9.1 Consistency models9.1.1 Common consistency models9.1.2 Virtues and limitations9.2 Linearizability9.2.1 Queue and stack9.2.2 Formal definition of linearizability9.3 Eventual consistency9.3.1 The shopping cart9.3.2 Variants of eventual consistency9.3.3 Implementation9.4 Consistency, availability, and partition tolerance9.4.1 History9.4.2 Conjecture vs. theorem9.4.3 CAP theorem