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December 15

disc full - can't delete

On my Windows 8 system, one of my external hard drives got 100% full. Now I can't delete anything - it says that the destination does not exist. Perhaps it is talking about the recycle bin. I've tried moving some files to another disc, but it says the same thing. I went to the command line prompt and tried to delete there, but it didn't actually delete. Is there a way to delete some files in a situation like this? Bubba73 ^{You talkin' to me?} 03:24, 15 December 2012 (UTC)

Try a defrag to combine some unused space into usable amounts ? Another option might be to delete something huge, which always tells me "That's too large for the recycle bin, do you want to delete it instead ?" (this was under Windows XP, though). StuRat (talk) 03:36, 15 December 2012 (UTC)

There is only one file huge enough to get the "too big for recycle bin" message, and I don't have enough room to copy it to another drive. Bubba73 ^{You talkin' to me?} 03:45, 15 December 2012 (UTC)

Try ⇧ Shift+Delete on a file to delete it without moving to the recycle bin. PrimeHunter (talk) 03:50, 15 December 2012 (UTC)

Thanks, Shift-delete worked. Now I can clean off some files and get enough elbow room. Incidentally, defrag would not start. I told it to empty the recycle bin, but it was empty. I did have 1.91GB free on the 3TB drive, but that wasn't enough. Bubba73 ^{You talkin' to me?} 03:53, 15 December 2012 (UTC)

Resolved

Wikisource content is being indexed as Wikipedia content (in Google)

For some reason, Google is indexing some content of Wikisource as Wikipedia content, see this. I have faced it before too. Any idea? --Tito Dutta (talk) 20:56, 15 December 2012 (UTC)

Googlebot must have come by a page with the link http://en.wikipedia.org/wiki/S:The_Complete_Works_of_Swami_Vivekananda/Volume_3/Lectures_from_Colombo_to_Almora. S: is a interwiki prefix for Wikisource so the link redirects there. PrimeHunter (talk) 21:23, 15 December 2012 (UTC)

Swami Vivekananda, specifically. Note that, given Google's often very fast handling of changes and new pages, there are strong indications that Google has special handling for Wikipedia articles - that they're not indexed in the same way regular web pages are. I suspect it's following the recent changes feed and is pulling articles (or diffs) using the MediaWiki API. If it gets the wikitext for that article, it will get the S prefix. I think the effect we're seeing here is an artefact of this - Google's magic-wiki-spider handles this subtly differently to how the MediaWiki wikitext renderer does - the latter generates a normal wikisource.org url, the former presents it as a wikipedia.org url even though it isn't one. -- Finlay McWalterჷTalk 21:50, 15 December 2012 (UTC)

What makes algorithms non-deterministic?

Hi! In the article deterministic algorithm we say, that threads can cause race conditions, which is a non-deterministic behavior. Or is it a misunderstanding? I'm no native speaker... :-) I have a liltle problem with that claim and in de:WP they couldnt solve my problem: I cannot believe, that a bunch of concurrent, deterministic algorithms transform into a non-deterministic algorithm (in the sense of the formal definition given in the article). E. g.: In a deterministic computing machine M the concurrent algorithms A1 and A2 each load data object O to register X, increment X, write X to O and halt; in my understanding this cannot ever produce more than one sequence of states (e. g. M starts up with 2 identical cores, which each use the same clock and memory without any caching or locking, so that they will behave as if there was only one core, if there wasnt the extra boredom+heat - esp. after the halt instruction). But nobody wants to believe me... *sob* :-) Could somebody explain me, where my example becomes non-deterministic? Is it possibly a homonym thing? Thx. Bye. --Homer Landskirty (talk) 21:00, 15 December 2012 (UTC)

The "What makes algorithms non-deterministic?" section of that article is specifically talking about real computers, stuck here in the muddy real world with us. They don't behave like your mathematically perfect deterministic computing machine. If you were to simulate a cycle-perfect machine, with everything (including interrupts and so forth) simulated deterministically, then algorithms within it would behave deterministically. But real computers, where timing is determined by analog events like the rotation of disks, the magnetic fields and air cushions beneath flying drive heads, the action of interference on bus lines, and a thousand other things, means interrupts which drive the OS don't behave perfectly deterministically, so threats aren't scheduled deterministically, and so a multithreaded algorithm will be affected. -- Finlay McWalterჷTalk 21:11, 15 December 2012 (UTC)

oh - ok - so there is a deterministic algorithm in the sense of theoretical informatics (e. g. with that funny turing machine, which has infinite memory... *lol*) and a real world deterministic algorithm concept (where random events r somehow compensated as good as possible... e. g. timing seems to b always indeterministic here, because there is no way to tell the exact time in real world... this allows race conditions to show up...)... --Homer Landskirty (talk) 22:11, 15 December 2012 (UTC)

In a theoretical context a nondeterministic algorithm is one where you assume a probabilistic distribution on its source of random bits and prove rigorously that the algorithm succeeds with some probability very close to 100%. In the real world the distinction is somewhat arbitrary—it comes down to whether you consider the source of (alleged) randomness to be part of the input or not. -- BenRG (talk) 22:23, 16 December 2012 (UTC)

oh - i thought about that today... without satisfying results: e. g. the program ssh-keygen asks for user input in the beginning and now i wonder if the algorithm is non-deterministic or not... the article says, that Fermat primality test is an example for a non-deterministic algorithm, although it just checks if an equation holds with different values for a... i think i will not try anymore to understand what they mean... :-) "functional programming" looks like a C program to me, too... sometimes... :-) it's a little bit like in that cartoon Calvin and Hobbes, when the father tells Calvin, that an outer point on a LP disc moves faster than an inner point, although they both do the same rounds per minute... *giggle* but it feels good, that i m not the only one who has problems with it... :-) --Homer Landskirty (talk) 23:01, 16 December 2012 (UTC)

The Linux ssh-keygen opens /dev/urandom and reads 32 bytes from it. That's randomness collected from real world sources like network and disk delays (hmm, I'd have thought it would use /dev/random, which is a better source still). -- Finlay McWalterჷTalk 23:20, 16 December 2012 (UTC)

the data from /dev/*random could still b seen as input to an deterministic algorithm... --Homer Landskirty (talk) 06:57, 17 December 2012 (UTC)

Actually, when I think about it, theoretical nondeterminism often means angelic nondeterminism, where one magically chooses the path that causes the algorithm to terminate as quickly as possible (for example, a nondeterministic factoring algorithm starts by correctly guessing a factor). That sort of nondeterminism is the N in NP. It's not directly related to randomness, since there may be only one best choice. What I described above would be called a probabilistic algorithm. I never thought about it, but this doesn't match the real-world use of "nondeterministic" very well at all... -- BenRG (talk) 00:35, 17 December 2012 (UTC)

maybe that's where my disturbance come from... we heard something about "demonic non-determinism", too... *giggle* it guesses wrong until it would have to do the same error twice... --Homer Landskirty (talk) 06:57, 17 December 2012 (UTC)

December 16

Google Instant

On my Google Toolbar in IE9, Google Instant search results do not appear. Instead, a more traditional list of results comes up, but just in a pop-up window below the bar. Altering search settings does nothing to fix the problem. Does anyone have any idea what might be occurring? It's not much of a problem, but I've found it a bit unusual. dci | TALK 01:56, 16 December 2012 (UTC)

Testing wifi link

I have a remote computer (linux) behind a router (the two connected via wifi on wlan0) to which I set up port forwarding for ssh (local ip 192.168.1.3) I don't have physical access to the computer. At some point I could not access the computer anymore, so I asked somebody with physical access to connect router and computer with a cable and to set up port forwarding for this connection (local ip 192.168.1.3; device eth0). Now I can connect to the computer again, however I need to set up the wlan only connection again, without cutting myself off. Is there a way to check whether wlan0 is working while eth0 is present as well? Or is there a way to disconnect eth0 (in software) for a while and have it automatically reconnect after some time? bamse (talk) 07:56, 16 December 2012 (UTC)

ping takes a -I option to allow you to specify which interface (eth0, eth1, wlan0, etc.) to use

to turn an interface off and then on: ifdown eth0 ; sleep 30 ; ifup eth0

-- Finlay McWalterჷTalk 12:24, 16 December 2012 (UTC)

Thank you. As for the ping, that would be issued from the remote computer, no? If so, it would only confirm whether the wifi link to the router is working and not whether port forwarding works, correct? bamse (talk) 18:16, 16 December 2012 (UTC)

Yes, it only validates that traffic is going out that way, not that an external device will preferentially send data in that way. All I can think of for the latter is to run tcpdump -i wlan0 and then send a bunch of traffic from some remote machine that should be relayed to the subject machine (by its local router) over wlan; you should see tcpdump report a bunch of packets (more than the usual network background chatter that it'll probably see). -- Finlay McWalterჷTalk 18:32, 16 December 2012 (UTC)

Or, rather simpler, netstat -i wlan0 will show you the number of packets received on that interface since it was brought up. As above, if you send the machine a bunch of packets you think should be delivered on that interface, if that's the case then that statistic should increase quickly. -- Finlay McWalterჷTalk 20:11, 16 December 2012 (UTC)

Thanks a lot. Thanks to your help I managed to fix it. bamse (talk) 23:34, 17 December 2012 (UTC)

