Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!public!thad From: thad@public.BTR.COM (Thaddeus P. Floryan) Newsgroups: comp.sys.amiga.hardware Subject: Re: The Fanning of the Amiga Message-ID: <3079@public.BTR.COM> Date: 16 Jun 91 11:14:44 GMT References: <3025@public.BTR.COM> <3004@public.BTR.COM> <1339@cbmger.UUCP> <00676835659@elgamy.RAIDERNET.COM> Organization: BTR Public Access UNIX, Mountain View CA Lines: 109 In article <00676835659@elgamy.RAIDERNET.COM> elg@elgamy.RAIDERNET.COM (Eric Lee Green) writes: > [...] > I'm just curious. I'm not such a fastidious housecleaner myself, but I > haven't had this rampant dust buildup that you so decry. Every time I open > the case I make a swipe at it with my wet-dry vac, of course, but last time > I did that was back in February when I installed a BridgeBoard. Do you live > in, like, a high dust area? As many who've visited can attest, my "setup" is quite clean. But this is Silicon Valley, and I have to clean the windows on my car every 2 days or so due to pollution/dirt/grime/etc. atmospheric contaminants. As far as the computers go, I suspect the problem is paper "dust" from printers; the "crud" that builds up is a gray-colored "fluffy" material; note, too, that it's only every 6 months or so I powerdown to clean the innards (and find the "crud"). >> a fan blowing ONTO a power supply will keep the supply cooler than >> will a fan sucking air OVER a power supply. > >Correction: AIR blowing onto a power supply will keep the supply cooler >than will a fan sucking air over the power supply. Whether that air is >coming from a fan or from a case opening doesn't matter. Six of one, half-a-dozen of the other! :-) A fan blowing directly onto the power supply and/or other heat-generating parts will continue to cool them, contrasted to a cooling system designed to evacuate hot air from an enclosure. A recent response from someone at Commodore clearly stated the A3000 *will* overheat if operated with its cover removed. >> If you want to perform a simple test for yourself, quickly go do some >> exercise and work up a sweat. Then choose to cool off by either: >> >> (a) standing in front of a fan blowing on you, or >> (b) standing behind a fan sucking air around you. >> >> I'm sure you'll quickly agree that choice (a) cools you better! :-) > > Down here in the Southland, before the advent of air conditioning, we > had something called the "attic fan". Basically, it was a huge fan up in > the attic that sucked air through a large opening in the hallway ceiling > and blew it into the attic and thus out the eaves. > [...] > In any event, back to the issue in question, yes, fans sucking air OUT of > an area can be quite as effective as fans blowing air INTO an area. > Especially when it's a multi-segmented area such as a house or computer, > where airflow can be easily adjusted by adjusting the "windows". (Ah, > anybody remember reversible window fans? If you wanted to cool one room, > blow air into that room... if you wanted to cool the whole house, blow air > OUT). > [...] > I assume you've never been a Southerner in the pre-air-conditioner era? > You learn a lot about fans and cooling under such conditions :-). Well, would having lived in San Antonio TX for 5-1/2 years, El Paso TX for 3 years, Las Cruces/White Sands Missile Range NM for 4 years, etc. qualify as being a "Southerner" ? :-) [An aside: TX and NM, though "hot", were nothing like the East Coast with its 95F and 95%RH (i.e. Washington DC, New York NY, Florida, Pennsylvania, etc.] Back then, (1950's and early 1960's) we had evaporative coolers that clearly blew cooled air INTO the houses/domiciles. Most home air conditioners, even today, blow refrigerated air INTO the home. Someone commented that wind tunnels suck air over their test areas. Hmmm, the world's largest wind tunnels (NASA/Ames Research Center) are just about 5 miles from where I'm sitting right now , and, as an AIAA member, I visit that site often enough to recall that their fans are blowers (per my recollection). Whatever, THOSE fans are NOT for cooling but, instead, for testing supersonic flight dynamics; nothing to do with venting hot air out of a computer. But I digress. I still maintain that a filtered positive-pressure computer cooling system is "better" than a non-filtered volumetric-evacuation system (as in the Amiga and most consumer systems), especially when the possibility exists (as with the Amiga) for overheating (when operated with the cover removed). Oh, sheesh, this opens up the door to a LOT of humor possibilties for cooling technique acronyms! :-) To wit: ASS = Air Suck System BIT = Blow It Through PIT = Pull It Through SIO = Suck It Out BII = Blow It In FITBIT = Filter It Totally, Blow It Through BARF = Blow Air Reasonably Fast FART = Forwarding Air Rapidly Through BITBLT = Blow It Through, But Leave Parts (on the board :-) etc. Seriously, I'm the guy who put IC cooling fins on my C64's IC chips seven years ago (that computer ran HOT), so I really don't want to make light of the need for proper cooling. I started this "thread" because I feel the issue of cooling (and cleanliness) has NOT been properly addressed by most manufacturers (along with the issue of "quiet" computers.) As just one example (which some of you have seen), I converted one of my AT&T 3B1 systems to a tower configuration earlier this year and showed it at the Silicon Valley AT&T UNIX Users' Group meeting; the overwhelming comment from everyone was "Is it on?" because I applied my theory of cooling to that system and changed the location of the fan ... the system actually runs BELOW ambient (measured using a YSI 43TC multiple thermocouple temperature instrument output to a Gould plotter) and it's almost totally SILENT except for the whirring of the hard drive ... I'm using the EXACT same fan that was in the stock 3B1. So it CAN be done, with filtered air, and a clean system as a (side) benefit. Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]