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August 15

Primary key

I have to design a series of tables for a database. One of the tables will look like this: (those are the fields): [1] numb_id int (11) AUTO_INCREMENT; [2] attribute-1 double; [3] attribute-2 double [3] attribute-3 double.

I make the first field a primary key.

My question is: will I gain in performance speed with the primary key vs. no primary key? My understanding is that there will be no gain in performance. Primary key is an index field, it means that DBMS will create a separate (index) table that will have this key in the first column but it is already in the first column. That column will be ordered but it is already ordered. It will then probably create pointers to each row in the first table to the row where the primary key is but it's not really needed. Once you get the row in the original table you can read this information directly. Is it all correct?

What could be the situation, what kind of structure the table should have to benefit from introduction of primary key in terms of improved performance. What could be the gain?

Thanks, - --AboutFace 22 (talk) 01:43, 15 August 2014 (UTC)

You don't mention the database system you are using, but the syntax looks like mysql. I don't know mysql specifically, but in general you get the first index for free - combined into the main table. This is called the clustered index. Typically the primary key will also be the clustered index unless you explicitly specify something different in your table definition. A database index is some variation of a tree data structure that allows for an efficient look-up of a specific key value or range of values. For secondary (non-clustered) indexes, the leaf node will be a reference to the record number of primary key value into the main table. After database system looks up the index record, a second look-up into the main table is performed to get the actual record. For a clustered index, the leaf node of the index is the record itself, so there is no extra work to retrieve the target record contents. How much performance gain that gives you depends on how often to access a record (or join to that table) using that primary key. -- Tom N talk/contrib 04:08, 15 August 2014 (UTC)

Thank you, Tom. I actually do not know the DBMS that is going to be used. I do not design the whole thing, only a conceptual framework so to speak. I do have some (fairly extensive actually but years ago) background in SQL server and dBase IV now defunct but this is not applicable here. Another person does the implementation. He mentioned a few options, MySql is one of them. The actual choice is still up in the air and will be apparently discussed at a later date but this is not something I can influence because I am not familiar with them.

This is also my impression that in order to be effective the primary key must be a clustered index, otherwise any advantage is not there. It sounds like you are saying that the primary key is always a clustered index even if not designed as such. Thanks, --AboutFace 22 (talk) 13:40, 15 August 2014 (UTC)

I believe each table normally has a hidden column, named something like ROW_ID, that sounds like it would be identical to your NUMB_ID column. So, you could possibly skip your column entirely. However, if you would ever want to change the numbering to be anything other than the order in which the rows are created, then you need to keep it in. Also, if you intend to display the column to the user, it might be easier to keep it in, than try to use the ROW_ID for that. StuRat (talk) 17:19, 15 August 2014 (UTC)

Thank you, StuRat, you are always helpful. Still one of my questions is unanswered: how much will I gain in speed of storage and retrieval with introduction of primary keys. --AboutFace 22 (talk) 17:59, 15 August 2014 (UTC)

It sounds like there would be no savings in speed by introduction of the primary key, if it's just redundant with the ROW_ID index which you get by default. It might actually slow things down by a slight amount, as there's some overhead in using it. However, as each DB management system is a bit different, I can't guarantee it. I'd do some benchmark testing to confirm it on your specific DB.

BTW, I don't think adding a primary key ever makes row creation faster, as there's now more info to store. It's designed to make retrieval faster. Deletes and updates may also be faster, as the first step there is retrieval of the desired record. And, of course, if you do a retrieval using some fields other than the primary key, it won't help the speed there, either. StuRat (talk) 22:28, 15 August 2014 (UTC)

Chili's credit card security

This restaurant chain has placed card readers on each table so you can pay by credit card there. However, they are wireless. What type of security precautions do they take so the credit card info can't be compromised ? (This is a practical Q, as I eat there myself, and want to know if it is safe to pay that way.) StuRat (talk) 22:21, 15 August 2014 (UTC)

Apparently it's a Ziosk. This on Chilis' website says it "meets the comprehensive PCI security standards". The Ziosk website doesn't say much at all about security considerations, except for mentions of "Secure payments" and "encrypted credit card reader". Rojomoke (talk) 07:28, 16 August 2014 (UTC)

Thanks. Of course everyone claims to have a secure system, but all the recent thefts of credit card info shows they were wrong. So, if they won't say how it is encrypted and secured, I guess I have my answer: don't trust it. I'll continue to pay with cash. StuRat (talk) 13:37, 16 August 2014 (UTC)

StuRat, your post last night made me thinking. What is the guarantee that cash registers at Sears, Macy's or other large department stores don't have wireless connections with their credit card readers. What would be a wired connection? A phone line which is perhaps much more expensive to operate in a long run. You also need lots of them to service a large store. The answer ultimately would be those credit cards with chips inside they are talking about now. Thanks for your note at my primary key post. --AboutFace 22 (talk) 14:52, 16 August 2014 (UTC)

I think the recent thefts show a more important point. Whether the connection is wired or wireless, how does it help anyone if the POS systems are hopelessly insecure? Also experience in Europe where chipped cards are the norm shows they help, but are no magic bullet. In other words, you can be pretty sure there will be breaches,a nd it may not be in the areas you think.

