Date: Thu, 10 Oct 2013 16:57:22 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-hardware@freebsd.org Cc: Ravi Pokala <rp_freebsd@mac.com>, freebsd-hackers@freebsd.org, Jia-Shiun Li <jiashiun@gmail.com> Subject: Re: What's the state of AF-4Kn support? Message-ID: <201310101657.22675.jhb@freebsd.org> In-Reply-To: <CE659940.F44B9%rpokala@mac.com> References: <CE659940.F44B9%rpokala@mac.com>
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On Monday, September 23, 2013 10:58:19 am Ravi Pokala wrote: > -----Original Message----- > From: Jia-Shiun Li <jiashiun@gmail.com> > Date: Sunday, September 22, 2013 11:22 PM > To: Ravi Pokala <rp_freebsd@mac.com> > Cc: "freebsd-hardware@freebsd.org" <freebsd-hardware@freebsd.org>, > <freebsd-hackers@freebsd.org> > Subject: Re: What's the state of AF-4Kn support? > > >On Wed, Sep 18, 2013 at 10:49 PM, Ravi Pokala <rp_freebsd@mac.com> wrote: > >> > >>... > > > >CC -hackers. > > > >Thanks for the clarification. Is there any 4Kn HDDs shopping now? I am > >not aware of any. > > Good question. I had the impression that some currently shipping drives > were AF-4Kn, but spot-checking some of the drives listed in > > src/cam/ata/ata_da.c::ada_quirk_table[] > > against their datasheets, suggests that they're AF-512e. So, their being > flagged w/ ADA_Q_4K is "just" a performance optimization. > > >BTW I believe UFS and ZFS have proper design for 4K-sectors, but FreeBSD > >needs some ecosystem connections to get samples early to test, > >incorporate supports and validate for it. Or we will need to wait until > >it appears on market and someone got caught into some kind of bugs. > > Yeah, based on my reading of the code, it looks like the ATACAM layer and > higher (GEOM, filesystems) take the physical block size into account. That > just leaves the bootstrap code. Now that I've taken a second look, it > seems as though at least 'pmbr' only works in terms of 512 bytes. :-( Yes, the BIOS calls have always only used 512 byte sectors. There would have to be an updated spec for those, and it would be a bit of a PITA to use. I suspect the "right" answer for this on x86 is UEFI. -- John Baldwin
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