# Version 6 Unix

> 6th Edition of Research Unix alias UNIX Time-Sharing System

**Wikidata**: [Q3547270](https://www.wikidata.org/wiki/Q3547270)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Version_6_Unix)  
**Source**: https://4ort.xyz/entity/version-6-unix

## Summary
Version 6 Unix, also known as Research Unix Edition 6 or UNIX Time-Sharing System V6, is an early operating system developed by Bell Labs. Released in May 1975, it is the 6th edition of the Research Unix line. It utilizes a command-line interface and was followed by Version 7 Unix.

## Key Facts
- **Full Name:** UNIX Time-Sharing System V6 (Research Unix Edition 6).
- **Release Date:** May 1975 (1975-05-00).
- **Developer:** Bell Labs.
- **License:** Dual-licensed under a proprietary license and the 4-clause BSD License.
- **Interface:** Command-line interface.
- **Successor:** Version 7 Unix.
- **Instance of:** Operating system.
- **Related Systems:** PWB/UNIX (1977 variant); xv6.
- **Copyright Status:** Copyrighted.

## FAQs
### Q: When was Version 6 Unix released?
A: Version 6 Unix was released in May 1975.

### Q: Who developed Version 6 Unix?
A: It was developed by Bell Labs, a research and scientific development company based in the United States.

### Q: What type of user interface does Version 6 Unix use?
A: The operating system uses a command-line interface.

### Q: What came after Version 6 Unix?
A: Version 6 Unix was succeeded by Version 7 Unix (the 7th Edition of Research Unix).

## Why It Matters
Version 6 Unix represents a pivotal release in the history of the Unix operating system. Developed by Bell Labs, it serves as a key milestone between the earlier internal versions and the more widely distributed Version 7. Its release in 1975 marked an important step in the evolution of multi-user, time-sharing systems.

This version is particularly notable for its licensing status; it is distinct for being available under the 4-clause BSD License in addition to its original proprietary license. This availability helped facilitate the study and teaching of operating system principles. For example, it is closely associated with xv6, a modern operating system used for educational purposes, and is often run in simulators like SIMH to preserve the experience of historical PDP-11 hardware. Its structure and design laid groundwork that influenced subsequent Unix variants, including PWB/UNIX.

## Notable For
- Being the **6th Edition** of the influential Research Unix line.
- Originating from **Bell Labs**, a major center for innovation in information technology and software.
- Serving as the direct predecessor to **Version 7 Unix**, a historically significant release.
- Being available under the **4-clause BSD License**, a rarity for early Unix editions.
- Functioning as a primary subject for **operating system education** and emulation (e.g., xv6, SIMH).

## Body

### Development and Release
Version 6 Unix was developed by Bell Labs, an organization headquartered in Murray Hill, New Jersey, United States. The inception and publication date for this specific version is recorded as May 1975. It is classified strictly as an operating system designed to manage computer hardware resources.

### Technical Specifications
The system is defined by its version number, 6, and operates strictly via a **command-line interface**. It is distinct from commercial variants like UnixWare or AT&T UNIX, existing as part of the "Research Unix" lineage.

### Licensing and Copyright
Unlike many proprietary systems of its era, structured data indicates Version 6 Unix carries a **4-clause BSD License** alongside its standard proprietary license. The system remains under copyright. References to its licensing are archived in historical documents, such as the Caldera license PDF.

### Historical Context and Relations
- **Predecessor/Successor:** Version 6 was immediately followed by **Version 7 Unix** (the 7th Edition of Research Unix).
- **Variants:** It is related to **PWB/UNIX**, an early variant created by Bell Labs in 1977.
- **Modern Relevance:** The system is frequently associated with **xv6**, a modern re-implementation used for teaching, and is often run via the **SIMH** PDP-11 simulator.

## Schema Markup
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  "@type": "Thing",
  "name": "Version 6 Unix",
  "description": "6th Edition of Research Unix, developed by Bell Labs in May 1975.",
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## References

1. [Source](https://minnie.tuhs.org/Archive/Caldera-license.pdf)
2. Freebase Data Dumps. 2013