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Re: Research using L4Hurd
From: |
Neal H. Walfield |
Subject: |
Re: Research using L4Hurd |
Date: |
04 Jul 2002 10:47:10 +0200 |
User-agent: |
Gnus/5.0808 (Gnus v5.8.8) Emacs/21.2 |
> Using a microkernel doesn't necessarily reduce the need for locking.
> For instance Hurd file servers are heavily threaded (one thread for
> each open file),
This is not typically true. You might be confusing this with select.
In this case, select sends an io_select rpc to each file descriptor it
is interested in polling.
> It might be possible to write servers in a more select-loopish
> fashion, without multithreading, but that's not the recommended way to
> do it on the Hurd, and I'm afraid it will be even more unnatural when
> moving to L4 and its syncronous ipc.
I think you are confused about L4 ipc. Although the ipc is
synchronous, rpc do not have to be. Which is to say, when the client
sends an ipc to a server, it blocks until either the supplied timeout
is reach or the server does a receive. The client, however, is not
obliged to do a receive from the same server. In fact, the client is
not required to do a receive at all.