Date: Sat, 02 Dec 1995 10:13:36 -0700 From: Steve Passe <smp@csn.net> To: Don Yuniskis <dgy@rtd.com> Cc: freebsd-hackers@freefall.FreeBSD.org (FreeBSD hackers) Subject: Re: No Thumbs??? (lack of concensus) Message-ID: <199512021713.KAA04430@clem.systemsix.com> In-Reply-To: Your message of "Sat, 02 Dec 1995 09:19:07 MST." <199512021619.JAA05853@seagull.rtd.com>
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Hi, >single *half* height or single *full* height? single, specifically I like the JDR Microdevices's ED-150 for 3.5" apps. It is well made mechanically, all metal except for the faceplate. The fan in this box is crap, unfortunately. >> used for things like tape drives). In its place I put a foam filter to catch >> dust. This allows airflow directly across the top of the drive. I also > >Hmmm... that's a good idea (tho' not quite as visually appealing! :>) Actually it looks like factory made if you take your time. With the above mentioned box I remove the top-third faceplate blockout and cut a piece of open-cell black foam slightly larger, which pops right in place from the back. Looks like what nature intended from the front. >> get a GOOD fan from someplace like Digikey. Panasonic makes a line of >> ball-beaing fans with much higher rated air-flows that the ones typically >> found in disk cabinents. The oem fans also usually die in short order, which > >And *another* good idea! I'll have to examine the fans on these cabinets >a bit more closely... I don't recall ever seeing a quality fan in such boxes. The specs on the panasonic fan I usually use: ball-bearing, 2.40 watts, 6.7 cfm, 32.0 db-A (digikey part# P9703-ND) >... >I was looking to put *two* 3243's in a fullheight external enclosure. >Or, a single 1991. But, same problems (I imagine) would plague each... I recommend 2 3243's in 2 half-height boxes. They stack in about the same space as a double height box and give you alot more flexibility. Put a root partition on both, you get some crash recover benefits. You also can do some load balancing and get better scsi thruput. Get a couple scsi-I ribbon cable connectors and build a 3" connector to attach the 2 boxes, no bulky 3 foot cable dangling between the two. One thing to consider, I have seen combinations of external boxes that became unhappy with mixed flat and round cables. Something to do with impedance mis-match. Remember that each box has approx. 8-12" of flat cable inside, so if you string together 3 or 4 boxes with round cables there are a lot of impedance changes happening. I like to build flat cables to connect all the boxes in a chain, including the link between computer and 1st box. >... >your intended application? :> Maybe just put a warning light and then >hardwire a circuit to (unceremoniously) remove power from the drive at hi-temp. I have wondered about this. At what temperature is it better to clobber the file system and spare the drive a few minutes more of over-temp condition? I suspect most modern drives will shut down when they get TOO hot. The problem is a drive that runs borderline for long periods of time, degrading its lifetime. I guess that reaching the warning (yellow) temp means orderly shutdown, if red is reached while program is still running just cut the power. >How warm does the 3243 case get (use *top* side of finger to test). If you mean the cabinent it is in, top of finger, wrist, big toe, it feels maybe 5 deg above room temp to me. If I can find an appropriate thermometer around here I will get an actual measurement. If you mean the 3243 drive itself, I don't know offhand, not eager to open up a cabinent to find out right now... -- Steve Passe | powered by smp@csn.net | FreeBSD
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