Wikipedia:Reference desk/Computing

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Wikipedia Reference Desk covering the topic of computing.

Welcome to the computing reference desk.
Want a faster answer?

Main page: Help searching Wikipedia

How can I get my question answered?

  • Provide a short header that gives the general topic of the question.
  • Type ~~~~ (i.e. four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
  • Post your question to only one desk.
  • Don't post personal contact information – it will be removed. We'll answer here within a few days.
  • Note:
    • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
    • We don't answer requests for opinions, predictions or debate.
    • We don't do your homework for you, though we’ll help you past the stuck point.

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

  • The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
See also:
Help desk
Village pump
Help manual

September 29[edit]

Edit box font size and Chrome[edit]

Right now I am using a 2009 Gateway running Widows 7 to edit WP. When I use the Chrome browser, the edit box font size for pages like the ref desk display at something like 6 to 8pts. I have looked for a default minimum font display size, and cannot find one. Is there eaither a Chrome or WP setting I should be looking for? The edit bozes with IE 11 and Firefox display normally. Thanks. μηδείς (talk) 00:46, 29 September 2015 (UTC)

Just to clarify, it's just the edit box? The rest of Wikipedia and other sites when displayed in Chrome are at a good size?
If it is indeed all text, then try hitting CTRL-0. Additionally, CTRL-- (control and the minus key) will decrease the text size and CTRL-+ will increase it. CTRL-0 will bring everything back to the default size (cancelling changes made by CTRL-- and CTRL-+). Dismas|(talk) 16:03, 29 September 2015 (UTC)
No, bizarrely, as far as I can tell, it is only the edit box at wikipedia, and only with the Chrome browser. The print is so small I can't make it out, so I have to use CTRL + to expand it, and then everything else of course gets huge. I am assuming there's got to be some weird glitch. μηδείς (talk) 20:31, 29 September 2015 (UTC)
The following steps might help tell what's causing the problem:
  1. Right click in the edit box and choose Inspect Element. The Developer Tools will appear.
  2. In the right side, click on Computed. This will show the final styles used for the edit box.
  3. Look for an item called font-size. Click the triangle to expand the item. This will show the source of this style.
What size is shown? What source is shown? This information might provide clues about what to check next. --Bavi H (talk) 01:55, 30 September 2015 (UTC)
Thanks, Bavi H, it says font size = 16.5 px and all the other font values are "normal". I use WP monobook too, in case that's relevant. The actual size is smaller than 8pt Calibri as displayed on MS word in the default viewing mode, I would guess 7 or maybe even 6pt, although MS Word doesn't go below 8pt for normal text text. I am editing in firefox right now, and everything is normal. I also did click on the restore default settings in the inspect element window, but nothing changed. μηδείς (talk) 20:55, 30 September 2015 (UTC)
I'm using Internet Explorer, but I'm assuming the Developer Tools in both browsers are close enough to the same. I set my Wikipedia preferences to use MonoBook, then examined the computed style of an edit box. I clicked the triangle next to font-size to see what's "inside" it. I see:
 ▼ [√] font-size: 13.33px
      [√] div#globalWrapper- 127%   load.php (1)
      [√] body- x-small             load.php (1)
This says the font-size is originally set to x-small in a body rule, then modified by 127% in a div rule, yeilding a final value of 13.33px. You're likely getting something similar. (I was hoping you might see a more obvious problem. For example, if you saw the final computed size was a small number, and saw some rule from a file like "user.css", that might suggest you need to disable a user preference somewhere in Wikipedia or a browser add-on.) If the computed styles don't suggest a cause, then I guess Chrome just renders the text box font size differently that other browsers.
  • If the problem started recently, maybe a recent update of Chrome changed how the textarea font size behaves. You might search for the exact version number and terms like textarea font size to see if others have reported the issue.
  • Maybe Chrome is only applying the x-small rule to the edit box text. Try unchecking the box next the x-small rule and see what happens. Or uncheck the 127% rule. Or uncheck both. This won't really solve the issue, but might help describe the problem in a bug report.
  • You might work around the issue with user CSS. In Wikipedia, you can edit one of the user CSS files in your preferences, but this will also affect other browsers you use. To just make a user CSS in just Chrome, you might install Stylish and write a new rule. Either way, trying entering something like textarea { font-size: 120%; } or textarea { font-size: 16pt; } and see if that helps.
--Bavi H (talk) 02:08, 1 October 2015 (UTC)
Thanks, I spent about an hour toggling the settings last night. Nothing under the inspect element windows showed any weird smalling factors. What I did eventually find was that Chrome was set at a 67% zoom factor for some reason. Setting that back to 100 made the edit box legible, if not still undersized. I think what I need to do is find out how to smallen the size of default text so that when the zoom is at 125% the normal text appears, well, normal.
As for recent changes, this 2009 Gateway is my backup computer, my preferred computer has some keyboard issues I probably won't budget to be fixed for a while, unless I decide to do so myself. Since the 2009 was slow and crashing all the time I reinstalled it from the rescue disks, and at that time and for the first time installed Chrome. Chrome works okay on the 2013 ASUS with the dead keyboard, also running windows 7, but it simply works horribly with this computer, with hesitant scrolling and a whole lot of other problems. In any case, The edit boz text is legible, so at this point I just have to spend the time getting the default text smaller. μηδείς (talk) 00:09, 2 October 2015 (UTC)

The cost of Video Conference Business Meeting[edit]

Why is video conferencing so horribly expensive? And why is Skype free of charge (for most services)? Is is so difficult to stream real-time information reliably?

According to [1] 2 hours would cost an estimated total of $2,070.

