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July 7

"Hashtag" usage

Sometimes e.g. on the BBC they say to contact them using a hashtag, e.g. "#BBCSport". I don't understand. Is this just to do with Twitter? I never use Twitter, and I don't understand much about it, but I thought "hashtags" were for flagging content. How can you "contact" someone using that mechanism? I thought Twitter contact addresses started with "@", no? 109.153.245.89 (talk) 01:01, 7 July 2015 (UTC)

The hashtag was brought to many people's attention via Twitter, yes. Though it is possible to use hashtags on Facebook too. And, though I don't have accounts on other social media, I assume sites like Instagram have the same functionality.

You can use '@' and '#' both on Twitter but there is a, sometimes subtle, difference between the two. In order to use '@', there must be an account with the name that follows the @. So, while there is an account called BBC which is maintained by the BBC and you can use the @ symbol to talk to them, there is no account called BBCGreatFridays. (I made that up as an example of a hypothetical promotion they may put on to talk about interesting things to do on the weekend.) They don't want to make up thousands of accounts, one each for every promotion they have going, so they might ask people to tag interesting doings on the weekends with '#BBCGreatFridays'.

Then when someone searches for the hashtag, they find everyone's postings about that subject.

By tagging things with @, the owner of the account gets a notification that someone said something to them. No notification is sent to anyone simply because someone used a #. So, to (finally) answer your question, you aren't really "contacting" the BBC by using a hashtag but you both know to use that tag and realize that someone at the BBC will be looking for it.

And finally, anyone can make up and start using any hashtag they want. So, if I wanted to start a hashtag for my local library's book drive, I could and there wouldn't be any need to create anything other than my own account to start using it. Then I could tell other people in my neighborhood to start using the hashtag. And people, again, could search for it.

That clearer? Dismas|^(talk) 02:06, 7 July 2015 (UTC)

How do you ensure that a hashtag is unique ? In your example, couldn't TGI Fridays have also said "If you think our Barbeque Chicken is great, use hashtag BBCGreatFridays !" StuRat (talk) 02:44, 7 July 2015 (UTC)

Short answer is that you can't. Just this past week I heard of some movement in the Middle East using some hashtag that fit what they were doing but I would have been absolutely gobsmacked if it hadn't been used by someone else before. I can't recall what it was right now though. Dismas|^(talk) 02:56, 7 July 2015 (UTC)

Also, there have been a number of times where a company or person has tried to promote themselves with a hashtag and people have used it for... alternate... purposes. link. Dismas|^(talk) 03:04, 7 July 2015 (UTC)

Thanks Dismas for the very helpful answer. 109.153.245.89 (talk) 03:11, 7 July 2015 (UTC)

All the cool kids call the symbol octothorpe, as its creators intended ;) SemanticMantis (talk) 15:03, 7 July 2015 (UTC)

• There's an argument for deference to Bell Labs in the context of American telephones, but they didn't invent the character and the Interwebs are not telephones. —Tamfang (talk) 08:54, 10 July 2015 (UTC)

Is ALGOL dead?

The article about ALGOL is not quite explicit about this. Is it dead? The last implementation of it appears to be S-algol (1979), but the article says "ALGOL is" not "ALGOL was". Is C a kind of evolution of ALGOL? Or is another language a modern ALGOL? --Yppieyei (talk) 01:22, 7 July 2015 (UTC)

Simula is a somewhat more modern ALGOL, One could argue that BETA (programming language) is the successor to Simula.

Lots of interesting info here:[1] --Guy Macon (talk) 10:29, 7 July 2015 (UTC)

• Old programming languages never die, they just fade away. There is always some legacy code out there that needs to be maintained. Looie496 (talk) 12:05, 7 July 2015 (UTC)

I do not dispute that there must be some ALGOL program being maintained by a geek somewhere. Apparently Burroughs large systems are an example of it. I am not sure someone still uses them. One day it becomes easier to implement a new system than to maintain an old one. I suppose no one uses BASIC as an entry language anymore, so, it is somehow dead now. Unless you consider it lives through its descendant Visual Basic .NET. Other big languages that flourished at the same time - LISP, COBOL, FORTRAN - seem to be more alive as such that ALGOL or BASIC. --Yppieyei (talk) 17:53, 8 July 2015 (UTC)

ALGOL is effectively dead, yes. As far as "modern ALGOL" goes, ALGOL is one of the most influential programming languages ever; pretty much every younger language takes at least some influence from it. As our article describes, ALGOL pioneered things such as the idea of separating code into blocks, and lexical scoping, as well as the Backus–Naur Form for formal descriptions of language grammars. In some sense you could consider any language incorporating any of those concepts to be a descendent of ALGOL. C is even closer to ALGOL than many other languages, being a member of the imperative language family, which is almost entirely patterned after ALGOL in terms of syntax and control flow; indeed, these languages are sometimes called "ALGOL-like", mostly in the '70s and '80s when use of ALGOL itself was still fairly common.

Classifying a language as "dead" is always going to be a matter of some debate. As you note, there's still a good amount of legacy ALGOL code being used, mostly on mainframes. COBOL is an even bigger example of a language that's widely considered "dead", but with lots of code still in widespread use. The world financial system runs on COBOL to this day. There was even a new COBOL standard released just last year! The consensus definition of a "dead" language seems to be one that is no longer being used for new large-scale software systems. There are plenty of people still programming in COBOL, and there's always some people interested in retrocomputing, but no one today is seriously considering building complex software from scratch in the language. Comparison with natural languages is useful; Latin and Classical Chinese are universally considered dead languages, yet people today still learn and even use them. The difference is that no one learns them as a native language.

Lisp and BASIC, two of the languages you mentioned, are kind of different, since today they are properly language families rather than single languages. No one is using the original Lisp 1 that John McCarthy created, or the original Dartmouth BASIC; they're using descendent languages like Visual Basic or Common Lisp and Scheme. To illustrate the contrast, C has its own descendent languages, most notably C++ and Objective C, but C itself is still enormously popular. --108.38.204.15 (talk) 22:20, 8 July 2015 (UTC)

Blurred bands on sides of photos or video

I'll often see banding on the side of images or video when they are posted to various news sites. I'm sure other sites do it as well but I see it most often on news sites. It is often used when someone has taken a photo with a cell phone in portrait mode and the space the site has for the photo is wider than the photo. So they will blur the sides where the empty space is. You can see an example here. What is the name for that? Thanks, Dismas|^(talk) 03:50, 7 July 2015 (UTC)

The term "blurred pillarbox" seems to attract the most relevant Google hits [2], but I have not found anything that indicates that this is an industry standard term. -- Tom N talk/contrib 05:50, 7 July 2015 (UTC)

Computer science and Axiom of infinity.

Our article Axiom of infinity asserts: "In...the branches of...computer science that use it, the axiom of infinity is..." etc.

I wonder, how and where - the axiom of infinity must be used by Computer science. Isn't Computer science consistent with the finitistic philosophy? HOOTmag (talk) 08:35, 7 July 2015 (UTC)

No. Computer science has nothing to do with finitism, which is a branch of mathematical philosophy. You can program computers to do all sorts of math -- no fractions and a finite number of bits are very common variations. Most PCs support IEEE floating point math, which does have the concept of infinity. --Guy Macon (talk) 10:12, 7 July 2015 (UTC)

Ok, I see I was not clear enough in the last question of my previous post, so I've just changed it.

However, I still wonder - how and where - the axiom of infinity must be used by Computer science.

Regarding IEEE floating point (which I think has nothing to do with infiniteness): AFAIK, every program using the floating point, has an upper bound for the number of digits of any integer (and of any real number), so that no program has to presuppose the infiniteness of natural numbers, hence doesn't need the axiom of infinity, does it? HOOTmag (talk) 10:27, 7 July 2015 (UTC)

I can't see how the axiom could come into play at a practical level. At a theoretical level it does, though. For example Alan Turing proved that there is no general solution to the Halting problem, but the proof clearly depends on the existence of an infinite number of natural numbers. Looie496 (talk) 12:01, 7 July 2015 (UTC)

The trivial fact (presupposed by Turing) that no maximal finite number exists, doesn't imply that there does exist - an infinite number - or an infinite set of finite numbers (as claimed by the axiom of infinity). HOOTmag (talk) 12:27, 7 July 2015 (UTC)

I agree with Looie - My understanding is that it doesn't come up much at all in software development or other applied computer techniques - or at least it doesn't really matter if there is or isn't an infinite set. For another example - Computability_theory is almost exclusively interested in functions on the natural numbers, and hence deals with an infinite set. There is also much more to the halting problem than the lack of a largest finite number. From the article "The difficulty in the halting problem lies in the requirement that the decision procedure must work for all programs and inputs" - hence the very framing of the problem depends on infinite sets existing, not to mention the proof techniques. SemanticMantis (talk) 14:56, 7 July 2015 (UTC)

Regarding Computability theory: yes, but I suspect it's a branch of mathematics rather than of Computer science, although the concept of Turing machine plays a significant role in this mathematical branch.

