# Matthew Dillon

> systems software engineer

**Wikidata**: [Q93062](https://www.wikidata.org/wiki/Q93062)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Matthew_Dillon)  
**Source**: https://4ort.xyz/entity/matthew-dillon

## Summary
Matthew Dillon is an American systems software engineer and computer scientist best known as the creator and lead developer of DragonFly BSD, an operating system forked from FreeBSD in 2004. He is also the architect of the HAMMER and HAMMER2 file systems that power DragonFly BSD, making significant contributions to Unix-like operating system development.

## Biography
- Born: July 1, 1966 in San Francisco
- Nationality: United States
- Education: University of California, Berkeley
- Known for: Creating DragonFly BSD and the HAMMER file system
- Field(s): Computer Science, Systems Software Engineering
- Residence: Berkeley

## Contributions
Matthew Dillon's most significant contribution to computing is the creation of DragonFly BSD in 2004, an operating system that emerged as a fork from FreeBSD with the goal of implementing advanced clustering, SMP scalability, and other innovative features. As the project's leader, he designed and implemented the HAMMER file system in 2008, which introduced novel approaches to data storage including copy-on-write semantics and snapshot capabilities. His work on HAMMER2 represents a second-generation evolution of these concepts with improved performance and reliability features. Dillon also contributed significantly to FreeBSD before creating DragonFly BSD, demonstrating his deep expertise in Unix-like system internals. Additionally, he developed the vkernel virtual kernel architecture, which provides a unique approach to virtualization within the DragonFly BSD ecosystem. His technical leadership has made DragonFly BSD a distinctive branch in the BSD family, known for its experimental features and innovative system design approaches that have influenced operating system research and development.

## FAQs
### Q: What is DragonFly BSD and why did Matthew Dillon create it?
A: DragonFly BSD is an operating system created by Matthew Dillon in 2004 as a fork from FreeBSD. Dillon created it to pursue innovative approaches to operating system design, particularly focusing on clustering, SMP scalability, and advanced file system technologies.

### Q: What are the HAMMER and HAMMER2 file systems?
A: HAMMER and HAMMER2 are file systems developed by Matthew Dillon for DragonFly BSD. HAMMER was introduced in 2008 and featured copy-on-write semantics, snapshots, and other advanced storage capabilities. HAMMER2 is a second-generation version with improved performance and reliability.

### Q: Where did Matthew Dillon study computer science?
A: Matthew Dillon attended the University of California, Berkeley for his education in computer science.

## Why They Matter
Matthew Dillon's work has had a profound impact on the Unix-like operating system ecosystem through his creation and ongoing development of DragonFly BSD. His decision to fork FreeBSD in 2004 allowed for experimental approaches to system design that might not have been possible within the existing FreeBSD project structure. The HAMMER file system, introduced in 2008, brought innovative features like built-in snapshotting and copy-on-write semantics to the BSD world, influencing file system design discussions across the industry. His vkernel virtualization architecture represents a unique approach to system virtualization that differs from traditional hypervisor models. Through DragonFly BSD, Dillon has maintained a platform for exploring advanced operating system concepts including clustering, distributed filesystems, and alternative SMP architectures. His work continues to serve as both a production operating system and a laboratory for operating system research, contributing to the broader understanding of system design principles and influencing other developers in the field.

## Notable For
• Creator and lead developer of DragonFly BSD operating system (2004)
• Architect of the HAMMER file system (2008) and its successor HAMMER2
• Developer of the vkernel virtual kernel architecture
• Significant contributor to the FreeBSD project prior to creating DragonFly BSD
• Maintains DragonFly BSD as an experimental platform for advanced operating system features

## Body
### Early Life and Education
Matthew Dillon was born on July 1, 1966, in San Francisco, California. He pursued higher education at the University of California, Berkeley, where he studied computer science. His educational background provided the foundation for his later work in systems software engineering.

### Career Development
Dillon established himself as a computer scientist and programmer, working primarily in the field of systems software engineering. His early contributions to FreeBSD demonstrated his expertise in Unix-like operating system internals before he embarked on creating his own project.

### DragonFly BSD Creation
In July 2004, Dillon initiated DragonFly BSD as a fork from FreeBSD. This decision marked a significant milestone in BSD development, creating a new branch focused on innovative approaches to system design. The project aimed to implement advanced clustering capabilities, improved SMP scalability, and other experimental features.

### File System Innovation
The HAMMER file system was introduced in July 2008 as part of DragonFly BSD. This filesystem incorporated copy-on-write semantics, built-in snapshot capabilities, and novel approaches to data integrity. Dillon later developed HAMMER2 as an evolution of these concepts with enhanced performance characteristics.

### Technical Leadership
As the leader of DragonFly BSD, Dillon has maintained technical direction for the project while implementing major system components. His work on the vkernel virtualization architecture demonstrates his continued innovation in systems programming and his commitment to exploring alternative approaches to established computing paradigms.

### Current Status
Dillon continues to reside in Berkeley and maintains active development of DragonFly BSD. His work serves both as a production operating system and as a platform for experimental operating system research, maintaining his position as a significant figure in the BSD community.

## Schema Markup
```json
{
  "@context": "https://schema.org",
  "@type": "Person",
  "name": "Matthew Dillon",
  "jobTitle": "Systems Software Engineer",
  "nationality": {"@type": "Country", "name": "United States"},
  "birthDate": "1966-07-01",
  "birthPlace": {"@type": "Place", "name": "San Francisco"},
  "alumniOf": [{"@type": "EducationalOrganization", "name": "University of California, Berkeley"}],
  "knowsAbout": ["Computer Science", "Systems Software Engineering", "Operating Systems"],
  "sameAs": ["https://www.wikidata.org/wiki/Q97033143", "https://en.wikipedia.org/wiki/Matthew_Dillon"],
  "description": "systems software engineer"
}

## References

1. [Source](http://bxr.su/f/usr.bin/calendar/calendars/calendar.freebsd)
2. [HAMMER(5) — HAMMER file system](http://bxr.su/d/share/man/man5/hammer.5)
3. [Source](http://bxr.su/d/share/man/man7/committer.7)
4. [Source](http://www.dragonflybsd.org/team/)
5. [Source](http://bxr.su/f/share/man/man7/security.7)
6. [Source](http://bxr.su/f/share/man/man9/buf.9)
7. [Source](http://bxr.su/f/sys/vm/vm_page.c)
8. [Source](http://bxr.su/f/sys/vm/vm_zeroidle.c)
9. [vkernel(7), … — virtual kernel architecture](http://bxr.su/d/share/man/man7/vkernel.7)
10. [Source](http://bxr.su/d/sys/vfs/hammer2/DESIGN)
11. [committer — instructions and rules for DragonFly committers](http://bxr.su/d/share/man/man7/committer.7)