Routemap source tree

Erlang OTP is a complex system. It can be a bit hard to find out where to look if you want to know the details of some implementation. This page is a simple routemap to the interesting parts of the Erlang OTP source code. With ‘interesting’ I mean for users who are interested in the internal workings of Erlang for example for performance reasons and networking.

/erts/

Erlang Run-Time System Application.This tree includes the virtual machine, the garbage collector, and the port mapper daemon. The documentation about ERTS shows that erl_driver, erl_nif, zlib, epmd, erl and erlang all belong to this basic application.

/erts/emulator/beam/

Erlang’s Beam VM: contains .c and .h files such as:

1. erl_process.c,
2. beam_emu.c,
3. binary.c, The implementation of Erlang binaries (doc)
4. erl_driver.h, Erlang drivers header, much more information in the docs
5. io.c,
6. bif.c the C implementations for builtin functions in the ‘erlang’ module (doc). It contains for example implementations of erlang:spawn() or erlang:link()
7. erl_bif_port.c,
8. erl_alloc.c (doc)
9. erl_nif.c (doc) – The coolest addition to the R13B03 release, Native Implemented Functions!

/erts/emulator/drivers/common/

1. inet_drv.c

/erts/emulator/hipe/

Erlang’s native code compiler. Interaction between Beam and Native code

1. hipe_bif0.tab ‘Secret’ erlang functions for destructive array operations.

/lib/

Contains the Erlang libraries. That means: lots of files written in Erlang code to implement lots of functions you use every day.

/lib/kernel/src/

1. application.erl
2. gen_tcp.erl
3. heart.erl
4. inet.erl

/lib/stdlib/src/

1. array.erl,
2. dict.erl,
3. gb_trees.erl
4. lists.erl
5. string.erl
6. ets.erl,
7. gen_server.erl
8. gen_fsm.erl
9. gen_event.erl
10. io.erl,
11. timer.erl,
12. unicode.erl
13. beam_lib.erl

Note: feel free to edit and point out more interesting parts of the source code.