fix ▁to ▁an ▁existing ▁release , ▁the ▁thread ▁would ▁be ▁" res erved ", ▁then ▁the ▁release ▁signature . ▁ ▁In ▁the ▁absence ▁of ▁the ▁invisible ▁file ▁red irection ▁of ▁the ▁Apol lo ▁Domain ▁file ▁system , ▁Clear Case ▁uses ▁the ▁virtual ▁file ▁system ▁provided ▁by ▁the ▁M V FS ▁feature ▁that ▁is ▁described ▁below . ▁The ▁" thread " ▁concept ▁corresponds ▁to ▁the ▁dynamic ▁view . ▁Support ▁for ▁derived ▁objects ▁in ▁a ▁view ▁is ▁similar ▁to ▁D SEE ' s ▁concept . ▁ ▁In frastr ucture ▁▁ ▁The ▁database ▁system ▁that ▁Clear Case ▁uses ▁is ▁R DM ▁Em bed ded ▁from ▁Ra ima . ▁In ▁Clear Case ▁termin ology , ▁an ▁individual ▁database ▁is ▁called ▁a ▁V OB ▁( Version ed ▁Object ▁Base ). ▁On ▁this ▁layer , ▁maintenance ▁takes ▁place ▁using ▁Ra ima ▁tool ing . ▁Ar ound ▁this ▁layer , ▁a ▁set ▁of ▁interfaces ▁with ▁accomp any ing ▁tools ▁are ▁used ▁to ▁manage ▁the ▁physical ▁database ▁system , ▁which ▁requires ▁specific ▁Database ▁administrator ▁skills . ▁ ▁The ▁most ▁important ▁service ▁is ▁the ▁At ria ▁location ▁Bro ker ▁Da emon ▁( AL BD ), ▁which ▁man ages ▁all ▁( L AN ) ▁communication ▁between ▁computers . ▁Begin ning ▁with ▁version ▁ 7 , ▁the ▁server ▁platform ▁runs ▁Web s phere ▁Application ▁Server ▁with ▁a ▁server