OK, short answer is because people, or business and governmental clients, pay for it. However, couldn't other IT companies provide the same service at a much cheaper rate and skew the market prices?--Jubilujj 2015 (talk) 07:17, 29 September 2015 (UTC)

If you're looking for a market analysis that accurately explains why professional video systems can command a high price ... prepare to be amazed! It costs loads of money to get a good answer to that type of question.
Although free information is a pervasive societal trend, there are a few areas - like well-researched business analysis - where information is decidedly not free. Who is out in the marketplace paying six figures for a video teleconference system? What motivates their purchase? How many transactions per year are taking place in this market? Companies like Gartner can sell you answers at market-price.
Although you might assess a product like Cisco TelePresence, and consider its service equivalent to a free alternative, evidently you are not the target customer for a hundred-thousand-dollar product. Those customers do exist, and they willingly pay large fees. Understanding who they are, why they pay, how much they can spend, is a valuable piece of information that you probably can't get on the cheap, in the clear. If this information was available, it would throw off the entire game-theoretic basis for this type of marketplace. Nimur (talk) 16:32, 29 September 2015 (UTC)
OK, maybe the issue could be focuses from the perspective of what computing hardware and software we need, not how the market works. After all this is the Computing RD. If someone pays more for a 1 hours business conference than it costs to travel to Europe, there must be a market reason, but from a computing perspective this is irrelevant. The question is more what hardware, software and access to infrastructure do we need to hi-def low-latency video conference across an ocean. What item in there makes it not payable to lil' people like me? --Jubilujj 2015 (talk) 19:28, 29 September 2015 (UTC)
I cannot achieve hi-def low-latency video conferencing with my internet connection, even to the nearest town, so I would need a dedicated link, probably delivered via a series of specially installed microwave links which would cost many thousands of pounds. Skype is a joke here, almost unusable. Are there places where Skype isn't annoying in its delays and lags? Were I a business with highly-paid employees, I would pay the high cost of proper video conferencing just to avoid the irritating delays in cheap "skype-type" connections. I assume that the companies who provide such links have software that sends and receives multiple-redundant packets to avoid stutters and lags. Perhaps we have some experts here who know the technicalities. Dbfirs 21:15, 29 September 2015 (UTC)
Do you know that these very-expensive video conferencing systems have not had a huge slump in sales in recent years? Some businesses do use Skype. Some of them curse it daily, when it doesn't have near the reliability and robustness that some paid services have. My employer now uses Vidyo, which does seem a decent bit more reliable than free services, but I have no idea what they pay for their license. You might want to read up on the history of some of these "free" services like Skype. How do they make money? Do they make any money, aside from securing additional rounds of venture capital? Sure, someone made a bunch of money when Microsoft acquired Skype, but that doesn't meant that the unit by itself is in any sense profitable. It could just be an attractive loss leader for MS. I also recall that Skype started out as a distributed service, so that when you used skype, your computer was also being used as free infrastructure for other calls. But I think that has changed now. SemanticMantis (talk) 21:09, 29 September 2015 (UTC)
The $1000/hr price is for a "telepresence suit", like this one: [2]. A remote group meeting would almost feel like a face-to-face meeting. A company would save lots of time and money using it. The service provider even cares that rooms in both ends have the same decoration, lightning and so on, for a more realistic immersion. There are also less expensive systems, that look like as if both participants were watching each other on a hi-def TV without network hiccups for $2,500/month flat. Or you could use a desktop video-confering like Skype (which is only free for basic uses) or ooVoo, for something less than $10/month.
It looks like the whole market spectrum is covered by some type of service of varying price and quality. Scicurious (talk) 22:18, 29 September 2015 (UTC)
It's worth mentioning that "free of charge" doesn't really mean "free". If you read the so-called "privacy" statement that goes along with Skype, you'll see that the only privacy they really guarantee is that the actual content of your call will be kept private. Who you talked to, who is in your address book, your name, email, etc, etc - are all theirs to do pretty much whatever they want with. They go to a lot of pains to ask you to connect up with your Facebook page so they can suck more information out of there. That kind of data is pretty valuable. Now, imagine you're a business - all of your customers and service providers are talking to you via video conferencing - now Microsoft know who you are, what you do, AND who all of your customers are. Would one of your competitors like to know who your customers are? When you talk to them? For how long you talked? Which of your employees were talking to them? What those employees' private email addresses are so they can poach your best people? I think they'd quite like to know that stuff...and Microsoft (it seems) will be happy to sell them that information. How much is it worth to you to keep your competitors ignorant of this? Probably more than the cost of a video conferencing system that guarantees actual, useful, privacy.
That said, if you use Skype to get free video calls to your mom, who lives halfway across the planet (as is the case for me) - then having Microsoft know that is not a big deal. So pick your battles! SteveBaker (talk) 14:59, 30 September 2015 (UTC)
I work for a global enterprise organization and have used Cisco Telepresence on many occasions. We have several rooms around the world that have 3 60"+ televisions that make up one end of the room, you sit around a table that terminates at the screens, which displays the corresponding room you are conferencing with, with a similar set up it looks like you're all sitting around the same table. You can be conferences to more than one room at a time, the system automatically "focuses" on who ever is talking. You can have people who don't have access to a room dialed into the meeting and you can have people watching the meeting online, we've had meetings with 300 people in them.You also have a projector in each room which a presenter can share their computer screen to. I believe the rooms are not just "plugged into the network/internet" but use several dedicated ISDN lines. Also, keep in mind that for business travel, the cost is far more than just the airfare, there's transfers, accommodation, per diem. Vespine (talk) 23:28, 30 September 2015 (UTC)

GTA San Andreas save files[edit]

Why all GTA San Andreas saved game files I downloaded from the internet start from the game's beginning in the airport and how to fix that (I'm running licensed game version)? All have the same file title as my original save file, GTASAsf1.b. Changing file name doesn't help, even though the slot's title is correctly displayed in the game. My path is C:\Program Files\Rockstar Games\GTA San Andreas\data where saved games are stored (in Win 7). Reportedly this may have something to do with game slot number, but I don't how to fix this either. Thanks in advance.-- (talk) 15:56, 29 September 2015 (UTC)

