Wikipedia:Reference desk/Archives/Computing/2008 April 14

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[edit] April 14

[edit] USB vs. headphone jack computer speakers

It seems that some speakers that work with laptop computers go through the USB port while others plug into the headphone jack of the computer. Is there an advantage to one type or the other? -- Mwalcoff (talk) 03:10, 14 April 2008 (UTC)

Advantage of the headphone jack: you already have one, you're not taking up a USB port.
Advantage of the USB port... I guess you could use it at the same time as you used the headphone jack? Usually these have their own soundcard so if you have a lousy soundcard I guess this could be useful. But otherwise.... no.
But honestly—I don't think there is any advantage of USB speakers. There's certainly no quality advantage, if that's what you're asking. --98.217.8.46 (talk) 03:17, 14 April 2008 (UTC)
It's pretty much personal preference. I have used many different types/brands of speakers on my computer, and in the last year, two comparative models, one USB, one headphone jacked, on my laptop, and I haven't found a true division between the two. Now, this is just one case, and I can't by any means say that it will always be this case, but this is just what I've found. Mastrchf91 (t/c) 03:27, 14 April 2008 (UTC)
The reason why I use USB instead of the headphone jack is that my laptops jack isn't working real well anymore (you have to wiggle it around, and often it is impossible to get sound to both of your ears, I suspect some wire has gotten loose and some soldering will fix it, but using the USB-headphone is just easier). That's pretty much the only reason I know why someone would switch. —Preceding unsigned comment added by 83.250.207.154 (talk) 03:41, 14 April 2008 (UTC)
Thanks. I was more concerned that the inexpensive Logitech X-140 speakers I was going to buy wouldn't work with my laptop and that I would have to buy more expensive USB speakers. But it looks like the X-140s do work with laptops via the headphone jack. -- Mwalcoff (talk) 04:08, 14 April 2008 (UTC)
USB speakers are nice in that the speakers can have power via the USB port and turn off and on with the PC. Cheap slow USB hubs are dirt cheap if you are running low on ports and keyboards, mice and speakers can use it.--Wonderley (talk) 05:34, 14 April 2008 (UTC)
My tablet has some pretty irritating interference noise that shows up in the headphone jack. I use a USB -> audio adapter to get around this issue. I can't think of an advantage of that sort of device if your headphone jack works the way it's supposed to, but lots of older computers have really crumby sound cards. APL (talk) 14:14, 14 April 2008 (UTC)
I don't like USB ports for two reasons:
1) Unlike a headphone jack, the rotation of the plug must match exactly. A USB port is better than a PS2 port (which is round and requires a specific rotation, meaning you may have to try an infinite number of rotations until you find the right one). Since a USB port is rectangular, there are really only two orientations you are likely to try, but I am still forever trying to plug them in upside down, especially when the USB port is tucked behind the computer so I can't see it or pointed down, as in some Dells, so again I can't see it.
2) USBs can "sag" in the port, with the weight of the cord pulling it enough so that it loses the connection. StuRat (talk) 17:30, 14 April 2008 (UTC)
Never heard of sagging. Does it happen often? Kushal 20:25, 14 April 2008 (UTC)
It's more common with a USB pen drive since they are a bit heavier, but yes, it happens occasionally. The orientation of the slot also matters. It's more likely to happen if the USB slot is horizontal than vertical. StuRat (talk) 21:44, 14 April 2008 (UTC)


In theory, a USB connection is of higher quality, because the signal stays in the digital domain longer. It only becomes analog right at the amplifier. With the headphone jack (coaxial) connection, the signal becomes analog inside your computer, and can pick up interference on the way to the amplifier. In practice, however, it doesn't really seem to matter. --Mdwyer (talk) 04:49, 15 April 2008 (UTC)
But if the USB speaker is using bad DAC's and amplifiers... Bad DAC's and amps are much more noticeable than computer interference, though you probably wouldn't hear any of it with those speakers. Also, 3.5mm jack does not equal to coaxial. --antilivedT | C | G 08:36, 15 April 2008 (UTC)
Has anyone mentioned that USB offers more power for speakers and the like than just the standard headphone jack? Mix Lord (talk) 01:01, 17 April 2008 (UTC)

