JdeBPA very quick précis is that it's a set of software tools that I'm close to releasing version 1.41 of, after a *long* hiatus involving a worldwide pandemic, broken disc drives, crushed PSUs, and some fairly eventful other stuff.
http://jdebp.info/Softwares/nosh/
They do system management, service management, user-space virtual terminals directly on display/HID hardware, and some login session stuff.
For an #Illumos analogy, think the SMF, plus SAC, plus ttymon. But done the #daemontools way.