PC Gaming Wiki's page on GTA:SA has some info about incompatabilities between saved games generated by older versions and the newer ones. It also has links to converters which it says fixes these problems. -- Finlay McWalterTalk 16:15, 29 September 2015 (UTC)
You must be running the "Second Edition" - all GTA San Andreas SKUs published since the Hot Coffee scandal have slightly different game logic (main.scm, script.img and several others were changed besides a file check for edited assets) hence why a downgrader is needed. Blake Gripling (talk) 10:02, 30 September 2015 (UTC)

Strength of password[edit]

Is the password '++++++++' equally strong as 'dJ+dhg3*'? A cracking algorithm won't know that I decided to repeat the same character 8 times, and when I decided to do that I had all letters and special characters available. --Scicurious (talk) 20:24, 29 September 2015 (UTC)

See Password_strength#Entropy_as_a_measure_of_password_strength. It depends on the threat model, but the entropy is fixed by the string length and the size of symbol list. Attacks designed by humans against human-generated passwords may well start with strings of constant symbols, string including sequential substrings, etc. SemanticMantis (talk) 20:46, 29 September 2015 (UTC)
Maybe I should try to incorporate the following into the section that SemanticMantis linked, but I'll put it here for now.
Basically the strength of your password is (the log of) its index in your adversary's dictionary. The problem is you don't know what's in your adversary's dictionary. It may not contain ++++++++ early on, but you can't be sure.
What randomly chosen passwords buy you is a guaranteed high probability of not being in the dictionary. If the attacker is going to test, say, 250 words (and this is something you can estimate, based on the price/performance of current hardware and how much they'd stand to gain by cracking your password), and your password is chosen uniformly at random from 280 words, the chance that they will crack your password is at most 1 in 230, no matter how cleverly they choose their dictionary. (This is similar to the fact that you will correctly guess 50% of random coin flips no matter what strategy you use; the attacker here has exactly 2−30 odds if their 250 words are a subset of your 280, and worse odds if they aren't.) In contrast, if you invent a password in your head, there's no way to bound the probability that the password is on the list. It's dangerous to rely on your adversary not having a good model of people's psychological preferences for certain passwords over others.
Note that what matters is how you generate the password, not what the password is. You might randomly generate ++++++++. That's okay because the chance of doing so is small and is included in the 2−30 upper bound. -- BenRG (talk) 03:01, 30 September 2015 (UTC)
True in theory, but in the real world, if your random password generator randomly picks "password" or "12345678", run it again.
Also, by international law, we can't discuss this without adding the following links:
--Guy Macon (talk) 07:22, 30 September 2015 (UTC)
Per the last one, rubber hose cryptography is an interesting read. One Julian Assange worked on some of the early Deniable_encryption software to counteract this, named rubberhose... SemanticMantis (talk) 15:31, 30 September 2015 (UTC)
Well responded, Citizen Macon. And in this context we might also mention . —Steve Summit (talk) 13:52, 3 October 2015 (UTC)
@BenRG: I was personally a little disappointed in how short and unreferenced that sections is. I for one encourage you to add anything you can to it. SemanticMantis (talk) 15:33, 30 September 2015 (UTC)
BenRG's statement is true more than just "in theory", but it's the a priori probability that is known. After (it happens that) the generator has chosen "password", the a posteriori probability that its choice (i.e., that string!) is in (and near the beginning of!) the attacker's dictionary is rather larger, even if never known precisely. --Tardis (talk) 18:44, 2 October 2015 (UTC)
Those are all good answers. Let me just add that it's quite likely that the string "++++++++" just made it into at least one cracking dictionary. —Steve Summit (talk) 13:40, 3 October 2015 (UTC)
In this case, I'd change my password as soon as I get a free minute.--Scicurious (talk) 19:30, 3 October 2015 (UTC)

https problem?[edit]

Starting a few days ago, Firefox (41.0) started giving the error

Error trips on many/most new connection attempts, to several urls (e.g. facebook, WP, google, etc.). Page always loads correctly when I click "try again", or manually reload/re-navigate. Problem has not manifested yet with other browsers, though my testing has been very limited. Problem persisted through an upgrade to Firefox. I have not noticed any similar issues with other devices using my same home network. Questions:
1. This has to be on my end, right? The error makes it sound like the server is configured incorrectly, but I can't imagine that so many servers would start having the same problem at once.

2. Is this an https problem?

3. Could this be some sort of malware or man-in-the-middle shenanigans?

4. Any ideas how to resolve the issue? Firefox is set to use https whenever available, a setting that I prefer to keep.
Thanks, SemanticMantis (talk) 20:55, 29 September 2015 (UTC)

This can occur for many reasons. One (usually benign) reason would be a corrupted certificate database. That database is a file, cert8.db located in your Mozilla user profile. You can delete your entire profile (taking a sledgehammer to the problem); or simply surgically delete only this file "cert8.db" from your profile directory; that will cause Firefox to "start over" with the default certificate database. This is the most probable cause, and the solution is directly-actionable.
The database may have been corrupted by a bug in Firefox, or an extension. It may have been caused benignly because of a crash or hang in the application. It may also have been corrupted by - and here's the bad news - malware or malicious behavior (internal or external to Firefox). (However, if it actually was malware, it didn't accomplish its job; if it had successfully modified your certificates file to inject bogus data, you'd never have seen any error message and never known a problem even existed!) Malicious corruption, in this case, is less likely than file-corruption-due-to-buggy-Firefox.
It is also possible that you actually have a different problem unrelated to the cert database - like a weird network firewall that started being misconfigured very recently. It is also possible that a lurking bug in Firefox is incorrectly showing you these warnings.
Obviously, the error message alone isn't enough to root-cause the problem... but on a hunch, try removing the cert database, and see if it helps.
Nimur (talk) 04:27, 30 September 2015 (UTC)
@Nimur: So far, so good; thanks! SemanticMantis (talk) 15:27, 30 September 2015 (UTC)

September 30[edit]

Facetime for android?[edit]