Yeah, the only difference is the ned for power. Headphone only speakers will be weaker. Headphone jack with additional power would sound better than just usb. 86.139.92.22 (talk) 11:19, 19 April 2008 (UTC)

[edit] MMORPG staff

(Copied from Entertainment desk) In a typical MMORPG's staff, does the lead programmer report to the lead sysadmin or vice-versa? NeonMerlin 16:27, 14 April 2008 (UTC)

Neither, I'd guess. The sysadmins are on the operations side of things, while the programmers are on the development side of things. They most likely both report to someone higher than themselves -- a VP or higher. --Mdwyer (talk) 04:45, 15 April 2008 (UTC)


This is from May 2004 Game Developer magazine :

SOE has established a separate operations department (about 30 people) who buy, set up, and maintain our game server hardware, push patches for all of our live games (including PlanetSide, Star Wars Galaxies, and EverQuest Online Adventures for PlayStation2) and monitor all the game servers 24 hours a day. The operations department does not report into the game development structure. They are totally separate and equal within the company. They have the power to say "no" to the game teams, and frequently do. This separation of power may seem extreme. For example, no game development team is allowed to push a patch to our customers. Instead we put in a request to Ops, who then push the files out to all servers after running their own checks, which includes checking with our QA group to make sure the patch has passed testing.

They go on to talk about how the programming and art departments have someone "on call" 24/7 in case there is a problem with the live servers. It's an interesting article. Worth looking up if MMORPGs are your thing. APL (talk) 13:03, 16 April 2008 (UTC)

[edit] black box on power cord

Dumb question, but I have wondered what the black box on the power cord for my laptop is.... the purpose. Thank you. Alicia —Preceding unsigned comment added by 24.113.8.103 (talk) 16:32, 14 April 2008 (UTC)

The article isn't great, but Wall wart covers some of this. I believe they generally are transformers. Friday (talk) 16:39, 14 April 2008 (UTC)
There are two possibilities. It could be an AC-to-DC power transformer. It could also be an interference filter. While they are not as common on power cords as signal cords, I have seen them on multiple laptop power cords. How do you know which is which? The transformer is wired into the power cord. It is either a big wall-wart that plugs into the outlet or a foot-heater than sits on the floor with the power cord stuck in both sides. An interference filter is usually a little donut shaped thing that slides over the power cord. Sometimes they snap a plastic box over it to keep it from sliding up and down the cord. -- kainaw™ 16:46, 14 April 2008 (UTC)
Mainly it does electric power conversion. A laptop will typically require low voltage (on the order of ones or tens of volts rather than hundreds) and a DC signal rather than AC. The wall output supplies a 50-60 Hz AC signal with RMS voltage of 110-240 V. The specifications for the output signal (laptop's input) and the allowed input signals (output of the wall socket) should be listed on the box itself. Some may also provide some additional surge protection. --Prestidigitator (talk) 17:00, 14 April 2008 (UTC)
Pictures of the intereference filter? See the ferrite bead article. --Mdwyer (talk) 04:43, 15 April 2008 (UTC)

[edit] Windows Vista posting a lot of nonexistant and double entries

See [1]. I consider this to be a sincere pain in the neck, and so I'm asking if anyone knows how to get rid of them. The empty files are a pain (clicking on them does nothing), and the duplicates are a pain (clicking on them shows they're the same folders) - there are documents only for the "my ..." objects. Is this a common error (I suspect it is), and how do I fix it? The computer did not always do this on Vista. At this point, I would prefer not to ignore it. Thanks.

PS. This might have something to do with an older user which I set up, and which is now removed from the computer, though, like I said, both links are to exactly the same folders on the hard disk. Chrissekely (talk) 16:50, 14 April 2008 (UTC)

[edit] Full harddisk backup - including operating system

Hi, my laptop is facing replacement of the wireless circuit for the second time in less than two years (I'm not buying a HP next time). They're replacing it for free, but I have to send in the computer and I guess they can't guarantee they won't wipe the hard drive. I'll back up the contents to DVDs and an external (USB) hard drive. However, it takes an evening to reinstall Windows XP including all the custom HP drivers that have to be installed in a specific order (and no, I don't want to use the HP recovery disk for various reasons). My question: Is there a backup utility, preferably run on a LiveCD, that will make a backup image of my harddisk on an external hard drive or DVDs? Then, if I get my computer back with a wiped drive, I could run the same LiveCD, restore my hard drive and operating system from the external backup and simply boot Windows from the hard drive after that. Any inconveniences encountered from replaced circuitry would be minor, I suppose, Windows usually handles that okay. Thanks! Jørgen (talk) 17:28, 14 April 2008 (UTC)

Symantec Ghost, Windows Home Server, Acronis True Image, ImageX and lot of others. --soum talk 17:31, 14 April 2008 (UTC)
I use Symantec Ghost and love it. If you also have a desktop, they make an adapter that allows you to connect a laptop hard drive to another computer and it makes all this even easier. The adpater is very inexpensive. I don't have one, but a friend of mine did and it worked great. I don't know where he got it, but it looked like this one:
http://www.cablestogo.com/product.asp?cat_id=906&sku=17705 --Wonderley (talk) 20:34, 14 April 2008 (UTC)
Don't send the hard drive to them at all. In general you should send in only the component that needs replacing and anything else that you can't detach from that component without voiding the warranty or risking damage. Hard disks and RAM are user replaceable on most laptops, and a reputable repair house will not need either one to replace your wireless card. Disreputable repair houses (which may contract with major vendors) have been known to, e.g., swap out expensive RAM with cheaper RAM and hope the user won't notice. Remove everything you can. -- BenRG (talk) 12:29, 15 April 2008 (UTC)
I imagine you could also use GParted for this sort of thing too, just copying partitions from one drive to another. --Captain Ref Desk (talk) 14:02, 15 April 2008 (UTC)
Thanks all! While reading the first answers I actually thought about the last two and I think I will try one of them (picking out the hard drive or using GParted, which as far as I understand is both free and CD-bootable) Jørgen (talk) 14:35, 15 April 2008 (UTC)

[edit] I cant go to Yahoo and Google,but I can still go to Wikipedia?!?!

I cant go to www.google.com or to www.yahoo.co.uk or to myspace,but I can still go to Wikipedia and some other sites?!?! Why is this happening? It started this morning! 79.175.80.90 (talk) 17:36, 14 April 2008 (UTC)

Any error messages? CaptainVindaloo t c e 17:56, 14 April 2008 (UTC)
Who (if anyone) has access to your computer besides you? What new software (if any) have you installed? What method do you use to log in and connect to the Internet? It could be any of several hundred different things, and without some background you're probably not going to get much in the way of useful help. It could be a late april fool's joke where someone modified your lmhosts file.

[edit] mac & pc

What is Mac, and how is it different from PC? Which one is better for professional users, and why? please post your best answer as soon as possible. i want the nswer for my assignment —Preceding unsigned comment added by 202.125.143.66 (talk) 17:58, 14 April 2008 (UTC)

We have articles on Apple Macintosh and Microsoft Windows.. those might get you started. Friday (talk) 18:03, 14 April 2008 (UTC)
It's my obligation to pop in and say that a Mac is technically a PC as well. I also hate those "Mac vs. PC" ads with an undying passion (Why haven't they made one about gaming? Oh, that's right, because it would go against them!). What do you mean by "professional" users? Offices, by and large, use Windows for both servers and workstations. Using Macs for these purposes would be ridiculous. Unix and Linux are used as well. So Macs are definately not for professionals, unless they are graphic designers or something. If you want even more professional, look at Unix and Linux. 206.252.74.48 (talk) 18:55, 14 April 2008 (UTC)
Businesses won't usually buy Macs in large quantities because Apple really doesn't gear its business model towards business purchasers right now. Dell and the like are better there, for prices, flexibility, and support. It's not unheard of to see 'professionals' with Apple laptops though. Server wise, Mac OS X Server isn't that bad (OS X being a Unix), and not completely unheard of; though again, companies like IBM primarily use Linux and are far more popular business-wise. -- Consumed Crustacean (talk) 21:16, 14 April 2008 (UTC)
A PC is a personal computer. It refers to any computer one would expect to see in a person's home as opposed to a server room at a large company. A Mac is a Macintosh computer, which is also a personal computer. A Mac is a subset of PC - it is a specific line of PCs made by Apple. It is far more likely that you are asking "What is the difference between Mac OS and Microsoft Windows?" They are both window-based operating systems. They run programs. Programs written for one rarely work on the other. So, the main deciding factor between the two is usually based on the software that you need to run. Another alternative (mentioned above) is Unix/Linux. There are many free variants of Unix/Linux. Of course, it is rare to get programs written for Windows or Max OS to run on Unix/Linux efficiently. So, again, the decision to use (or not use) Unix/Linux is based on the software you need to run. -- kainaw™ 19:13, 14 April 2008 (UTC)

You might consider reading [this] version of an essay, originally In the Beginning...was the Command Line by Neal Stephenson. Kushal 20:18, 14 April 2008 (UTC)

Just wanted to stick up for OP's use and understanding of the expression "PC". It's fine - in this context it's concise and unambiguous. Your teacher doesn't want to have to read "x86 based computer running a Microsoft OS, of the type often found in a home" every two lines or so. Good luck. --90.209.36.146 (talk) 21:21, 14 April 2008 (UTC)
There seems to be an urban myth that mac is better suited for graphic and video applications and so on. But that is not true as most programms used by professionals like photoshop etc.. are available for both windows and mac. Whats more important is a good profiled screen and a professional video interface.

Professionals can and do use both. At the moment they are functionally equivalent for most purposes and it is a matter of preference. Windows machines often have more trouble with malware than Macs, on the whole, and Macs, on the whole, are more expensive than PCs and harder to modify at a hardware level. There are lots of little trade-offs in either direction. --Captain Ref Desk (talk) 13:09, 15 April 2008 (UTC)

I don't think the original questioner wanted a debate over which is better, so let's return to the basic differences. The major difference between Macs and PCs is that they run different operating systems -- Macs typically run Mac OS X, while PCs typically run Microsoft Windows. (Some computers that would be called "PCs", which is a pretty vague term as discussed above, run other operating systems such as Linux. This is less common, but possible, on Mac computers.)

Because they run different operating systems, they have different software available to them. And perhaps the most immediately noticeable difference is that the graphical user interfaces of Mac OS X and Microsoft Windows are fairly different. I hope this helps. rspeer / ɹəədsɹ 18:10, 15 April 2008 (UTC)

[edit] Automated description of graph features

Does anyone know if any work has been done on having a program interpret a graph (or a dataset) and describe its features? For example, the software would be able to look at a noisy graph and say "The graph has a positive slope between here and here, and then plateaus here, and then starts curving back down to zero," or something. In other words, describing a graph much like a human would.

Anything like that already, or any research being done on this?

— Sam 20:01, 14 April 2008 (UTC)

Maybe someone has, but if not: any mathematically-aware programmer (or programming-aware mathematician) could come up with something like this in a couple of hours using existing software (Maple, Matlab, etc) to do the actual calculus (or modelling). —Preceding unsigned comment added by 90.209.36.146 (talk) 21:40, 14 April 2008 (UTC)
Well, I don't know that that's actually the case, which is why I was asking. I'm an AI researcher, and I can already see a large number of difficulties. The key problem is that the computer has to "chunk" the graph into the same set of features that we see when we look at the graph. It has to know whether a graph is bumpy because that's a "feature" or because of noise. It's certainly not impossible, but I don't believe it's a couple hours work. — Sam 13:23, 15 April 2008 (UTC) —Preceding unsigned comment added by 205.234.170.131 (talk)
Not an optimal solution, but you could preprocess it with some sort of filter (like a Hodrick-Prescott Filter, but something else would probably be more appropriate) , then try to fit a third (or higher)-degree polynomial onto this function and finally have your program interpret the result based on the resulting tops, bottoms and inflection points? Jørgen (talk) 14:34, 15 April 2008 (UTC)
Given that the HP filter is a cubic order filter anyway, you may as well just fit the polynomial to the original. You could try fitting polynomials of degree 1 to n-1 (where n is your number of points), and pick the one with an optimal combination of fit and low degree (e.g. try to minimise degree + some constant * amount of variation around polynomial fit). You would then be able to analyse everything in terms of the polynomial rather than the original series. Confusing Manifestation(Say hi!) 04:52, 16 April 2008 (UTC)

[edit] Computer on TV

I recently purchased a 'VGA to TV Converter S-Video+RCA out cable adapter' so I could put a PC on my TV, but I cant seem to get it to work!

I've tried everything including having the pc hooked up with just the S-video cable, with just the RCA video cable and both. Any suggestions would be great :)

Thanks!! --Zach (talk) 21:15, 14 April 2008 (UTC)

Do you have the TV on the right input? Useight (talk) 21:21, 14 April 2008 (UTC)
How exactly does it fail to work ? Does the TV only have static on it ? If so, there may be multiple input modes to select from, like "cable", "antenna", "S-video", etc., that you can toggle through using the remote control or directly on the TV. StuRat (talk) 21:34, 14 April 2008 (UTC)

[edit] DSL and my IP address

I have noticed that my IP address changes from time to time, but I as yet have not undertaken the research to determine exactly when or how often I get a new one. I'm using my phone company's offering, so I have a DSL Modem with 4 little green lights; I note that the LGLs stay on when the computer sleeps, but upon waking up it takes 10-15 seconds before mail, browsers, etc are able to communicate. One explanation might be, upon sleeping my IP address is released, and upon wakeup a new one must be acquired, which takes a few seconds.

Anyone with real insight as to how that process actually works? It's pretty clear that I get a new IP after rebooting; do they really get dropped and reassigned more often than that?

The other thing that surprises me (I'm old, so a lot of current technology does that) is that, today for example I seem to be 209.181.somethingelse, which might be a nice, traditional Class C address. Yesterday I was 89.61.something, a B address. I would have expected Qwest has a pool of IP addrs (all in the same domain, yes?) that it would draw from as needed, and therefore the first couple of octets would stay the same from assignment to assignment. Apparently not.

Sharing of wisdom appreciated!

--209.181.224.8 (talk) 22:14, 14 April 2008 (UTC) Danh

Well, I'd say see DHCP which what they're no doubt using to assign your IP address. I'm not sure under exactly what circumstances it will try to get a new address. But when it tries to get a "new" address, it doesn't necessarily change; if the "old" address hasn't been assigned to anyone else it will may be assigned back to you. (My machine here has had the same IP address for something like two years. But it might change anytime.) As for the address ranges... It's possible that they have more than one pool of IP addresses. Like they had one and needed more, or something. Also, the whole "Class C" address thing is mostly moot nowadays -- address blocks come in many more sizes independent of the "class" of the address; see CIDR about that. -- Why Not A Duck 23:21, 14 April 2008 (UTC)
As Why said, take a look at the DHCP article. The short version is that you are given a 'lease' on an IP address for an amount of time. That time is not standard, and is configured in the DHCP server. Usually, when your lease time expires, you can renew the lease, and you'll get the same IP back. However, if you're offline and your lease expires, the address will be given to someone else. When you log back in, the server will find a different address in the pool to give you.
Assuming a Windows machine, if you get to a DOS command window and type "ipconfig /all" it will show you information about your lease, include when you got it and when it expires.
About that pool: Yes, Qwest has a pool of IP addresses, but those pools could be from all over. Keep in mind that Qwest is the product of a lot of smaller companies merging together. Still, geographic regions typically stick to one octet. For example, out here, the addresses are all 71.208.x.x.
Finally finally, I hope your other address is a typo... 89.61.0.0 is in RIPE space -- that is, it is registered in Germany. You should NEVER have received that address from a Qwest DHCP server. I used the WHOIS tool to look up the IP owner. --Mdwyer (talk) 04:39, 15 April 2008 (UTC)