From owner-freebsd-hackers Sun Dec 17 9:31:14 2000 From owner-freebsd-hackers@FreeBSD.ORG Sun Dec 17 09:31:11 2000 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by hub.freebsd.org (Postfix) with ESMTP id 9070F37B400 for ; Sun, 17 Dec 2000 09:31:10 -0800 (PST) Received: from fledge.watson.org (robert@fledge.pr.watson.org [192.0.2.3]) by fledge.watson.org (8.11.1/8.11.1) with SMTP id eBHHUse49472; Sun, 17 Dec 2000 12:30:54 -0500 (EST) (envelope-from robert@fledge.watson.org) Date: Sun, 17 Dec 2000 12:30:54 -0500 (EST) From: Robert Watson X-Sender: robert@fledge.watson.org To: Andrew Reilly Cc: Jordan Hubbard , Patryk Zadarnowski , Tony Finch , SteveB , freebsd-hackers@FreeBSD.ORG Subject: Re: kernel type In-Reply-To: <20001217203917.A42764@gurney.reilly.home> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: robert@fledge.watson.org Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sun, 17 Dec 2000, Andrew Reilly wrote: > Yeah, but in what sense is that use of Mach a serious microkernel, if > it's only got one server: BSD? I've never understood the point of that > sort of use. It makes sense for a QNX or GNU/Hurd or minix or Amoeba > style of architecture, but how does Mach help Apple, instead of using > the bottom half of BSD as well as the top half? What I'd really like to know, and haven't had a chance to investigate much, is to what extent the Mach primitives are used by their userland environment. I.e., does their software really just use the BSD ABI/API, or does it rely on the Mach IPC primitives for performance in their graphics subsystem. If it relies only on the BSD interface, that gives them a path towards migrating more in the direction of a pure FreeBSD kernel, if they desire, or swapping it out with whatever they choose, as well as leveraging a lot of other work (in particular, security work) based on UNIX-like ABI/API's. If they do rely on the Mach primitives, then that may be less easy. Robert N M Watson FreeBSD Core Team, TrustedBSD Project robert@fledge.watson.org NAI Labs, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message