procd is described as 'process and system init service for OpenWRT. It's less resource intensive as it's intended for embedded devices, works with busybox and uClib, hotplug2, libubox and ubus. It watches configuration files to start or restart services and init scripts' and is an app in the OS & Utilities category. There are eight alternatives to procd for a variety of platforms, including Linux, BSD, PC-BSD, FreeBSD and DragonFly BSD. The best alternative is systemd, which is both free and Open Source. Other great apps like procd are sysvinit (Free, Open Source), OpenRC (Free, Open Source), nosh (Free) and finit (Free, Open Source).
systemd is a replacement for the init daemon for Linux (either System V or BSD-style). It is intended to provide a better framework for expressing services' dependencies, allow more work to be done concurrently at system startup, and to reduce shell overhead.
Finit is a small SysV init replacement with process supervision similar to that of daemontools and runit. Its focus is on small and embedded GNU/Linux systems, although fully functional on standard server and desktop installations.
Using the tooling in this repo, I am able to boot from linux to sinit as PID1, and from there to Emacs acting as PID2 using --script mode, performing all typical rc.boot system initialization using Emacs lisp until we hit the getty.