Skyrim help

I don't know if this belongs here or on the Entertainment desk, but bear with me. I just purchased Skyrim for the PC, and when trying to attack, I'm told to press M1 or M2. But I'm on a PC with a keyboard. What are M1 and M2 on a keyboard? 216.93.234.239 (talk) 23:16, 16 December 2012 (UTC)

Mouse button 1 and Mouse button 2 (generally left and right mouse buttons). Incidentally you might find the default set has your left mouse button control your right hand, and vice versa - if so, you can (and really should, it drove me mad until I did) change it in the control settings. -- Finlay McWalterჷTalk 23:28, 16 December 2012 (UTC)

Thanks, just trying to figure out what they were talking about was driving me crazy.  :) 216.93.234.239 (talk) 23:31, 16 December 2012 (UTC)

December 17

PC Memory stick as Random-Access Memory

What is an efficient way to use a 32Gb USB memory stick as RAM? The stick behaves like a hard disk but I don't want directories and files, I just want random access to bytes as fast as possible. My application is solving large sets of simultaneous equations held as matrices in RAM. Assume small programming knowledge. I might manage disk read/write at DOS interrupt level but have no idea how to address a USB interface. DreadRed (talk) 10:21, 17 December 2012 (UTC)

With a memory-mapped file. But the USB bus is orders of magnitude slower than RAM, so it will work that much slower than RAM, regardless of how you address it. -- Finlay McWalterჷTalk 10:39, 17 December 2012 (UTC)

You'd be better off buying lots of ram. Memory is cheap, how much is your time worth? But either way matrices can be worse than you think because of the way they access memory. There's all sorts of programming tricks people do to even get better memory access with proper ram so the cache is used better, it isn't easy as obvious tricks like aligning on page boundaries and chunking in small squares can lead to less obvious problems like cache thrashing where a cache line is overused. Dmcq (talk) 12:46, 17 December 2012 (UTC)

Although this is only related to your question indirectly: What do your matrices look like? Are they sparse? In that case your memory requirement goes down significantly. Also using an iterative solver rather than a direct elimination method will reduce memory requirements significantly.31.54.249.205 (talk) 00:01, 19 December 2012 (UTC)

Yes the equation matrices from FEM analysis are sparse. However the significant savings by sparse matrix methods are data dependent and therefore do not seem useful in a massive infinitely-scaleable multi-processor approach where the cost in terms of hardware engagement and running time must be predictable. DreadRed (talk) 07:45, 20 December 2012 (UTC)

Rather than implementing these routines from scratch, have you looked into LAPACK and it's derivatives? ScaLAPACK is specifically designed for distributed-memory machines such as a computing cluster. PLASMA is optimized to scale well on multiple core systems, and MAGMA takes advantadge of multiple cores and GPUs. 209.131.76.183 (talk) 15:07, 20 December 2012 (UTC)

Word frequency tables

Can anyone help me find these in the format I want ? Here's what Wiktionary has: [1]. Here's what I would like different:

1) No numbers or formatting text, just the words, in order from most common to least (one word per line in the file). This part is critical.

2) All the words in a single file, as opposed to files for the first 10000 words, next ten thousand, etc. This part is optional.

3) All non-alphabetic characters, like apostrophes, stripped off. This will make duplicates out of words like "cant" and "can't", so those should be combined into one, at the proper location in the file (the total of both frequencies). This part is optional.

4) Common proper nouns should be included, too. This part is optional.

I prefer US English, or both US English and British English, but not British English alone. So, do we have anything like that out there ? StuRat (talk) 16:45, 17 December 2012 (UTC)

Given a source list of frequency tables (can you specify), as long as they are in some regular format it should be trivial to merge in your desired form with a bit of custom software (I'd do it in QBasic!) . -- SGBailey (talk) 17:04, 17 December 2012 (UTC)

Possible, but not exactly trivial. It would take me several hours, and I'm already planning on rearranging the files to suit my needs, so I'd prefer if they are at the proper starting point already. StuRat (talk) 17:08, 17 December 2012 (UTC)

Given that you already play with Python, this is not really hard. Do you want to work with the Wiktionary tables, or do you want to create your own from a text corpus? In either case, as long as your result tables fit main memory (and that should be true even for very large word lists today), it's a simple application of some string operators, sort, and print. --Stephan Schulz (talk) 23:45, 17 December 2012 (UTC)

You may have better luck searching for concordances. I hopped over there, then to the Corpus_of_Contemporary_American_English, which led me to their concordance product here: [2], which is viewable as an html table. If you sign up, they will send you an .xls file, from which you can easily port to a single-word-per-line raw text file. Only catch is, only the first 5k words are free. Because it is a professional grade research tool, they charge for the full 100k database. SemanticMantis (talk) 20:16, 17 December 2012 (UTC)

Depending on your application, you may or may not be worried about the methodological details that make the COCA list rather different than the wiktionary list. COCA gives you full details of why their product is better, here [3]. SemanticMantis (talk) 20:19, 17 December 2012 (UTC)

I'm amazed this isn't available for free, like lists of prime numbers are. StuRat (talk) 00:07, 18 December 2012 (UTC)

That frequency list is from TV shows... so I guess you're looking for speech. Wikipedia would produce a different set of course. If you have a few sources with a lot of words (maybe a million?) you could run through and generate your own.

Here's what I ran from the command line to get most of what you want (assuming you have a mac or linux, or can otherwise run perl). Copy paste the list into a text file, or all in order if you want to do more than one at a time, then run this (you can break it up of course too):

cat wordlist.txt|perl -pe 's#^\d+\s*(.+?)\s+.*#$1#;s#[^\w\n]##g'

That won't combine duplicates (there are 4 duplicates in the first 1000), for that here's a dirty way to do it (you probably should have enough ram for this, but depending on your list size, beware): cat wordlist.txt|perl -pe 's#^\d+\s*(.+?)\s+.*#$1#;s#[^\w\n]##g'|perl -e 'while(<>){$word{$_}=$x;$x++};foreach(sort {$word{$a} <=> $word{$b}} keys %word) {print}' Shadowjams (talk) 03:07, 18 December 2012 (UTC)

The apostrophe in "can't" is not essentially a non-alphabetic character because it represents the character "o" that is hidden in the standard contraction of the two words "can not". English contains many such examples such as "it's" which means "it is" (or "it has" but nothing else, occasional abuses notwithstanding). DreadRed (talk) 08:37, 18 December 2012 (UTC)

My code handled it fine. Shadowjams (talk) 14:07, 18 December 2012 (UTC)

How to disable "Accessibility features" in Windows 7 ?

I apparently held the shift button down too long, and it tried to "help" me by beeping at me and locking up the keyboard. A reboot solved it for now, but how do I prevent Windows 7 from ever doing this again ? StuRat (talk) 17:45, 17 December 2012 (UTC)

This has been in there since at least Windows 98. To disable it in 7, open the Ease of Access Center (in the Control Panel, just use the Start Menu search). Under "Make the keyboard easier to use", you'll find the settings to disable the various keyboard accessibility features. The one you're looking for is under "Set up Filter Keys", but you'll probably want to disable the other ones as well. 209.131.76.183 (talk) 18:19, 17 December 2012 (UTC)

Thanks. I had "Turn on filter keys" unchecked, and assumed that was sufficient. But apparently you have to pick "Set up filter keys" to disable the "feature" of it turning back on when you hold down the shift key. StuRat (talk) 18:34, 17 December 2012 (UTC)

Those options drive me crazy when they are accidentally triggered, but I suppose that it makes a world of difference for people who don't have good enough control of their hands to use the modifier keys as designed - they can sit down at any computer and be able to turn on the feature without fighting through menus that are hard for them to use. For my personal computers I always turn it off, but I can see why it is on by default. 209.131.76.183 (talk) 19:03, 17 December 2012 (UTC)

lol,this can be helpful for me to,Thank you.74.178.177.48 (talk) 21:01, 17 December 2012 (UTC)

Resolved

Oldest Computer stuff

Hello fellow users, I'm Tailsman67,I'm a freelancer hacker and programer and I'm here to ask,"What is the oldest Computer?" and "IS the first Computer really the first?" and "What is the first program?",thank you? — Preceding unsigned comment added by 74.178.177.48 (talk) 21:06, 17 December 2012 (UTC)

See History of computing hardware - as with a lot of inventions, which the first X is often depends on how you define exactly what X is. -- Finlay McWalterჷTalk 21:12, 17 December 2012 (UTC)

Ada Lovelace's algorithm for calculating Bernoulli numbers on the Analytical Engine is often described as the first computer program - see Ada lovelace#First computer program. If my memory serves, I think it has a bug. -- Finlay McWalterჷTalk 21:15, 17 December 2012 (UTC)

Weren't the first programs the punch cards you switched to make your water- or steam-powered loom weave a different pattern? I'm not sure that counts as a Turing machine-like thing, though. Sagittarian Milky Way (talk) 23:08, 17 December 2012 (UTC)

A Sundial is the oldest analog computer. This one is from Marcianopolis. DreadRed (talk) 08:55, 18 December 2012 (UTC)

A similar example I heard of were hand-cranked organs, like this one: [4]. You could load a new program by replacing the cylinder, or edit the program by changing the pegs. StuRat (talk) 01:17, 18 December 2012 (UTC)

I seem to remember reading that Leonardo da Vinci had made a programmable toy out of wood and springs, basically a robot. ¦ Reisio (talk) 02:55, 18 December 2012 (UTC)

Yes, and the ancient Greeks did similar things. StuRat (talk) 21:02, 18 December 2012 (UTC)

This image shows one early use of computers. HiLo48 (talk) 09:50, 18 December 2012 (UTC)

Returning to the OP's question seriously, several of the first serious "electronic" computers were developed during World War II, and details of them were naturally hidden behind massive security at the time. Several countries have competing claims. While we now know a lot more, we cannot be certain that all details have been released. In fact, it's almost certain that some information has been destroyed forever. HiLo48 (talk) 16:52, 18 December 2012 (UTC)

Before the electronic ones the first mechanical one that was built that looked like a modern design was by Konrad Zuse and the first design like a modern one was Babbages. However one should really consider Zuse's initial machines as more like a modern scientific programmable calculator than a general purpose computer. Plus there were other systems in between like the Scheutzian calculation engine, based on Babbage's difference engine, Hollerith's tabulating and calculating machines which could be rigged together to do some quite complex work, and a complex number calculator which could be accessed at a distance via a teletype but however wasn't programmable. Plus all these were digital in operation, there were many analogue computers as well. Dmcq (talk)

If you'd like to see a reproduction of a programmable cart like Hero of Alexandria built there's one here [5]. He made some much more complex things too. Dmcq (talk) 19:27, 19 December 2012 (UTC)

Thanks,all of you,Kudos.74.178.177.48 (talk) 19:28, 21 December 2012 (UTC)

What's the cheapest that 2GB DDR2 667 SODIMMs have been?

And when was that? Sagittarian Milky Way (talk) 22:50, 17 December 2012 (UTC)

Real cheap. Recently and now. ¦ Reisio (talk) 02:56, 18 December 2012 (UTC)

CamelCamelCamel is a great resource for this sort of question. Here's the price history on Amazon for a particular model of 2GB DDR2 667 SODIMM: [6]. You can use the search to find charts for others. 209.131.76.183 (talk) 12:45, 18 December 2012 (UTC)

December 18

DOS find command in Windows 7

I issue the following two commands in an empty directory, so neither should find any files to search:

find "call"  *

find "call"  *\*

The first command correctly says "File not found - *". The 2nd command hangs forever (but doesn't seem to use any CPU time). What's it doing, and how do I prevent it ? Also, is there a better way to repeat a search recursively in all sub-directories (all the way down) ? StuRat (talk) 01:09, 18 December 2012 (UTC)

You should be able to use PowerShell for a decent "native" grep alternative. You could also just grab a win32 build of grep from http://gnuwin32.sf.net/. ¦ Reisio (talk) 03:03, 18 December 2012 (UTC)

Grep won't work in Windows in this case because Windows doesn't see *\* as a valid path. Here's how I would search recursively for a string:

for /r . %i IN (*) DO find "call" %i

Other commands simply display an error that the path cannot be found or that is incorrectly spelled. But even if *\* was accepted by Windows, it would only search one level deep.—Best Dog Ever (talk) 03:08, 18 December 2012 (UTC)

grep works fine (and recursively) in Windows… if you have it. ¦ Reisio (talk) 03:24, 18 December 2012 (UTC)

What I was saying is that you can't search for a string in the Windows command prompt using the *\* wildcard no matter what command you use.—Best Dog Ever (talk) 03:30, 18 December 2012 (UTC)

Luckily you don’t have to, you can use . or the name of the top-level directory instead (and in fact wouldn’t want to use */* to "search recursively in all sub-directories (all the way down)", even if you could. ¦ Reisio (talk) 03:36, 18 December 2012 (UTC)

Thanks so far. So what exactly does my 2nd command attempt to do ? It behaves as if it's waiting for more input. StuRat (talk) 19:35, 18 December 2012 (UTC)

The help for Find (find /?) says: 'If a path is not specified, FIND searches the text typed at the prompt or piped from another command', and you're getting the first of those - try typing lines that do and don't contain "call". It seems to be a bit of a bug that it ignores the invalid filespec. AndrewWTaylor (talk) 13:17, 19 December 2012 (UTC)

Yes, it then repeats any line I type containing "call". I agree, seems like a bug. StuRat (talk) 08:35, 22 December 2012 (UTC)

SHA1 and MD5 collision attacks

I'm aware that both SHA-1 and MD5 have been broken with collision attacks. Some of which I guess can be run very quickly. But have there been any published attacks that can break both at the same time? In other words, find an arbitrary input that can collide with a predetermined sha1 and md5 checksum? Shadowjams (talk) 02:48, 18 December 2012 (UTC)

• The article Preimage attack covers what you are talking about. IETF RFC 4270: Attacks on Cryptographic Hashes in Internet Protocols contains references to published attacks. DreadRed (talk) 09:03, 18 December 2012 (UTC)

I know both discrete attacks exist, but does that attack apply to both on the same input block? The article doesn't seem to say as much. Shadowjams (talk) 10:05, 18 December 2012 (UTC)

Hashes are calculated independently for each 512-bit block so that is where collisions are sought. DreadRed (talk) 12:21, 18 December 2012 (UTC)

Alright, that's not an answer to my question. Shadowjams (talk) 13:26, 18 December 2012 (UTC)

You can't seriously hope to find a simultaneous attack on both SHA-1 and MD5, can you? DreadRed (talk) 07:49, 19 December 2012 (UTC)

Well that's the question. Never say never when it comes to cryptography. How long was it predicted MD5 would last in 1992? Shadowjams (talk) 20:20, 19 December 2012 (UTC)

FileMaker

Anyone use FileMaker?

I was asked if I could set up a members database and have it searchable, etc etc. The users are all around the world, so having it on a web site is best. In fact, optimally, they'd like the web site to pull data from the database for use on the site (showing lists of members, locations, how many members do we have that answered XX to YY question, etc). I've never had to set up a database myself, though I've installed and run a couple forums that relied on them. Shortly after being asked about this, the person who asked found FileMaker for another project that they're working on. They found it easy to use and now think that they might not need me to do anything. I took a look at the FileMaker web site and I don't see right off where it'll do what they want. Am I misreading things? Would they be better served by having an SQL database? Or is there some third solution that I remain unaware of? Thanks, Dismas|^(talk) 06:09, 18 December 2012 (UTC)

FileMaker is, as of version 12, a SQL database in its own right (from version 9 it could interact with other databases via their SQL interfaces). It does sound like, to make it accessible from around the world, you need a web app. FileMaker PRO does support this ([7]). To do that someone would have to code a webapp (in say PHP) which interacted with FileMaker (using their own API). Then you'd need to make that accessible on the web - it's likely that you'd get a FileMaker hosting solution (one that supports their Instant Web App capability - a web search finds lots of filemaker hosting companies) and host it there. They could certainly change to a different database, and / or write the webapp in another language (allowing different hosting); they could abandon their local database altogether and store the data in the cloud, and have everyone (including their own admin staff) access it by a webapp. But I think all of this requires engineering to write that webapp. -- Finlay McWalterჷTalk 15:25, 18 December 2012 (UTC)

Note (so you understand what you're looking at when you read some of the "FileMaker hosting" pages) - some organisations use FileMaker PRO as a kind of distributed groupware thing. Their employees around the world have their own copies of FileMaker PRO and they connect those up to a shared server to make changes (just as if they were back at HQ). It sounds like your members are just regular people who don't all own a copy of FileMaker, and so who can't avail themselves of this. That's why you need a webapp. -- Finlay McWalterჷTalk 15:30, 18 December 2012 (UTC)

Update: it looks like Instant Web Publishing means you don't need to write a webapp - they essentially have the FileMaker interface presented via HTML, which is done automatically. Writing a webapp is needed only if you want to have more control over how it appears and what people can do. Like other databases, FileMaker has security segregation between users - but if I were exposing a real database over the internet (particularly when you have to comply with various countries' data protection laws, which may be the case if you're storing details about people) then I'd want that set up by someone with lots of experience with FileMaker, so the security doesn't get cocked up. -- Finlay McWalterჷTalk 16:21, 18 December 2012 (UTC)

Thanks for the breakdown. It's a non-profit organization and they already have a web site. I don't know who they host it with. And you're correct in that not everyone would own a copy of FileMaker. After reading the link that you provided and reading over your explanation, it does seem like they might be able to do what they want with FM. Thanks again, Dismas|^(talk) 09:08, 19 December 2012 (UTC)

Playing Blu-ray discs on my computer

Is it just a matter of 'get Blu-ray drive, install drive, insert disc'? Or does my system need to be of a certain spec in order to play Blu-rays correctly? Don't really know much about them at all, TBH - just been musing over getting a BR drive for my computer now that my DVD burner is playing up on me... --Kurt Shaped Box (talk) 19:35, 18 December 2012 (UTC)

It should play immediately, once the drive and driver are installed. However, since Blu-Ray is capable of displaying a higher resolution image, the question comes up as to whether your PC can display it at full resolution, color depth, and frame rate without lagging. This involves the monitor, graphics card, GHz, etc. StuRat (talk) 19:38, 18 December 2012 (UTC)

That's a thought. My machine does lag sometimes when playing downloaded 720p/1080p HD videos (the latter moreso)... --Kurt Shaped Box (talk) 19:51, 18 December 2012 (UTC)

And the Blu-Ray player should have a minimum requirements list for your PC. That really is a minimum, though, meaning if you have anything else running while watching a Blu-Ray movie, you will need more oomph (technical term) to avoid lag. StuRat (talk) 20:20, 18 December 2012 (UTC)

No, you can't just rock up with a BluRay disc and get it to play. You need the right software to decode it. Often this will come bundled with the drive, unless it's an OEM device. See here and here for more. - Cucumber Mike (talk) 21:56, 18 December 2012 (UTC)

That's what I'm calling the driver, codecs included. StuRat (talk) 22:06, 18 December 2012 (UTC)

I'm pretty sure that I already have the required software installed anyway, but that's no biggie if not. I was more concerned about hardware requirements. Perhaps I should spend some of my probable Xmas gift money on a dedicated graphics card - what's considered good these days anyhow? It's literally been a decade since I paid attention to developments in computer hardware. My current machine has some on-motherboard graphic chipset thing that so far (mostly) works well enough for what I use it for... --Kurt Shaped Box (talk) 22:20, 18 December 2012 (UTC)

Really most any dedicated graphics card that's say not more then 3 years old would do (I mean in generation and real generation not the pseudo-generation due to renaming), even many older if all you care about is bitstreaming H264 and perhaps high quality basic post processing like deinterlacing. With the rise in GPGPU there may be advantages to a slightly more powerful card but it depends on your requirements. But really I have to say, basically most any dual core CPUs except perhaps for some of the Atoms and Pentium Ds (i.e. Pentium 4 dual cores) should be able to handle 1080p software decoding without issue particularly with the sort of bitrates for most downloads. Perhaps they will have fairly high usage but they can handle it without significant drop frames or other issues. I know from experience even one of the old socket 939 A64 x2/dual cores has no problem. So how old is your computer? Even if it has a 16x PCI-express slot so can handle a video card upgrade easily, it may still be worth upgrading the whole. It'll be a bit more but not that much more. The new Intel Ivy Bridge and AMD Trinity chips would often have at least as good GPU performance as the low end GPU you're likely looking at and presuming your computer is really as crap as suggested, you'll likely get more RAM and get a much faster CPU, and that's even with Trinity.

Note that Bluray software is not simple. Because of the DRM restrictions, just having the right codecs doesn't help and a lot of free software doesn't work well without a decrypter like AnyDVD HD which isn't free and I'm not aware any free decrypter works well (it's difficult because of the continous updates required). Most cheap and OEM versions of software which does support Bluray like WinDVD, PowerDVD, Total Media Theatre will not support Bluray. (Obviously OEM versions with Bluray drivers usually will support.) And remember you also need to get updates for your software otherwise it's likely to stop working with new discs.

Nil Einne (talk) 03:41, 20 December 2012 (UTC)

I currently have (cutting and pasting) "AMD Athlon 64 X2 4400+" with "2.00 GB Single-Channel DDR2 (6-6-6-18)". My motherboard does have a 16x PCI-express slot. Well, the manual that I have for what I think is my motherboard (though it may be from another one that died a couple of years ago...) says that I do, but I haven't had chance to open my PC to look yet... --Kurt Shaped Box (talk) 15:47, 20 December 2012 (UTC)

Is this a virus?

I had a program blocked today by my firewall, i think it was trying to send info to the internet. From the information it gives, it looks like a virus that is trying to pass as some legitimate windows program. Look at its location on the hard drive too! The folder name is so arbitrary.

http://i45.tinypic.com/1fd3yc.jpg

Is this a virus? Please share thoughts! :)

PS: I can't think for the life of me why i would have some crap from microsoft, with the publisher being russian...

137.81.118.126 (talk) 19:56, 18 December 2012 (UTC)

Looks iffy to me. I'd get rid of it. StuRat (talk) 20:16, 18 December 2012 (UTC)

I'd compress it with heavy algorithm, not into the file type .ZIP (since Windows natively supports it) and leave the compressed file there. You never know if it's actually legit; you may need it again. -- 143.85.199.242 (talk) 23:04, 18 December 2012 (UTC)

Appears to be a trojan common in Russian-speaking countries. If you don't already have it then please download MalwareBytes Anti Malware and scan the file as that is the recommended fix. MalwareBytes is pretty good at this thing anyway if you've never used it. Good luck! ツ Jenova20 ^(email) 23:42, 18 December 2012 (UTC)

Solve chess

How long would it that the Titan supercomputer to solve chess? — Preceding unsigned comment added by 67.60.98.242 (talk) 20:01, 18 December 2012 (UTC)

Depends on what you mean by "solve". If you mean to use a brute force approach to look ahead from the start of the game to all possible games, and use that to decide each move, that's not possible (would take longer than computer would last). StuRat (talk) 20:15, 18 December 2012 (UTC)

I am not interested in a practical application, an academic result will be sufficient. Are we talking decades, centuries, millenia or the age of the earth here? — Preceding unsigned comment added by 67.60.98.242 (talk) 20:21, 18 December 2012 (UTC)

Let's see. If you brute force it, this site says there are some 10¹²⁰ possible moves: [8]. That would take longer than the universe will last to solve. However, if you just look at board configurations, the number is far lower. This is because you can arrive at the same board position by many different sequences of moves. This site lists only some 140 million board positions: [9]. So, if you had each of those in the database, and the appropriate move for each, then looking them up should still allow for a perfect game, in a small amount of time. StuRat (talk) 20:35, 18 December 2012 (UTC)

Good idea. Is the reason that it has not been solved then because of the time to create 140M databases? — Preceding unsigned comment added by 67.60.98.242 (talk) 20:50, 18 December 2012 (UTC)

Yes. StuRat (talk) 20:55, 18 December 2012 (UTC)

Well, depending on what 67 means. If a (fast) oracle would hand you the correct move from any position, and if that's really all there are (I haven't checked that), then such a database would be perfectly feasible. The problem is computing the correct move. (What's a correct first move for White, for example?) --Trovatore (talk) 21:38, 18 December 2012 (UTC)

Oh, I guess you already went into that. Never mind. --Trovatore (talk) 21:39, 18 December 2012 (UTC)

To go a bit further, each pawn or piece can have it's board position modeled by 6 bits (3 bits gives us one of 8 horizontal positions, since 2³ = 8, and 3 more give us the vertical). Some pieces would need an additional bit, so a king stores whether it has yet castled, and a pawn whether it has been promoted to a queen. So, let's just round this 6 or 7 bits up to 8 bits, or 1 byte per piece or pawn. That's a complete board position modeled by 32 pieces × 1 byte, or 32 bytes (less as pieces are taken). Along with those, you'd want to store the next move, so maybe 4 more bytes for that (2 for white's move if it's white's turn, and 2 for black's). So, a total of at most, 36 bytes. Multiply that by 140 million possible board positions, and we get 5GB. That should fit easily on a hard drive, but for maximum speed, we'd want it in memory. A high-end PC could handle that. Add a proper index/hash to search through the board positions, and it could move basically instantaneously, from a human POV. However, actually generating all this data in the first place would take vastly more computation time. StuRat (talk) 20:55, 18 December 2012 (UTC)

Endgame tablebase could be relevant here. bamse (talk) 21:32, 18 December 2012 (UTC)

The source used above [10] gives no real argument for the alleged 140 million positions. It's a gross underestimate. Chess#Mathematics and computers says: "The number of legal positions in chess is estimated to be between 10⁴³ and 10⁴⁷". See also Shannon number and Solving chess. PrimeHunter (talk) 22:50, 18 December 2012 (UTC)

Expanding on the above, lets assume we can now build a computer storage array that contains the equivalent of one million 1 TB drives. That's 10¹⁸ bytes. Assuming that each position could be mapped to a unique address and we use roughly a byte of storage to store some piece of information (such as moves to win, loose or draw), we can represent roughly 10¹⁸ positions. Well short of our goal for now. Populating data for a game of that magnitude would not be a huge problem. Assuming 1 million processors calculating 1 million positions per second, they could process a universe or 10¹⁸ positions in as little as a few weeks. Note that all of these assumptions could be off by many orders of magnitude, but these are minor going into the next step of the estimation.

If we pick the middle ground for the total number of legal positions, say 10⁴⁵, we will find that our current technology falls short by a factor of 10²⁷ or 2⁹⁰. A liberal application of Moore's law, where both storage capacity and processing power double every two years, would place the expectation for a final solution 180 years in the future (give or take a couple of hundred years). Of course Moore's law is not guaranteed. A molecular crystalline storage device capable of storing 10⁴⁵ bytes might be the size and mass of a small moon.

Perhaps sometime in the year 2200, there will be a chess showdown between Ganymede and Titan, which uninterestingly always ends in an agreed draw before the first move. -- Tom N (tcncv) talk/contrib 04:17, 19 December 2012 (UTC)

Or with Black resigning - if you believe as I do that Chess is won for White. Rich Farmbrough, 16:29, 20 December 2012 (UTC).

That 140 million positions given above is an estimate of the number of "logical positions", which means ones likely to occur in a game. That sounds very low to me. Also, to solve chess, you have to consider all all positions, not just that tiny subset. Of course, there are ways to reduce that 10¹²⁰ by many orders of magnitude. Bubba73 ^{You talkin' to me?} 06:41, 20 December 2012 (UTC)

I could see a solution for perfect play having a table with 140 million positions or so (although I do agree it does sound low). The solution doesn't need to involve every possible position, or even those that are likely to come up in a normal game. It only has to include positions that the board can get into given perfect play on its part. To actually build a table for perfect play, many many more positions would have to be evaluated, and that's where you get into the values like 10^45 above. So even if the solution is reasonably small, actually finding the solution could take ages and tons of resources. 209.131.76.183 (talk) 13:59, 20 December 2012 (UTC)

Of course "perfect play" might mean winning in the shortest number of moves, whereas a more useful definition would be simply winning. To simplify the problem, provided one can calculate to a win, one can prune vast amounts of the game tree. Conversely an unqualified the claim that one can use unique compressed positions as the key to the problem fails, since apart form the above mentioned extra bits for promotion, castling (and, presumably, en-passant), one also needs to take into account the "draw by repetition" rule and the "50 move rule". Rich Farmbrough, 16:29, 20 December 2012 (UTC).

No, perfect play is the same as optimal play, which wins in the shortest number of moves, if it can win by force. Bubba73 ^{You talkin' to me?} 00:39, 21 December 2012 (UTC)

The standard way to record a game position is Forsyth–Edwards Notation. This does take into account promotion, castling and en passant, and also the 50-move rule. Draw by repetition isn't allowed for, but this draw can be claimed by one of the players; it doesn't have to be.-gadfium 02:03, 21 December 2012 (UTC)

python

how do you find the index of the largest int in a list? and how do i find what item occurs most often in a list? thanks, 70.117.119.138 (talk) 23:55, 18 December 2012 (UTC)

Both of these involve a simple iteration through the list, keeping tabs as you go. Have you tried to get this working youself - if so, please show us where you failed. For tasks that look like homework, you'll find Wikipedia editors will help you but they won't (for your benefit) do the work for you. 87.114.106.165 (talk) 01:48, 19 December 2012 (UTC)

For the first one, try "print myList.index(max(myList))". However, this will only return the first index with the max value. If there are more than 1, you might not want this behavior. "myList.count(max(myList))" will tell you if there are more than 1.

For the second, I think iteration is needed. Again, you need to think about what to do if you get a tie (2-way, 3-way or more). StuRat (talk) 19:39, 19 December 2012 (UTC)

For the second task, if you are using a fairly recent version of python, collections.Counter is perfect for the job, provided everything in the list is hashable. For the first one, as well as StuRat's answer, another option is to use the max function's key argument, for example:

   >>> max(enumerate([1,4,0,7,2]), key=lambda x:x[1])
   (3, 7)

This returns a tuple containing the index and value of the maximal element (if two or more are maximal, returns the first one). That lambda function is equivalent to operator.itemgetter(1) by the way, if you prefer using that. 130.88.99.231 (talk) 16:21, 21 December 2012 (UTC)

December 19

List of non-x86 computers geared for home users?

Can you give me a list of non-x86 computers available to home users (routers excluded)? --83.84.137.22 (talk) 11:43, 19 December 2012 (UTC)

Raspberry Pi springs to mind - mostly since mine is right in front of me - but strongly suspect there is other cheap(ish) single board computers available. WegianWarrior (talk) 12:03, 19 December 2012 (UTC)

If you aren't looking for something new, then any PowerPC-era Mac will work. Devices that run Windows CE/Embedded Compact are often ARM-based. Many tablets and some low-end netbooks are ARM-based. Otherwise, you're looking into the single board computer world mentioned above. They are usually targeted for small kiosks, industrial control and digital signage, but there is no reason you couldn't use one as a home user. 209.131.76.183 (talk) 13:09, 19 December 2012 (UTC)

Updating XP in one session.

I've got an old Compaq Presario SR1520 NX running XP (don't laugh, it's fast enough for me).

However, it's time to replace the 320GB drive with a larger one, and re-install XP, which I've done several times in the past. I use the restore DVD's that came with the computer (service pack 2).

Each time I have re-installed XP, it seemed that, for a few weeks, there would be several updates each week. My guess is that the powers-that-be thought that one giant update would take too long for most consumers, so they limited each update so as not to take too much time (This is just a wild guess on my part).

I would like to update to the latest XP, no matter how long it takes, with one update session. How do I do that? And apologies if this is so basic that I should have known. Bunthorne (talk) 16:52, 19 December 2012 (UTC)

You should download and install XP Service Pack 3, instead: [11]. That should eliminate all those updates that were basically taking you from SP2 to SP3 the hard way. However, there still will be updates that were added after SP3, so it's not a total cure. StuRat (talk) 19:23, 19 December 2012 (UTC)

ADVISORY! As of October of this year, microsoft no longer supports Windows XP. It may be a great time to consider upgrading to Windows 7 (avoid 8). Phearson (talk) 00:59, 20 December 2012 (UTC)

Microsoft will support Windows XP until April, 2014: [12].

Also, you can just slipstream the service pack into a custom installation disk, along with any other updates you need: [13]. That way, your copy of Windows would already be up to date by the time the installation is complete.—Best Dog Ever (talk) 03:25, 20 December 2012 (UTC)

I'm assuming you're using the automatic update feature of Windows. You can force it to find and install all the available and installable updates by going to the Windows Update page on the web. Once one set of updates has been installed, you can immediately (normally after a reboot) check for any others. --Phil Holmes (talk) 14:30, 21 December 2012 (UTC)

Success of object oriented programming paradigm

I understand that it's easier to develop OO programs and work in a team and encapsulation, than to work with an imperative programming paradigm, but why isn't the function paradigm not more successful? Or the logical paradigm? OsmanRF34 (talk) 18:23, 19 December 2012 (UTC)

December 20

Browseprotect.exe

I downloaded a screensaver (yesterday), since then a file "Browseprotect.exe" (in all cap) is asking permission to access internet. AVG pops up with options allow, block etc. Can you tell me if it is a legitimate system file and if it is a virus then how I can remove it (full scan or search and delete (though I can't find the file in search)! --Tito Dutta (talk) 05:45, 20 December 2012 (UTC)

There are plenty of "free screensaver" sites that bundle in malware, so I certainly would not trust this new program. I can't find much about "browseprotect.exe", but is some information online on "browserprotect.exe" that seems to come along with some free downloads and is hard to get rid of. Unfortunately, all of the sites that look promising are blocked on our company's network. (Although the obviously scammy "free pc fixer" sites are allowed...) I did a search for the filenames in ICE that confirms that there is no component of Windows 7 that contains "browseprotect.exe" or "browserprotect.exe". 209.131.76.183 (talk) 14:53, 20 December 2012 (UTC)

Yep, it's malware. These "free screensavers" almost exclusively make their money on selling advertisement and personal information. i kan reed (talk) 17:45, 20 December 2012 (UTC)

How big can an internal HD be?

Low large of a capacity can an internal drive on serial ATA on a Windows computer be these days? Is the maximum capacity limited by the motherboard, SATA, Windows, NTFS, or what? Bubba73 ^{You talkin' to me?} 05:45, 20 December 2012 (UTC)

The largest hard drives manufactured today for PCs are 4 TB in capacity: [14].

The theoretical limit for the NTFS file system used in the newest releases of Windows is 256 TB. The ext4 file system used in Linux can support volume sizes up to 1 EB. Older motherboards without UEFI can only boot off of drives that are 2 TB or less in size. UEFI supports a maximum volume size of 8 ZB.

So, to answer your question, the capacity is limited by the tolerances within the hard drive itself, assuming the rest of the software and hardware in your computer is relatively new. Hard drives are increasing in capacity every year. The 4 TB drives hit the market in 2012 and 3 TB units were introduced in 2011, and so on. They've been increasing in capacity steadily since they were introduced in the late 1950s.—Best Dog Ever (talk) 06:41, 20 December 2012 (UTC)

It's usually possible to trick the computer to boot from the first < 2 TB (or 2 GB etc) and then load drivers needed to make use of the whole space. Common trick with BIOS limitations. Electron9 (talk) 17:27, 20 December 2012 (UTC)

The theoretical limit of NTFS is one yobibyte (2⁶⁴·64K). The implementation in Windows 8 is limited to 256TB, according to the article. -- BenRG (talk) 00:25, 23 December 2012 (UTC)

Thanks, and there is nothing on the motherboard, SATA, Windows, etc, that prevents a Windows system from using the whole 4TB? Bubba73 ^{You talkin' to me?} 07:19, 20 December 2012 (UTC)

It's basically down to which SATA standard version your controller complies with minus any chip bugs. As for Microsoft it's depend on driver (supplied by manufacturer) and filesystem (by MS). Beware the Windoze bugz ;) Electron9 (talk) 17:27, 20 December 2012 (UTC)

When I got this computer last year, 2TB internal drives were the largest you could get with the computer. It has eSATA and 8 or 9 months ago I got a 6TB external HD (two 3TB drives, RAID0), with eSATA and USB2. I tried to use eSATA, of course. But I couldn't write more than about 2TB to it. At about the 2TB mark, it would drop down to less than 5MB/sec, and a while after that it would stop. I tried it many times. I got an eSATA to USB3 adapter, put it on my USB3 port, and it works OK. I think something in my system doesn't support more than 2TB on SATA/eSATA. Bubba73 ^{You talkin' to me?} 00:45, 21 December 2012 (UTC)

