The ACID acronym did not invent database transactions, but Theo Härder and Andreas Reuter's 1983 framework gave the field a durable four-part vocabulary—atomicity, consistency, isolation and durability—for discussing transaction guarantees.
IBM's ARIES recovery method combined write-ahead logging, log sequence numbers, repeating history and compensation records into a restart algorithm that could support fine-grained locking and partial rollback.
Google Spanner used synchronous replication, multiversion storage and the TrueTime clock API to provide externally consistent transactions across globally distributed data, then evolved toward a full relational SQL system.
Jim Gray unified concurrency control, recovery and the transaction abstraction into a framework for keeping shared databases correct even when operations overlap and systems fail.