Hello everybody. I have one question: Can i download facetime for android device? My girlfriend have iphone and facetime app ;/ I want too, but i have samsung galaxy 3. — Preceding unsigned comment added by (talk) 21:16, 29 September 2015 (UTC)

Edited: I found amazig website, and now i have facetime app on my android, this is the website: (WP:SPAMLINK redacted) Regards. — Preceding unsigned comment added by (talkcontribs)

That appears to be a link to malware. FaceTime is an Apple product and is only available on iOS and Mac. It is not presently available on other systems. Nimur (talk) 04:06, 30 September 2015 (UTC)

Identifying a Google Chrome process[edit]

If I have multiple tabs open in Google Chrome (on Windows 7) and one tab causes my PC to lock up, I'd like to be able to use the Task Manager to close just the affected tab. I am able to bring up Task Manager + Processes, and I do see processes for all the tabs (plus a couple extras). However, I can't identify which process goes with which tab. So, I currently just start randomly killing the processes until I hit the problem tab. I see I can turn on various columns in the Task Manager + Processes window, but none of those seem to help. I had hopes for the "Command Line" column which seems to be the full command line used to spawn the tab, that would presumably include the title, but it seems to truncate at maybe 256 characters, which is apparently before it hits the title. Any other ideas ? StuRat (talk) 17:33, 30 September 2015 (UTC)

ProcExp and ProcMon (free from Microsoft) are the industry-standard tools for this sort of thing. Tevildo (talk) 19:49, 30 September 2015 (UTC)
I may try those. Do you know if either would solve this problem ? StuRat (talk) 01:06, 1 October 2015 (UTC)
That is, one can obtain them from Microsoft without payment, rather than their being devoid of Microsofticity. Just in case anyone's confused. Tevildo (talk) 19:51, 30 September 2015 (UTC)
A comma after "free" would have made that clear. StuRat (talk) 01:06, 1 October 2015 (UTC)
I recommend Process Hacker over ProcExp/Process Explorer. It's open source and has a lot more features. I don't think either utility will display Chrome tab names, though. ProcMon/Process Monitor tells you what files and registry keys are accessed by a process, which probably won't help here. -- BenRG (talk) 02:32, 1 October 2015 (UTC)
What do you mean when you say your PC locks up? Apparently it's not a total system freeze, since you can apparently get to Task Manager and kill processes. Is it just Chrome that locks up, so you can't close the tab from within Chrome? In any case, no page should be able to cause a lock up, so this qualifies as a bug in Chrome (or, possibly, something else, like display drivers). If you want, you could check if there is already a Chrome bug report for your issue, and file one if there isn't. -- (talk) 20:19, 30 September 2015 (UTC)
Seems to be a piece of malware that pops up an alert saying I have a virus and have to call some phone number, at which point they would want my credit card number to fix my problem ("my problem" apparently being too much money in my bank account). I close the alert and it pops right back up. I can't select another tab. I could kill and restart Chrome, but I might have something open in another tab, like if I am editing Wikipedia and try looking up something to add to the edit when the malware strikes. If you have a suggestion of how to avoid this type of malware, I'm open to that too, but I also want to know how to identify a Chrome tab's process. StuRat (talk) 01:12, 1 October 2015 (UTC)
Chrome's built-in task manager should solve your problem. Press Shift+Esc or choose More tools → Task manager in the menu. -- BenRG (talk) 02:32, 1 October 2015 (UTC)
I'll try that. Are you sure it allows that selection when an alert on the current tab is "unanswered" ? StuRat (talk) 14:03, 1 October 2015 (UTC)

October 1[edit]

Fast[er] file extracter[edit]


Are there faster file unpackers on the market faster than the latest version of Winrar? I've seen many benchmarks with competitors (e.g., 7Zip, WinZIP), but most of them are about compression ratio or the time required to compress files. For example, a 1.5GB 7zip files takes around 2 or 3 minutes to unpack with Winrar on my PC, despite a 840 Evo SSD. Am I asking too much? Some on the web recommend to increase the process priority, however I'm afraid of it messing with the file's integrity. Matt714 (talk) 02:24, 1 October 2015 (UTC)

I'm fairly sure most decompressors for most file formats tend to use the same library, so you'll see little difference between 7zip, WinZIP or WinRAR when decompressing the same file. It's unlikely process priority will change anything, unless you're doing something else with significant CPU usage on your computer, however it also won't effect file integrity. For something like 7zip LZMA2 at maximum settings decompressing large files, this will often be CPU limited rather than IO limited, perhaps even on a recent HD decompressing to the same HD (although this will depend a bit on how the OS and decompressor caches, so could vary from 7-zip to WinRAR to WinZIP). So your SSD may very well be irrelevent. Nil Einne (talk) 09:07, 1 October 2015 (UTC)
Actually from further testing I'm not sure if decompression normally is CPU limited, even with LZMA2 at maximum settings although I was lazy to test fairly compressible files of large sizes. However I'm also fairly surprised it takes 2-3 minutes to decompress a 1.5GB file. Are you dealing with lots of small files by any chance? SSDs are a lot better at dealing with lots of small files then HDs, but they're still going to be a fair amount slower then when dealing with large files depending also probably on the file system. Alternatively, if you're dealing with extremely compressible files, and extracting something like 75GB from the 1.5GB file, well then SATA-600 is limited to 600MB/s at most and not all SSDs can even achieve that with maximum throughput, so it's not exactly surprising it will take 2+ minutes to write, even if you only have a small number of highly compressible large files. Nil Einne (talk) 17:02, 1 October 2015 (UTC)

Thanks for your input. I just re-tested the 1.5GB file, and it took around 2 minutes (exactly) to extract (not counting the moving time by Windows) -- seems like I was overestimating the required time. My system has a i7-4930k with 16GB DDR3. Also tested 7Zip, and instead of 1m57s it took 2m01s; so WinRar it is Matt714 (talk) 21:14, 1 October 2015 (UTC)

With some more testing, I return to my original statement that decompression may very well be CPU limited presuming we're talking about something like LZMA2 with maximum compression, even with large files. Anyway how many repetitions did you do? A 4 second difference would likely be in the margin of error of any test unless you did probably at least 5 per decompressor including multiple restarts and only have an average of 1 second difference between repetition.

