You are interested in getting familiar with the GNU/Hurd system architecture, or specific components of it? Here is a collection of texts to read.
A lot of stuff is still missing (open issue documentation).
Basic Knowledge
Before you can go details, you have to learn the basics about operating system architecture. Yes, really.
Operating Systems Basics
You can find good free, self-paced online courses about operating systems on https://www.udacity.com/ . A free textbook about operating systems is called Operating Systems: Three Easy Pieces.
GNU/Hurd System Architecture
Capabilities
shapiro capintro 1999: What is a Capability, Anyway?, Jonathan Shapiro, 1999. This is an easily readable introduction with good examples. In the author's own words, the text provides a layman's introduction to capabilities, describing what they are, what they do, and why they result in better security than today's computer systems.
Our use of capabilities. The Wikipedia, capability-based security article. Alternatively/additionally, [shapiro_capintro_1999].
In the GNU/Hurd system, a capability is represented by a Mach port.
Wikipedia, object-capability model. Albeit not directly tailored at the GNU/Hurd operating system architecture, this article anyway does a good job at describing general principles of a capability-based system architecture.
Quick overview
You may want to start reading a quick overview of how the GNU/Hurd system starts, and thus how it is structured.
FAQ
Specific Components
The GNU/Hurd system is composed of the Hurd servers running on top of the GNU Mach microkernel. Mach only handles scheduling tasks and threads, memory management, and message passing. Mig is used to abstract RPCs on top of Mach's message passing. Eventually, the Hurd servers and Unix processes discuss with each other using these RPCs.
Depending on your background, you may want to start reading the documentation from userlandish interfaces (Hurd) or from the micro kernel itself (Mach).
Presentations
2016
- FOSDEM: presentation by Manolis Ragkousis: Adding GNU/Hurd support to GNU Guix (slides)
- FOSDEM: presentation by Samuel Thibault: Hurd, Rump kernel, sound, and USB (slides)
2015
- FOSDEM: presentation by Samuel Thibault: Along the GNU Hurd RPC way -- A starting guide to contributing to the GNU Hurd (slides)
- Debconf 15: presentation (including video) by Samuel Thibault: Debian GNU/Hurd Status update (slides|video|transcript)
2014
- FOSDEM: presentation by Samuel Thibault: GNU/Hurd DDE userland device drivers (slides, video)
2013
GNU Hackers Meeting in Paris: presentation by Samuel Thibault: Recent developments in the Hurd (slides, video)
FOSDEM: presentation by Samuel Thibault: The GNU/Hurd architecture, nifty features, and latest news (slides)
2011
- GNU Hackers Meeting in Paris: presentation by Samuel Thibault: GNU/Hurd, aka. Extensibility from the Ground (slides, video)
2010
GNU Hackers Meeting in the Hague: video of the presentation by Neal Walfield: GNU/Hurd: It's About Freedom (Or: Why you should care)
Debconf 10: presentation (including video) by Michael Banck: Debian GNU/Hurd -- Past. Present. And Future? (slides)
Fosdem 2010: Why is Anyone Still Working on the GNU Hurd? (Sun., 10:30, Alt-OS Developer Room)
- Fosdem 2010: Porting KGI graphics drivers from Linux to GNU Hurd (Sun., 13:00, Alt-OS Developer Room).
2004
2004-07-02
Ognyan Kulev, presentation of the Hurd, at the seminar LIO and friends, http://debian.fmi.uni-sofia.bg/~ogi/hurd/liofest-20040702-hurd.ppt, in Bulgarian.