Regarding the sentence you've quoted from the article "halting problem": It only assumes that no finite set contains all programs (or all inputs), but this doesn't imply that there does exit an infinite set containing all programs (or all inputs). HOOTmag (talk) 16:33, 7 July 2015 (UTC)

To the last bit - No? How do you figure? If no finite set contains all inputs, then all inputs must form an infinite set. Or are you thinking about category theory and thinking such a collection may fail to be a set? Or maybe you're getting philosophical, and just want to deny that a statement like "all inputs" has any rigorous meaning? Anyway, the distinction between math, applied math, mathematical logic and theoretical computer science is a bit blurry, and often has more to do with convention and history than any real difference in methods. You may find computability theory occasionally covered in a "topics in X" type course in a math program, but computer science is where computability is typically covered. My WP:OR experience is that computer science as a research topic in academia almost always implicitly allows for the conceptual existence of infinite sets, just like almost all areas of math do. But for fairly obvious reasons, it's hard to find a WP:RS that says "The theory of computer science generally allows for the conceptual existence of infinite sets" - even relatively few mathematicians dwell that much on the axioms unless they are doing a type of research that is focused on certain axioms. For examples of the ubiquity of AOI in CS, here's some course notes where they introduce induction for the purpose of proving things in computer science [3]. And you certainly cannot use induction as a system for valid inference if you aren't allowing for the natural numbers to exist. Really, anything that ever acknowledges existence of the natural numbers must then also allow for infinite sets. Additionally, here are some computer science textbooks that use and explain AOI for computer scientists [4] [5] [6]. Generally, AOI "must" be used in CS in exactly the same places where it "must" be used in math or logic. While the day-to-day practice of writing software doesn't often need to invoke AOI, that's not what we usually mean by "computer science". Computer science uses infinite sets frequently. Though I can't cite a ref for that claim, hopefully the examples above are fairly persuasive evidence in support. SemanticMantis (talk) 17:28, 7 July 2015 (UTC)

1. "If no finite set contains all inputs, then all inputs must form an infinite set". Your assertion presupposes AOI, which cannot be logically proved. Notice that if - AOI had been wrong - so that no infinite object (set / collection / class / whatever) had existed, then the correct fact indicated by you - that "no finite set contains all inputs (integers / objects / whatever)" - wouldn't have implied your pseudo-conclusion that "all inputs (integers / objects / whatever) must form an infinite set (collection / class / object / whatever)".
2. "Or are you thinking about category theory and thinking such a collection may fail to be a set?". No. I'm thinking from an absolutely logical point of view. For this discusstion, it doesn't matter whether you name it a "set" or a "collection" or a "class" or whatever; The point is, that without assuming AOI in advance, you cannot conclude that there exist infinite objects (sets collections classes or whatever), even when you do know in advance - that for every finite number (and every finite input and likewise) there exists a larger finite number (and a larger finite input and likewise).
3. "I can't cite a ref for that claim, hopefully the examples above are fairly persuasive evidence in support". Thank you for the sources, but I still wonder whether CS must assume AOI. Take Turing machine as a simple example: its classic definition assumes, that every Turing machine has - an infinite storage tape - being an infinite object (of course). However, I wonder whether - this assumption contained in that classic definition - is really needed for reaching all the theorems we have already reached about Turing machines; Just try to think about that: What would have happened to those theorems, if we had only presupposed a more modest assumption which had assumed, that "for every Turing machine which uses a given finite storage tape - one can build another Turing machine which uses a longer finite storage tape"? Such a modest assumption, only assumes that no finite set (collection / class / object / whatever) contains - all Turing machines - or all finite lengths of storage tapes used by Turing machines, but this doesn't imply that there does exist an infinite set (collection / class / object / whatever) which contains - all Turing machines - or all finite lengths of storage tapes used by Turing machines; Yet, all the theorems about a Turing machine would have (probably?) been reached - even under the modest assumption mentioned above, wouldn't they?

HOOTmag (talk) 18:54, 7 July 2015 (UTC)

The last paragraph makes the most sense to me. Points 1/2 are confusing. Can you find examples of serious scholarly research that deals with arbitrarily large natural numbers but yet does not allow for the existence of natural numbers as an infinite set? I don't know how that's supposed to work, but maybe I'm just ignorant of some of the alternative finitism constructions. Even finitism says that classical finitsm allows countable infinities, and only rejects uncountable sets. That is a much more common distinction, but that's a whole different question. You seem to be talking about what the article calls "strict finitism."

Of course there are many results in CS that don't depend on AOI. I don't have time to do more research today, but I imagine there is research in CS much like the people in math who work with the axiom of countable choice (or various weaker versions), or use no axiom of choice at all. Much like you can do a lot of math without uncountable choice, you can probably prove a lot of CS results without AOI, and only allow arbitrarily large but finite sets. But since we don't actually compute on infinite sets, anyway, most CS researchers are happy to use infinite sets as a convenience for proving things. I think maybe a few of us got confused by the original wording - to me your point 3 is much clearer and would be a better way to start future discussion. I'd suggest trawling google scholar with searches like /[(strict) finitism], computability, ultrafinitism/ and see what you can find. This paper [7] and refs therein might be a good starting point. SemanticMantis (talk) 19:15, 7 July 2015 (UTC)

The original aim of AOI is to reject strict finitism (this is a well known fact in the philosophy of mathematics), whereas my original question has been about whether the current computer science can be consistent with strict finitism, i.e. without AOI.

As for the new source you've provided: thank you, I will have a look at it after I have my dinner... :) HOOTmag (talk) 19:25, 7 July 2015 (UTC)

This thread mentions that Peano arithmetic and (ZF − Inf) + ¬Inf are bi-interpretable. I know nothing about model theory but I think that means that anything provable in PA can't really be said to depend on Inf. -- BenRG (talk) 19:31, 7 July 2015 (UTC)

Correct. Axiom of infinity, is a huge step (of Set theory) - that goes far beyond Peano arithmetic (which only assumes that for every finite object there exists a larger finite object, without presupposing the existence of infinite objects). HOOTmag (talk) 19:36, 7 July 2015 (UTC)

Practical computer scientists don't spend a lot of time worrying about the precise axiom set used to prove a given result. They make free use of mathematics, and mathematics includes infinity. For any particular result, maybe you can reformulate it and rework the proof in such a way as not to rely on infinity. But so what? You don't gain anything; you just make life harder on yourself for no benefit. --Trovatore (talk) 04:27, 8 July 2015 (UTC)

Please have a look at the first sentence of this thread, just under the title. This is my point ! Whether the sentence I've quoted from our article is correct. HOOTmag (talk) 06:54, 8 July 2015 (UTC)

Well, exactly. The "branches ... that use it". Not that must use it. Just use it. You are unjustifiably conflating the two things, and this is your fundamental mistake. --Trovatore (talk) 07:41, 8 July 2015 (UTC)

I think you'd better interpreted "use it" as "must use it". Had one interpreted "use it" as "can use it without it being necessary", one could have added - to our article - lots of other branches that could have used it, e.g. Yoga exercises, tips for journeys to Antarctica, and the like. HOOTmag (talk) 08:36, 8 July 2015 (UTC)

To satisfy the Gricean maxim of relevance, it doesn't have to be necessary, but ideally it ought to help. I don't see any obvious way that knowing about the existence of completed infinite totalities helps you do yoga, though I certainly wouldn't exclude it. But having a mathematical framework that includes completed infinities is helpful in all sorts of situations even if they don't, at the end of the day, refer to completed infinities as their direct objects of discourse. --Trovatore (talk) 16:46, 8 July 2015 (UTC)

I removed computer science from the article, not on the grounds that it doesn't use Inf but just because once you start listing specific branches of mathematics (or fields that use mathematics) there's no end to it.

The original question was how much of computer science you can construct without depending on Inf. I know you (Trovatore) feel that these kinds of questions aren't interesting and people should just use the axioms that are true and not worry about subsets, but they are interesting to a lot of people including me and the OP. -- BenRG (talk) 22:45, 8 July 2015 (UTC)

Hmm? I never said they weren't interesting. I think they are interesting, but they're not really computer science. They're more like reverse mathematics. --Trovatore (talk) 23:02, 8 July 2015 (UTC)

command-line tools for matrix arithmetic?

Is anybody aware of a nice little collection of shell tools for manipulating matrices represented as text files? I'm thinking addition, multiplication, inverse, determinant, identity matrix creation, scaling and rotation if the matrix is a Rotation matrix, etc. I'll write my own if I have to, but it seems like the sort of things someone's probably written already. —Steve Summit (talk) 14:20, 7 July 2015 (UTC)

GNU Octave has an interactive command-line prompt. It can execute interactively, in a REPL-style environment; and it can run pre-written scripts or execute single commands and then terminate. It is an excellent tool for matrix math and linear algebra.

Here is Simple File I/O from the Octave documentation. You can load and save matrix data using plain-text files, or binary files. You may wish to use the "csvread" or "textread" style functions.

