Re: offtopic: userland active context switches ?

Marnix Coppens (
Fri, 06 Aug 1999 17:33:24 +0200

At 15:54 6/08/99 +0100, you wrote:
>During a system call the userspace process switches to kernel mode and
>the kernel executes the code on behalf of the process.
>Is it possible to create a client/server pair both in userspace where the
>can pull off the same context switch trick and run code in the server
along the
>same lines ?

Solaris Doors are similar to this. Richard Stevens' IPC book has a link to
a Linux implementation: .

Doors are like LPC (local procedure calls), except that a new thread
is created in the server (when initializing the doors mechanism), in
which the client can run server code, with the full Unix permission
mechanism and all.

Marnix Coppens

Reality is that which                   | Artificial Intelligence
when you stop believing                 | stands no chance against
in it doesn't go away. (Philip K. Dick) | Natural Stupidity.

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