Date: Fri, 19 Jan 1996 01:50:32 -0800 From: "Ulf Zimmermann" <ulf@z-code.ncd.com> To: "Andrew V. Stesin" <stesin@elvisti.kiev.ua>, gibbs@freefall.freebsd.org (Justin T. Gibbs) Cc: scsi@freebsd.org Subject: Re: Aaptec 3985 controller Message-ID: <9601190150.ZM23924@zolaris.z-code.com> In-Reply-To: "Andrew V. Stesin" <stesin@elvisti.kiev.ua> "Re: Aaptec 3985 controller" (Jan 19, 5:54) References: <199601190354.FAA22288@office.elvisti.kiev.ua>
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On Jan 19, 5:54, Andrew V. Stesin wrote:
> Subject: Re: Aaptec 3985 controller
> Hello,
>
> # >I just got the bad news from Adaptec that the documents for the AIC-7810
chip,
> # >which makes the raid things like XOR, will not public available till the
end o
> # >f
> # >the year. :(
> #
> # That sucks, although it doesn't surprise me. I got the impression the
> # 7810 documents wouldn't be availible for a while when I asked for
> # them the last time.
>
> I occasionally have read the manuals of this new adaptec toy,
> and got a strong impression that it becomes RAID with the
> presence of software drivers (analog of 'ccd'?) only.
> Am I missing something?
>
No, you are wrong. The 3985 has a PCI-PCI bridge on board. On the internal PCI
bus are 4 chips: 3 x AIC-7870 (SCSI controller, like on 2940) and the AIC-7810
which is a chip build on the same platform like the whole AIC-7xxx serie. This
chip performs via hardware the XOR of the data, which goes into a 1/4 MB big
buffer on the PCI bus. From this buffer the 3 7870 reads the data and writes it
to the harddisk. But recovering are done via Sequencer/OS-driver. Aka rebuild
of the harddisk.
Ulf.
[Rest deleted]
>-- End of excerpt from Andrew V. Stesin
--
Ulf Zimmermann, NCD Software, 101 Rowland Way, Suite 300, Novato, CA 94945
phone: 415-899-7941, email: ulf@z-code.ncd.com, phone-home: 510-865-0204
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