Nimur (talk) 14:25, 7 July 2015 (UTC)

You can use NumPy; here's a trivial example. If in.arr is

  1 3 5
  2 5 3
  0 2 -3

then this program will read that in as a matrix, transpose it, multiply the original by the transpose, and save the output to out.arr

#!/usr/bin/python2

import numpy

f = open("in.arr", "r")
m = numpy.matrix(numpy.loadtxt(f))
print "original:\n", m

tm = m.getT() # transpose
print "transposed:\n", tm

mult = m * tm
print "multiplied:\n", mult

numpy.savetxt("out.arr", mult)

-- Finlay McWalterᚠTalk 14:38, 7 July 2015 (UTC)

• These are both great solutions, but I read the question a little differently. I thought Steve meant to rule out loading up things like Octave or Python/NumPy... which aren't usually considered "shell tools" like grep et al. are. That said, I don't know of any sort of "native" Bash shell tools to do matrix manipulation, and I would use one of the options above. SemanticMantis (talk) 14:47, 7 July 2015 (UTC)

On the one hand, SemanticMantic is exactly right. But on the other hand, I was already thinking of using Mathematica or MathCAD (which I don't have a copy of), meaning that I should have been thinking about Octave or something. :-) —Steve Summit (talk) 15:01, 7 July 2015 (UTC)

A great accompaniment to to NumPy/SciPy/MatPlotLib is IPython (and particularly ipython-notebook) which gives an interactive Mathematica-like workbook environment - a (static) example is here; one need only run the ipython-notebook service on one's local machine and one can alter the various in [X] sections and re-run each individual calculation. -- Finlay McWalterᚠTalk 15:11, 7 July 2015 (UTC)

C# Command line options in Visual Studio 2010?

Hello everyone. How would I get the command line options for the csc compiler that Visual Studio uses to compile a a C# project? I can get the options for a C++ project by simply accessing the projects properites and clicking Linker tab and selecting the Command Line tab. This show me the command line options VS uses to compile the C++ project. What I want to know is how do I do this in a C# project? If this isn't possible, then how would I use the C# compiler(csc.exe) to compile a VS 2010 project? I think the input file would be the Program.cs right? —SGA314 I am not available on weekends (talk) 19:31, 7 July 2015 (UTC)

This is the relevant page from the Microsoft website. Tevildo (talk) 22:29, 7 July 2015 (UTC)

I can't go to external links. My ISP has most links blocked. —SGA314 I am not available on weekends (talk) 14:27, 8 July 2015 (UTC)

You can't get to microsoft.com? Okay.... In Visual Studio, Help > Index > command-line building. Tevildo (talk) 23:13, 8 July 2015 (UTC)

Um, where would the VS help file(chm or hlp) be stored at? For some reason, VS won't open up the help file. I go to the Help menu and click View Help but nothing happens. I think VS is supposed to startup a server that lets my browser browse the help pages. So where are the help pages? —SGA314 I am not available on weekends (talk) 13:39, 9 July 2015 (UTC)

The actual help files, in Microsoft Help Viewer format, should be in C:\ProgramData\Microsoft\HelpLibrary2. Tevildo (talk) 19:20, 9 July 2015 (UTC)

I don't have the C:\ProgramData\Microsoft\HelpLibrary2 but I do have the C:\ProgramData\Microsoft\HelpLibrary. The directory contains various folders that have *.mshi, *.mshc, and .*metadata files. I believe VS starts a local web server that interprets these files into HTML webpages. Where would the server executable be located? —SGA314 I am not available on weekends (talk) 16:06, 10 July 2015 (UTC)

Can I capture item details in a Windows Explorer list as text items?

If I have a Windows Explorer (Windows 7) file with twelve items in it, and I want to capture the names or details of those items as text, can I do this by some method like cut and paste so that I can simply send the text describing the files, but not the files themselves? For example, I want to email a friend to let her know I am sending her 12 songs. How can I copy the names of the songs from the WE file and paste that into gmail without actually dragging the files themselves into the email as attachments? Thanks. μηδείς (talk) 21:27, 7 July 2015 (UTC)

This may help [8]. SemanticMantis (talk) 21:56, 7 July 2015 (UTC)

Thanks, SM, that was unintuitive of Windows, but very helpful on your part. μηδείς (talk) 22:10, 7 July 2015 (UTC)

Resolved

July 8

L1 and L2 cache

Do I understand correctly? Does L1 cache generally equals "CPU cache" and L2 generally equals "RAM"? if so, what is L3 than? Ben. Ben-Yeudith (talk) 01:03, 8 July 2015 (UTC)

No. With modern CPU architectures, all Lx caches are on the CPU, just different hierarchies. See CPU cache for more. Older CPU architectures (like 20 years ago or so), had external caches, but these were still distinct from normal RAM (system memory). AFAIK, all CPU caches whatever the hierarchy and location can be considered a type of RAM. Nil Einne (talk) 03:11, 8 July 2015 (UTC)

Nice to know that... So if we say the Memcache software of servers creates a RAM memory cache the real meaning is it actually a CPU cache based caching? Ben-Yeudith (talk) 09:15, 8 July 2015 (UTC)

If you are talking about Memcached, that's something completely different from a CPU cache. --Guy Macon (talk) 09:58, 8 July 2015 (UTC)

I have a Drupal site and In my Cpanel I use Memcache to build cache on the RAM... in relation to what User:Nil Einne wrote, I ask what type of memory this? the Memcached article speaks about RAM, or it different than what I think. Ben-Yeudith (talk) 11:30, 8 July 2015 (UTC)

OK. I understand the question. This has absolutely nothing to do with LI, L2 or L3 cache. They share the name "cache" but its like the difference between being "next in line" for a teller at your local bank and being "next in line" for the throne when the Queen of England dies. Completely different concepts. The memcache you configure using cpanel is just ordinary RAM on the web server, used in a clever way to make high volume websites faster.

Here is the best explanation I know of Drupal caching: https://openconcept.ca/blog/mmallett/apc-varnish-memcache-and-caching-beyond-drupal-core

In the Drupal context, everything called "caching" is simply ordinary reads and writes to RAM. Caching info in RAM and retrieving it later can be used to avoid having to get the info from disk, or it can be used to avoid asking another server for the info. --Guy Macon (talk) 12:54, 8 July 2015 (UTC)

Why would Memcached won't use the CPUcache? Isn't it preferable from the regular RAM cards? Ben. Ben-Yeudith (talk) 09:17, 9 July 2015 (UTC)

CPU cache is tiny and fast. It's used by the operating system to keep tiny things easily accessible for what would seem to a human person like tiny periods of time. Programs can't access it. So sure, it's preferable, in the same way a bullet is preferable to a 747. Bullets are very small and very fast, but you wouldn't ride one across the Atlantic. —Noiratsi (talk) 11:46, 9 July 2015 (UTC)

Programs generally have no control over the CPU cache. It's "invisible" to software; the CPU moves data in and out of cache automatically. I highly recommend that anyone interested in computers read this series of articles by Ulrich Drepper (former lead maintainer of glibc) about how computer memory works. Fair warning: it's a bit dense, and will take some time to get through, but you will learn a lot. --108.38.204.15 (talk) 14:21, 9 July 2015 (UTC)

Where do you report grammatical errors?

These are the errors.

Type Walter Mercado and see that there is a mistake in the first section of the article - "early years". The mistake is:"He also studied singing had a talent for dancing." Another mistake is on the Ilana Kratysh article in the "early and personal life" section, where it says "and she often attends synagogue.". — Preceding unsigned comment added by 65.88.88.17 (talk) 04:12, 8 July 2015 (UTC)

You don't need to "report" it. "This is Wikipedia, the encyclopedia that anyone can edit." Almost true; true enough for your purposes anyway. Find the relevant section, click on the blue [edit] link, make your fix, add an edit summary, and hit "save". --Trovatore (talk) 04:16, 8 July 2015 (UTC)

• If you'd rather not correct it yourself, every article has a Talk page, which is easier to find than this page and more likely to be read by someone who cares about the article. —Tamfang (talk) 08:49, 10 July 2015 (UTC)

New pages

Hi

I am a Computer Science student and often refer to Wikipedia before going else where to find information for assignments etc. There are a few areas I have searched for recently which do not seem to exist on Wikipedia so I am interested in writing some content to help others.

Are there any hard and fast rules I should abide by? To avoid my pages being removed or deleted for example after hours of work?

Many Thanks Joanne — Preceding unsigned comment added by 86.140.255.99 (talk) 09:35, 8 July 2015 (UTC)

Have a look on Help:Contents: that should tell you all you need to know.--Phil Holmes (talk) 10:07, 8 July 2015 (UTC)

It seems unlikely that any area of Computer Science you've come across in an assignment is not already covered in depth on Wikipedia. Make sure to search carefully. Maybe you could tell us what information you couldn't find? The people on this helpdesk will certainly know where to look to see if we already have an article on it. —Noiratsi (talk) 18:48, 8 July 2015 (UTC)

Write PHP multiple picture upload and database storage code for me

How to upload multiple picture at a time using php and mysql and save the url's of the images with seperator along with form data in the database ?106.51.131.180 (talk) 12:31, 8 July 2015 (UTC)

Could our Quickbooks connectivity issues be caused by our network setup?

Hello,

I am an employee in a small business. We have a server machine that has our Quickbooks company file on it, which we connect to with other computers that have Quickbooks. Our computers are actually all connected together using a firewall, "Netgear ProSafe FVS318N".

