Date: Sat, 18 Mar 1995 14:30:39 +1000 From: Bruce Evans <bde@zeta.org.au> To: dleeds@eagle.ais.net, rgrimes@gndrsh.aac.dev.com Cc: hackers@FreeBSD.org, questions@FreeBSD.org Subject: Re: ultrastor 34f Message-ID: <199503180430.OAA07994@godzilla.zeta.org.au>
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>> I want to know if the ultrastor 34f controller (scsi-2) VL will work with >> freebsd, I heard it does, but want to know if it is stable and works >> well before I buy it. >The Ultrastor 34F does work, it is stable, it does have the nasty habit >of causeing high interrupt latency as it seems to grab the bus for long >periods of time. ``long'' is apparently about 250 usec. For the BT445C the latency is < 16 usec. (I can't measure the overhead directly but I can measure the maximum time that it takes for several instructions. A U34F hogs the bus in such a way that 10 inb() instructions take 250 usec longer, while with a BT445C they only take 16 usec longer.) There are some other problems: 1) media detection is not completely implemented in the driver. 2) there are some performance problems. Command overhead is higher. The driver or the controller doesn't seem to handle scatter/gather well. The speed of reading /dev/rsd0d drops by 40% when memory gets fragmented. >Utrastor is also out of business, so if you are buying one get a real >good deal on it. >If any one wants one of these I will gladly sell mine for $150.00 as $50 would be a good deal :-). Bruce
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