Matthew Dillon (born 1966) is an American

software engineer Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining software applications. It involves applying engineering principles and computer programming expertise to develop ...

known for

Amiga Amiga is a family of personal computers produced by Commodore International, Commodore from 1985 until the company's bankruptcy in 1994, with production by others afterward. The original model is one of a number of mid-1980s computers with 16-b ...

software, contributions to

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

and for starting and leading the

DragonFly BSD DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD in ...

project since 2003.

Biography

Dillon studied

electronic engineering Electronic engineering is a sub-discipline of electrical engineering that emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current flo ...

and

computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

, where he first became involved with

BSD The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

in 1985. He also became known for his

programming, his C compiler DICE and his work on the

Linux kernel The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

. He founded and worked at Best Internet from 1994 until 1997, contributing to

in that time. His "Diablo" internet news transit program was very popular with many ISPs. In 1997, Dillon gained commit access to the FreeBSD code and heavily contributed to the

virtual memory In computing, virtual memory, or virtual storage, is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a ver ...

subsystem, amongst other contributions. Concerned with problems he saw in the direction FreeBSD 5.x was headed in regards to concurrency, and coupled with the fact that Dillon's access to the FreeBSD source code repository was revoked due to a falling-out with other FreeBSD developers, he started the

project in 2003, implementing the SMP model using light-weight kernel threads. The DragonFly project also led to the development of a new

userspace A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware prote ...

kernel virtualisation technique in 2006, called Virtual Kernel, originally to ease the development and testing of subsequent kernel-level features; a new file system, called

HAMMER A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nail (fastener), nails into wood, to sh ...

, which he created using

B-tree In computer science, a B-tree is a self-balancing tree data structure that maintains sorted data and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree generalizes the binary search tree, allowing fo ...

s; HAMMER was declared production-ready with DragonFly 2.2 in 2009; and, subsequently,

HAMMER2 HAMMER2 is a successor to the HAMMER (file system), HAMMER filesystem, redesigned from the ground up to support enhanced Computer cluster, clustering. HAMMER2 supports online and batched Data deduplication, deduplication, Snapshot (computer storag ...

, declared stable in 2018 with DragonFly 5.2. Most recently, Dillon has gotten a number of headlines around

CPU A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, log ...

errata An erratum or corrigendum (: errata, corrigenda) (comes from ) is a correction of a published text. Generally, publishers issue an erratum for a production error (i.e., an error introduced during the publishing process) and a corrigendum for an a ...

. In 2007, this was after Theo de Raadt of

OpenBSD OpenBSD is a security-focused operating system, security-focused, free software, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by fork (software development), forking NetBSD ...

raised the alarm around the seriousness of some of the errata for

Intel Core 2 Intel Core 2 is a processor family encompassing a range of Intel's mainstream 64-bit x86-64 single-, dual-, and quad-core microprocessors based on the Core microarchitecture. The single- and dual-core models are single- die, whereas the quad-co ...

family of CPUs. Dillon has independently evaluated Intel's errata, and did an overview of

Intel Core Intel Core is a line of multi-core (with the exception of Core Solo and Core 2 Solo) central processing units (CPUs) for midrange, embedded, workstation, high-end and enthusiast computer markets marketed by Intel Corporation. These processors ...

errata as well, suggesting that several of them were so serious as to warrant avoiding any processor where the issues remain unfixed. Dillon has since been a fan of

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a hardware and fabless company that de ...

processors, and, subsequently in 2012, he has discovered a brand-new deficiency in some

processors for which no existing erratum existed at the time. Dillon continued his work around CPU issues as late as 2018, presenting solutions to tackle the latest security vulnerabilities like Meltdown, some of which have been subsequently adopted by

as well. Dillon was a frequent guest on bsdtalk during the runtime of the show, and was interviewed several times for KernelTrap.

References

External links

Matt Dillon home page

fro
SlashNet

OSNews interview
(March 13, 2004) {{DEFAULTSORT:Dillon, Matthew 1966 births Living people Engineers from San Francisco University of California, Berkeley alumni American computer programmers Amiga people BSD people DragonFly BSD FreeBSD people Free software programmers Kernel programmers