We have had continual issues with losing connection to the server on all our machines. This would happen seemingly randomly. An error message would come up saying something like "ABORT: Quickbooks has lost connection to the company file", although this may not be the exact message. We have gone back and forth speculating what the cause of this may be. Most of our computers are using Windows 7 or Windows 8. The "Server" machine is Windows 7.

My co-workers explain to me that they had experienced much less issue with connectivity when we were using Windows XP, and that the issue is related to either our version of QB, or some incompatibility with QB and the "newer" windows operating systems. (We are using Quickbooks Enterprise, manufacturing and wholesale 14.0)

I personally don't think this makes any sense, and rather look to our network configuration, although i am a novice with regard to knowledge of networking and its devices. Why do we have a firewall as the center of our network? Since the clients appear to randomly drop connection with the server's Quickbooks database, wouldn't one be able to say it is because a firewall generally blocks all ports of communication unless you write special rules to let this or that one through?

Is it possible that i am correct, and that by switching to a Network Switch instead of a Firewall device, we may enjoy longer periods of using QuickBooks without interruption? Is there possibly something else going on here that i don't understand?

Thanks in advance for all help and advice!

216.173.144.188 (talk) 14:41, 8 July 2015 (UTC)

The NetGear ProSafe did have connection drop issues with VPN. I doubt you are using VPN inside your office. A firmware update fixed those issues. Are you running the latest firmware? If not, it is a good idea to update it. Then, are you running open wireless access to the switch/firewall with the default admin password? If so, it would be trivial for someone nearby to be using your network and, whenever they like, kick people off the switch. 209.149.114.69 (talk) 18:12, 8 July 2015 (UTC)

We have not been using the VPN style setup on the firewall. We do have wireless communication set up, but we are not using the default credentials. We will try to update the firmware anyway. You are saying its perfectly normal for a company to operate with a firewall connecting all devices, instead of a switch? If that is so, i wonder if it does have to do with incompatibility with new windows versions, or perhaps an EMF from the lights on the wires or something like this.

216.173.144.188 (talk) 18:27, 8 July 2015 (UTC)

Internally, it is just a switch. It is not a firewall. The firewall is between the external/wan port and the internal switch. So, all 8 of the ports that you can physically plug into transfer between one another without any hint of a firewall. Further, you will see it is set up in two sets of 4. Any communication to a port in one set of four is sent to all four. They broke it into two sets of four to call it a switch instead of a hub. It is really just two hubs. The wireless access is completely different. It is wireless N if memory serves. You could be getting high interference on the wireless connection, causing disconnections. So, the first step is to identify if a computer hard-wired into the switch also has the disconnect problem. If not, you have limited the problem to wireless connected computers. That is most likely interference. Many things cause WiFi interference: walls, microwaves, bluetooth devices, other wifi devices, UFOs, etc... 209.149.114.69 (talk) 19:11, 8 July 2015 (UTC)

Yeah, we get a lot of problems with UFOs ... — Preceding unsigned comment added by 109.153.232.72 (talk) 00:07, 9 July 2015 (UTC)

July 9

Rendering of mathematical formulae on web pages

At "proofwiki.org", the source of the pages contains stuff like "$\triangle ABC$", "$d^2 = \dfrac {b c} {\left({b + c}\right)^2} \left({\left({b + c}\right)^2 - a^2}\right)$" and so forth, and also stuff like "\(\displaystyle \frac {BD} {DC}\)", "\(\displaystyle \implies\)" etc. etc. All of this is rendered into very pretty formulae on the page. How does this rendering get done? Also, since the formulae look miles better than anything on Wikipedia, could Wikipedia use the same technology? 109.153.232.72 (talk) 00:05, 9 July 2015 (UTC)

They're using MathJax. If you have an account, you can enable MathJax rendering in your user preferences, which means MediaWiki will use MathJax to render formulae for you as long as you're logged in. This is not turned on for Wikipedia and other Wikimedia projects by default for reasons related to performance and browser support. There is continuing work being done on MediaWiki's math support, which should eventually allow state-of-the-art math handling to be the default on all wikis using MediaWiki. --108.38.204.15 (talk) 02:01, 9 July 2015 (UTC)

I see, thanks for the very clear and helpful reply. 109.153.232.72 (talk) 02:44, 9 July 2015 (UTC)

remote db

Hi, is it better to replicate data needed from a remote db ot to join remote tables? Thank u 188.29.164.64 (talk) 18:46, 8 July 2015 (UTC) — Preceding unsigned comment added by 188.29.165.190 (talk)

From the point of view of distributed databases, you separate your query into independent queries that pull only what is needed from the remote database. Consider this: select loc.name, loc.age, rem.cost from local.table loc join remote.table rem on loc.name=rem.name and loc.age<10; I don't replicate remote.table. I first query local.table for all names where age<10. Then, I send that to the remote and ask for "name, cost" for all records where name is in the list I've sent. When I get back the "name, cost" set, I use that for my query to produce the final result. The reasoning is rather simple. Network traffic is very slow, so you send as little over the network as possible. If that is what you mean by "replicate data needed," then you are correct. You only replicate the data needed. If by "replicate data needed" you mean "copy all the tables from the remote server to the local server," then you are incorrect. That moves data that will not be used across the network. 209.149.114.69 (talk) 11:52, 9 July 2015 (UTC)

thank you a lot, but is it better to load needed fields while reading or to transfer them just after their update/ins/del? — Preceding unsigned comment added by 188.29.165.190 (talk) 06:23, 10 July 2015 (UTC)

The time of transfer doesn't make much difference. It is about the quantity of data transferred. The big trick in distributed databases is to reduce overall network traffic. It isn't about timing (until you start talking about building an ACID compliant distributed database). 199.15.144.250 (talk) 17:01, 11 July 2015 (UTC)

Program reinstalls

Hi! My computer had a program called OffersWizard, so i uninstalled it. But after a couple of days, it reinstalled itself back. I uninstalled it again, and it reinstalled itself again. How can i prevent the program to reinstall itself? — Preceding unsigned comment added by 217.209.38.254 (talk) 13:19, 9 July 2015 (UTC)

A program cannot install itself. A program that isn't there can't do anything at all. Something else is reinstalling it -- you have to figure out what. Very likely it is an extension in your internet browser. You can find complete instructions for removing OffersWizard at http://malwaretips.com/blogs/ads-by-offerswizard-removal/, also a few other places. Looie496 (talk) 13:42, 9 July 2015 (UTC)

Some Malware uses AddOns of the Browser and a program. You need to remove both of it. See also MSConfig --Hans Haase (有问题吗) 15:13, 9 July 2015 (UTC)

A program certainly can install it self, I'll give you a few websites to visit and then we can have the argument again. You could argue that it wasn't "THE PROGRAM" that installed it self per se, it was the website that installed the program, or it was YOU who installed the program by visiting the website, but that's a purely semantic argument. Also, when you "uninstall" a program, for malicious software it's fairly common for a piece of the software to hide it self from the uninstall program so that you actually aren't completely uninstalling it, but leaving behind a piece that will then "reinstall it self". In both cases I think it's perfectly acceptable to say "the program installed it self". Vespine (talk) 23:40, 9 July 2015 (UTC)

Visual Studio 2010 C++ LNK1123 Error?

Hello everyone. I am trying to compile a C++ project in Visual Studio 2010. However, whenever I try to compile it, it errors out giving me an error message saying, "error LNK1123: failure during conversion to COFF: file invalid or corrupt." I have read that this is caused by a version inconsistency in the compiler and that this can be fixed by updating VS with the SP1 update. Does anyone know of any other way to fix this? I am using Visual Studio 2010 Pro running on Windows 7 Ultimate X64. An a point of interest, this error manifest it self for every C++ project I try to compile. Thanks for your help in advance. —SGA314 I am not available on weekends (talk) 14:10, 9 July 2015 (UTC)

Does anyone know the answer to this? —SGA314 I am not available on weekends (talk) 18:26, 9 July 2015 (UTC)

See this StackOverflow thread and this MSDN article. Tevildo (talk) 19:28, 9 July 2015 (UTC)

Wo. No need to be like that. I wasn't claiming anything. I really can't access MSDN. I thank you for your help very much and meant nothing by what I said. I just really can't access MSDN or Microsoft's site. —SGA314 I am not available on weekends (talk) 17:37, 10 July 2015 (UTC)

OK, if you genuinely can't get to MSDN, we need to fix that problem first. You may be the victim of browser hijacking or have some malware on your system. What browser are you using? What happens if you type http://go.microsoft.com into your browser's address field? DO NOT type it into the search box, or anything similar that's in the vicinity - and be sure to include the "http://". Do you get an error page? Does the URL change, and, if so, what does it change to? It might be an idea to try a different browser, and see if the results are any different. Tevildo (talk) 17:47, 10 July 2015 (UTC)

I got the impression SGA is working with some sort of highly restricted internet services, restricted by an employer, not malware etc. I could be totally wrong, if so sorry to SGA. (There have been a few other ref desk users over the years that say they have highly restricted internet abilities - I usually take them at their word, but it can be problematic - if they can't see refs we post, then we have to paste content here to make it useful, and that process can often be very time consuming.) SemanticMantis (talk) 17:56, 10 July 2015 (UTC)