I am a bit surprised given your specs it's taking so long if you're referring to large files. My own testing on a much weaker (single threaded) CPU took slightly under 2 minutes for a 3GB file. However, it will probably depened on precisely how well the file compressed. But are you sure you aren't decompressing a lot of small files? If it's IO limited your CPU is probably largely irrelevant.

BTW why are you moving stuff around, rather then extracting directly in to the desired location? That could easily waste more than 4 seconds.

Nil Einne (talk) 16:06, 2 October 2015 (UTC)

7z files can also be bzip2 compressed, decompression is much slower than LZMA2: 5.28s against 2.23s for 85MB in this test. (At maximum compression level, LZMA2 used 15 times more memory 4MB vs 66 MB) Ssscienccce (talk) 22:02, 3 October 2015 (UTC)
In general, when designing compression algorithms there are always going to be tradeoffs between compression time, decompression time, and compression ratio. If you find you're spending too much time decompressing files, you might want to look for a different algorithm that's optimized for that (and that, yes, might not fare so well on compression time or ratio). —Steve Summit (talk) 13:35, 3 October 2015 (UTC)

Why hasn't flash memory become cheap enough to give away?[edit]

The per-byte price of flash-memory storage media, including USB flash drives and SD cards, has continuously dropped over the past decade or so. But the unit prices of commonly available ones haven't decreased nearly as much. While I can now get a 32 GB microSD card for a tenth of the price of a 512 MB SD ten years ago, it still costs in the neighbourhood of $10. Why doesn't anyone make 512 MB cards that now sell for less than a dollar, that could serve as a replacement for optical and floppy disks? While online file transfers have largely taken over, there's still a need for offline media that one can cheaply give away. Are the per-unit fixed production costs so high as to disallow such an approach? Or am I the only one who would want such a product? --Paul_012 (talk) 06:26, 1 October 2015 (UTC)

I don't know where you are located, but in India pen drives are sold for Rs 100-150 (the same as a local beer, or $1.5-$2) and have your 512 MB storage capacity. If they are sold for $1.5-$2 as a unit including postage, I suppose their market price for businesses might be less than the amount of $1 that you refer to. I don't know how does this would compare to the floppy disks of past ages, but it's certainly cheaper than printing 100s of pages.--Scicurious (talk) 07:01, 1 October 2015 (UTC)
Yea, it's all that extra junk that goes with it. There's the connector, the plastic case, the package, someone's time to stock it and sell it in the store, etc. They might be able to reduce some of that. I have one flash drive with no case, it's just a circuit board and a connector. Very compact and cheap, but also ugly and fragile. They could maybe sell a package of 100 of those in 512MB size for less than $100 (less than $1 each). If there was enough demand, I'm sure they would. StuRat (talk) 14:00, 1 October 2015 (UTC)

@Paul 012, Scicurious, and StuRat: hardware producers focus on profit. there is not enough people to buy massproduced low capacity flashes in the society to make it profitable.

Are you sure it hasn't? USB sticks are a pretty common giveaway at trade shows etc, and Alibaba shows lots of retailers who'll sell USB sticks in bulk (1 GB for under a $1). Smurrayinchester 15:47, 1 October 2015 (UTC)
(One extra point on giveaways - one disadvantage of flash media is that they're difficult to write in bulk. You can fairly easily get machines which accept a big pile of blank CDs or DVDs, and can just write them, label them and spit them back out, but for most companies writing a file to a big pile of USB sticks or memory cards still has to be done manually (unless you can do it at the manufacturer during formatting). You can make it easier by using USB hubs/multi-card readers, but it's still much more manual, and still more expensive than a cheapo optical disk.) Smurrayinchester 12:05, 2 October 2015 (UTC)
I have a drawer full of USB sticks that I've been given. Some don't work at all and I toss them to the garbage. Some don't handle rewrite and shrink in size every time I delete a file. A few (very few) have quality that I'd pay a tiny bit for. The only real use I've found is to put movies on them for my kids so they can plug it into the TV and watch them. Turns out that USB sticks don't scratch and turn to crap as easy as DVDs. (talk) 17:17, 1 October 2015 (UTC)

Where are the files of a tool in Linux[edit]

How can I find what files a tool is using? I know that the binary 'fortune' is stored at /usr/games/fortune, and that the data is stored at /usr/share/games/fortunes. The first can be discoverd with 'whereis fortune', but what command would output the second? Or simply output a list of directories being accessed by a tool, be it for reading or writing files? That is, how can I monitor what a tool is doing. --Scicurious (talk) 13:30, 1 October 2015 (UTC)

