Neha Patil (Editor)

NextBSD

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Written in
  
C

Source model
  
Open source

OS family
  
Unix

NextBSD

Developer
  
Jordan Hubbard, Kip Macy

Working state
  
Still in launch phase (see below)

Initial release
  
2015; 2 years ago (2015)

NextBSD is an operating system initially based on the trunk version of FreeBSD as of August 2015. It is a fork of FreeBSD which implements new features developed on branches but not yet implemented in FreeBSD.

Contents

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 (BAFUG).

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 OS X.

Basic Architecture

  • FreeBSD-current kernel + Mach IPC
  • Common Object Runtime (create/delete/retain/release)
  • Libdispatch / ASL / Libnotify
  • launchd
  • launchctl
  • json config files
  • legacy rc system
  • cooperating daemons
  • Tasks

    The units of resource ownership; each task consists of a virtual address space, a port right namespace, and one or more threads. (Implemented as an extension to a process.)

    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. (No modifications)

    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. (Unsupported)

    Ports

    Secure, simplex communication channels, accessible only via send and receive capabilities (known as port rights).

    IPC

    Message queues, remote procedure calls, notifications, semaphores, and lock sets. (Mach semaphores and lock sets are not supported).

    Time

    Clocks, timers, and waiting - (rudimentary shims).

    Standards adherence

    Current BSD operating system variants support many of the common 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:

  • FreeBSD, an open source general purpose operating system.
  • NeXT NEXTSTEP and OpenStep, based on the Mach kernel and 4BSD; the ancestor of Mac OS X
  • Apple Inc.'s Darwin, the core of OS X and iOS; built on the XNU kernel (part Mach, part FreeBSD, part Apple-derived code) and a userland much of which comes from FreeBSD
  • References

    NextBSD Wikipedia