▁current ▁version ▁is ▁ 6 . 0 . ▁ ▁V MD S ▁has ▁been ▁designed ▁as ▁a ▁spatial ▁database . ▁This ▁gives ▁V MD S ▁a ▁number ▁of ▁distinct ive ▁characteristics ▁when ▁compared ▁to ▁conventional ▁attribute ▁only ▁rel ational ▁databases . ▁ ▁Dist ributed ▁server ▁processing ▁V MD S ▁is ▁composed ▁of ▁two ▁parts : ▁a ▁simple , ▁highly ▁scal able ▁data ▁block ▁server ▁called ▁SW M FS ▁( Sm all world ▁Master ▁File ▁Server ) ▁and ▁an ▁intellig ent ▁client ▁API ▁written ▁in ▁C ▁and ▁Mag ik . ▁Sp atial ▁and ▁attribute ▁data ▁are ▁stored ▁in ▁data ▁blocks ▁that ▁res ide ▁in ▁special ▁files ▁called ▁data ▁store ▁files ▁on ▁the ▁server . ▁When ▁the ▁client ▁application ▁requests ▁data ▁it ▁has ▁sufficient ▁intelligence ▁to ▁work ▁out ▁the ▁optim um ▁set ▁of ▁data ▁blocks ▁that ▁are ▁required . ▁This ▁request ▁is ▁then ▁made ▁to ▁SW M FS ▁which ▁returns ▁the ▁data ▁to ▁the ▁client ▁via ▁the ▁network ▁for ▁processing . ▁ ▁This ▁approach ▁is ▁particularly ▁efficient ▁and ▁scal able ▁when ▁dealing ▁with ▁spatial ▁and ▁topological ▁data ▁which ▁tends ▁to ▁flow ▁in ▁larger ▁volumes ▁and ▁require ▁more ▁processing ▁then ▁plain ▁attribute ▁data ▁( for ▁example ▁during ▁a ▁map ▁red raw ▁operation ). ▁This ▁approach ▁makes ▁V MD S ▁well ▁su ited ▁to ▁enter prise ▁deployment ▁that ▁might ▁involve ▁hundreds ▁or ▁even ▁thousands ▁of ▁concurrent ▁clients . ▁ ▁Support ▁for ▁long ▁transactions ▁Rel ational ▁databases ▁support ▁short ▁transactions ▁in ▁which ▁changes ▁to ▁data ▁are ▁relatively ▁small ▁and ▁are ▁brief ▁in ▁terms ▁in ▁duration ▁( the ▁maximum