RISC/os is a discontinued

UNIX Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

developed by MIPS Computer Systems, Inc. from 1985 to 1992, for their computer

workstation A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstat ...

s and

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

s, including such models as the MIPS M/120 server and

MIPS Magnum The MIPS Magnum was a line of computer workstations designed by MIPS Computer Systems, Inc. and based on the MIPS series of RISC microprocessors. The first Magnum was released in March, 1990, and production of various models continued until 1993 w ...

workstation. It was also known as UMIPS or MIPS OS. RISC/os was based largely on

UNIX System V Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

with additions from

4.3BSD The History of the Berkeley Software Distribution begins in the 1970s. 1BSD (PDP-11) The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify an ...

UNIX, ported to the

MIPS architecture MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, ...

. It was a " dual-universe" operating system, meaning that it had separate, switchable runtime environments providing compatibility with either

System V Release 3 Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

. MIPS OS was one of the first

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculation ...

operating systems for

RISC In computer engineering, a reduced instruction set computer (RISC) is a computer designed to simplify the individual instructions given to the computer to accomplish tasks. Compared to the instructions given to a complex instruction set comput ...

-based workstation-class computers. It was also one of the first

64-bit In computer architecture, 64-bit Integer (computer science), integers, memory addresses, or other Data (computing), data units are those that are 64 bits wide. Also, 64-bit central processing unit, CPUs and arithmetic logic unit, ALUs are those ...

Unix releases for RISC based microprocessors, with the first 64-bit versions appearing in 1990. MIPS OS supported full 32-bit and 64-bit applications simultaneously using the underlying hardware architecture supporting the MIPS-IV instruction set. Later releases added support for

System V Release 4 Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

compatibility,

R6000 The R6000 is a microprocessor chip set developed by MIPS Computer Systems that implemented the MIPS II instruction set architecture (ISA). The chip set consisted of the R6000 microprocessor, R6010 floating-point unit and R6020 system bus controlle ...

processor support and later

symmetric multiprocessing Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all ...

support on the

R4400 The R4000 is a microprocessor developed by MIPS Computer Systems that implements the MIPS III instruction set architecture (ISA). Officially announced on 1 October 1991, it was one of the first 64-bit microprocessors and the first MIPS III impleme ...

and R6000 processors. During the early 1990s, several vendors including DEC,

Silicon Graphics Silicon Graphics, Inc. (stylized as SiliconGraphics before 1999, later rebranded SGI, historically known as Silicon Graphics Computer Systems or SGCS) was an American high-performance computing manufacturer, producing computer hardware and soft ...

, and Ardent licensed portions of the software MIPS had written for the RISC/os for their own Unix variants. Evans & Sutherland licensed RISC/os directly for its ESV series workstations. MIPS' influence was most visible as the

C compiler This page is intended to list all current compilers, compiler generators, interpreters, translators, tool foundations, assemblers, automatable command line interfaces ( shells), etc. Ada Compilers ALGOL 60 compilers ALGOL 68 compilers cf. ...

and development tools shared by virtually all commercial Unixes for the MIPS processor, the low memory operating system code, and the ROM code for MIPS processors. Because of its early UNIX heritage, RISC/os was limited in comparison to modern UNIX variants for example, even the last releases of RISC/os did not support

shared libraries In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and subr ...

. In July 1992, Silicon Graphics purchased MIPS Computer Systems for $220M. Support for RISC/os was subsequently phased out.

References

{{DEFAULTSORT:Mips Risc Os Discontinued operating systems MIPS operating systems MIPS Technologies UNIX System V Unix variants

See also

References