# ChorusOS

> Microkernel real-time operating system

**Wikidata**: [Q670316](https://www.wikidata.org/wiki/Q670316)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/ChorusOS)  
**Source**: https://4ort.xyz/entity/chorusos

## Summary
ChorusOS is a microkernel real-time operating system designed for embedded systems and distributed computing environments. It was initially developed by Chorus Systèmes and later acquired and continued by Sun Microsystems and Oracle Corporation.

## Key Facts
- ChorusOS is a microkernel real-time operating system designed for embedded systems
- It was initially developed by Chorus Systèmes, with contributions from Institut National de Recherche en Informatique et en Automatique
- Sun Microsystems, a defunct American company founded in 1982, acquired and continued development of ChorusOS
- The operating system version 5.0 was documented on Oracle's website
- ChorusOS supports multiple hardware platforms including MIPS, ARM, SPARC, PowerPC, and Motorola 68000 architectures
- The software is distributed under multiple licenses including Sun Public License, GNU LGPL, Mozilla Public License, and BSD licenses
- As of 2019, the official documentation was maintained at https://docs.oracle.com/cd/E19048-01/chorus5/index.html

## FAQs
### Q: What hardware platforms does ChorusOS support?
A: ChorusOS supports multiple hardware architectures including MIPS, ARM, SPARC, PowerPC, and Motorola 68000 family processors.

### Q: Was ChorusOS open source software?
A: ChorusOS was distributed under multiple licenses including Sun Public License, GNU Lesser General Public License, Mozilla Public License, and BSD licenses.

### Q: Is ChorusOS still actively developed?
A: As of the available information, ChorusOS version 5.0 documentation was maintained on Oracle's website as recently as 2019.

## Why It Matters
ChorusOS was significant as one of the early microkernel-based real-time operating systems, providing a lightweight alternative to traditional monolithic kernels for embedded systems. Its microkernel architecture allowed for better modularity and reliability, which was crucial for critical embedded applications. The system's ability to support multiple hardware platforms made it versatile for various industrial and embedded computing needs. Although it was eventually overshadowed by Linux and other real-time operating systems, ChorusOS contributed to the development of embedded systems and influenced subsequent real-time operating system designs. Its acquisition by Sun Microsystems and continued development by Oracle Corporation demonstrated the commercial importance of specialized operating systems for embedded markets.

## Notable For
- Being one of the early commercial microkernel-based real-time operating systems
- Supporting a wide range of hardware platforms from its inception
- Its acquisition and continued development by major companies like Sun Microsystems and Oracle Corporation
- Licensing under multiple open source and proprietary license models
- Its use in critical embedded systems requiring real-time processing guarantees

## Body
### Origins and Development
ChorusOS was initially developed by Chorus Systèmes, a French software company specializing in operating systems for embedded systems. The development involved contributions from Institut National de Recherche en Informatique et en Automatique (INRIA), a French national research institute in computer science and control. The system was later acquired by Sun Microsystems, a prominent American computer hardware and software company founded on February 24, 1982. Following Oracle's acquisition of Sun Microsystems in 2010, ChorusOS development continued under Oracle Corporation.

### Technical Specifications
ChorusOS is based on a microkernel architecture, distinguishing it from monolithic kernel designs. The operating system version 5.0 was documented and made available through Oracle's documentation portal. It supports multiple hardware platforms including MIPS architecture, ARM architecture, SPARC, PowerPC, and Motorola 68000 family processors. The system is designed for embedded environments and distributed computing where real-time processing is essential.

### Licensing and Distribution
ChorusOS was distributed under multiple license models, including the Sun Public License, GNU Lesser General Public License (LGPL), Mozilla Public License, and BSD licenses. This hybrid licensing approach allowed for flexibility in deployment and modification. The software was copyrighted, as indicated by its copyright status, and was available in multiple languages including English, German, Spanish, French, Italian, Japanese, Korean, Polish, Russian, and Chinese.

### Documentation and Availability
The official documentation for ChorusOS was maintained on Oracle's website at https://docs.oracle.com/cd/E19048-01/chorus5/index.html, with documentation available in English as of November 29, 2019. The system has entries in multiple Wikipedia language editions, indicating its international recognition and usage in embedded computing communities.

## References

1. [Source](https://cds.sun.com/is-bin/INTERSHOP.enfinity/WFS/CDS-CDS_SMI-Site/en_US/-/USD/ViewLicense-Start?LicenseUUID=Gj3ACUFBWeYAAAEY4N85AXiO&ProductUUID=x3vACUFBCl8AAAEYK1Q5AXi.&cnum=&evsref=&sln=)
2. [Source](https://linuxfr.org/news/adeos-des-noyaux-dans-le-noyau)
3. [Source](https://docs.oracle.com/cd/E19048-01/chorus5/806-6903/6jfqio0u2/index.html)