lsof will get you most of the way there... but it takes some skill to use and understand lsof output. It also won't tell you if the file access is more indirect, e.g. if a helper process or daemon is involved.
For me, the more interesting question is: how can I determine which source-code was used to build a specific executable program that is on my *nix system? This is more useful to me; with source, I can determine and debug program behavior (including, but not limited to, file system access). Unfortunately, finding source can be a lot more difficult: essentially, you depend on your software vendor to maintain a complete "reverse look-up" database that maps specific source projects to specific files that ship with the "distro." Few distributors make this procedure easy; there is often a lot of hunting and guessing. My favorite commercial Unix distributor makes this lookup process much easier, but their software is regrettably non-free. Linux, on the other hand, is free - but the source comes from thousands of places and is managed by an uncountable number of independent contributors and organizations. So, if I boot up my trusty and reliable Ubuntu 9.04 box, and I find "fortune" on my disk at /usr/local/bin/ ... it is not easy to know who authored, built, and delivered that version of binary. I have to dig through old Canonical archives, mailing lists, and FTP servers; and I have to already know where to look.
Nimur (talk) 14:10, 1 October 2015 (UTC)
use rpm -ql package-name to see what files belong to a package (RPM-based distros; there must be a similar command for dpkg.) You can monitor file access by tracing a process's syscalls. For me, strace worked well. I've used it on two or three occasions to investigate bugs (in unrelated software) which I would later report to the maintainers Asmrulz (talk) 16:26, 1 October 2015 (UTC)
The above answers are useful, but for data that "belongs" to a certain program (like fortune), if the packager follows standards like the Filesystem Hierarchy Standard (FHS), you can just look at the standard directories. In this case, fortune is following the FHS, and so it keeps the fortune lists in /usr/share/games where they belong. The "Unix way" has long been to store files in a standardized directory tree, rather than just scattering them wherever as is the norm on some other platforms. See Unix filesystem and man 7 hier. -- (talk) 21:53, 1 October 2015 (UTC)
One technique that often works is to run strings on the (binary of the) program in question. Often this will reveal the hard-coded pathnames the program will use. (And you could narrow the search down with strings | grep / or something.)
Another (even more hard-core) technique is strace, which lets you snoop on all the system calls (and, in particular, all the file-opening calls) a running program is making. —Steve Summit (talk) 13:28, 3 October 2015 (UTC)

I broke the Assume Good Faith option for myself[edit]

Moved to WP:VPT. Dismas|(talk) 13:41, 2 October 2015 (UTC)

I see no result for "Geo-IP", why?[edit]

Geo-IP doesn´t work, is this user using an open proxy? --Poker chip (talk) 16:55, 1 October 2015 (UTC)

It works for me, giving the following results:
Provider: Globe Telecoms
Region: San Juan (PH)
This is similar to the info in a WHOIS [3].
I take it you're aware Geo-IP loads a Google Maps where it shows the results and this may happen after it loads an ad (and the site also seems a bit slow). Even so, in future, if you have problems try using a different geolocation service in case the one you're using is playing up, or simply lacks info for that particular IP for whatever reason. Note the absence of a result in any geolocation service is probably not an indication of an openproxy.
Nil Einne (talk) 17:14, 1 October 2015 (UTC)
I don´t understand this, but yes I see now a result on Geo-IP but I have first not having any result. I saw this "map" and the error message that there couldn´t be found any location to this ip" I have seen this error 2 times and I was interested why it isn´t showed. And I think it is an open proxy because he has edited in the german IP but he is located in a country miles away. --Poker chip (talk) 23:00, 1 October 2015 (UTC)
Geolocation service do have problems, one reason why it's generally a good idea to check another service if you're having unexpected results. Not sure what you mean by "he has edited in the german IP". If you mean the editor has edited from a German IP before, well there are only about 9 edits for that IP, and there's nothing that looks like it will establish a clear link to another editor, so you may simply be mistaken about who this editor is. Even if you are correct, it's always possible that the editor went on holiday in the Philippines. (Although the IP seems to have edits over about 3 months, so it would likely have been a long holiday.) Note that someone from the Philippines editing the German wikipedia isn't a definite sign of an open proxy, there are definitely German speakers in the Philippines, including German tourists and ex-pats or migrants as well as locals who've learnt German. German may not be English, but it isn't exactly Njerep language either. Nil Einne (talk) 15:53, 2 October 2015 (UTC)

October 2[edit]

What makes ssh time out?[edit]

When I log into an Ubuntu Linux box on my home network via ssh (from a Cygwin/Windows box nearby), I find that my sessions time out after some large amount of time (at least 30 minutes...maybe hours?) when I'm not actively using them. When I do the same thing to a Linux box on the other side of the planet run by my ISP, the timeout is MUCH shorter - so evidently this timeout can be adjusted on the server-side. How do I do that? SteveBaker (talk) 14:02, 2 October 2015 (UTC)

On my OSX system, man sshd_config returns in part:
This suggests to me that adding the lines

ClientAliveInterval 600 ClientAliveCountMax 3

to /etc/ssh/sshd_config (or someplace analogous)
should give you an timeout of 30 minutes. I have not tested this and know nothing of the vagaries of different sshd distributions, versions, etc. SemanticMantis (talk) 14:44, 2 October 2015 (UTC)
And, for cases where you are not the server administrator, you can configure the client to perform keepalives: ssh_config may include the ServerAliveInterval option:
It's up to you to decide if you want to configure the server, or the client, or both... there are usually no problems if keepalives are sent in both directions.
Nimur (talk) 15:01, 2 October 2015 (UTC)
I've always wondered about this, but (slothful me) never delved into it to figure it out. The poor-man's solution I sometimes use is a little one-off ad-hoc keepalive pinger, invoked on the remote system:
while sleep 60; do echo 00 | unhex; done &
(where unhex is a little hex-to-binary filter that's been sitting in my personal bin directory since 1981 or so). This sends an invisible null character down the line once a minute, and usually works to keep the connection from timing out. (And even if I did know the magic sshd option to keep sessions from timing out, but the relevant machine wasn't under my control, I might still choose to use this user-level workaround.) —Steve Summit (talk) 13:17, 3 October 2015 (UTC)

Mass rename / format files[edit]

Somehow, I've managed to remove the name and extension of over 400 photos and video files. So I'm stuck with files name 1,2,3 without the corresponding prefix to denote what type of file they actually are. Is there some way I can undo this or set them back up.

