Wikipedia:Reference desk/Archives/Computing/2011 July 18

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July 18

Computers and ambient temperatures

Can today's desktop computers and flat-screen monitors operate safely and seamlessly in ambient temperatures between 80 and 100 degrees F? Is it ever dangerous (for the health of the computer and/or screen) to do so? Bielle (talk) 00:35, 18 July 2011 (UTC)

100 F is probably around the upper limits of what is advisable - My Acer netbook manual for example gives a maximum operating temperature of 35°C (95°F). I'd check the manual for your particular computer. If you have to routinely use it in these temperatures, I'd check that the cooling is working efficiently - vents not blocked, free of dust inside etc. With a laptop, the surface you put it on can make a difference too - something hard (so vents aren't blocked) that conducts heat well would be ideal. Your lap is ironically probably the worst place for a laptop in these conditions, and it may not be too comfortable either. AndyTheGrump (talk) 00:57, 18 July 2011 (UTC)

Hard drives will die earlier from excessive heat...unless you have a rugged computer, or custom cooling...you shouldn't run it at 100 degrees.Smallman12q (talk) 01:59, 18 July 2011 (UTC)

Erm, I ain't no physicist (as is probably obvious), but I think that link illustrates a flawed understanding of thermodynamics. To quote: "They [HD's] only consume around 10 or 12 watts under load, and around 7 watts at idle. But unlike your CPU, they're generating a lot of mechanical movement, which means friction-- and heat disproportionate to the power input". If they are generating more heat output than power input, we have a competitor for Andrea Rossi's Energy Catalyzer, and can build ourselves computers that actually push electricity (I said I wasn't a physicist) back into the mains socket. If they are consuming '10 or 12 watts', I'd hope that most of it is being converted into heat, as all the alternatives wouldn't do the computer and/or the user much good. AndyTheGrump (talk) 02:13, 18 July 2011 (UTC)

I think you just misunderstand his using of the word "disproportionate". I think what he means is that more energy per watt input is lost as heat by the hard drive than other computer components. -RunningOnBrains^(talk) 04:31, 18 July 2011 (UTC)

I don't think so. The comparison to the CPU suggests that he's very confused. He implies that the CPU is frictionless, or nearly so, and that it emits less heat in proportion to input power than the hard drive, both of which are completely wrong. -- BenRG (talk) 07:10, 18 July 2011 (UTC)

Neither the CPU nor the hard drive are doing any net work (they're not carrying water uphill or charging a battery), so 100% of the input energy ends up as heat. Also, Watts measure power, not energy. 130.76.64.121 (talk) 17:20, 18 July 2011 (UTC)

Actually one of the few relatively recent (2007) large scale public studies has suggested temperature isn't that big a factor within the first 3 or so years and also only at the extreme (e.g. 45 degrees C) [1]. Even the page you linked to talks about 45 degrees C. In other words, 100 degrees F should ambient temperature shouldn't have a massive effect on life span unless you have poor airflow. Decent airflow is obviously important under such ambient temperatures since you ideally want to keep the HDs under 45 degrees C. Incidentally that page seems a bit silly for reasons other then physics, you should always be worried about data loss no matter what your HDD temperature so should keep backups of important data. And BTW, people do use computers in countries where temperatures close to that range aren't uncommon and commonly they aren't rugged. If you're throwing your computer around or exposing it to sandstorms or rain or whatever then you may want one, but there's no reason to recommend it for 37 degrees C. Nil Einne (talk) 03:28, 18 July 2011 (UTC)

Thanks, folks. Well, there goes that argument for getting air conditioning. Sounds like the computer is more at risk from wildly shedding cat. Bielle (talk) 16:34, 18 July 2011 (UTC)

internet speed

hi,

i have always used torrents for downloading and uploading movies and tv shows, and was quite happy with the speed i got (200 kbps), but suddenly, a week back, the speed dropped to, like, 20, or sometimes, even 10. but when i download from megaupload or a normal download through my web browser (chrome), the speed is back at 200.

can anyone explain the drastic difference in speed?

thanx — Preceding unsigned comment added by 117.197.233.58 (talk) 03:47, 18 July 2011 (UTC)