Yes, I can understand not being able to access YouTube or Facebook or the BBC - I myself can't access Wikipedia from my work machine - but I find it hard to believe that any rational boss or ISP would block access to MSDN and allow access to Wikipedia. This leads me to suspect that SGA has a non-human-related problem with his (or her) setup. Tevildo (talk) 19:03, 10 July 2015 (UTC)

No, SemanticMantis was right. It is my IS. Not any malware. I just wanted to know if anyone has had this problem before and they found a way to fix it(other than updating Visual Studio). —SGA314 I am not available on weekends (talk) 19:41, 10 July 2015 (UTC)

Well, what you need to do is disable incremental linking - Project Properties > Configuration Properties > Linker (General) > Enable Incremental Linking -> "No (/INCREMENTAL:NO)". But I still think it's worth trying to get you access to MSDN, where the answers to your questions can be found. What _does_ happen when you try and get to microsoft.com? Tevildo (talk) 20:19, 10 July 2015 (UTC)

Incremental linking is already disabled. There is a web filtering system that's setup on my ISP. Its called Sophos. And there is no way around it. I have read the log file and heres what it says,

Invoking CVTRES.EXE:

   /machine:x86
   /verbose
   /out:"C:\Users\dainen\AppData\Local\Temp\lnkBA6F.tmp"
   /readonly
   "Debug\1.res"

LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt

This happens after the it loads the referenced libraries. I think I might be able to fix this by changing the targeted .NET framework version. How would I do this? —SGA314 I am not available on weekends (talk) 14:40, 13 July 2015 (UTC)

Why was 0-1 not used for 'S' in Hollerith code?

'A' = 12-1, 'B' = 12-2, ... 'I' = 12-9, then 'J' = 11-1, 'K' = 11-2, ... 'R' = 11-9, so there's a pattern of when the Numeric punch gets to 9, then you move to the next Zone punch (note for alphabetic encoding, 0 is considered a zone punch) you start at 1 again. But not so when you come to 'S', which suddenly is 0-2, not 0-1. Why? Was it so that 'Z' would neatly land on 0-9? 20.137.7.64 (talk) 17:36, 9 July 2015 (UTC)

It began with 32 characters, ending with "...LMNOPQR/" (the slash was the last character). Then, the entire alphabet was added, but to be backwards compatible, the / was retained after the R. So, it goes "...PQR/STUV...". That is why there is a jump between R and S. 209.149.114.69 (talk) 18:04, 9 July 2015 (UTC)

Makes sense, but I'd like a citation so I can read more about this. --174.88.133.209 (talk) 22:51, 9 July 2015 (UTC)

Have you ever wondered why sites that show the coding, like this, place a / between R and S? That isn't a typo. 199.15.144.250 (talk) 13:34, 11 July 2015 (UTC)

I'm not sure of the exact reason - but punched cards were read at phenomenal speed - and there were issues where some code combinations would make the card liable to tear in half when accelerated rapidly from the stationary card deck and into the reader. Also some early punches used air, blown through the holes in the card, to operate switches (rather than an optical detector)...in that case, air could leak through one hole and out of another under some perverse conditions inside the reader. So much of the hollerith code is an effort to work-around those kinds of mundane electro-mechanical systems. SteveBaker (talk) 22:27, 12 July 2015 (UTC)

July 10

An open-source scheduling system

Hi there,
I look for a scheduling system, which sets employees according to their demands,
and can update it in an exchange server. 14:03, 10 July 2015 (UTC) — Preceding unsigned comment added by Exx8 (talk • contribs)

old school AOL screen names

I'm writing a historical novel that takes place around 1996-1997. What were the requirements restrictions for screen names back in the heyday of America Online? How many characters minimum/maximum? What types of characters were allowed/disallowed? Since your screen name was also your email address (if i recall correctly), I'm sure this severely limited what your name could be.--Captain Breakfast (talk) 14:14, 10 July 2015 (UTC)

I checked my archived files, which I knew contained a mailing list for AOL from the mid-90s. The character set for over 2,000 AOL addresses is a-z A-Z 0-9 and _. I didn't see a single dash or period. There are many names that are 15 characters long, but none longer than 15 characters. While this is not the rules from AOL, it is a representation of the result of AOL rules. So, if you are looking for names that look plausible, you can stick to alphanumeric strings of 15 characters max, with use of the underscore as necessary. 199.15.144.250 (talk) 13:30, 11 July 2015 (UTC)

Wow, that is extraordinarily helpful. Thank you!--Captain Breakfast (talk) 23:34, 11 July 2015 (UTC)

Hard drive holes

Why do hard drives have "void holes" on them covered by a sticker that if removed will allow atmosphere into the drive platters and ruin them? They say "void if removed" or similar. What I mean is, the purpose seems obvious to ruin the drive my question is why are they part of the design of drives that 99% of people will not want to ruin? It's like putting a hole covered by a sticker on every car tire that says "void if poked with a drawing pin". Why include it as part of the design? — Preceding unsigned comment added by 120.206.155.12 (talk) 14:29, 10 July 2015 (UTC)

Uh, I don't the platters being exposed to atmosphere would damage them. A hard drive is a magnetic storage medium. Therefore, they most likely wouldn't be affected by exposure to oxygen. Although they could be affected by rust. However, this would require an oxidization agent like water. Now if you took some magnets and waved them closed to the drive, thats another story. That's pretty much the most effective way to erase data from a hard drive. —SGA314 I am not available on weekends (talk) 16:48, 10 July 2015 (UTC)

The atmosphere contains dust and dust can cause a head crash. -- BenRG (talk) 17:00, 10 July 2015 (UTC)

True, I didn't think of that. —SGA314 I am not available on weekends (talk) 17:30, 10 July 2015 (UTC)

I don't think such holes exist. Most drives I've seen have a hole for pressure equalization with a label saying "do not cover this hole". If there's a sticker saying "warranty void if removed" it probably covers a screw or otherwise prevents you from opening the drive case. -- BenRG (talk) 17:00, 10 July 2015 (UTC)

Thank makes much more sense as for I have seen stickers on many other products that cover screw wholes. —SGA314 I am not available on weekends (talk) 17:31, 10 July 2015 (UTC)

Typical hard drives are open to atmosphere, albeit with a filter in between the outside air and the inside. See our article. However I agree with BenRG; I'm not sure the stickers you're talking about are covering the breather hole. --108.38.204.15 (talk) 08:10, 11 July 2015 (UTC)

The drive is very sensitive to dust. I recall an analogy that may help...if one track of the hard drive was as wide as a 6 lane road, the drive head would be the size of a 747 airplane, flying at an altitude of about three feet. On that scale, a human skin cell (a common component of dust) would be the size of a car. Clearly, dust is a bad thing.

So the common trick is to arrange for there to be positive air pressure inside the drive, so that even if there is a tiny leak, air will escape from the drive and not leak into it. But there are several approaches to doing this.

Parts of a HDD

That said, I agree that the stickers are probably covering screws, which if removed would result in the likely-hood of dust getting into the drive and wrecking it. Some other drives have a waxy plastic substance (ogjpoured into the screw holes so that it's evident if they have been tampered with. SteveBaker (talk) 22:20, 12 July 2015 (UTC)

I've mucked around with dead hard drives before, because taking things apart is interesting, and the little stickers the op is talking about definitely exist and are not covering screw holes. There is just a void if you poke through it. Could it be something to do with the manufacturing process, like this hole is needed to remove air from the inside, or to fill it with an inert gas, and then the hole is sealed? I'm just guessing at this point, but mostly posting to confirm these holes do exist and aren't covering screws. 81.138.15.171 (talk) 09:02, 13 July 2015 (UTC)

Enlarge the picture and see the notes by hoovering the mouse over it, there on commons, only. Below the breather, a filter is installed to keep the dust of. Another filter is installed in the dirve to catch any particles in the airflow from the rotating platter. --Hans Haase (有问题吗) 22:17, 13 July 2015 (UTC)

Hmmm - I checked the numbers on my disk head/747 analogy. The numbers are a bit outdated! current 'fly height' of a modern hard drive is about 3 nanometers - and a human skin cell is about 30,000 nanometers across. So if the 747 is flying 10 feet off the ground, the skin cell is the size of mount everest! SteveBaker (talk) 22:30, 13 July 2015 (UTC)

Indeed, is gives litten addition to the known analogy diskheads vs Boing 747. But the heads are parked on the inner side of the platters and the platters speed up first before the heads leave the parking position. 20 Years ago WD made a frimware bug making the heads leave before completing the spin up. ASUS M/Bs booted very quick and accessed the drives before spin up. The problem was WD not ASUS, but in the BIOS a delay for spin up could set. If any human skin cell is not gluing on the platter, it has the chance to be blown into the inner filter pad. --Hans Haase (有问题吗) 12:19, 14 July 2015 (UTC)

4g pocket wifi slow issues

If a 4g pocket wifi module is a lot slower than advertised is the problem likely to be the 4g or the wifi? 90.198.254.18 (talk) 18:53, 10 July 2015 (UTC)

A 4G connection is shared with other users on the repeater, also known as mobil phone network cell. WIFI from Your router is a dedicated DSL on Your phone line. Public WIFI is also shared with other users. This does not affect any if all the users do not overload by demand the installed bandwith. --Hans Haase (有问题吗) 22:25, 13 July 2015 (UTC)

July 11

What are the frequencies used by 2G, 3G, and 4G?