Trouble is, I can't really determine which files are videos or just pictures. -- (talk) 15:16, 2 October 2015 (UTC)

Yikes! Realistically, it is probably faster for you to use a batch renaming tool to fix the bulk of the file names and extensions; then manually sort these files and rename the rest one-by-one, using guess-and-check to fix any incorrect file extensions. If you're really proficient, tools like file (command) can make educated guesses about file types... a script can wrap that command and automate your work... but I'd bet you'll spend more time learning to use it efficiently than manually modifying 400 files. If this is a problem that you never expect to need to solve again, the slow and arduous process of hand-correcting each file might really be the fastest way out.
If you are on Windows (... I make this presumption based on the new filenames you accidentally created!)... you might find the software mp3tag useful. Canonically, it is designed for batch modification and renaming of music files, but if I recall correctly, it will happily rename any other file type. It has a "regular expression"-style, wildcard-substitution file naming utility that will be more familiar to Windows users than many of the more general purpose, Unix-esque batch file manager softwares.
Nimur (talk) 17:07, 2 October 2015 (UTC)
I suppose you did not wanted to say prefix, but suffix, in reference to the file extension. Scicurious (talk) 18:56, 2 October 2015 (UTC)

Batch renaming is the easy part. Figuring out which are which is more challenging. Taking the harder part first:

The simplest solution that might work, depending on your OS settings and the original filetypes, would be to rename all of the files to be images (e.g. .jpg) then load thumbnails in your file explorer/viewer. If you're lucky, the ones that aren't images won't display properly. If they all display, try the same technique but with a video extension. If that works, skip the next paragraph.

If that didn't work, sort the files by size. This will cut down on some of the guesswork. If they were all taken with the same camera with the same settings, the size of the images will be relatively similar. In some cases, they'll might even be the same. Video files won't be so consistent, so look for patterns, moving those that look like video files out to a separate directory. You'll have to do some trial and error for videos that are about the size of images.

The renaming part. Operating under the assumption of Windows, open the directory with your presumed images. Holding CTRL-SHIFT, right click in an open part of the directory (i.e. don't click on a file) and select "Open command window here". In the console, you want the "rename" command. So if all of your files have no extension and you want them all to be .jpg, just type "rename *. *.jpg" (without quotes). If they're all jpg and you want them to be .mov, you would do "rename *.jpg *.mov". Good luck! — Rhododendrites talk \\ 22:00, 2 October 2015 (UTC)

October 3[edit]

OGG recorder[edit]

Which free (gratuit preferably libre) software enables you to make OGG recordings on Windows 7?—Eat me, I'm an azuki (talk · contribs · email) 12:21, 3 October 2015 (UTC)

Audacity would likely be a good choice for you.--Phil Holmes (talk) 12:53, 3 October 2015 (UTC)

Wikipedia tense[edit]

Please consider this example snippet from our article on Russ Jackson which I refer to in support of my broader question:

"Jackson is an Officer of the Order of Canada[8] and was awarded an honorary doctoral degree in law by McMaster University in 1989. He will be added to Canada's Walk of Fame in 2012.[9]"

Nobody has changed "will be" to "was" in these three years (and I don't know if the investiture happened - that would take human research). Should Wikipedia implement an automatic way of flagging instances like this, triggered by a parse of the grammar, prompting an update such as "[please update]" like the useful ones we have for "[citation needed]" and "[by whom?]"? Hayttom (talk) 16:21, 3 October 2015 (UTC)

I've updated that particular instance. In fact, it was original research, predicting the future, so should never have been added with that exact phrasing. It would be interesting to know if anyone can write a script to find such predictions, and the more general sentences that need updating. We have some bot experts ... Dbfirs 16:51, 3 October 2015 (UTC)
Please read the original edit adding this fact before throwing around phrases like "original research, predicting the future". A "prediction" in the form of an announcement from the Walk of Fame organizers seems like a reasonably reliable source to me. It might have been more exact to say "is to be" instead of "will be", but that's a minor point. -- (talk) 20:39, 3 October 2015 (UTC)
Yes, that's the point I was making. The original edit should have been "It was announced that ...". Dbfirs 20:42, 3 October 2015 (UTC)
Oh how thoroughly I hate the "on such-and-such-date it was announced that" sentence structure. I have seen articles with entire paragraphs made up of announce porn. Nobody cares when Mr. Passive announced something. Announcements are a clumsy sentence structure carrying non-notable and irrelevant information. (talk) 02:08, 4 October 2015 (UTC)
Yes, I agree that it's probably better not to put it in Wikipedia at all until it happens, then there is no problem with tenses and updates, but people like to be first to add details of future events to articles, so we are unlikely to prevent the recording of announcements. Dbfirs 09:25, 4 October 2015 (UTC)
That bot thing sounds like the kind of thing I was imagining. I presume that's how peoples' ages get updated.Hayttom (talk) 04:29, 4 October 2015 (UTC)
  • For ages there's a smart template that subtracts birthdate from today. —Tamfang (talk) 06:31, 4 October 2015 (UTC)

@Hayttom and Dbfirs:that bot requires strong AI.

Bookmarklet to insert preset text into browser text box[edit]

How could I create a Bookmarklet (in Chrome, but I imagine it would work elsewhere) that, upon clicking, would copy a particular block of text into whatever text box were selected? As an example I'm thinking about the Cluebot autoarchiving text one adds to a talk page to start auto-archiving. It's not exactly something to memorize and a bit of a hassle to look up every time -- but it's not really any more convenient to load up a text file or something, either. I'd like to be able to click in a particular spot and paste away from my browser (or, perhaps, click the bookmarklet and then specify where, if that's required). If cursor position is impossible because of the need to click the bookmarklet, maybe just insert it at the top of the text box? This may be better for Wikipedia:Village pump (technical), but the answer most likely does not require specificity to Wikipedia. — Rhododendrites talk \\ 16:54, 3 October 2015 (UTC)

Have you tried saving a text file with the text you want, then cutting and pasting from there to wherever you need it ? I've done this before. StuRat (talk) 19:56, 3 October 2015 (UTC)
Indeed. That's one of the approaches I mentioned above that I'm trying to improve upon. — Rhododendrites talk \\ 22:28, 3 October 2015 (UTC)

Take a look at [4]. It looks like it can create exactly what you want. --jpgordon::==( o ) 21:30, 3 October 2015 (UTC)

