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The event pipeline The fundamental Adeos structure one must keep in mind is the chain of client domains asking for event control. A domain is a kernelbased software component which can ask the Adeos layer to be notified of:
· Every incoming external interrupt, or autogenerated virtual interrupt; ·
Every system call issued by Linux applications, ·
Other system events triggered by the kernel code (e.g. Linux task switching, signal notification, Linux task exits etc.).

From: Life with Adeos: http://www.xenomai.org/documentation/xenomai-2.4/pdf/Life-with-Adeos-rev-B.pdf

Question: Adeos is supposed to be between the hardware and the Linux kernel, I can understand about Adeos telling the Linux about hardware interrupts but Why should Adeos know about the "system call" issued by Linux?

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Linux system calls offer direct access to hardware in some cases. E.g. read() and write() can be applied to raw devices in /dev, ioctl() can be used to poke values into hardware registers. I assume it is simpler to intercept such activities at syscall time than to anticipate everything a device driver might do and infest it with callbacks.

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yes, thanks, I forgot about "write". Good reminder. So, is it only about the system calls which deal with the hardware? Adeos won't know about the normal system calls issued by Linux? –  TheIndependentAquarius Apr 2 '12 at 0:54

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