Just wondering. - 121.54.32.162 (talk) 05:50, 11 July 2015 (UTC)

They are in the UHF band between 800MHz and 2200MHz. The bands may differ between countries and carriers. You can look at particular mobile phones to see their specs. Graeme Bartlett (talk) 06:08, 11 July 2015 (UTC)

See GSM frequency bands, UMTS frequency bands, and E-UTRA#Frequency bands and channel bandwidths for the details. Tevildo (talk) 10:10, 11 July 2015 (UTC)

Latest literature review on teaching writing through computer between 2011- 2014

I need latest literature review on given topic I need literature review for my research different literature review on given topic between 2012-2104113.199.162.97 (talk) 11:02, 11 July 2015 (UTC)

Is there a reason you can't use Google Scholar? Go to scholar.google.com and search for "teaching writing through computer". When the list comes up, click on the "Since 2012" link on the left. Magically, you will see a list of publications on the topic. 199.15.144.250 (talk) 13:20, 11 July 2015 (UTC)

Time zones on iPhones

Does iPhone require a 3G signal to set the time when you go abroad? Or is gps and a 2g signal sufficient? 82.132.234.205 (talk) 13:16, 11 July 2015 (UTC)

Consult Apple's official support page on this topic. Time zone setting is carrier-specific: it is not specifically tied to the technology that is generally called "3G." Depending where you go, you may or may not actually have 3G coverage. Whether your cellular carrier sends correct time zone information is independent of that detail. If the setting is incorrect, the best way to start troubleshooting is to contact the cellular provider.

In some versions of iOS (e.g. iOS 7 and others), certain iOS devices may use location services to set the time zone. This may be possible even if you have no cellular connection at all. If you need more specific technical information for a specific device/model/software-version, consult the developer website at http://developer.apple.com to see how time zones and locations are set and queried.

Nimur (talk) 19:19, 11 July 2015 (UTC)

Influence on computer science from biology and linguistics

What are some authors and concepts from biology or linguistics that influenced, inspired, or stirred developments in comp. sci? The only author I can find right now is Chomsky with his concept of Chomsky hierarchy, but non-reliable sources close to me claim that there are more. --Socio scie (talk) 22:22, 11 July 2015 (UTC)

Fractals are quite useful in computer animation, and Benoit Mandelbrot made major contributions to that field. (He was a mathematician, but fractals also describe many biological systems.) StuRat (talk) 23:04, 11 July 2015 (UTC)

Fractals are rather a concept from mathematics that found its way into many science, including computer science and biology among many others. That does not match what the OP was asking for. --YX-1000A (talk) 13:00, 12 July 2015 (UTC)

I see fractals as having multiple origins, in many different fields. The fractal nature of biological systems were noted long before that name was invented for it. The mathematics of fractals merely describes what already existed.StuRat (talk) 23:54, 12 July 2015 (UTC)

Off the top of my head, genetic algorithms, neural networks, and possibly the whole concept of programming languages. -- 50.0.206.24 (talk) 01:13, 12 July 2015 (UTC)

• Basically everything that belongs to artificial intelligence, since it is intended to replicate natural intelligence. Looie496 (talk) 14:36, 12 July 2015 (UTC)

I am not sure AI is meant to replicate natural intelligence as it is, rather than just emulate its working. That's comparable to a wheel trying to emulate (but not replicate) legs. Or comparable to a reverse engineering a human, not worrying about how the human solves problem, and only concentrating on the result. Otherwise, who would want a computer that acts like humans, but does not surpass them? --YX-1000A (talk) 15:51, 12 July 2015 (UTC)

On the flip side, DNA computing. There are also special-purpose supercomputers like MDGRAPE and Anton designed to instantiate algorithms used in molecular dynamics simulations, usually of biological macromolecules.

More traditionally, genetic algorithms and neural networks are good answers. We have somewhat crappy articles on the general category of evolutionary algorithms and bio-inspired computing - swarm intelligence is also a good example. It's stretching the definition of biology (how far out do you get to keep the 'bio' in 'biophysics'?) but everything that boils down to Shannon entropy arguably qualifies. Opabinia regalis (talk) 22:18, 12 July 2015 (UTC)

You can avoid bioinformatics. It would seem that there would be some biology influence there. There isn't. It is mostly a lot attempts to implement NP-Hard algorithms on massive data sets. The implementation helps biology, but biology doesn't influence the implementation. 199.15.144.250 (talk) 12:24, 13 July 2015 (UTC)

Larry Wall's training as a linguist is often cited as having affected the design of the Perl programming language which he created. This is touched upon in Perl#Design, but Wall went into more detail in a 1995 Usenet post now available as the essay Natural Language Principles in Perl. -- ToE 14:56, 13 July 2015 (UTC) Perl poetry, such as Black Perl, is a side effect of Perl's natural language elements.

July 12

Only 3 operating systems

After some observations, i have noticed that there are only 3 types of operating system: Mac OS, Linux and Windows. My question is: Are there more types not based on these 3? I know iOS is Mac OS. Possibly for other computers? RocketMaster (talk) 03:35, 12 July 2015 (UTC)

See Operating system#Examples of operating systems and List of operating systems. It's true that most modern operating systems on microcomputers are descendants of or heavily influenced by Unix (this includes Android, iOS, OS X and Linux), with the major exception to this being Windows (and ideas from Unix have influenced that too). On mainframes, Unix derivatives are also common, but there are still proprietary operating systems in common use on some manufacturers' computers.-gadfium 03:54, 12 July 2015 (UTC)

There was OS/2. StuRat (talk) 04:22, 12 July 2015 (UTC)

And many others such as DOS, CP/M, the Apple II system, others in microcomputers and many for minicomputers and mainframes. Bubba73 ^{You talkin' to me?} 04:27, 12 July 2015 (UTC)

You're fixating on desktop computer operating systems - and only on the current popular ones! There are many more operating systems suitable for personal computers, and many more have existed historically (even if they are uncommon today). If we consider other types of computer systems - servers, microcontrollers, distributed systems, video-game consoles, application-specific software - there are many more operating systems.

Start by reading list of operating systems. There are hundreds of them in that list!

You might not be familiar with these softwares as operating systems, at least not by brand name; but surely you've seen a video game console, or an airplane, an ATM, a digital motion picture projector at a movie theater, or a microwave oven. All of these devices commonly have computers inside of them. Many of these computers run an operating system, and that does not necessarily need to be Windows, not Linux, and not OS X.

Nimur (talk) 08:25, 12 July 2015 (UTC)

Just as an interesting FIY, almost all ATMs do actually just run on windows. Vespine (talk) 23:45, 12 July 2015 (UTC)

You are absolutely correct: it is true today that most ATMs you will encounter out in the wild are probably running Windows XP or one of the newer Embedded Windows softwares. There was a time when almost all ATMs ran OS/2, but this has probably not been true for the last decade. Modern ATMs were probably a poor example to demonstrate my point! Nimur (talk) 05:37, 13 July 2015 (UTC)

Specifically, the CEN/XFS client-server architecture for financial applications on the Microsoft Windows platform dominates, although Linux is making inroads.

http://www.telegraph.co.uk/technology/internet-security/10543850/Hackers-target-cash-machines-with-USB-sticks.html may be of interest. --Guy Macon (talk) 07:24, 13 July 2015 (UTC)

Deleting photos from Gmail's people widget

I have long been aware that if I upload an attachment to gmail, I am uploading an attachment to google. That has never been a problem.

But I have recently received private images from third parties not aware of google policies, and the private images they have sent me started appearing under their name on the right side of my browser when I read their emails. Some are images I don't like or, much more seriously, which the sender would not want shared or displayed. I understand one can turn off the display of the people widget. From googling I see no way to tell google to erase those images that belong to parties who did not give their consent for the image's use. I understand that if you even delete the email entirely, the image remains.

Is there any simple way to get these images removed from google's servers? Is there any regulatory agency or published legal action of relevance in the United States? Thanks. μηδείς (talk) 03:50, 12 July 2015 (UTC)

Removing Content from Google: Legal Help. You should consult an attorney, because this process is neither easy nor risk-free.

Nimur (talk) 15:37, 12 July 2015 (UTC)

Yes, thanks, I was afraid of that. It looks like I'll have to await regulatory action or a class-action lawsuit. μηδείς (talk) 17:25, 12 July 2015 (UTC)

The emails are appearing in your browser when you read your own emails, is that correct? It seems to me very likely that Gmail is displaying those pictures to you because they exist in your own archived messages. That doesn't sound like a privacy breach to me. You were the person the images were sent to and you are the one seeing them.