Which operating system are you running? Assuming you're running Windows, you must initialize any disks above 2 TB with a GPT — not an MBR: [15]. Windows XP is not supported. It must be running Windows Vista or later.—Best Dog Ever (talk) 01:05, 21 December 2012 (UTC)

Windows 7 then, 8 now (both 64-bit). I think I did use GUID. Bubba73 ^{You talkin' to me?} 01:23, 21 December 2012 (UTC)

So, you checked the GPT radio button shown in this picture: [16]?—Best Dog Ever (talk) 02:47, 21 December 2012 (UTC)

It seems to me that a few years ago, HDs were rapidly getting larger and cheaper/GB. They don't seem to be doing that now. Is that right? Bubba73 ^{You talkin' to me?} 02:40, 21 December 2012 (UTC)

It hasn't been consistent from year to year:

Year	Maximum capacity
2012	4 TB
2011	3 TB
2010	2 TB
2009	2 TB
2008	1 TB
2007	1 TB
2006	750 GB
2005	500 GB
2004	300 GB
2003	250 GB
2002	160 GB
2001	120 GB
2000	80 GB

I think I rounded one of the figures above because I remember there was a year when they had 1.5 TB drives. But still, I don't notice a trend myself. In the 80s and 90s there were some years where it jumped like 300% and other years where it increased 50%, just like recent years.—Best Dog Ever (talk) 02:55, 21 December 2012 (UTC)

In terms of price/GB, price/GB has been continuing to drop and I don't believe there has been a major change in the rate. However there was a massive price/GB increase after the Thailand floods and prices are only now beginning to reach preflood levels. Nil Einne (talk) 04:36, 21 December 2012 (UTC)

I concur, the Thailand floods messed the supply and price of disc drives seriously. Electron9 (talk) 19:24, 21 December 2012 (UTC)

That probably explains my casual observation that it hasn't dropped compared to a year or two ago. Bubba73 ^{You talkin' to me?} 19:29, 21 December 2012 (UTC)

Parse two-dimensional array from string in C#

I have run into the following problem at work. I am given a string such as this:

{ {a, b}, {c, d} }

I am supposed to parse this into a two-dimensional string array, such as s, so that:

s[0][0] == "a"
s[0][1] == "b"
s[1][0] == "c"
s[1][1] == "d"

The number of items in both dimensions can vary. I can get to know these dimensions beforehand. The format is otherwise always the same: the whole array is surrounded by { - } brackets, and so are the rows within the array. The rows, and the individual items inside the rows, are separated by commas (,). But I don't know at all how to write the parsing code. Is there a pre-existing library that can do this? Or if I have to write the parsing code myself, how can I do it? JIP | Talk 07:21, 20 December 2012 (UTC)

I would tackle this by deleting the outer {} elements, using a regex to get all the text inside the inner {} pairs, and then string.Split to get the individual elements. Don't think it would be too hard to code up in 2 loops. --Phil Holmes (talk) 14:26, 21 December 2012 (UTC)

You don't really need str.Split() when you use regex. Use one or the other. See here for regex, and this question for str.Split. --Wirbelwind(ヴィルヴェルヴィント) 22:14, 21 December 2012 (UTC)

Serving scaled images and relative widths

Pagespeed is telling me to serve scaled images. However the design uses relative widths. Is there any way to combine the two? bamse (talk) 15:14, 20 December 2012 (UTC)

Firstly, of course, Pagespeed is just advice, and if you have good cause to ignore it, there's no shame in that. But do you really want the browser scaling images for you? The browser's image scaler tends to be rather poor. For background images in an adaptive design, I often find myself putting a fade-gradient on the edge of a background image, so that it fades to the background colour. Then I have the background non-repeating of a fixed size with a specified background colour too. That way it fills the background of the element acceptably, regardless of the size to which that cell is resized, and without scaling in the browser. -- Finlay McWalterჷTalk 15:42, 20 December 2012 (UTC)

Example; the original image (without the fade on the right) is on Commons -- Finlay McWalterჷTalk 16:11, 20 December 2012 (UTC)

Thanks a lot for sharing the idea and code. Unfortunately fading is not an option in my case. The images appear together with text in a table-like listing: think a forum with avatar images on the left and some text around it. Let's say the container of the image is 10% of the full width. As far as I understand, there is no way to prevent image scaling by the browser if the image is supposed to fill all of the container (correct?). I read somewhere that one could use javascript to provide differently sized images (to be further resized by the browser) based on the display size. Is this really worth the effort, particularly for a site which would typically not be accessed from small mobile phone screens? bamse (talk) 22:24, 20 December 2012 (UTC)

As a side question, is there some online-tool that allows to calculate recommended image resolution (of the stored image) based on the eventual display size (in % of screen size)? bamse (talk) 22:26, 20 December 2012 (UTC)

The connection to the server was reset while the page was loading.

The above message has been appearing in my browser with apparently increasing frequency - this applies across at least 7 machines using Palemoon and Firefox. Similar errors appear in IE.

Clicking on "try again" is usually successful, however.

I have attempted to discuss the matter with Talk Talk my ISP, but since they tell me that 0870 numbers are free to call, don't know the difference between dropped packets and a dropped line, don't return calls and will on no account pass me to a supervisor, I have little faith other than they may have performed a whoosh test, and it may have shown everything to be fine.

In an attempt to diagnose the problem I have re-pointed my DNS to Google DNS, reset the router many times over the last few weeks and preformed a few network diagnostics viz:

1. emulated an http connection by using telnet
2. checked traceroutes and pings for basic connectivity and possible route-flap (seems ok, but hard to be sure)
3. used ping -t to check for packets being dropped - 0% to Google, .1 % to Wikipedia

My options seem to be based on getting a new router or switching ISPs. I am tempted to switch ISPs anyway since this bunch seem such a shower, but I'm not convinced that it will solve this problem. Any ideas? Rich Farmbrough, 16:00, 20 December 2012 (UTC).

Your symptom sounds like you may have a software proxy server or web cache - either on your machine, or somewhere upstream, provided by your ISP - that is misbehaving. Unfortunately, diagnosis of an amorphous symptom like this requires a lot of effort and often results in no progress fixing the problem; but from your described troubleshooting steps, it sounds like you are on the right track and have the technical proficiency to proceed. So, here's my recommendations:

First, isolate whether the cache or proxy is local on your machine, or upstream by your ISP, by connecting a different machine to your cable or DSL modem. If the symptom reproduces on other computers on the same connection, the problem is not your fault! An amorphous cache server configuration bug exists, it's your ISP's fault, and there is essentially nothing you can do to fix it until a skilled-enough technician happens to repair the error (and that sounds unfortunately unlikely). Try to work around the bug; you can try using HTTPS/SSL/TLS in your browser, or try to disable caching, or so forth.

If the problem only occurs on your machine, and not on others, check for common cache and proxy and firewall software. It sounds like the problem occurs in all browsers, so it is not likely due to a browser setting. Other places lower down the system stack to check include your system network settings and your antivirus programs. Antivirus programs sometimes set up such network trickery for your "protection," and it has been my experience that their implementations are often imperfect. Again, try to workaround the problem using non-caching or secure HTTPS pages. Finally, check for malware "web accelerators" and similar ill-intentioned software that lives in your network stack; sometimes this can be quite well-hidden. Good luck with the troubleshooting. Nimur (talk) 18:38, 20 December 2012 (UTC)

Thanks, yes I thought some kind of caching, even worried that someone was intercepting my traffic clumsily. As I don't use an explicit local cache or proxy, and I'm getting this on 7 machines I shall provisionally blame the ISP, and probably move, hoping the new bunch aren't even more hopeless. Rich Farmbrough, 23:07, 20 December 2012 (UTC).

I've had the same thing, too.

Basically, screens start loading and even displaying, and when I cut the connection (I'm on 56k), the page vanishes and displays that silly error message. It's been increasing slowly and steadily from 2008 on , even after reinstalling, and jumped up recently when the "Edit saved" pop-up came up on wikipedia. (Is that malware? it looks damn genuine to me.)

To make a long story short, it's like some demon in my machine that decides, "If you don't stay connected 24/7, you don't deserve that WP content," which is silly. After all, I received most of the info, and all I want is a tall ship and a browser which shows me that info rather than a full-screen error message.

Cancel seems to avoid the error message, but it's a pain and a half to push cancel on each page before cutting the connection. - ¡Ouch! (^{hurt me} / _{more pain}) 06:51, 21 December 2012 (UTC)

Yes, I get the same error message sometimes, especially when it is raining heavily, but in my case the problem is almost certainly an intermittent internet connection (delivered via a microwave chain). Dbfirs 09:31, 21 December 2012 (UTC)

How is Google connecting merchandiser ID data to the person using Google?

