Why is atomic called so and how does it work?

The term "atomic" originates from the idea of an atom — an indivisible particle. In programming and systems, it means an operation that is executed completely or not at all, without intermediate states.

How atomic works:

• The operation either completes successfully and changes are committed,
• Or it fails and the system reverts to the original state.

In multithreaded or distributed systems, atomic guarantees that parallel operations do not lead to data inconsistency.

Example: in a database, a transaction is an atomic operation. If a transaction has multiple requests, either all are applied or none.

In programming, atomic operations are often implemented through special processor instructions (e.g., compare-and-swap), which allow safe data modification without locks.