When you say "I understand that if you even delete the email entirely, the image remains", is this something you have tried? I can't see where the picture could linger after the message containing it was deleted. I suppose it's possible that a thumbnail version, created automatically for easy previewing, could hang around in a cache for a short time. —Noiratsi (talk) 18:12, 12 July 2015 (UTC)

Changng PDFs into black and white

How can I change my color PDFs into b/w to cut the file size down?--86.176.9.176 (talk) 14:40, 12 July 2015 (UTC)

One obvious way is to print it to a PDF writer and select black and white in the output options. I don't know how much in size the file would be reduced. --TrogWoolley (talk) 16:02, 12 July 2015 (UTC)

If you can run Ghostscript ("gs") from the command line, you can do:

    gs -q -sDEVICE=pdfwrite -sColorConversionStrategy=Gray -o OUTNAME FILENAME

You may also need to specify a page size (e.g. -sPAPERSIZE=a4) for the output file.

See here, and in particular here, here, here, and here. --70.49.171.162 (talk) 18:54, 12 July 2015 (UTC)

It's unlikely to save much space. Removing the color from text and vector graphics will have almost no effect on the size. Bitmapped images are likely to be encoded as JPEG or JPEG 2000, which encode color pretty efficiently (usually it's less than 1/3 of the total image size). -- BenRG (talk) 19:57, 13 July 2015 (UTC)

One issue that comes up when changing color files to black and white is what precisely you mean. For example, if you have yellow text on a white background, do you want that text to become a very light grey (having the same darkness as yellow) on a white background, or do you want it black on white, to be more visible ? StuRat (talk) 22:00, 12 July 2015 (UTC)

Even worse, what happens when the top half is orange text on a white background and the bottom half is black text on an orange background? --Guy Macon (talk) 07:28, 13 July 2015 (UTC)

I assume that the question wants to make the PDF grayscale, not black and white. Black and white is technically just two colors: completely black or completely white. However, most people say "black and white" when they mean "grayscale." If the question is really about grayscale, it appears that it is incorrectly assuming that changing color to grayscale will reduce file size. Grayscale is not smaller than color. If I have 8 bits for color, I use all 8 bits for color. If I have 8 bits for grayscale, I use 8 bits for grayscale. You can convert, say, 32-bit color to 8-bit grayscale. You could just as well convert 32-bit color to 8-bit color. Changing bit depth is a separate process from changing color type. You could also change 32-bit grayscale to 8-bit color to reduce file size. 199.15.144.250 (talk) 12:19, 13 July 2015 (UTC)

There's also black and white dithering (using just black dots, but spacing the black dots out to achieve the appearance of grays). That looks worst of all.

32-bit greyscale seems like excess bit depth, compared to 8-bit, for most applications, like a photo. 32-bit color, on the other hand, is a rather noticeable improvement over 8-bit color. Also note that under the HSL and HSV color spaces, only the L (lightness) or V (value) need be retained when converting to greyscale. StuRat (talk) 13:13, 13 July 2015 (UTC)

Our MRI produces 32-bit grayscale and there are still times that they have to go back and repeat the process on a specific area because the image becomes blurred when zooming in. The bit depth is all based on need. I'm sure newer MRI machines use 64-bit grayscale to avoid repeat scans. 199.15.144.250 (talk) 14:18, 13 July 2015 (UTC)

At 32 bits, there should be 2³² shades of grey, which is over 4 billion. I can't imagine that the MRI looks blurry due to 4 billion shades of grey not being enough (and "blurry" isn't how one would describe insufficient color depth, in any case). It must be blurry for some other reason, like the patient moving during the scan. In fact, if the 32 bits was the problem, then rescanning again at 32 bits wouldn't make it any better. StuRat (talk) 15:09, 13 July 2015 (UTC)

In tractography (is there an article... yes!) mapping 2D images to 3D requires immense bit depth. I used "blur" to avoid getting technical about artifacts such as barring, striping, or starring. Similar effects appear in dithering. Scans are not always done on the entire body. You can mechanically zoom in on a specific area as opposed to doing a software zoom, which is where the interpolation artifacts show up. I don't work over in the CT lab, but I assume they have the same issues that MRI has. 199.15.144.250 (talk) 15:28, 13 July 2015 (UTC)

Yea, that's the same issue with digital zoom versus optical zoom. Digital zoom is just about useless, since the resolution (pixels per inch or cm) just isn't there, and you can't create missing information with software.

Re: "mapping 2D images to 3D requires immense bit depth", I don't think that's quite the right name for it. It may require lots of working memory (RAM), but that isn't really bit depth. For example, if you wanted to represent 8 layers as a single image, you could have eight 8-bit pics all combined into one by making each pixel 64-bits, but that's not the same as a single 64-bit pixel. StuRat (talk) 15:36, 13 July 2015 (UTC)

This is quickly getting very off topic... The shoulddistance (void) between layers is where interpolation takes place. Please note that I do not work on the MRI software, but I do listen to the engineers. It is not as simple as interpolating between point X/Y on one image and point X/Y on another. You have to interpolate between the vectors of interpolation as well. This is where artifacts appear. One way to fix the problem is to take more images with less void - which is more expensive and makes the entire scan take a lot longer. Another way to fix the problem is to scan at a higher bit depth. I never really cared for the mathematical reason it works. My focus is on trying to find a way to explain to people that when you a logarithmic increase in storage needs because your MRI machine is producing much larger images, linear growth in data storage machines isn't going to work. Management literally (yes, literally) gave me the "it took 15 years to fill 50TB of space, so we should be good with 100TB for another 15 years." 199.15.144.250 (talk) 15:58, 13 July 2015 (UTC)

Interpolation seems like a bad thing in the context of medical scans, since it makes it look like you have better resolution than you really do. So, if there's a medical problem in the void area, which doesn't extend onto either adjacent layer, the interpolation will show a layer in the void with no problem, which is a dangerous lie. Better to show nothing there than to show that. StuRat (talk) 20:09, 13 July 2015 (UTC)

Returning to 199.15.144.250's point, it's correct that converting color to grayscale will not necessarily reduce the file size. However, if the PDF contains, for example, JPG images with 24-bit color, then reducing these to 8-bit grayscale may well indeed reduce the file. Before posting the gs command line above, I tested it on a copy of the 191-page rail accident report (the official report on the Lac-Mégantic disaster) that I happened to have on my computer, which contains a number of color photos. The file size shrank from 2,987,415 bytes to 2,486,924. --174.88.133.35 (talk) 04:35, 14 July 2015 (UTC)

July 13

Will Windows 10 automatically update drivers?

Will Windows 10 automatically update drivers? I keep getting offers from WinZip for some software that updates drivers on Windows 7 and 8. Will that still be useful after Windows 10 is installed? Bubba73 ^{You talkin' to me?} 02:28, 13 July 2015 (UTC)

For many years now Microsoft has been working with hardware manufacturers to make drivers available automatically through Windows Update. Some manufacturers make use of that facility; others offer their driver updates (and sometimes their own automatic updater tools) via their own websites. Many do both. In Windows 10 Microsoft will certainly continue working with hardware manufacturers to try and increase the number of automatic driver updates available. I wouldn't expect any dramatic increase in the number of drivers available from Windows Update when Windows 10 is released; rather, if Microsoft has their way, a gradual increase over time.

Third-party software that offers to update your drivers is almost certainly ad-supported or similar. It might even be thoroughly malicious. I would avoid it. —Noiratsi (talk) 07:28, 13 July 2015 (UTC)

An update: I have done some research into WinZip's "Driver Updater" software, which is presumably what you're referring to. It sounds like they offer a free version which (this may be an exaggeration) tells you all your drivers are out of date and asks you to buy the paid version in order to update them. One user (a blog post from June 2014) reports that WinZip's utility told him all his drivers were out of date but several other utilities found no problems at all. I'm sure you can do more research of your own if you want to know more. —Noiratsi (talk) 07:47, 13 July 2015 (UTC)

That is the one I'm talking about. I tried the free version and it listed several drivers that it said were out of date, but you had to get the paid version to actually update them. I didn't do it, and it sounds like it would not be worth it. Thanks. Bubba73 ^{You talkin' to me?} 16:05, 13 July 2015 (UTC)

Is my Realtek NIC fried?

