Serializability and Heterogeneous Trust from Two Phase Commit to Blockchains

ly, distributed systems deal with some set of participants (sometimes called “nodes,” “processors,” or “processes”), usually computers, which execute computation and send messages to each other over the network. Observers are abstract entities that observe messages in the system and make demands about system properties. Observers define the requirements on the system: how many failures it needs to tolerate, and what tasks it must perform under what circumstances. Participants are merely components of the system, although some entities (such as people) can be both observers and participants. Not all systems always satisfy all observers. There are some traditional assumptions about this setting. For instance, we usually assume that once a message is sent, it will eventually