On Wed, 8 Mar 2000, Brian Pomerantz wrote:
>On Wed, Mar 08, 2000 at 05:38:29PM -0800, Michael wrote:
>> Consider that the poor little controller chip on the raid card is
>> vastly underpowered for what you are asking it to do in raw IO speed
>> plus handling all the raid calculations. ...
>
>The "poor little controller" has a > 200MHz StrongArm in it. Which
>since all it does is calculates parity, it should be plenty for the
>three channels it has on it.
Actually, most of the higher end RAID controllers (Mylex, and others) have
hardware ASIC parity calculators. An ASIC capable of doing a 64k parity
calculation in basically one CPU clock cycle is a _significant_ improvement.
MMX/SSE/SIMD/etc. are good, but they are nothing compared to what an FPGA
can do. (esp. for XORing a bunch of bits)
Additionally, the strongarm is doing more than just parity. And it can more
than flood a 32bit/33MHz pci channel. (64/66 it might have a little trouble.)
--Ricky
