RISC/os is a discontinued

UNIX Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user 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, a ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

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

workstation A workstation is a special computer designed for technical or computational science, 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 syste ...

s and

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

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 19 ...

workstation. It was also known as UMIPS or MIPS OS. RISC/os was mainly based 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 began in the 1970s when University of California, Berkeley received a copy of Unix. Professors and students at the university began adding software to the operating system and released it as BSD to ...

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 it had separate, switchable runtime environments that were compatible 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 a maximum of 32- bit units. Compared to smaller bit widths, 32-bit computers can perform la ...

operating systems for

RISC In electronics and computer science, a reduced instruction set computer (RISC) is a computer architecture designed to simplify the individual instructions given to the computer to accomplish tasks. Compared to the instructions given to a comp ...

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

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, a ...

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 control ...

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 Technologies, 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 f ...

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 Evans & Sutherland is an American computer graphics firm founded in 1968 by David C. Evans (computer scientist), David Evans and Ivan Sutherland. Its current products are used in digital projection environments like planetariums. Its simulation b ...

licensed RISC/os directly for its ESV series workstations. MIPS' influence was most visible as the

C compiler C, or c, is the third letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''cee'' (pronounced ), plural ''cees''. History "C ...

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 computing, a library is a collection of resources that can be leveraged during software development to implement a computer program. Commonly, a library consists of executable code such as compiled functions and classes, or a library can ...

. 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