Date: Wed, 22 Dec 1999 07:07:59 -0800 From: Greg Shenaut <greg@bogslab.ucdavis.edu> To: hardware@FreeBSD.ORG Subject: Re: [Q] AHA 15xx controller Message-ID: <199912221508.HAA86323@thistle.bogs.org> In-Reply-To: Your message of "Wed, 22 Dec 1999 20:04:26 %2B1100." <99Dec22.195539est.40336@border.alcanet.com.au>
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In message <99Dec22.195539est.40336@border.alcanet.com.au>, Peter Jeremy cleopede: >On 1999-Dec-22 17:02:39 +1100, Youlgok <youlgok@attglobal.net> wrote: >> Are AHA-1505 or 152x supported by FreeBSD-3.3-stable? > >I'll leave this one because I'm not certain. > >> And which one is the most recommendable? > >The 154x cards are probably the best choice. The 1505 and 152x cards >are PIO-only, so you incur a hefty CPU overhead - best avoided unless >you like seeing how many `+' symbols you can get on a systat -v screen >:-). I don't know the 1535. > >> I found from Adaptec's web page that they sells AHA-1505 >>kit at $55.00. > >This sounds quite expensive. You should be able to find an >NCR-based PCI card for that much. I recently bought 6 Tekram DC-310's from egghead.com at $23 each. On the topic of the 152x vs the 154x, though, the PIO only mode of the former may or may not be less efficient than the busmaster DMA of the latter: DMA, even busmaster DMA, does steal cycles and represents a performance hit on the CPU. And in addition to that, if you have more than 16MB of RAM, the DMA-ed data from the 154x, but not the 152x, will have to be copied up from a bounce buffer. Adaptec's theory, if I remember it correctly, was that using the fast block-mode copy-in/copy-out instructions could in many cases be faster than busmaster DMA. Greg Shenaut To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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