[okl4-developer] Capability Passing in OKL4 3.0

[Gernot Heiser]

>>>>> On Fri, 30 Jan 2009 15:24:59 +1100, Andrew Reilly <andrew.reilly at dolby.com> said:
AR> I haven't been paying much attention to the addition of
AR> capabilities.  Where is a good place to start reading about
AR> them?  Are they capabilities in the sense of Amoeba, or AS400?

They are segregated (kernel-protected) caps, unlike Amoeba (sparse
caps) or AS400 (tagged). More like Eros, KeykOS or (dare I say?) Mach
(without the sucking performance).

The implementation is presently incomplete: caps only control access
to threads (and as such en/disable IPC), and there is no good support
for dynamic protection domains, but that'll all come in the future.

If you have a general understanding of caps, then a good starting
point for learning about OKL4 caps is probably the API overview slides
Toby referred to (see http://wiki.ok-labs.com/Release/3.0).

Gernot