Hi, On 27.04.2013, at 16:36, gaober wrote:

drivers in linux are in kernel mode.but in a microkernel-based system,drivers are like apps,do they operate the device directly?or the microkernel will do something to operate device.

Yes, in a microkernel system the device drivers operate the device. The microkernel only provides isolation (=address space), communication (=IPC) and scheduling. Device interrupts are transformed into IPC by the microkernel and forwarded to a registered thread. Matthias. -- Dipl.-Inf. Matthias Lange <mlange@sec.t-labs.tu-berlin.de> Security in Telecommunications TU Berlin / Deutsche Telekom Laboratories Ernst-Reuter-Platz 7, 10587 Berlin Phone: +49 - 30 - 8353 58 553 Mobile: +49 - 160 - 587 28 07 Web: http://www.fgsect.de