Date: Thu, 17 Jan 2008 08:15:15 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> Cc: freebsd-fs@freebsd.org Subject: Re: Can FreeBSD benefit from MacOS X ZFS? Message-ID: <20080117081214.B51764@fledge.watson.org> In-Reply-To: <86sl0xibpz.fsf@ds4.des.no> References: <alpine.BSF.1.00.0801141829370.10868@ibyngvyr.purzvxnyf.bet> <86sl0xibpz.fsf@ds4.des.no>
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On Thu, 17 Jan 2008, Dag-Erling Smørgrav wrote: > Wes Morgan <morganw@chemikals.org> writes: > >> As the subject says... Can FreeBSD benefit from the macos port of zfs? I >> know this is a VERY new announcement, but not knowing much about macos x in >> general I'm wondering how much it might help our tree, with respect to both >> the memory and 32-bit issues. Just throwing it out there for discussion, if >> anyone has any knowledge of both. > > Did you miss the part where Apple no longer sell 32-bit computers? Actually, the first generation MacBook/MacBook Pro's donly have 64-bit support, and both the kernel and user address spaces are 32-bit on those systems. They did, however, have PAE to support larger physical memories. More recent Intel Macs have 64-bit address support for userspace but 32-bit kernels. Unlike with FreeBSD, the Mac OS X kernel runs in its own dedicated 32-bit address space rather than splitting a single 32-bit address space with userspace. This leads to greater system call overhead (system calls require a full context switch) but much more kernel address space. My impression has been that Apple has also had challenges dealing with ZFS's run-away resource use, however... Robert N M Watson Computer Laboratory University of Cambridge
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