Dryad daG architecture Simplicity depends on generality Front ends only see graph data-structures Generic scheduler state machine Software engineering: clean abstraction Restricting set of operations would pollute scheduling logic with execution semantics Optimizations all above the fold Dryad exports callbacks so applications can react to state machine transitionsDryad DAG architecture • Simplicity depends on generality – Front ends only see graph data-structures – Generic scheduler state machine • Software engineering: clean abstraction • Restricting set of operations would pollute scheduling logic with execution semantics • Optimizations all “above the fold” – Dryad exports callbacks so applications can react to state machine transitions