▁and ▁Sof tr icity ▁essentially ▁work ▁by ▁intercept ing ▁filesystem ▁and ▁registry ▁requests ▁by ▁an ▁application ▁and ▁redirect ing ▁those ▁requests ▁to ▁a ▁pre installed ▁isolated ▁sand box , ▁thus ▁allowing ▁the ▁application ▁to ▁run ▁without ▁installation ▁or ▁changes ▁to ▁the ▁local ▁PC . ▁Though ▁VM ware ▁Th in App ▁and ▁Sof tr icity ▁both ▁began ▁independent ▁development ▁around ▁ 1 9 9 8 , ▁behind ▁the ▁scenes ▁VM ware ▁Th in App ▁and ▁Sof tr icity ▁are ▁implemented ▁using ▁different ▁techniques : ▁ ▁VM ware ▁Th in App ▁works ▁by ▁pack aging ▁an ▁application ▁into ▁a ▁single ▁" pack aged " ▁EX E ▁which ▁includes ▁the ▁runtime ▁plus ▁the ▁application ▁data ▁files ▁and ▁registry . ▁VM ware ▁Th in App ’ s ▁runtime ▁is ▁loaded ▁by ▁Windows ▁as ▁a ▁normal ▁Windows ▁application , ▁from ▁there ▁the ▁runtime ▁rep laces ▁the ▁Windows ▁loader , ▁filesystem , ▁and ▁registry ▁for ▁the ▁target ▁application ▁and ▁presents ▁a ▁merged ▁image ▁of ▁the ▁host ▁PC ▁as ▁if ▁the ▁application ▁had ▁been ▁previously ▁installed . ▁VM ware ▁Th in App ▁rep laces ▁all ▁related ▁API ▁functions ▁for ▁the ▁host ▁application , ▁for ▁example ▁the ▁Read File ▁API ▁supplied ▁to ▁the ▁application ▁must ▁pass ▁through ▁VM ware ▁Th in App ▁before ▁it ▁reaches ▁the ▁operating ▁system . ▁If ▁the ▁application ▁is ▁reading ▁a ▁virtual ▁file , ▁VM ware ▁Th in App ▁handles ▁the ▁request ▁itself ▁otherwise ▁the ▁request ▁will ▁be ▁passed ▁on ▁to ▁the ▁operating ▁system . ▁Because ▁VM ware ▁Th in App ▁is ▁implemented ▁in ▁user - mode