I'm worried and anxious about the internal NIC on my ASUS motherboard being potentially damaged recently. It all happened when, for some reason, my wireless extender box gave up on me not too long ago. At first I thought it was just the router itself, but I connected the DSL modem to my rig and while it initially worked and was able to acquire a DNS address, unplugging the cable and reconnecting it again resulted in this on the terminal upon keying in the ipconfig /all and nslookup commands:

Address: fec0:0:0:ffff::1

I was thus unable to browse the web from that point on; releasing and renewing the lease does the trick, and changes the address back to 192.168.1.1, and I am able to get back online by forcing a different DNS server as well. It just irks and worries me that reproducing the problem doesn't yield the same issue with another PC i.e. plug it in on the ethernet jack, wait for a few minutes, unplug it and then replug it again. I tried reinstalling the driver to no avail, and went so far as to downloading and running SystemRescueCD to check if it's just Windows being bonkers, but the symptoms seem to persist regardless. I am running out of options right now, and I'm not that arsed to tell my folks about having the board RMA'd either. Blake Gripling (talk) 11:21, 13 July 2015 (UTC)

Maybe the RTL WLAN or used Transceivers with it did not earn my full trust on reliability, but this may not be caused by Realtek. Until the device is soldered into a retail product, there are several steps neccessary to make the whole product work. With the RTL ethernet chips, I do not know any single failure of hardware. The only things happened, longer time ago, software certificates was stolen from Realtek to sign malware with it and recent drivers or branded driver software labeled to other manufacturers names using realtek devices in their hardware have had some problems. I guess You have a problem with network configuration, beginning from damaged or cheap cables, sometimes failed connection due special lenght in combination with the used pulse transformers in the ethernet devices which make You solve the problem by using another network cable, followd by malware, bad driver versions, man in the middle attacks, cracked and pwnd router. As You described to work with other DNS server configuration to solve such problems, note somebody might route all Your internet traffic to and over another place! I suggest You to net drivers for the NIC from http://www.realtek.com.tw/ only. If this does not solve the problem, backup all your data, reinstall Your computer in an unaffected internet connection with all devices free of malware, immediately install operatingsystems security updates and antivirus software, get a the recent firmware update for Your router, flash it and reconfigute it. Note there are vulnerabilities like the USB stack used in the routers kernel. Your Devices in the LAN gets the DNS resolved by the router. If somebody changes the DNS server settings in the router, all Your devices in the LAN are affected by that change, retrieving these pages stored in the DNS server the router is set to with not change on Your computer at this time. But when downloading, it comes from the page the DNS server resolves to. --Hans Haase (有问题吗) 21:24, 13 July 2015 (UTC)

Microsoft’s Metro

What really is Metro? Is it a programming language? Or a markup language? Where can I learn it? --Biolongvistul (talk) 15:41, 13 July 2015 (UTC)

It is a design language. That is similar to a markup language, but unlike a markup language, it is aimed at designers, not display engines. 199.15.144.250 (talk) 15:47, 13 July 2015 (UTC)

I think it might be very confusing to suggest that a design language is like a markup language. A markup language is a system for annotating text. It has a formal syntax. It tells the computer how to interpret documents or data. A design language, on the other hand, is not a 'language' in the same sense at all. It might be better described by its alternative name "design vocabulary". It's just a set of visual ideas that a designer may make use of. —Noiratsi (talk) 16:43, 13 July 2015 (UTC)

July 14

Do unread Facebook messages expire?

(Transferred from W:RDM due to recommendation) Despite having had a Facebook page for years, I have never once checked my messages. I didn't know I had them. So recently, when I found out, I wanted to read some old things just to see who and why people were writing someone who never went on Facebook. Well, I got one message from 2013 to load, but nothing older than that.

These messages are mostly from 2011, with a few from 2012. Are they not loading because of how long they've sat unread? --Ye Olde Luke (talk) 01:40, 14 July 2015 (UTC)

If they meant for them to expire, they would presumably have removed the link to them, too. I suspect that the server they were on was retired, or something like that, so that they have become inaccessible. StuRat (talk) 04:54, 14 July 2015 (UTC)

Are you by any chance guessing there, StuRat? --Viennese Waltz 08:33, 14 July 2015 (UTC)

You can read a bit about how FB Messenger works on the developer's blog. For efficiency reasons, the servers are structured so that the most recent messages are stored in a queue on a fast-access server (Facebook uses a variant of what's called the publish–subscribe pattern to send its messages, and Facebook has no way of knowing whether a user will read the next message on a phone or a computer, so they need to be ready for either contingency), while older messages are kept on traditional servers. I had a quick check, and although messages for 2010 and earlier take a few seconds to load, they do appear. Are you sure you have messages from that era? (Also, it's worth checking your "Other" inbox, which is where messages from groups and strangers are filed - I have some from before 2012 although when I try to load these I get errors, probably because of the way Groups, Pages and Messages work on Facebook have all changed over the last 4 years). Smurrayinchester 09:08, 14 July 2015 (UTC)

Sorting in Excel

As it will be quite hard to explain, what I want to do, I will show it with an example. So I have such table in Excel (this is just a small part of it)

1	foo	1	something
2	bar	3	completely
3	lorem	4	random
4	ipsum	5	text

And I want to get such result

1	foo	1	something
2	bar
3	lorem	3	completely
4	ipsum	4	random
		5	text

As you can see, I want to get the same values in several columns for each row. In this case, the main column, by which I want to sort the data, is the first one and I want, that 3rd column sorts by the same values. --Edgars2007 (talk/contribs) 09:10, 14 July 2015 (UTC)

VLOOKUP is your friend here. First, create a column containing all the possible index numbers, like this (I'm going to mark Excel cell references, to make this a bit clearer) So, here's your table. If the data isn't sorted, sort each pair of columns by the index (don't use the "Expand selection" operation when doing this sort) to close up empty rows and ensure everything is ordered:

There's a lot of tables here, so I'm hiding this, but hopefully the answer is in here

A B C D 1 1 foo 1 something 2 2 bar 3 completely 3 3 lorem 4 random 4 4 ipsum 5 text 5 Add a column ("E") containing a list of all possible index numbers A B C D E 1 1 foo 1 something 1 2 2 bar 3 completely 2 3 3 lorem 4 random 3 4 4 ipsum 5 text 4 5 5 Now do VLOOKUP magic. VLOOKUP takes a number (or other string), finds that in the left-most column of an array you specify, and gives you the matching entry from that row of that array (to find entries, it needs the lookup values to be sorted). For this simple example, the VLOOKUP you want is: A B C D E F G 1 1 foo 1 something 1 =VLOOKUP(E1;$A$1:$B$5;2;FALSE) =VLOOKUP(E1;$C$1:$D$5;2;FALSE) 2 2 bar 3 completely 2 =VLOOKUP(E2;$A$1:$B$5;2;FALSE) =VLOOKUP(E2;$C$1:$D$5;2;FALSE) 3 3 lorem 4 random 3 =VLOOKUP(E3;$A$1:$B$5;2;FALSE) =VLOOKUP(E3;$C$1:$D$5;2;FALSE) 4 4 ipsum 5 text 4 =VLOOKUP(E4;$A$1:$B$5;2;FALSE) =VLOOKUP(E4;$C$1:$D$5;2;FALSE) 5 5 =VLOOKUP(E5;$A$1:$B$5;2;FALSE) =VLOOKUP(E5;$C$1:$D$5;2;FALSE) The first variable ("E1" to "E5") is the cell whose value Excel will search for, the second ("$A$1:$B$5" or "$C$1:$D$5") is the array that Excel will search in (I've added the dollar signs to allow the formula to be auto-filled easily - if you've not come across this before, the Excel blog explains), the third variable ("2") is which column of the table contains the answer, and the fourth ("FALSE") tells Excel you want an exact match, not just a near-hit. This should resolve as: A B C D E F G 1 1 foo 1 something 1 foo something 2 2 bar 3 completely 2 bar completely 3 3 lorem 4 random 3 lorem #N/A 4 4 ipsum 5 text 4 ipsum random 5 5 #N/A text If the #N/As are a problem, you can use an IFERROR function to hide them, like so: A B C D E F G 1 1 foo 1 something 1 =IFERROR(VLOOKUP(E1;$A$1:$B$5;2;FALSE);"") =IFERROR(VLOOKUP(E1;$C$1:$D$5;2;FALSE);"") 2 2 bar 3 completely 2 =IFERROR(VLOOKUP(E2;$A$1:$B$5;2;FALSE);"") =IFERROR(VLOOKUP(E2;$C$1:$D$5;2;FALSE);"") 3 3 lorem 4 random 3 =IFERROR(VLOOKUP(E3;$A$1:$B$5;2;FALSE);"") =IFERROR(VLOOKUP(E3;$C$1:$D$5;2;FALSE);"") 4 4 ipsum 5 text 4 =IFERROR(VLOOKUP(E4;$A$1:$B$5;2;FALSE);"") =IFERROR(VLOOKUP(E4;$C$1:$D$5;2;FALSE);"") 5 5 =IFERROR(VLOOKUP(E5;$A$1:$B$5;2;FALSE);"") =IFERROR(VLOOKUP(E5;$C$1:$D$5;2;FALSE);"") This gives: A B C D E F G 1 1 foo 1 something 1 foo something 2 2 bar 3 completely 2 bar completely 3 3 lorem 4 random 3 lorem 4 4 ipsum 5 text 4 ipsum random 5 5 text

Hope this helps. Smurrayinchester 09:39, 14 July 2015 (UTC)

This looks very good. Thank you :) This will really save a lot of time. --Edgars2007 (talk/contribs) 09:56, 14 July 2015 (UTC)

Ruler Add-on

Is there any add-on for Mozilla Firefox that I can use as a ruler, measuring distances on the screen in pixels, like you use the ‘Eyedropper’ to get the colour of a pixel? — Preceding unsigned comment added by Biolongvistul (talk • contribs) 13:10, 14 July 2015 (UTC)

Both "screen ruler" and "kruler" both allow you to measure distance on the screen in pixels, but they are not Firefox add-ons. They are independent programs. 209.149.113.136 (talk) 13:54, 14 July 2015 (UTC)