Tiny Mainframe, Shared History

Field notes

The project separates coordination from storage: commands enter an ordered shared log, while each replica applies them to state it owns locally. The page describes maps and indexes held in memory or on SSD, allowing reads to occur inside the application process rather than through a database protocol. It also notes that a read requiring the latest state may need to catch up first. S3-backed storage is identified as prototype work, and the implementation is described as drawing on Meta’s Delos research.