I did find that. It generated a long line of JS that, given my relatively poor knowledge of the language, isn't easily readable. When I searched for any mention of that site elsewhere, I found nothing, which did not fill me with confidence. I suppose I could use it as a starting point and figure out what it's actually doing along the way... — Rhododendrites talk \\ 22:28, 3 October 2015 (UTC)
Here's a tool to make it easier to figure out. Create the bookmarklet using that .ru page, then drag the link it generates to Hit control-enter and *poof* a nicely beautified readable version of the bookmarklet. The name and ID versions are very simple:
javascript: void(function(id, text) {
    document.getElementById(decodeURI(id)).value = 
         decodeURI(text) + document.getElementById(decodeURI(id)).value;
}('foo', 'bar'))
The clicking one has considerably more parts, of course. --jpgordon::==( o ) 05:02, 4 October 2015 (UTC)
@Jpgordon: Very nice. Thanks! — Rhododendrites talk \\ 14:26, 4 October 2015 (UTC)

Dell Latitude E5450[edit]

I recently started a new job and they supplied me with a Dell Latitude E5450. It has 8GB of memory. I'd like to find out if it can take 16GB. I found this spec sheet which says that models manufactured after Jan. 2015 can use 16GB. How do I find out if my laptop was manufactured after January? And most importantly if it can accommodate 16GB? Thanks, Dismas|(talk) 19:41, 3 October 2015 (UTC)

You might try running the download from, which is designed to give you info like that. StuRat (talk) 19:54, 3 October 2015 (UTC)
I had completely forgotten about Crucial! Thanks, Dismas|(talk) 03:07, 4 October 2015 (UTC)

Google line chart variable Y max value[edit]

I have a lot of line charts on a website using Google's charts. Foe a few charts, I have between 3 and 6 columns of data. I don't want to see the first column. I want that to be the maximum Y value for that row of data. To make sense of this request... I have sales. I have a total sale quantity in the first column. I have categorized SOME of the sales in the other columns. So, the sum of the other columns is always less than the first column. I want to see a line chart where I see all by the total sales column as a percent of the total sales column. Right now, I think that I have to create a new data set with the percent of total for each category and graph that. I would prefer if there was some way to simply provide the API with one column of values as the total value and the others will automatically be shows as a percent of total. (talk) 21:50, 3 October 2015 (UTC)

October 4[edit]

system font del Capitán[edit]

I just noticed that in OS X El Capitan the system font is no longer Helvetica. Anyone know what it is? —Tamfang (talk) 06:29, 4 October 2015 (UTC)

Wikipedia:WHAAOE: San Francisco (2014 typeface) 731Butai (talk) 08:18, 4 October 2015 (UTC)

Grover's Algorithm[edit]

In the atricle about Grover's algorithm in the second (and last) figure : why after performing  U_\omega on  |s\rangle, the result is not at the left of  |\omega\rangle as for a reflection around  |\omega\rangle ? (talk) 09:40, 4 October 2015 (UTC)

Trace route[edit]

when u do a trace route u see many different companies in the hops. can they see your internet traffic? (talk) 10:53, 4 October 2015 (UTC)

Yes, that's how the internet works. Usually the traffic goes from your ISP to their upstream provider, often to a national provider, through a Internet exchange point, over an international connection, through another IXP, and back through another chain of suppliers. Yes, they can all see your traffic, and so can governments which force them to provide the government with a copy of the traffic. That's why encryption on the internet is so important. (talk) 12:41, 4 October 2015 (UTC)

Finding Unitary transformation[edit]

I am looking for some Unitary transformation that satisfies  T(\alpha|0xz\rangle + \beta|1yz\rangle) = |1yz'\rangle where  |x\rangle, |y\rangle \in \{|0\rangle,|1\rangle\}, |z\rangle =|000...\rangle ,\alpha^2+\beta^2 = 1 (|z\rangle is actually grabage for storing another data, if needed), and I can't find one... (talk) 13:16, 4 October 2015 (UTC)

Searching for terms and specifics on FB groups[edit]

Some of the FB groups I'm a member of have huge amount of posts daily. However, a lot of it is reposts and rubbish that I'm not interested in.

Is there any way to search for what I want based on terms, as occasionally buried beneath the clutter there are some gems.

From what I can tell, the way the group works is as you scroll down it loads additional portions of content. So just using the search facility in my browser seems to be inadequate without having to spend a lot of time scrolling down, waiting for sections to load which again isn't very efficient. — Preceding unsigned comment added by (talk) 16:38, 4 October 2015 (UTC)

Semi-transparent window in legacy RHEL/CentOS?[edit]

Is there any evidence that the X server in CentOS 4 (or Red Hat Enterprise Linux 4) really supports compositing? After I added the following settings to /etc/X11/xorg.conf:

Section "Extensions"
        Option          "Composite"     "Enable"

I noticed that the composite extension appears in the output of xdpyinfo:

[root@localhost tmp]# xdpyinfo
    .            .
    .            .
    .            .
number of extensions:    31
    .            .
    .            .
    .            .

We want to adjust the window opacity on-the-fly in our Qt application. It seems that enabling compositing is the way to go (otherwise we may need to emulate the transparency effect by contents propagation). But weird artifacts appears after composite extension is turned on. Is it because xdpyinfo reports incorrectly or something?

Version info. in the system:

CentOS: 4.8
Xorg: 6.8.2
metacity window manager: 2.8.6

Migrating to newer CentOS version should resolve the problem, but our application is too complicated to do the migration easily in short time. - Justin545 (talk) 17:17, 4 October 2015 (UTC)

nul device that remembers[edit]

Is there a feature like the ">nul" device that writes data to a non-existent place, except instead of discarding the data immediately it keeps say 10 items in RAM and removes the 10th item every time a new item is written to it. The 10 items can be accessed like normal files. The number 10 is an arbitrary number, it could be 1 or 1000000 doesn't matter. Thanks for your help. — Preceding unsigned comment added by (talk) 20:45, 4 October 2015 (UTC)

Somewhat similar in concept, in Unix there is a /tmp directory where temporary data was written, and a daemon was run each night to erase it all (where I used to work). StuRat (talk) 21:07, 4 October 2015 (UTC)