NextBSD


NextBSD is a fork of the FreeBSD operating system. As of 2019 the website seems defunct, and the later commits on GitHub date from October 2019. The Wayback Machine captures of the website after 2016-12-15 are domain squatter pages and as of 2021-03-17 the site is redirecting to a fake "Apple Support" page.

Features

The basic features of launchd, notifyd, asld, and libdispatch work.
These can be installed by cloning the NextBSD repository from GitHub, building GENERIC or MACHTEST kernels, installing a new world on an existing 10.x or CURRENT system, and then following the instructions in the README.
Launchd will start the initial jobs that are part of the repo now.

Planned Features

The project refers to an installer as the first planned milestone on their website.
Future plans include convert to rc and tying notifyd in to potential consumers.

History

NeXTBSD was announced by Jordan Hubbard and Kip Macy in August 2015 at the Bay Area FreeBSD Users Group.

Relationship to FreeBSD

NeXTBSD is based on the FreeBSD-CURRENT kernel while adding in Mach IPC, Libdispatch, notifyd, asld, launchd, and other components derived from Darwin, Apple's open-source code for macOS.

Technology

Basic Architecture

  • FreeBSD-current kernel + Mach IPC
  • Common Object Runtime
  • Libdispatch / ASL / Libnotify
  • launchd
  • * launchctl
  • ** json config files
  • * legacy rc system
  • * cooperating daemons

    Mach Kernel Abstractions

Tasks

The units of resource ownership; each task consists of a virtual address space, a port right namespace, and one or more threads.

Threads

The units of CPU execution within a task. Simple extension to kthreads.

Address space

In conjunction with memory managers, Mach implements the notion of a sparse virtual address space and shared memory.

Memory objects

The internal units of memory management. Memory objects include named entries and regions; they are representations of potentially persistent data that may be mapped into address spaces.

Ports

Secure, simplex communication channels, accessible only via send and receive capabilities.

IPC

Message queues, remote procedure calls, notifications, semaphores, and lock sets..

Time

Clocks, timers, and waiting -.

Standards adherence

Current BSD operating system variants support many of the common Institute of [Electrical and Electronics Engineers|IEEE], ANSI, ISO, and POSIX standards, while retaining most of the traditional BSD behavior. Like AT&T Unix, the BSD kernel is monolithic, meaning that device drivers in the kernel run in privileged mode, as part of the core of the operating system.
A selection of significant Unix versions and Unix-like operating systems that descend from BSD includes: