Wikipedia:Reference desk/Archives/Computing/2010 September 7

= September 7 =

Second Internet Line Cable
Hi, I help manage the wired and WiFi internet access for a Bed & breakfast-sized apartment of around 30 people. Currently, I have one TV cable plugged into a modem, which is then plugged into a series of routers that help cover the entire house. Frequently, when all residents are using the internet at once, the connection is unstable and will randomly drop users off the Wifi access.

I am thinking of connecting a second TV cable into a second modem and plugging some routers into that to help spread the load.

My questions are: (1) Will I have to contact my ISP (Time Warner) and pay for the cost of an additional connection? And (2) will this indeed work?

Thanks, Acceptable (talk) 00:07, 7 September 2010 (UTC)
 * We need some more information. First, are you sure you have several routers, and not merely several wireless access points?  And do you have any diagnosis about what actually is occurring when the network fails?  (Are the users unable to obtain an IP, for example?  Or are they unable to locate a wireless network?)  There are some "best practice" guidelines for creating and managing a scalable wireless network (for example, here is Cisco's product lineup brochure).  It is very unusual to have "several" routers in order to service ~ 30 connections - you really only need one, and the rest of the house should be covered with WAPs.  Can you describe your network topology and the failure symptoms a bit more?  Nimur (talk) 01:51, 7 September 2010 (UTC)


 * First, are each of your routers on the same channel? Neighboring routers should be on different channels -- either 1, 6, or 11 -- to prevent interference. Also, lay out your network so wireless signals from each router overlap each other by 15-20%. Otherwise, they will compete for connections from users.


 * If the bottleneck is really your cable connection, then you can purchase another cable connnection and cable modem from your ISP. You will also need to purchase a router with two WAN ports, like this wireless model or this wired model. You can then plug in an ethernet cable from each cable modem into each of the two WAN ports in the router. This is called channel bonding. You can also installl a network card with three or more ethernet jacks in a desktop computer, using it as a router. Here is an example of such a card.


 * Another solution would be to ask your ISP for more bandwidth. Most cable connections are capped at a much lower speed than what is available. If you pay them more money, they can probably increase the speed of your connection. I also have a cable-internet connection. I pay my ISP an extra $20 per month for twice as much bandwidth (23 mbps).--Best Dog Ever (talk) 02:45, 7 September 2010 (UTC)

Recording a Skype conversation
I have a client here in Canada whose wife is still in their country of origin. He uses Skype to talk to her regularly. He wants to bring her to Canada but our wonderful officials are skeptical that he talks with her as frequently as he says he does. Is there any way to record the Skype conversations to prove that he does talk with his wife? 99.250.117.26 (talk) 02:34, 7 September 2010 (UTC)
 * You can always just use a microphone and record it from the speakers.Sir Stupidity (talk) 03:02, 7 September 2010 (UTC)
 * I've used Pamela. It's easy to use and the sound quality is excellent.--Best Dog Ever (talk) 03:04, 7 September 2010 (UTC)
 * Uh, careful there. Recording actual conversations might be problematic due to wiretapping laws (this is not legal advice, but rather advice to seek legal advice by a qualified professional in the field of law, should you really want to record the conversation). Consider the situation that your client some day decides to break up with his wife, and she suddenly "doesn't remember" agreeing to the recordings. If your legislation requires two-party consent to recordings, and there's no proof that she agreed, she might drag him to court.
 * Therefore, I would suggest that you investigate if there are any ways to record the connection data, similar to call detail records on a regular phone line. That way, the actual conversation stays private. -- 78.43.71.155 (talk) 08:31, 7 September 2010 (UTC)
 * Would a recording actually help? Surely officials want a log of calls made.  However, I doubt a log of Skype calls would do because they might claim he could tamper with the evidence in his favour.  I suggest your client uses a regular land line for a while so he can build up an independant log of call activity at the phone company, a log which the officials can then obtain through a legal request to the phone company.  Astronaut (talk) 12:05, 7 September 2010 (UTC)

Way better than recording the speakers with a microphone, just record your stero output direct from the sound card. Also, to the pseudo-lawyers ranting about recording calls being wiretapping, it ain't illegal if you say you're recording the call, then the other person can hang up if they don't want to be recorded. This happens all the time with call centers that say "this call might be monitored for training purposes" etc etc. Quadrupedaldiprotodont (talk) 14:02, 7 September 2010 (UTC)

Viruses
How do you tell if a program has a virus? --The High Fin Sperm Whale 03:59, 7 September 2010 (UTC)


 * Simple answer: someone else has identified it as a virus and a search of your computer reveals that common feature. Real answer: You have to define "virus" first, and then realize that any program that does something you don't want without you knowing it is a "virus" for all practical purposes. Is there a more practical application you're interested in? Shadowjams (talk) 06:11, 7 September 2010 (UTC)
 * (ec) Well, if files for an application are indeed infected (i. e. code is attached to files) then there are three possibilities. The original application will either not run at all (i. e. if the malicious code is appended to the main executable clumsily), it will hang or crash or break in the middle of an operation (if the virus code is appended to a different file which is not run at startup, or if the code only corrupted a portion of the file), or it will run as normal (because the malicious code is appended in such a way that it does not interrupt the operation of the original file). In most cases it will be the first, rarely the second, the third may take place also. Is this going in the direction you were thinking? Note that by now many 'viruses' (malware, etc.) are so large and intricate that they will be (sets of) standalone files rather than a kilobyte or two in size attaching itself to a file. Back in the day, viruses were small, small, small, with the most prevalent not exceeding a few kilobytes, and many l'art pour l'art viruses were under 100 bytes in length! Hope this helps. --Ouro (blah blah) 06:17, 7 September 2010 (UTC)
 * It depends on the type of virus. A virus as described above will add to the size of a file, sometimes a few hundred bytes, sometimes many thousands of bytes.  There is also strange behavoir: programs crashing, things that used to work just not working any more (for example: a virus might disable access to the task manager), a flurry of unwanted results in an internet search, messages popping up, and so on.  A macro virus will make your office document bigger.
 * However, all the recent virus/malware I've seen has come in separate programs that are started when the computer starts, either as a service or as a startup program configured in the registry like a regular program. Some malware makers think they are providing you with a genuine product (and market it such to their customers who pay them to place their ads on x thousand PCs), which creates an entry in the list of installed programs - just one you didn't want or know was being installed.  You may nothing about it until a friend mentions that they got some spam or a virus in an email from you.
 * In all, it is a good idea to familiarise yourself with the normal operation of your computer, what programs and services start, the kind of noises (fan and disk) that it makes, and how it performs under various conditions. That makes it easier to spot times when it seems to be misbehaving or taking much longer to do something.  Astronaut (talk) 11:57, 7 September 2010 (UTC)

Run a virus scanner Quadrupedaldiprotodont (talk) 13:59, 7 September 2010 (UTC)


 * I was more thinking of how to figure it out before you install a program. I want to install hugin.exe, but I want to know it's safe. Is there any way to tell without putting my computer at risk? --The High Fin Sperm Whale 16:31, 7 September 2010 (UTC)
 * From looking at the site and the fact that it has a Wikipedia article with no mention of malicious dangers, I'd say it is pretty safe. And most antivirus software will detect viruses (if there are any) during or even before an install, and take measures to ensure the safety of your computer. But if you're really worried, you could install the program inside a virtual machine such as VirtualBox, Windows Virtual PC or QEMU. So that if it did turn out to be a virus, only the virtual machine would be affected and you could simply close and delete it with no danger to your actual OS. 1230049-0012394-C (talk) 17:58, 7 September 2010 (UTC)


 * Assuming the virtual machine is configured correctly, of course. If it has internet connectivity, malware can still contact its botnet and start spamming. And if the VM has remembered network connections to its host that give it write access there.... Unilynx (talk) 18:09, 7 September 2010 (UTC)


