Wikipedia:Reference desk/Archives/Computing/2015 August 23

= August 23 =

What is it called?
Is there a name for a real-time system with several independent components where the objects operate entirely independently? An example would be a bank of elevators. --Halcatalyst (talk) 15:15, 23 August 2015 (UTC)
 * Perhaps a JBOD (Just A Bunch of Disks) is what you are looking for? This architecture has multiple independent hard drives that can be accessed independently from one another.  If this is not what you are looking for could you provide a little bit more context to your question?  Thanks! --Stabila711 (talk) 15:45, 23 August 2015 (UTC)
 * I think op looks for a more general term for a group of (similar) embedded systems which operate independently. And I guess it depends on the actual context... as example "array" for "multiple individual components to create a single system". In another context like the upcoming self-driving cars (or industrial manufacturing robots etc.) one would probably refer to it as a "fleet" instead due to the implied mobility. Then there's "cluster" for computing, but the computers don't really "operate entirely independently" there. Rh73 (talk) 16:02, 23 August 2015 (UTC)
 * Maybe I made it sound like too much of a technical question. The example is the key: I'm thinking of what is running rather than what makes it run. What makes it run (the software, with all its levels) results in a working system in which the components do the same sorts of things over period of time, but otherwise they are unrelated to one another. Probably I used the word "real-time" wrong. I heard somebody long ago refer to something similar as a "state system." The elevators are in different states (at different floors, going up or down, etc.) But a professor of computer science I asked had never heard the term. --Halcatalyst (talk) 16:39, 23 August 2015 (UTC)
 * "Real-time" is alright. While the article real-time computing focusses on the computing aspects it's common to refer to motor/brake control systems in elevators and other machinery as real-time as well (at least here in Germany). And you probably mean State machine... the execution logic behind elevator controls is a classic example for FSMs and like the first or second thing taught in programming, so it's strange your prof didn't make the connection :) Rh73 (talk) 17:13, 23 August 2015 (UTC)
 * Thanks, that's it! --Halcatalyst (talk) 21:26, 23 August 2015 (UTC)
 * The state machine – A virtual camshaft built with software. -- Hans Haase (有问题吗) 15:34, 24 August 2015 (UTC)
 * I don't think that is it. State machines can be either completely independent and run asynchronously or, as in the GPU's within graphics chip, be either completely synchronous or grouped together into synchronous clusters where the clusters are asychronous with each other.  I think the key here is whether these identical systems are running synchronously or asynchronously.  I think your question relates more closely to ideas like SIMD, MIMD, etc.  In a bank of elevator controllers, they are all running the exact same program - but they each have different data (the buttons people are pressing in the elevator) and they are all in different states for much of the time (door-opening, door-closing, moving upwards, moving downwards, etc) - this is a classic "MIMD" (multiple instruction stream, multiple data stream) setup.  But in the GPU of a SIMD graphics chip (Single instruction stream, multiple data streams), the individual fragment processors are all running the same instruction from the same program in perfect lock-step - albeit with different data relating to the pixel on the screen that they are each working on.  Then there is the possibility of having a bunch of computers in a server farm, where they may all be running entirely different programs, and I suppose one could imagine systems where different programs operated on the same data - but in different ways (MISD maybe).  We'd see that (for example) in a hurricane prediction system, where several programs, each based on different mathematical models of the atmosphere - are fed the same stream of realtime satellite data in an effort to gain a consensus result from several less-than-perfect mathematical models.  The space shuttle used the concept of having multiple computers run the exact same software on the exact same data which then 'voted' on the correct course of action so that a glitch in one computer would not cause the entire launch to fail. SteveBaker (talk) 15:39, 24 August 2015 (UTC)

Verifying the Ashley Madison data
Wikipedia policy is not likely to allow us to link to the Ashley Madison leak data. However, it is desirable for us to come up with a way to verify for the future which version of the data is authentic, i.e. to have a reliably sourced record of the Impact Team public key. I was trying to deduce this back from a news source that published a signed message at Talk:Ashley Madison... but I could use some help here. Wnt (talk) 19:23, 23 August 2015 (UTC)


 * Ashley Madison allows anyone to register any name with zero verification (not even the usual conformation email) then charges money to delete accounts. This makes the alleged list of users completely unreliable. I don't see any point in differentiating the cryptographically signed Impact Team data dump from any other, possibly-modified data dump. Both have the exact same reliability: zero. --Guy Macon (talk) 15:51, 24 August 2015 (UTC)