It sounds like your Internet provider has probably implemented Traffic shaping and they're now limiting the speed of torrents. The only way to be sure is to literally ask them if this is the case, although if you haven't changed any hardware/software your side then it must be them though.  ZX81  ^talk 04:05, 18 July 2011 (UTC)

You might want to randomize the ports you're using, or switch clients. ¦ Reisio (talk) 03:23, 19 July 2011 (UTC)

Well, there is also the slight possibility that there aren't that many seeders with fast connections for a particular file the OP wants to download. Hence the slowdown. --Ouro (blah blah) 06:26, 19 July 2011 (UTC)

(Advanced networking) Bridging routers with multiple internet connections

Hi all. I saw the above (unanswered at the time of writing, doesn't bode well for getting an answer here!) question on extending a wireless internet connection with two routers. My question is related, but different. Imagine a situation where you have a row of houses, say...5. Every house has an internet connection and a router. Is it possible to bridge these all together, sharing the cumulative internet speed equally to any and all IP addresses given out? Assume for simplicity that each house uses a different provider and therefore aren't hogging the same bandwidth for that street. My limited knowledge of how these things work tells me that one router has to be "master" and all others are clients, so would that preclude the internet connection from the clients from being routed to the overall network? --Rixxin (talk) 16:04, 18 July 2011 (UTC)

At a theoretical level this is all perfectly possible. Professional network-grade switching and routing equipment has all kinds of high-capacity and high-availability features that allow channel bonding, dynamic trunking, adaptive load balancing and route failover. The path your packets take around your ISP's network, or around a large internet company like Google, or indeed over the public telephone network, can be through a varying network of fused and redundant connections, where switching equipment knowns about its peers and routes traffic intelligently. This kind of stuff is just what you'd expect from mainline equipment from Cisco, Nortel, Juniper, and the like. Whether it's a hierarchical scheme or not, or whether it's a master-slave scheme or not, is just a function of the inter-router protocols used. But things fall apart when people try to do this kind of stuff with the rinky dink home ADSL modem/routers they bought at Fry's for $60; building redundant channel-bonded failover networks isn't a feature that Linksys and Netgear and Belkin see as applicable for this market, so these products don't try to address this. -- Finlay McWalter ☻ Talk 16:39, 18 July 2011 (UTC)

computer makes continuous beeps before loading the bootloader, but my hardware seems fine?

I didn't know if I caught a virus while on spam patrol (I was vetting a known spamming IP's edits and the links they put up).

Basically the system (a Windows Vista) suddenly without warning started the soft shutdown process (i.e. windows closed one by one). When the system rebooted, the BIOS loaded fine and the power self-on test seemed to be okay -- no fatal errors by text, but when it starts time to load the bootloader it starts making very loud beeping noises.

I used a ubuntu flash drive (I also have ubuntu on the system) to try to diagnose the problem. I am going to try to change the default bootloader to Linux to see if it's merely a corrupted boot sector, but I've never had a problem like this before. I tried reinstalling grub (without changing configuration files) on the master boot record. This fixes the beeping problem, which makes me think it's a boot sector virus. However, grub won't load and the screen is blank. I can boot from the ubuntu flash drive successfully though, and it sees everything.

elle _{vécut heureuse} ^{à jamais} (be free) 17:46, 18 July 2011 (UTC)

converting mid to mp3 AND editing jpg photograph

I would be grateful if a user could please answer the following two questions. 1) how do I convert a song downloaded as mid to mp3? 2) how can I crop a photograph saved as jpg and also how can I enlarge it? Thank you.Simonschaim (talk) —Preceding undated comment added 18:39, 18 July 2011 (UTC).

For 2) Irfanview. 92.28.249.93 (talk) 20:22, 18 July 2011 (UTC)

For 1) use TiMidity++ to render MIDI to WAV, and then Audacity (or lots of other things) to convert the WAV to MP3. For the first part, at the command line, you do something like:

timidity foo.mid -Ow which will create foo.wav

-- Finlay McWalter ☻ Talk 21:11, 18 July 2011 (UTC)

Thank you Finlay McWalter. I found your information very helpful. Simonschaim (talk) —Preceding undated comment added 14:35, 19 July 2011 (UTC).