 * I think you would be pretty safe downloading it from the official site. I did just that with the previous version and had no problems, I just scanned it for viruses after download using AVG (my virus scanner). The Hugin install program I used then is "Hugin_2009-4-0_win32_setup.exe" and is 20,393,805 bytes long.  The MD5sum is 356535bfb5a2a7e13599378e837fa635   A newer version is now available.  As a general rule, I'll always buy a disk or download from the official site, and never get programs from other sources like torrents.  Hope that helps.  Astronaut (talk) 09:31, 8 September 2010 (UTC)


 * Purely technical answer: There is no 100% way to tell if a file is a virus unless you have the source code, understand every line of the source code, and compile it with a non-infected compiler. Period.
 * Reasonable answer: Run it through []. If that doesn't detect pretty much nothing on the planet will, since it uses pretty much every scanner to test. --70.104.22.63 (talk) 03:15, 12 September 2010 (UTC)

Batch file question - how to find the newest document in a subdirectory structure
How can I find out which PDF file in a subdirectory structure full of PDFs is the newest file? dir *.pdf /s /b delivers a list of all pdfs in the subdirectory structure with full paths (which is what I want), but doesn't sort them by date. dir *.pdf /b /o-d does sort by date, but doesn't descend into subdirectories. Combining these two into dir *.pdf /s /b /o-d doesn't deliver the expected result - it sorts by date, but per directory, while I'm looking for the *one* newest file of all directories. To sum it up, what I have is:

c:\mypdfs\bar\new.pdf c:\mypdfs\bar\newer.pdf c:\mypdfs\foo\old.pdf c:\mypdfs\foo\older.pdf c:\mypdfs\ney\newest.pdf c:\mypdfs\ney\oldest.pdf

What I want is c:\mypdfs\ney\newest.pdf c:\mypdfs\bar\newer.pdf c:\mypdfs\bar\new.pdf c:\mypdfs\foo\old.pdf c:\mypdfs\foo\older.pdf c:\mypdfs\ney\oldest.pdf (actually I only need c:\mypdfs\ney\newest.pdf, I don't care if the rest shows up or not)

What dir *.pdf /s /b /o-d delivers is c:\mypdfs\bar\newer.pdf c:\mypdfs\bar\new.pdf c:\mypdfs\foo\old.pdf c:\mypdfs\foo\older.pdf c:\mypdfs\ney\newest.pdf c:\mypdfs\ney\oldest.pdf

The code only needs to run on W2K or newer, so in addition to the builtin batch cmds, the usual standard tools of these Windows versions are available. Any ideas? -- 78.43.71.155 (talk) 08:22, 7 September 2010 (UTC)


 * Use Windows explorer, search for *.pdf, sort by date modified? --86.148.22.79 (talk) 09:07, 7 September 2010 (UTC)
 * Windows explorer isn't exactly a batch file solution, or is it? ;-) -- 78.43.71.155 (talk) 10:22, 7 September 2010 (UTC)
 * Good point. I read the question but not the header. --Phil Holmes (talk) 11:01, 7 September 2010 (UTC)