From this article: " If you bought a T shirt at The Gap in the mall with your credit card, you could start seeing a lot more Gap ads online later, suggesting jeans that go with that shirt." If you read the article, you'll see that what it's supposing is that Gap uploaded its sales data using this Conversions API that Google is going to offer to advertisers. So that's how your shirt purchase got known in the Internet. But how is your identity getting connected to Google ID whateverUser395, or even if the name Joe Blow on your credit card were loaded up by Gap and your Google ID was Joe Blow, there could be twenty other Joe Blows in the world. I don't remember giving any hard ID like address, and definitely not SSN, when I created a Google account. I wonder how uploaded advertiser data can get pinned to given Google IDs especially when it says in the article "Neither the advertiser nor Google will be able to track you individually." 20.137.2.50 (talk) 18:34, 20 December 2012 (UTC)

Google is getting scarier each year. OsmanRF34 (talk) 18:41, 20 December 2012 (UTC)

You might read business intelligence and data mining for a start. Also, keep in mind that 100.0% accuracy is not necessary; if a few errors occur, a few targeted advertisements "convert" to untargeted advertisement, which is not a total loss to the advertiser. So, the specific data-mining and identity aggregation methods in use only need to be accurate enough to provide competitive advantage over alternative advertisement strategies. Nimur (talk) 21:09, 20 December 2012 (UTC)

Content supervision

When a software designed to monitor what webpages a person visits (like the ones installed on computers in work and academic environments), does it merely record the URLs of the webpages you visit, or does it record the content of those websites as well? Like for example, if you're looking up porn on Tumblr, does it only know that you've been on Tumblr or does it know specifically what you were looking for on that site? And does using the "site:example.com" function of Google also give away your activities? 74.15.143.46 (talk) 23:04, 20 December 2012 (UTC)

The firewalls I used to administer would record the URLS, not just of the "pages" you visit though. If you visit a page the images are fetched by a separate request, so their urls will be recorded too. it is also possible to record information over and above the url, but often search terms are in the URL. I suggest for a fuller answer you look at the manuals of the software in question, familiarise yourself with HTTP and SSL, and get in the habit of looking at the URL in you address bar as you browse to understand more of what is going on. Rich Farmbrough, 00:27, 21 December 2012 (UTC).

But the thing is, I'm not installing or running the software. I'm merely asking on the off chance that I'm having my personal web browsing activities monitored (I honestly don't know if that is indeed the case, and can't tell if it is). 74.15.143.46 (talk) 02:42, 21 December 2012 (UTC)

The thing is, it should be fairly obvious software could record everything if it wanted to, so it's a pretty meaningless question. Most set-ups don't record everything simply because there's little point (recording the entire URL would usually be enough, they could always visit the URL later to check what the content was if it hasn't disappeared and when it isn't you normally just have to record the request rather then the response to get an idea of what the person is doing such as by revisiting the page) and it would take a lot of storage space if you have a large number of users and they use a fair amount of bandwidth but you can't rule it our in some arbitary set-up. And even if the software doesn't normally record everything, it may still analyse pages and record stuff that may be of concern or the IT admins could choose to record stuff if a user is of concern. If you are concerned, your best bet is to read the appropriate policies or employment contract or whatever is relevant to your situation, seek help for any areas that confuse you and then don't do anything that violates it. For your personal internet access, choose a service provider that provides sufficient guarantees to allay your concerns. Note that presuming someone else has administrative control of the computer you're using then there's nothing stopping them recording everything done on the computer including stuff which you would not expect to pass through the network, as well as either recording a decrypted copy of stuff which uses end to end encryption lime HTTPS or otherwise enabling themselves to decrypt encrypted traffic. If you also have administrative control in addition, you could try to stop this but it may itself be a violation. Nil Einne (talk)

I work in IT for a fairly large corporation. I can tell you first hand that some of the systems in place these days used for large volume content filtering are very sophisticated indeed. We use a system that doesn't just "track" what you look at, but can heuristically analyse images in websites and email in real time and automatically flags it if meets the rules for inappropriate content, (the volume of flesh tone being the most obvious, but not only, example). It then goes on to be assessed by a human, but the system does 99% of the work.Vespine (talk) 05:39, 21 December 2012 (UTC)

Every color from black to brown to yellow to sallow white to white to pinkinsh white? Do you get lots of false positives like beach volleyball or lion films or teleconferencing with unusually skin-toned clothes or something? Porn is overrated. After seeing every kind of woman's body naked (about 3 months) I lost the phallomanipulative compulsion. (one of the last ones was Elaine Benes. Oh baby, you have no idea how hot she is until you've seen her (photoshopped) naked (and gotten a bit closer in age) Sagittarian Milky Way (talk) 21:22, 21 December 2012 (UTC)

I used to hope I'd get somewhat closer to you in age, too. But achieved fuck all. ;)

To OP. There could be some process capturing your screen in 30-sec intervals. That would defeat end-to-end encryption and many other tricks. The server could challenge the process using some kind of question only that process would answer, sl killing the process would draw some attention, too. Or maybe it's bayesically the kind of thing Vespine mentioned. - ¡Ouch! (^{hurt me} / _{more pain}) 18:31, 22 December 2012 (UTC)

December 21

What was/is the original Linux OS?

What was/is the original Linux OS?13:02, 21 December 2012 (UTC) — Preceding unsigned comment added by 189.115.209.8 (talk)

Start by reading History of Linux. When first announed, Linux included a kernel, the bash shell, and gcc (a C compiler). This was the operating system: the kernel and the user-interface (i.e., a command-line interpreter). More recently, the user-interface utility now named X.org was ported; many utilities like desktop managers and commonplace software packages became bundled as "Linux distributions," and many software forks split off. There is still one canonical repository of "the" source-code, hosted at http://kernel.org - though this contains source for the Linux kernel only, and not for full distributions of GNU/Linux or alternative operating systems. Nimur (talk) 17:22, 21 December 2012 (UTC)

If I understand the question correctly, the OP is interested in which the original linux distribution (i.e. packaged bundle of linux kernel and tools) was. Have a look at Linux_distribution, and especially at the nice timeline plot in that article. The answer to the question is probably that (apart from a few short lived efforts) Slackware is the oldest distribution which is still around. The other major distributions such as RedHat, Debian and derivatives are independent of Slackware though, so it is doubtful you can call Slackware the 'original' distribution. 81.156.176.219 (talk) 22:15, 21 December 2012 (UTC)

I will be sincere here. Linux is a kernel not an os. But I saw some people on some places saying something like the kernel being an os or something like that. So I decided to post that here to see what answers I would get.177.98.122.31 (talk) 10:19, 22 December 2012 (UTC)

As you read more about operating systems, you will learn that the term is not very clearly defined, especially around the edges of its use-cases. For very simple systems, like the very earliest incarnations of Linux, there was no significant distinction between "the kernel" and "the system." This was especially true for the earliest Linux, because its scheduler was deeply architected to take advantage of the Intel 386 system. So, the kernel and its platform-driver were the same pieces of code. And, in the very beginning (during development), the kernel booted and did nothing; perhaps it ran Linus's test hello world program. Eventually, it booted and ran the bash shell. That was the operating system. Now, in modern use, we distinguish kernels from system-software as a whole; because (especially in the last few years), the code has become clean and standard enough so that you can easily separate these entities. You can replace Linux Kernel with GNU Hurd, and the "operating system" appears identical - not just the user interface, but even things OS programmers think about, like your USB keyboard driver, and your X.org server. So, on modern GNU/Linux distributions, we can "cleanly" say that the kernel and the OS are "separate parts." That clean separation is not always true for other systems, even some Linux systems. Nimur (talk) 18:35, 22 December 2012 (UTC)

Hash that allows for similarity comparison

Disclaimer: This is not for security. It is not for true hashing. It is for a very specific task that has absolutely nothing to do with common hashing tasks.

Is there a one-way function (like a hash) that allows for similarity comparison? Example, I want to hash names. I hash John Lennon and John W. Lennon. I want the result to allow me to identify that those two things are much more similar than a hash of Paul McCartney. So, this function requires two things. 1: It is one-way. I don't want to know the original information. 2: It retains similarity. 128.23.113.249 (talk) 13:24, 21 December 2012 (UTC)

I think you might need to be a bit more specific about your requirements. What kind of data are you hashing (presumably not names of musicians), and what does "similarity" mean in this context? Do you actually require the hash to be one-way, or is it just that it can be one-way? How much smaller do you want the hash to be than the original data? If you actually are interested in names, then are you aware of soundex and similar algorithms to group words with similar pronounciations together? 130.88.99.231 (talk) 16:01, 21 December 2012 (UTC)

The data will be names. But, the names cannot be known. Therefore, there must be a one-way hash-like function. So, assume the function spits out 8 digit numbers. I give you 12345678 and 12245678 and you can see that the original names, which you don't know, are about 90% similar. The end goal is to identify similarity of names without having an easy means of knowing the original names. 128.23.113.249 (talk) 18:27, 21 December 2012 (UTC)

If similar inputs give similar outputs, and if (as you apparently do), you also want to be able to reliably conclude the reverse (given similar hashes, you want to know that the names are similar), then it's hard to see how you can prevent someone from inverting the function, by just searching. What you're looking for seems (almost?) provably nonexistent. --Trovatore (talk) 18:37, 21 December 2012 (UTC)

Perhaps Soundex would work for your purposes? —Chowbok ☠ 20:20, 21 December 2012 (UTC)

I suppose I could be a little more explicit about what I mean by "just searching". Suppose I have one of your hashes, and I want to know the input that generated it. I start generating inputs and evaluating the distance between their hashes and the given hash. I change a little bit and see if it improves or degrades the cost function (that's the distance between the hash of my chosen input, and the target hash). Now if I always accept a change that improves that, and always reject one that degrades it, that's called greedy descent, and it might not work because I could get stuck in a local minimum.

But there are lots of strategies to avoid this fate. A simple one is simulated annealing.

