Hi, I've just run across a paper which mentions the HelenOS USB stack and the DDF framework:
www.cs.hs-rm.de/~kaiser/wamos14-proceedings.pdf Here comes the abstract: This paper provides an introduction in supporting USB in a Microkernel-Framework. In order to understand the main thoughts, a quick overview about the USB-specification is provided. Microkernels have a small trusted code-base, so the major part of the USB-Framework has to been implemented in userspace which is the USB-drivers themselves and the UHCI. The several USB-drivers has to cooperate with each other or the UHCI by exchanging messages. The task of sending and receiving messages is handled via IPC. This leads to a bottleneck by communicating to the kernel, because each IPC is realized as a system call. In case of HelenOS, a microkernel operating system we choose to use as example, a solution is provided by reducing the communication overhead. Jakub _______________________________________________ HelenOS-devel mailing list [email protected] http://lists.modry.cz/listinfo/helenos-devel
