erts

ERTS stands for the Erlang Run-Time System. It is the runtime environment for Erlang programs and is a core part of the Erlang/OTP platform. ERTS comprises the BEAM virtual machine, runtime libraries, and the services that support concurrent, distributed, and fault-tolerant applications written in Erlang.

The BEAM VM at the heart of ERTS executes Erlang bytecode and implements lightweight processes, message passing, and strong fault isolation. Each Erlang process has its own heap and garbage collector, and the run-time includes a preemptive scheduler designed to efficiently utilize multi-core CPUs. ERTS also provides facilities for input/output, ports for interfacing with external programs, and the mechanisms for linking and monitoring processes, which enable robust fault tolerance and supervision strategies.

In addition to local concurrency, ERTS supports distributed Erlang. Nodes running ERTS can communicate, spawn processes across machines, and share code. Features such as hot code swapping allow upgrading parts of a running system without downtime, and the runtime handles code loading, upgrading, and distribution of code across nodes.

Packaging and usage: In an Erlang/OTP installation, the erts-<version> directory contains the runtime system. The version of ERTS must match the corresponding release of Erlang/OTP. ERTS runs on multiple operating systems, including Linux, Windows, and macOS, making Erlang applications portable across environments.

History and governance: ERTS was developed by Ericsson as part of the Erlang project and is maintained as a core component of the open-source Erlang/OTP platform. It is widely used in telecommunications, distributed systems, and concurrent programming domains.