Solaris

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Stands for: Sun's System V Release 4 Unix, SunOS 5 under a new name, now Oracle Solaris

Sun Microsystems' Unix from 1992 onwards, built on System V Release 4 and marketed under a new name when Sun left its BSD-based SunOS behind; now Oracle Solaris, with OpenSolaris's open source fork living on as Illumos.

Solaris is SunOS 5 under a marketing name. On 4 September 1991 Sun announced that its next major operating system release would switch from the BSD-derived source base of SunOS to one based on AT&T's System V Release 4, and from that point used Solaris as an overbrand covering the operating system, the OpenWindows desktop and Open Network Computing; SunOS 4.1.1 was rebranded Solaris 1.0, and SunOS 5.0 became part of Solaris 2.0. Solaris superseded SunOS in 1993, reached x86 with Solaris 2.1 in June 1993 and a single SPARC and x86 source base with 2.4 in 1994, and became known for scalability on SPARC and for originating DTrace, ZFS and Time Slider. In June 2005 Sun released most of the code under the CDDL as OpenSolaris; after Oracle's 2010 acquisition the OpenSolaris distribution was discontinued and public updates to the kernel source stopped, so Solaris 11 is effectively closed again, and the community forked the code as Illumos. Oracle released Solaris 11.4 in 2018; the current code base supports 64-bit SPARC and x86-64.

The switch from BSD. In 1987 AT&T and Sun announced a collaboration to merge the most popular Unix flavours of the time, BSD with the features then unique to SunOS, System V and Xenix, into System V Release 4. On 4 September 1991 Sun announced that its next major release would move from its BSD-derived source to SVR4; the internal designation stayed SunOS 5, but the marketing name became Solaris, justified as an overbrand covering the operating system, OpenWindows and Open Network Computing. Sun immediately applied the new name backwards, so SunOS 4.1.1 shipped as Solaris 1.0, and the SVR4 system arrived as Solaris 2.0. Customers went on calling the BSD line SunOS, which is why the two names coexist in every old runbook.

The releases that mattered. Solaris superseded SunOS in 1993. The first two Solaris 2 releases were SPARC only; an x86 version of 2.1 came in June 1993, and 2.4 in 1994 supported SPARC and x86 from one source. The release numbering dropped the '2.' with Solaris 7, so Solaris 7 carries SunOS 5.7 and the current Solaris 11.4 carries SunOS 5.11 at its core. Solaris 10 brought 64-bit x86 applications, zones (the branded zones that later ran Linux applications) and the features the system is remembered for: DTrace, the dynamic tracing framework, and ZFS, the file system with built-in volume management and snapshots, with Time Slider as the desktop face of the snapshots.

Open, then closed again. In June 2005 Sun released most of the Solaris code base under the Common Development and Distribution License and founded the OpenSolaris project to build a developer and user community. After Oracle acquired Sun in 2010 the OpenSolaris distribution was discontinued, and Oracle later stopped providing public updates to the source code of the Solaris kernel, effectively turning Solaris 11 back into a closed-source proprietary operating system. OpenSolaris was forked as Illumos and lives on through several Illumos distributions. Oracle kept developing Solaris after a large layoff of its engineering staff and released 11.4 in 2018.

Where it is met today. Solaris runs on SPARC and x86-64 servers in the kinds of estates that bought Sun in the 1990s and 2000s: telecommunications, banking, big databases. For a network engineer the practical inheritance is the vocabulary, zones, ZFS pools, and the knowledge that the host's tooling is System V and not Linux. The SunOS entry tells the BSD half; the Sun Microsystems record on the industry timeline tells the company's story to its end inside Oracle on 27 January 2010.

Also known as: oracle solaris, solaris 2, solaris 10, solaris 11, opensolaris, illumos

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