Wikipedia:Reference desk/Archives/Computing/2016 March 10

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

March 10

how to record sound on android

There is built-in video record programs available on android Phones. Is there any built-in or hidden voice/sound record programs to record audio available on android Phones? Thank you.175.157.42.95 (talk) 15:44, 10 March 2016 (UTC)

My Samsung has something called Voice Recorder. Dismas|^(talk) 15:49, 10 March 2016 (UTC)

stacking computers

I have five small form factor computers that are constantly running and use 100% of the CPU. Currently I have them standing upright but I need to save some space, so I'm considering putting them horizontal and stacking them. I'm concerned about the heat - will they get to hot like this?

(I could just test this, but I don't want to interrupt them running right now.) Bubba73 ^{You talkin' to me?} 21:38, 10 March 2016 (UTC)

It depends on the airflow used to cool them. Micro-ATX cases typically induct air at the front and blow it out at the rear - but some kinds also blow it out the top or through the side. I don't know about other smaller form-factors, but the idea is usually similar. Cases intended for rackmount know to only rely on front and rear flow; if your plan involves obstructing side flow, you may be able to move the case fan, or add another. In any event, computers very rarely rely on thermal conduction through the case to the air, so racking or stacking them should not, by itself, cause a problem. -- Finlay McWalter··–·Talk 21:51, 10 March 2016 (UTC)

they all have an air intake in the front and one fan blowing out the back. Bubba73 ^{You talkin' to me?} 01:12, 11 March 2016 (UTC)

I disagree with the last statement. Computers may not rely on thermal conduction through the case for cooling, but that doesn't mean that such thermal conduction won't affect them. A computer wedged between two other (hot) computers may be operating at an effective ambient temperature higher than it was designed for, and the cooling system may not be able to keep it cool enough to operate. It would be like running the computer while it's in an oven. Mnudelman (talk) 22:38, 10 March 2016 (UTC)

When stacking computers, you can use something as a spacer to separate them. Smart people probably (re-)use something like (styro)foam packaging, but blocks of wood also work fine in my experience. The Quixotic Potato (talk) 00:31, 11 March 2016 (UTC)

How will putting them horizointal save space?? The volume is still the same. DuH!--31.109.183.147 (talk) 01:51, 11 March 2016 (UTC)

The volume would be the same but it would have a smaller footprint and use less desk space. I have them spaced several inches apart. Right now they occupy 29"x16", stacking them would occupy 14"x16" - slightly less than half. And there is potentially at least one more. Bubba73 ^{You talkin' to me?} 02:25, 11 March 2016 (UTC)

Why would you put them on your desk anyway? Do you often need physical access to them? I would put them under the desk. The Quixotic Potato (talk) 04:08, 11 March 2016 (UTC)

They are actually on a small chest of drawers next to my desk, but it has limited space. And I also have a minitower on the table that has air intake on the side, so it wouldn't be good to stack it. There is no room for them under my desk and I need them to be near since they are connected by a KVN switch. Bubba73 ^{You talkin' to me?} 04:38, 11 March 2016 (UTC)

PS - in this room there are two people, two desks, two office chairs, bookshelves that are 6-7 feet wide, a legal-width filing cabinet, three tables, a chest of drawers, two laser printers, three monitors, three UPSs, a stereo system, assorted modems, routers, hubs, power strips, power supplies, external HDs, and - at last count - seven computers (they may be multiplying). Bubba73 ^{You talkin' to me?} 05:09, 11 March 2016 (UTC)

What, no cats??
Assuming the OS and the processors are compatible, and assuming each computer has access to keyboard/mouse/monitor, you could install freeware like Core Temp on each computer, build your stack, and use Core Temp to closely monitor your processor temps for awhile. The max temps for your processors should be available online, and I assume any temp tolerable by your processors would be ok for the other components (I'm correctable on that last point). ―Mandruss ☎ 05:21, 11 March 2016 (UTC)

Or SpeedFan. In the first datasheet for the Intel® Core™ i7 Processor Family for LGA2011-v3 Socket Intel says that the minimum device storage temperature beyond which damage (latent or otherwise) may occur when subjected to for any length of time is minus 25 degrees Celcius... Some people use liquid helium or liquid nitrogen to cool down their CPU. Here is a CPU heat sink cooled to minus 196 degrees celcius. The Quixotic Potato (talk) 05:46, 11 March 2016 (UTC)

For a more typical case, my main computer is a laptop with an Intel Core i5-4200M. The processor runs at 99% busy pretty much 24/7 (scientific distributed computing running in the background). Max temp is 100°C and Core Temp says I never get above 91° (getting a cooling pad anyway). ―Mandruss ☎ 06:30, 11 March 2016 (UTC)

There are servers using one unit hight in the rack only. This 2 inch are 5,08 cm, using 4 cm (40 mm) noisy fan motors. IBM sells those machines as blade, but many server manufacturers offer such machines. ATX compatible cases, using riser cards to support one or two extension cards. A Flex-ATX power supply also uses 40 mm fan motors and is installed in such cases. The CPUs have installed the heatsink only. The airflow is performed with a wall of fan motors between upper and lower case body. Sometimes a plastic airflow guide is installed. The way how to cool the system is not a problem, it just needs to be functional and keeps the components inside the range of the specified temeratures with least price and high relyability. All those machines pull the air from front in to backside out. This machine uses Heatspeaders like Notebooks.[1] --Hans Haase (有问题吗) 12:48, 11 March 2016 (UTC)

So if the total VOLUME occupied by the computers hasn't changed - then the energy density didn't either. So the only concern is airflow. If you were using a fan to move the hot air out of the way - then probably there would be no problem in having them horizontal - but if you're just relying on convection, then there might be a problem because you'll wind up with stagnant 'pockets' of hot air near the center of each board - and that may cause difficulties.

If your ONLY concern is desktop 'footprint' and you're making your own rack to hold them in - you could perhaps consider a compromise of mounting each board at 45 degrees to the horizontal. This would reduce the footprint on the desk - it would be even smaller than stacking them horizontally - but still provide at least some convection airflow. SteveBaker (talk) 14:15, 11 March 2016 (UTC)

Well, probably the best thing to do is to use measuring software and then see what happens with stacking. SpeedFan says that anything over 50C is too hot for the CPU but the i5-2400 and i5-2500 specs say that it is OK up to 74C. Bubba73 ^{You talkin' to me?} 23:14, 11 March 2016 (UTC)

Bubba73, note electrolytoc capacitors have increased wear on higher temperatures. Some magnetic disk drives are designed for horizontal use only, some for less wear in one position only and some for mobile usage in any position. Mainboards do not care but it might be not an advantage for cooling to oberate them bottom top. --Hans Haase (有问题吗) 12:22, 12 March 2016 (UTC)

the hard drives are vertical right now. The cases look like they are designed to go either way. Bubba73 ^{You talkin' to me?} 22:53, 12 March 2016 (UTC)

Resolved