 * I'm not sure I agree. One is an authentic dump from a major hack, notable in its own right. The other would be a forgery. 74.113.53.42 (talk) 22:14, 24 August 2015 (UTC)
 * Right, this is perhaps the distinction between WP:RS and WP:Verifiability. With crypto-signed data dump, we can at least verify that the data is consistent with a certain published set. The source can be reliable at reporting something ("This is the data we collected"), even if the details of what they are reporting make the data set itself unreliable for the reasons Guy discusses above (e.g. this email occurring on this list does not imply a specific person used a specific service). SemanticMantis (talk) 22:32, 24 August 2015 (UTC)
 * It's perhaps also worth remembering that there are multiple levels of data from the hack. For example, there are the CEOs emails. Then there is the credit card transaction data (which could be compared to banks records). Even within the user information data, there's an obvious difference between an email which doesn't even exist attached to the name of a famous person, and some random person no one has ever heard of with a real email, name, birth date and whatever else all matching being found in the released data set. While it's impossible to know if the Impact Team has tampered with any of the data, and there could in some scenarios be reasons someone else made a fake profile with all the real data or even misused a credit card, what's there may be in some cases something a person would consider sufficiently suspicious to have a serious talk with their partner. And if it comes to a court case, showing that the data was that released by the Impact Team would probably be useful. Nil Einne (talk) 14:29, 25 August 2015 (UTC)

Can School WiFi block VPNs?
I am living on campus in a US university and using the school's WiFi system. I apologize, but I have only an elementary understanding of how VPNs work. I am looking to play Xbox Live games and PC games online, but am having trouble connecting to online servers.

On the Xbox, I have a "Strict NAT" setting and can play certain games without problems, while other games I have a hard time connecting to certain servers. While on the PC, I am unable to play Battlefield 4 or RuneScape.

I tried downloading a VPN to see if I can play online games through the VPN, but the 3 VPNs that I've tried all have been unable to connect to their VPN servers.

Does this mean that the school is blocking access to the VPNs?

Would trying other VPN services be fruitful? Or is there likely a "blanket ban" on all VPNs?

Does anyone have any other suggestions as to how I can play online games on the Wifi?

Thanks. Acceptable (talk) 23:56, 23 August 2015 (UTC)
 * It is likely that your university has blocked the ports used for VPN. It is unlikely that any VPN will work if the ports are blocked.  My university did the same thing and banned all online console gaming from their network as it slows down the network for people using it for educational purposes. --Stabila711 (talk) 00:03, 24 August 2015 (UTC)
 * Ultimately this is a question for your service provider. If you aren't supposed to be playing games on the service, then you shouldn't be trying to bypass the security which is in place. But if that's where you actually live, are you not allowed to use it for some personal use? That seems pretty harsh in this day and age. Online gaming doesn't actually use that much bandwidth, certainly not much as watching youtube videos. Vespine (talk) 06:23, 24 August 2015 (UTC)
 * It is actually pretty common for universities around mine to block online console gaming. They also throttled youtube down to an unbearable level during "peak hours."  It might not take up a lot of bandwidth individually but multiple that tiny amount thousands of times and it can become a massive problem.  Since the university owns the network and provides the service they can limit it however they want.  They probably block the consoles by looking at the host data that is naturally sent with each Internet packet request.  When it sees a gaming console identifier it blocks the request. --Stabila711 (talk) 06:43, 24 August 2015 (UTC)


 * Change the port of Your VPN server, if You are the administrator. If the VPN was not blocked intensionally, the MTU of the affected network adapters needs to be increased. -- Hans Haase (有问题吗) 15:31, 24 August 2015 (UTC)
 * ( FYI - "Intentional" and "Intensional" are very different things in English :) SemanticMantis (talk) 22:27, 24 August 2015 (UTC)
 * We recently had a question about VPNs in China here. While it's unlikely any school or university in the Western world employs such advanced techniques as the Great Firewall, the article linked by BenRG in reply to that question gives some tips that will be applicable to your situation as well. In short: there is virtually nothing your university can do to stop you from accessing a VPN without otherwise crippling your internet access (though the overhead may simply be too large to allow gaming); there's a wide array of tricks you can employ to obfuscate a VPN connection. The most effective thing your university could do is to simply make the use of a VPN against their terms of service; that would allow them to just cut you off from their network entirely or even expel you if they catch you using a VPN anyway. -- Link (t&bull;c&bull;m) 11:41, 25 August 2015 (UTC)

Upgrade vs Clean Install to Win10
I recently purchased a dell XPS laptop that shipped with Win8.1. When I turned on the laptop, the first thing I did was to download and install Win10. I did not change any setting or download anything prior to the installation of Win10.

