RE: Research using L4Hurd

[Volkmar Uhlig]

> > When I said "unnatural", I was thinking of the restriction that each
> > thread can have at most one outstanding ipc call, i.e. a 
> > call that is waiting for a server to receive it. Is that correct?
> 
> In Mach, Mach proxies and buffers the requests so that you do not have
> to wait for the server to do a receive.

On top of synchronous IPC it is possible to implement asynchronous IPC.  There 
is no functional requirement to have the kernel dispatch between outstanding 
IPCs if a user thread can implement the same thing. Thus, it seems only 
"unnatural" due to the fat and very high-level IPC mechanisms of MACH.

- Volkmar