 * This is not a complete solution, and is just a command line, not a batch file, but might be a start --
 * That will get you a full list sorted by date. In this case, the first line of the output is the newest file, with date and size information.  Extracting just the file name from that single line is left as an exercise for the reader ;-)  -- LarryMac  | Talk  12:55, 7 September 2010 (UTC)
 * Nope, that's not really helpful, either - as it doesn't descend into subdirectories. Sorting by date within a single directory is not a problem, that's what dir /o-d is for (the "-" doing what you achieved with "sort /r"). Also, matching for "Directory of" means it's not language-independent. -- 78.43.71.155 (talk) 13:17, 7 September 2010 (UTC)
 * I left off the /s on the dir command, but I assure you the proof of concept works; you might have at least given that a try. Language independence was not listed as a requirement, so if you're going to reject honest efforts to assist and change the requirements, then I'll stop right here.  -- LarryMac  | Talk  13:23, 7 September 2010 (UTC)
 * Sorry to burst your bubble there, but I did try it, including the /s, before posting my comment, and it does not sort the way you claim. The newest pdf shows up at the fifth position from below. Thinking about it, this also has to do with the language issue - dates are in DD.MM.YYYY format here (and even if we were using MM/DD/YYYY, it probably gets messy once we have files from different years - a YYYY-MM-DD style display would help, but Windows doesn't offer that). Also, your solution doesn't provide the file including its full path (which is what I need and why I was using the example above). -- 78.43.71.155 (talk) 14:06, 7 September 2010 (UTC)
 * Sorry to burst your bubble there, but I did try it, including the /s, before posting my comment, and it does not sort the way you claim. The newest pdf shows up at the fifth position from below. Thinking about it, this also has to do with the language issue - dates are in DD.MM.YYYY format here (and even if we were using MM/DD/YYYY, it probably gets messy once we have files from different years - a YYYY-MM-DD style display would help, but Windows doesn't offer that). Also, your solution doesn't provide the file including its full path (which is what I need and why I was using the example above). -- 78.43.71.155 (talk) 14:06, 7 September 2010 (UTC)


 * Here is the question you asked - "How can I find out which PDF file in a subdirectory structure full of PDFs is the newest file?". Registry settings can address the date format and collating sequence.  When you ask strangers for help and you receive a good faith effort at providing that help, the common response is "thank you."  I won't hold my breath.  -- LarryMac  | Talk  00:55, 8 September 2010 (UTC)


 * With Unix utilities (for Windows, see UnxUtils, MSYS, or Cygwin, although the first two might not have stat(1)), you can do something like this:

find. -name "*.pdf" -print0 | xargs -0 stat -c "%y %n" | sort
 * You can use sort -r to put newest first or tail to restrict the output, etc. The arguments to stat depend on the version of that program; it's different under BSD, for instance, but these features are still available.  --Tardis (talk) 15:31, 8 September 2010 (UTC)

Try the Windows for /F variant: del a for /F "usebackq delims==" %i in (`dir /b /s *.pdf`) do @echo %~tfi >> a sort /R a

As LarryMac points out, you will need to tweak the date format with a registry setting. BTW, doesn't seem to work as a single piped command (directly into sort command). Probably a way to fix this but I don't know what it is. --CaritasUbi (talk) 23:11, 9 September 2010 (UTC)


 * The following code avoids messing with the registry, but will only work on NTFS and recent versions of Windows:

188.98.137.254 (talk) 20:57, 10 September 2010 (UTC)

Google translate default/detect language
I sometimes use Google translate but I find it annoying that it always defaults to Spanish -> English translation. Is there a way I can get it ti detect the input language automatically, or keep the last language used, perhaps in a cookie? And why does it default to Spanish anyway, it's not like it's the first in the list? Astronaut (talk) 11:31, 7 September 2010 (UTC)
 * Spanish is a popular language. And there is an auto detect feature, and it is set to default from my computer.Sir Stupidity (talk) 11:56, 7 September 2010 (UTC)
 * (e/c) It's more clever than it looks. If you frequently request translations from another language, your default will indeed eventually switch to that language, and a couple more languages may be moved to the top of the drop-down menu. I assume that it defaults to default to Spanish because it is the most frequently requested language on English-language Google.—Emil J. 12:00, 7 September 2010 (UTC)
 * (That is, unless you keep changing your IP and deleting your cookies to prevent Google from keeping track of you.—Emil J. 12:09, 7 September 2010 (UTC))
 * It sometimes retains/detcts the language if I use IE 8's Google translate accelerator, but otherwise the cookie is not working for me. Astronaut (talk) 13:30, 7 September 2010 (UTC)

Google
If google for some reason decided they wanted to shut down all of their services tomorrow (email, search, maps, etc)


 * 1) Would they legally be allowed to?
 * 2) What would be the impact on society? —Preceding unsigned comment added by Half charged (talk • contribs) 13:45, 7 September 2010 (UTC)


