Solaris is a multitasking, multiprocessing operating system and distributed computing environment for Sun's SPARC computers from SunSoft. It provides an enterprise-wide UNIX environment that can manage up to 40,000 nodes from one central station.Solaris is known for its robustness and scalability, which is expected in UNIX-based SMP systems. An x86 version of Solaris is available that can also run applications written for Sun's Interactive UNIX. In the early 1990s Sun replaced the BSD-derived sun OS 4 with a version of UNIX System V Release.4 (SVR4), jointly developed with AT&T. The underlying release name was SunOS 5.0, but a new marketing name was introduced at the same time: Solaris 2.(SunOS 4.1.x micro releases were also retroactively named Solaris 1, a convention generally ignored; the name Solaris is almost exclusively used to refer to SVR4-derived SunOS 5.0 and later.)Solaris is considered to be the SunOS operating system plus a graphical user environment, ONC+, and other components. The SunOS minor version is included in the Solaris release name; for example, Solaris 2.4 incorporated SunOS 5.4. After Solaris 2.6, Sun dropped the "2." from the name, so what we know as Solaris 7 incorporates SunOS 5.7, and the latest release SunOS 5.10 forms the core of Solaris 10.