What is Sailfish?

Built upon mer middleware(TODO: WTF is mer?)

(TODO: Put boot process into own article)

A kind of Linux distro with glibc and systemd, loads hardware drivers from Android and runs bionic-based programs through droid-parts/libhybris. (For more info, see High-level Overview.)

HAL with middlewares that make it possible to call Linux programs but have the calls proxied through to the hardware layer through Android libs and blobs.

Comes out of Nokia and the meego days, maintained by Jolla Oy in Finland.