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Date: Tue, 12 Mar 2013 08:19:43 -0700
Message-ID: <CAJP=Hc_1Z+gEL2N_X0L3fzFG80bY3MhwJyQ0HY9D1+_k45tM6A@mail.gmail.com>
Subject: Re: Unmapped buffers: to be merged in several days
From: Jim Harris <jim.harris@gmail.com>
To: lev@freebsd.org
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Cc: Konstantin Belousov <kostikbel@gmail.com>, arch@freebsd.org
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On Mon, Mar 11, 2013 at 11:53 PM, Lev Serebryakov <lev@freebsd.org> wrote:

> Hello, Jim.
> You wrote 12 =D0=BC=D0=B0=D1=80=D1=82=D0=B0 2013 =D0=B3., 2:22:47:
>
> JH> Please note that XOR checksumming support only exists in the
> JH> E5-1600/2400/2600/4600 series (Sandy Bridge Xeon) and C5500/C3500
> series
> JH> (Jasper Forest - based on Nehalem Xeon) processors.  The SNB Xeon
> series
>   And  what  about  ICHxR/ICHxDO (where x =3D 7, 8, 9, 10) chipsets? They
> support
> software RAID5 in Windows drivers, is it support pure-software? I
> understand, that it is not true-hardware RAID, but does they have XOR
> engine for unmapped buffers?
>
>
The XOR calculations for ICH-based RAID5 are all done strictly in software
on mapped buffers - no hardware offload.