# happi/theBeamBook

A description of the Erlang Runtime System ERTS and the virtual Machine BEAM.

Repository: https://github.com/happi/theBeamBook
Canonical: https://ross.abutalabs.com/products/thebeambook
Language: Erlang
License: NOASSERTION
License Family: other
Last push: 2026-04-26T08:42:38+00:00

## Health v2 (maintenance only)
Score: 70/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 79, release rhythm 40, longevity 100
- inputs: {"age_days": 3450, "days_push": 129, "days_rel": 458, "gap_med": 0, "n_releases_24m": 6}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4050, forks 267 (observed 2026-08-28T04:08:33.810760+00:00)

## What it is
An open, collaboratively written book documenting the internals of the Erlang runtime system (ERTS) and the BEAM virtual machine. It is written in AsciiDoc and published as a PDF, a GitHub Pages site, and a printed first edition.

## Use cases
- learn how the BEAM virtual machine works
- understand Erlang runtime system internals
- study BEAM instruction set and scheduler design
- prepare for contributing to the Erlang/OTP VM
- find a reference on ERTS memory management and processes

## When to choose
- you want a deep, technical reference on Erlang/OTP VM internals
- you are a systems programmer or VM engineer working with BEAM
- you prefer free, community-maintained documentation with source available

## When to avoid
- you need a beginner tutorial on writing Erlang programs
- you want guaranteed up-to-date coverage of the latest OTP release
- you need formal documentation rather than a work-in-progress book

## Facets
- artifact type: learning-resource
- maturity: active
- function: documentation
- domain: programming-languages, documentation, developer-tools
- platform: cross-platform
- tags: erlang, beam, virtual-machine, erts, asciidoc, book

## Member repositories
- happi/theBeamBook (main) score 70

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:33.810760+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:23:40.837827+00:00, confidence not recorded.
  - readme: https://github.com/happi/theBeamBook (fetched 2026-08-28T04:08:33.810760+00:00, sha 6c82b6da053a)
- Data as of 2026-08-30T08:39:29.467469+00:00.