This might not work all the time, but it's probably going to work a significant fraction of the time, and it's hard to see how any scheme fitting your requirements can be made resistant to it.

On the other hand, since you say you don't care about "security", maybe you're not interested in preventing someone from recovering the input if he's willing to work that hard; you just don't want it to be trivial. That's probably possible. I'd start with a search on "obfuscation". --Trovatore (talk) 18:58, 21 December 2012 (UTC)

It sounds like you want fuzzy hashing (context triggered piecewise hashes) (which we don't have an article on?). ssdeep does a version of that, although I'm sure there's something better for text. The soundex is a step in the right direction but I don't think it directly does what you want. Does anyone know if there's some better wiki articles on fuzzy hashing? I don't know the name of any algorithms that implement it, but that's what I'd start to investigate. Shadowjams (talk) 07:53, 22 December 2012 (UTC)

And, even ignoring the hashing issue, which names are most similar is still difficult to define. I'd assume the family name is most important, but this is sometimes the last name and sometimes the first name, depending on the culture. Then the given name may be next, or perhaps a nickname. Middle names are less important, but there can be any number of those. And what do we do about aliases, nom de plumes, etc. ? StuRat (talk) 08:23, 22 December 2012 (UTC)

Is a hash of length 27x26 bits ok?

(OR) If it is, you zero all bits first. Then you process all pairs of letters (JO, OH, HN, LE, etc.) as follows:

-Treat A as 0, B as 1, ... , Z as 25.

-Compute N = 26 * (first letter) + (second letter). If there is only one letter (W for example in JOHN W LENNON), make that the second letter and make the first letter 26.

-Set the Nth bit of the hash.

That way, the bit pattern will resemble the letter pattern. The XOR of two hashes is the "distance."

If 27x26 is too large, take the first letter modulo 9 and the second modulo 13. Voilâ, a 9x13-bit hash at the price of some accuracy.

Close to trivial, and probably inferior to soundex, but maybe my hashing strategy is closer to the thing you had in mind. Hope that helps. - ¡Ouch! (^{hurt me} / _{more pain}) 18:05, 22 December 2012 (UTC)

Is it possible to display 2 Excel 2007 spreadsheets on screen at the same time?

Resolved

I'm using Excel 2007 and have 2 spreadsheets open. Is there a way I can display both on the screen at the same time? What I would love to do is to snap one spreadsheet to the left side of my monitor and the other spreadsheet to the right side of my monitor. But Excel won't let me do this and I don't see an option to turn it off. I'm using Excel 2007 and Windows 7. I have one monitor. A Quest For Knowledge (talk) 14:21, 21 December 2012 (UTC)

Nevermind. I figured it out. You go to the View tab on the ribbon and click Arrange All. A Quest For Knowledge (talk) 14:46, 21 December 2012 (UTC)

For older versions of Excel, you can just open the spreadsheets in different instances of Excel, then resize as required. Dbfirs 21:01, 22 December 2012 (UTC)

Is the data rate of a connection the same as that of the slowest device in the path?

Consider two (simplified) networking systems. In one, a high-speed device sends data over fiberoptic cabling to a device with a low upper limit of bitrate (eg, 56K). The second system is the same, but the cabling is telephone line rather than fiberoptic. Would the download speed of the recieving device be any different between the two systems, given that fiberoptic is "faster" than phone lines?

Is it like a car changing speeds at different parts of its journey (the total average speed of the car is not the same as its slowest speed)? Or is the total average speed generally the same as that of the slowest device or technology (computer, NIC, UTP, hub, switch, modem, phone line, server, etc) that the data travels over? ± Lenoxus (" *** ") 01:18, 22 December 2012 (UTC)

Think of the bits of data as being like cars then and your telephone line being like a road through a small town. Just because a multi lane highway brings cars to the outskirts of town does not mean that any more cars are going to be able to go down the small road in town every hour. The time for all the data to download is normally far longer than it takes for the first item of data to arrive after being sent, even a small web page consists of tens to hundreds of thousands of bits, so the rate going through the slowest part is what is important. Dmcq (talk) 01:49, 22 December 2012 (UTC)

That's a good analogy, and it carries through to the case where the only roads are narrow over the whole distance. There are likely to be delays further back along the route, so even the last (56K) narrow road might be unused at times if it is waiting for traffic that was delayed further back. The analogy doesn't quite carry through to average speed, because it's congestion that causes the main delays further back, and it's the number of cars that get through per unit of time that matters. Your 56K is the main limiting factor, but congested telephone lines further back might mean that download is even slower than the 56K narrowest part. Good buffering (car parks, but with engines running ready to go again) at the right places can mitigate this effect. Dbfirs 09:01, 22 December 2012 (UTC)

Buffering doesn't help, it actually makes things worse by hindering TCP's ability to adapt to the available bandwidth. See bufferbloat. I think the OP is simply asking whether fiber-optic cable is really faster than a phone line, and the answer is not much if at all. Optical fiber says that a typical index of refraction is 1.6, meaning the signal travels at about 5/8 of the speed of light, while speed of electricity says that it can be as much as 97% of the speed of light in unshielded copper, though I suspect it's slower than that in phone lines. Optical fiber also needs fewer repeaters, which add delay. However optical fiber is "faster" in that you can pack more bits longitudinally in it, meaning you can transfer more data in a given time, though each bit takes just as long to arrive. -- BenRG (talk) 00:07, 23 December 2012 (UTC)

Egyptian Arabic Wikipedia

1. Why accept the establishment of Egyptian Arabic Wikipedia (Meta) with it is known that the Egyptian Arabic dialect?
2. Can this version is canceled? --41.130.174.90 (talk) 10:31, 22 December 2012 (UTC)

Our article about that version of Wikipedia is at Egyptian Arabic Wikipedia. It has nothing to do with this English version and it has nothing to do with this reference desk which is about computing questions. Why not ask your questions at that Wikipedia instead? In general all that is needed for starting a new Wikipedia is a demonstration that there would be sufficient support, that obviously was shown. Basically the attitude I believe you'll find anywhere on Wikipedia to your idea of stopping something that has support is that if you don't like it that's your problem and you can go and lump it. Dmcq (talk) 12:21, 22 December 2012 (UTC)

My laptop speakers have become crackly & tinny - how to restore the sound myself?

Hello, the left speaker doesn't put out at all, and the right one, as of 15 minutes ago, started putting out a severely ruined sound that is more tinny and crackly than true sound. I now can't make out the words 3/4 of the time.

Instead of buying external speakers, how do I get in there and actually repair the workings of the speakers so that they put out correctly again?

The computer is a Dell Inspiron 1720 and went out of warranty in September. I hope to get a killer replacement next month (preplanned for quite some time) but would like to know how to fix the speakers in order to tide me over until then. Thanks kindly. --70.179.167.78 (talk) 17:29, 22 December 2012 (UTC)

I'd suggest just using headphones until then (or external speakers, when home). Laptops are quite difficult to repair, and you're likely to damage something else in the process. Plus, you'd likely need to buy new speakers to install into the old laptop, and, unlike external speakers or headphones, those can't be reused elsewhere, so it's just throwing money away on something you will only use for a month (less than that, including delivery and installation time). There's also some possibility you just have some loose wires to deal with, but, unless you're an expert at soldering, that's not easy to repair, either. StuRat (talk) 17:44, 22 December 2012 (UTC)

Video calls

How do video calls work on phones. Do they work over 3g data? Im confused as many mobile networks don't class video calls as mobile data. Clover345 (talk) 17:35, 22 December 2012 (UTC)

Ping hosting provider

I am deciding on a hosting provider and am considering companies that are located in another country (than most expected visitors to the website). I would like to compare ping and download time for various providers. Is there a tool to do that, and more importantly, which server/ip should I ping? bamse (talk) 17:42, 22 December 2012 (UTC)

Ping time is measuring the delays in the route to the hosting server. Download speed also depends on this route, and also on congestion at the hosting server and their link to the internet. I don't know of a tool, but if you use these tests, make sure that the slowest link is not your own internet connection. I would also want to look at data on server downtime. Dbfirs 20:54, 22 December 2012 (UTC)

What other Chrome Apps are like Session Buddy?

Just an hour ago, in the last crash-restart, my Session Buddy lost all of its sessions that it has ever saved, and I have no idea how to recover them. I had 44 tabs open, and would prefer to find them anyhow.

But for the future, in case Session Buddy goes wrong again, I'd like to run another app like Session Buddy that will hopefully have all the previous sessions if Session Buddy no longer does, or vice-versa.

So what apps are like Session Buddy that can hopefully save my sessions if Session Buddy doesn't? Thanks. --70.179.167.78 (talk) 21:11, 22 December 2012 (UTC)

how do I prevent text from being part of a link? (esp. Google Docs)

I always have to do really funky things, like click on the next line, write some text and then backspace so the text can be adjacent to the link but not actually part of it. It's so annoying! When I use "clear formatting" on the part that I don't want to be part of the link, it doesn't work at all! How do people explicitly specify that a link should stop? 72.229.155.79 (talk) 22:33, 22 December 2012 (UTC)

Youtube's 500 Internal Server Error

Occasionally when I go on Youtube, there's an error that's called the '500 Internal Server Error', and a pack of monkeys were sent to deal with the situation, which I'm pretty sure it's for humor. But is this actually real?