Illumos

Illumos (stylized as "illumos") is a partly free and open-source Unix operating system.^[3] It has been developed since 2010 and is based on OpenSolaris, after the discontinuation of that product by Oracle. It comprises a kernel, device drivers, system libraries, and utility software for system administration. Its core has become the base for many different open-sourced Illumos distributions,^[4] in a way similar to how the Linux kernel is used in different Linux distributions.^[5]

Illumos

Developer	Illumos Foundation
Written in	C
OS family	Unix (SVR4)[1]
Working state	Current
Source model	Open source with binary blobs
Initial release	2010; 15 years ago (2010)
Repository	github.com/illumos/illumos-gate
Available in	English
Platforms	IA-32, x86-64, SPARC, ARM (under development),[2] DEC Alpha
Kernel type	Monolithic
License	CDDL, BSD, MIT
Preceded by	OpenSolaris
Official website	illumos.org

Name

The maintainers write illumos in lowercase,^[6] since some computer fonts do not clearly distinguish a lowercase L from an uppercase i: Il (see homoglyph).^[7] The project name is a combination of words illuminare from the Latin for to light, and OS for Operating System.^[8]

History and development

The OpenIndiana operating system is one of many Illumos distributions.

Illumos was announced via webinar on 3 August 2010,^[9] as a community effort of a group of core Solaris engineers to create a truly open source Solaris, by swapping closed source bits of OpenSolaris with open implementations.^[10][11][12] OpenSolaris itself is based on System V Release 4 (SVR4) and the Berkeley Software Distribution (BSD).

The original plan explicitly stated that Illumos would not be a distribution or a fork. However, after Oracle announced the discontinuation of OpenSolaris, plans were made to fork the final version of the Solaris ON kernel,^[a] allowing Illumos to evolve into a kernel of its own.^[13] As of 2010^[update], efforts focused on libc, the NFS lock manager, the crypto module, and many device drivers, to create a Solaris-like OS with no closed, proprietary code. As of 2012^[update], development emphasis includes transitioning from the historical compiler, Studio, to GCC.^[14] The "userland" software is now built with GNU make,^[15] and contains many GNU utilities such as GNU tar. At the time,^{[clarification needed]} Illumos had been lightly led by founder Garrett D'Amore and other community members/developers such as Bryan Cantrill and Adam Leventhal, via a Developers' Council.^[16]

As of 2019 its primary development project, illumos-gate, derives from OS/Net (aka ON),^[17] which is a Solaris kernel with the bulk of the drivers, core libraries, and basic utilities, similar to what is delivered by a BSD "src" tree. It was originally dependent on OpenSolaris OS/Net, but a fork was made after Oracle silently decided to close the development of Solaris and unofficially killed the OpenSolaris project.^[18][19][20]

Features

• ZFS, a combined file system with integrated logical volume management, providing a high level of data integrity for very large storage capacities.
• Solaris Containers (or Zones), a low overhead implementation of operating-system-level virtualization technology for x86 and SPARC systems.^{[clarification needed]}
• DTrace, a comprehensive dynamic tracing framework for troubleshooting kernel and application problems on production systems in real time.
• Kernel-based Virtual Machine (KVM), a virtualization infrastructure. KVM supports native virtualization on processors with hardware virtualization extensions.
• OpenSolaris Network Virtualization and Resource Control (or Crossbow), a set of features that provides an internal network virtualization and quality of service including: virtual NIC (VNIC) pseudo-network interface technology, exclusive ip zones, bandwidth management, and flow control on a per interface and per VNIC basis.

Distributions

See also: OpenSolaris § Derivatives, Solaris (operating system) § Open source derivatives, and Comparison of OpenSolaris distributions

Distributions, at illumos.org^[21]

• DilOS, with Debian package manager (dpkg + apt) and virtualization support, available for x86-64 and SPARC.^[22]
• NexentaStor, distribution optimized for virtualization, storage area networks, network-attached storage, and iSCSI or Fibre Channel applications employing the ZFS file system.
• OmniOS Community Edition, takes a minimalist approach suitable for server use.^[23]
• OpenIndiana, a distribution that is a continuation and fork in the spirit of the OpenSolaris operating system.
• SmartOS, a distribution for cloud computing with Kernel-based Virtual Machine integration.
• Helios, a distribution powering the Oxide Computer Rack.^[24]
• Tribblix, retro style distribution with modern components, available for x86-64 and SPARC.^[25]
• v9os, a server-only, IPS-based minimal SPARC distribution.^[26]
• XStreamOS, a distribution for infrastructure, cloud, and web development.^[27]

Discontinued:

• Dyson, derived from Debian using libc, and SMF init system.
• OpenSXCE, distribution for developers and system administrators for IA-32/x86-64 x86 platforms and SPARC.^[28]

Illumos Foundation

The Illumos Foundation was incorporated in the State of California in 2012 as a 501(c)6 trade association, with founding board members Jason Hoffman (formerly at Joyent), Evan Powell (Nexenta), and Garrett D'Amore. As of 2024, its status in California is "dissolved".^[29]

Notes

1. The "OS/Network" consolidation (project), considered the heart of the Solaris kernel