 * I really don't see anything that would legally prevent Google from shutting down all their services. They're still a privately-owned company, right? J I P  &#124; Talk 13:55, 7 September 2010 (UTC)
 * Google is now a publicly traded company (see History of Google), which means that they'd have to deal with shareholders if they wanted to liquidate. However, it also says that "The vast majority of Google's 271 million shares remained under Google's control", which presumably means that they could force a liquidation if push came to shove. Buddy431 (talk) 14:29, 7 September 2010 (UTC)


 * To explain Buddy431's comment about having to "deal with shareholders": The directors and, generally, the managers of any company (with more than one shareholder) have a fiduciary duty to maximize shareholder value.  If the managers of Google were to shut down all their services tomorrow, and if the board of directors didn't immediately fire all the managers, install new ones, and get them to restart the services, many shareholders would immediately file a class-action lawsuit in order to kick out the directors and managers and get them to restart the services.  This would take a while, of course.  To directly answer the first question, it would not be illegal for Google to shut down all their services; no laws would be broken, unless maybe Google has entered into agreements with governments, and those governments have laws that forbid a shutdown.  But a shutdown would not last long anyway, because of the fiduciary duty lawsuits &mdash; unless the directors and managers could show that it was in the best interest of the shareholders to shut down the services.  If they could show that (and I do not think this is remotely possible), then, yes, they would even be immune to any fiduciary duty lawsuit.  Comet Tuttle (talk) 16:57, 7 September 2010 (UTC)


 * Remember as well Google isn't simply a company providing free stuff as some people still think, but a massive company which deals with a large variety of people and companies on a commercial level with contracts and the like. These likely create responsibilities which would cause problems for them if they try to just 'shut down' their services. For example, they have a search deal with Yahoo in Japan and others use their search too, Youtube has a variety of deals with media companies, I'm pretty sure some mobile phone companies and networks have deals with Google for search, maps and of course the open source Android, many companies pay for Google Apps (and while it's not something I've looked in to I suspect the even the free edu variant does involve some sort of contract which Google can't just terminate willy-nilly), there are likely a variety of other support contracts and the like involved etc. And let's not forget the master of them all, Google's advertising business (i.e. all the advertisers). Of course there would likely be a variety of more direct creditors like banks and suppliers who won't be too happy either... Nil Einne (talk) 17:44, 7 September 2010 (UTC)

Did you guys forget about Google Analytics?Smallman12q (talk) 22:19, 7 September 2010 (UTC)


 * I don't see how Google Analytics changes anything. When you sign up for Google Analytics, Google doesn't tell you, "We warrant that Google Analytics will be available for you to use in perpetuity."  Comet Tuttle (talk) 23:29, 7 September 2010 (UTC)


 * The section Service Levels in their TOS states that:

Google does not guarantee the Service will be operable at all times or during any down time (1) caused by outages to any public Internet backbones, networks or servers, (2) caused by any failures of Your equipment, systems or local access services, (3) for previously scheduled maintenance or (4) relating to events beyond Google's (or its wholly owned subsidiaries') control such as strikes, riots, insurrection, fires, floods, explosions, war, governmental action, labor conditions, earthquakes, natural disasters, or interruptions in Internet services to an area where Google (or its wholly owned subsidiaries) or Your servers are located or co-located.
 * Shutting down their services is not beyond their control. (On a side note, its interesting to see they account for riots, and insurrection).Smallman12q (talk) 00:10, 8 September 2010 (UTC)


 * I believe that interpreting a license for you is getting close to offering legal advice, which we do not do at the Reference Desk, but I would urge you to re-read the terms of service, especially the all-caps section about warranties, and pay close attention to where, exactly, you think Google makes any affirmative guarantee at all about the availability of Google Analytics. Comet Tuttle (talk) 04:14, 8 September 2010 (UTC)