I recently found out that this is considered an "upgrade" whereas a clean install would require me to use something like Windows Media Creator Tool to boot off a USB/hard drive and re-install Win10.

So far, Win10 has been working well for me. Is it worth to re-install Win10 cleanly? Will I see battery or performance benefits? I plan on using the laptop for gaming. Thanks. Acceptable (talk) 23:59, 23 August 2015 (UTC)
 * As long as you do it right, a clean install wouldn't hurt. However, in this instance I doubt it would help much either.  Upgrades really only present a problem if you have a lot of programs or drivers that may have compatibility issues.  Since you upgraded right away those issues are moot.  As for the performance issues, I wasn't able to find specific benchmarks for windows 8.1 upgrade to 10 vs. clean install to 10.  However, I did find one regarding XP to Vista (here) and their tests showed that it didn't make a significant difference either way.  I will keep looking for more recent benchmarks but in the meantime I wanted to post what I found. --Stabila711 (talk) 00:18, 24 August 2015 (UTC)


 * As long as it is working right, I wouldn't do a clean install. The problem with doing a clean install is that you have to reinstall practically everything.  That means tracking down installation CDs or finding the original download.  Then finding registration codes, getting the updates, and setting your your settings.  It generally takes me about 2 weeks working a xcouple of  hours a day to get a new computer or a clean install working like I want it.  I had problems with a Win10 upgrade (it could no longer get to the network.) I tried everything I could think of, to the point of trying a USB wireless and a USB-to-ethernet cable adapter.  Nothing worked.  I took it to a repair shop and they couldn't figure it out either.  It looked like I was to the point of rolling back to Win 8.1, which they said would mean reinstalling everything, or buying a new computer.  If I have to reinstall everything, I might as well buy a new computer with Win10 on it, which is what I did.  I've had it 5+ days and I'm still quite a way from getting it like I want it.  Bubba73 You talkin' to me? 04:15, 25 August 2015 (UTC)
 * This sounds like a driver issue. As stated before upgrades have a known issue when drivers are involved.  You could have used a computer that could connect, go to the website for you computer, download the Ethernet driver, put it on a flash drive, and import it to the one that wasn't working (not that that matters anymore since you got a new one).  Also, you may want to look for a new place to bring your computer for troubleshooting.  The first thing they should have done was try to reinstall the driver.  --Stabila711 (talk) 04:21, 25 August 2015 (UTC)


 * They are about the only place in town. I thought of the driver - I told it to update the driver but it said that I had the best one.  I uninstalled the ethernet adapter in device manager and rebooted to Win10 would see it. It did and said that it was functioning normally.  And for about 8-10 hours after I went to Win10 - no such problem.  Then Win came up and said that the network adapter was disabled.  I checked that it was enabled.  Also, rebooting fixed the problem.  I think it happened twice that first day, starting after several hours.  Then the next day it started happening more and more frequently - about 10-12 times.  Finally it happened just a couple of minutes after rebooting, and then rebooting would no longer fix it.  (nor would full shutdowns or unplugging the power.)  Bubba73 You talkin' to me? 05:11, 25 August 2015 (UTC)


 * (OR ahead) I had some issues with the wireless adapter after upgrading to Win10, but only when I was running the laptop on battery. Turns out there was a setting to let the system turn off the adapter to save power when the laptop was not plugged in, which is a pretty freaking stupid setting for a wifi device on a laptop, but anyway... I don't recall if that was in the settings for the wireless or the settings for power modes, and I'm not near that laptop now, but it's something you can check. -- LarryMac  | Talk  13:56, 25 August 2015 (UTC)


 * And I think there must be a whole lot of junk on the old one. On both computers I basically have the C drive for Windows and installed programs.  On the old one it occupies 408MB but only 101MB on the new one. I don't have everything installed on the new one yet, but there certainly isn't 300+ MB more.Bubba73 You talkin' to me? 05:19, 25 August 2015 (UTC)