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 ====================================== FreeBSD 2.1.0 is available now! -------------------------------------- FreeBSD: Turning PCs into Workstations ======================================
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