 * Re: the impact on society, I would guess not that great. People would be rather annoyed if they lost data stored in some way with Google.  Almost all of Google's services are available in similar form from other providers (the only exception I can think of offhand is StreetView).  People would switch to using these other providers and, after a short period of confusion and overload on many of them, things would settle down. Warofdreams talk 14:19, 8 September 2010 (UTC)

Web
Explain this http://cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.cache.click.down2crazy.com/ 86.72.16.66 (talk) 16:30, 7 September 2010 (UTC)


 * See subdomain. Comet Tuttle (talk) 17:00, 7 September 2010 (UTC)

Frustrating ADSL problem
This has been bugging me for 4 months and I've tried loads of different ways to fix the problem with no avail. Problem is that my ADSL modem keeps disconnectiong (randomly and intermittently) during which the DSL light flashes, then DSL and Internet lights go off, then after some random amount of time the DSL light flashes then the modem connects to the internet again. While the DSL light is flashing, the DSL status on the modem software says 'synchronising'. DS and US line attenuation before and during the problem is typically in the low 30's and my telco guy says he only gets worried above 50. So, I've called the telco people multiple times; they checked the exchange, resynched my line from the exchange, replaced the line from the repeater to my house, and checked line noise many times. I've tried 4 different ISP's to no avail. I've also tried two brands of modems, including a swap-out of the current modem (duoPlus 300WR). I suspect something is triggering the modem to disconnect and 'synchronise the line' - any gurus out there know how to stop this trigger? Any other ideas? Sandman30s (talk) 20:17, 7 September 2010 (UTC)
 * How about your network card? Are it's drivers fully updated?Sir Stupidity (talk) 00:54, 8 September 2010 (UTC)
 * It's Windows 7 so it should be, but I will check thanks Sandman30s (talk) 11:00, 8 September 2010 (UTC)
 * Perhaps the problem is the power feed - either noise on the line, a loose connection in the circuit, or some other form of unstable power. A major appliance − refrigerator, air conditioner, or even a hairdryer − might cause a momentary power drop that is causing the modem to reset.  A noisy power source might also generate interfere in the DSL signal.  If you can borrow one, try installing a UPS for the modem, which may serve as a power conditioner, to see if this improved things.  Alternately, you can try a long extension cord to power the modem from another room (another circuit) in your house.  --  Tom N (tcncv) talk/contrib 04:01, 8 September 2010 (UTC)
 * It's already connected to a UPS (PC on one circuit and modem on other circuit). This was done even before I had the problem. The modem does not go OFF; it merely disconnects on the line and keeps synchronising. Sandman30s (talk) 11:00, 8 September 2010 (UTC)
 * I'd bet there's an electrical noise generator somewhere near. You're probably familiar with this exact thing happening during lightning storms.  It was said that Christmas Tree lights (some types) had a similar effect.  Do you think there could be some sort of spark generator or similar nearby?  If it happens often enough, you could try to listen for it with an Amplitude Modulation radio tuned off the stations - you might be able to hear a crackle? --Phil Holmes (talk) 14:29, 8 September 2010 (UTC)
 * I don't know of a noise generator anywhere near my house... but there is a crackle on my land line phone connected to the splitter. Maybe I should move my modem far away from all the other electronic gizmos near the modem and try giving it clean power... but that is going to be a mission and a half. Thanks for the suggestions! Sandman30s (talk) 18:56, 8 September 2010 (UTC)

How do I fix my MBR from Ubuntu?
i have ubuntu and win7 installed on my laptop. windows won't boot, and the only os boot option is GRUB. i installed ubuntu because windows gave me and i know why.

so tl;dr how do i fix my MBR from ubuntu?

/and i can't use CDs —Preceding unsigned comment added by Boodalu (talk • contribs) 22:47, 7 September 2010 (UTC)


 * Ask in ##linux on irc.freenode.net ¦ Reisio (talk) 06:54, 10 September 2010 (UTC)


 * Change the section header to distinguish this question from others with the same header. Astronaut (talk) 00:18, 11 September 2010 (UTC)