However I'm not recommending mass panic. People seem to worry about this sort of stuff too much when they are end users. Sure you should take reasonably protections like making sure you hide your pin entry, a cursory check for any skimming devices and not handing your credit card over to a dodgy looking person who disappears with it for minutes, but there's no need to analyse the security of every machine except for personal interest reasons. (And speaking of dodgy people, I wonder how many people willingly hand over their unchipped card to someone who disappears with it and yet are worried about the security of machines.)

Obviously it's annoying to have to replace your credit card or make reports and wait for your bank to cancel transactions you didn't make but if you're paying attention to your statements (which you should be), you should primary consider such credit card misuse fraud a concern of the banks and stores involved, not yours, unless you're in some weird jurisdiction or with some weird bank with totally crap credit card liability policies. (Identity theft is of course another issue.)

Nil Einne (talk) 15:58, 16 August 2014 (UTC)

Note that recent major thefts of credit card info have been either from the back office systems or from malware infected POS terminals (like that suspected in the Target#2013 Security Breach). The payment details were not snatched from the air while being transmitted from a card reader to the store's systems. Your card information is probably just as safe as if you were to go to the desk and pay there with your card. The added security provided by Chili or any other location with portable POS devices, is that you don't hand over your card to someone who disappears off into a back room and skims your card. In any case, the Payment Card Industry Data Security Standard mandates that information such as the PIN remain encrypted at all times. Unfortunately, not all information is required to be encrypted and that is how the thieves are able to get access to customer names, card numbers, expiration dates, etc, but not the PIN numbers. The thieves are then able to shop online, so long as they can avoid things like 3-D Secure, but can't produce a duplicate card and go shopping at regular stores, or retrieve cash from ATMs. Astronaut (talk) 15:58, 16 August 2014 (UTC)

Yes, they do take the credit card away for several minutes. I wish they would just bring the card reader right to the table. So maybe the Ziosk is the safest way to use a CC, although still not as safe as cash. StuRat (talk) 03:18, 17 August 2014 (UTC)

Of course carrying around lots of cash all the time makes the risk of being mugged or pick pocketed higher :P I think the physical risk outweighs the virtual one by a long shot. I work in IT for a financial institution and I think people worry FAR too much about how secure their credit card is. I think Nil Ennie's reply is very reasonable. Banks guarantee credit cards against fraud, credit cards now are safer than ever before. Do you remember the days of swiping your card in those carbon imprint machines? You think "that" was secure? Vespine (talk) 23:02, 17 August 2014 (UTC)

I carry my wallet in my front pocket, not back, deep down in the pocket, so it would be difficult to steal. I also have a secret compartment for the big bills (be careful how you read that), so anyone eyeballing me as I use it to pay a restaurant bill will only see small bills. StuRat (talk) 16:46, 19 August 2014 (UTC)

August 16

JPEG color

I need to determine the HTML color code - #rrggbb - of part of an existing JPEG image. The color is consistent enough that any pixel will do within the resolution of my mouse. Is there a web tool that will do this?   Mandruss |talk  07:34, 16 August 2014 (UTC)

Pixlr - open image from URL, use the eyedropper, then click the colour palette to see the colour numbers. It won't work for every image, because some sites will check the HTTP referer and will refuse to send the image of they don't think it's an ordinary request (this is will be true for other web based services too). 80.189.67.91 (talk) 07:55, 16 August 2014 (UTC)

Thanks @80.189.67.91:. Perfect.   Mandruss |talk  08:45, 16 August 2014 (UTC)

<span> tag as template parameter

I'm trying to create my first userbox template, and I need it to support an HTML <span> tag as parameter 1. I can't get it to do the substitution, I guess because the tag is being resolved too early in the process and the result is not a valid template parameter.

The template is here and the transclusion is here. Correct answerer will have my eternal gratitude.   Mandruss |talk  08:55, 16 August 2014 (UTC)

I have cross-posted at Wikipedia:Village_pump_(technical) because it may be the better place for this type of question. Feel free to ignore if you agree.   Mandruss |talk  10:03, 16 August 2014 (UTC)

Does Firefox's about:config actually do anything?

When I go to about:config in Firefox, I get this supposed-to-be-scary warning that I might hose the whole thing up if I do something wrong. But lots of times, I just can't tell that it does anything at all.

For example, I just changed spellchecker.dictionary from en_GB to en_US, closed Firefox, and restarted. But in this window, it still puts a red wavy line under "color", but not under "colour".

Similarly, whether I have plugins.click_to_play set to true or false, it doesn't seem to matter: Either way, videos autoplay in Facebook without my consent, unless I actually disable Shockwave Flash.

This is really kind of frustrating. I've used Firefox for years, because they're open-source and because I thought they were committed to user control of the experience. Starting to wonder about switching. Maybe to Chrome? Anyone know whether you have better control there? (Don't suggest IE; I'm a Linux user.) --Trovatore (talk) 09:01, 16 August 2014 (UTC)

For disabling the autoplay on Facebook, you might want to look into F.B. Purity which has a few features including disabling the autoplay of videos on your news feed. Dismas|^(talk) 10:46, 16 August 2014 (UTC)

Since the release of Firefox 4 Mozilla has been desperately trying to emulate Google Chrome. Such "improvements" include habitually bumping the version number up and up (since apparently the great unwashed masses think Product 27 is better than Product 3 because its version number is bigger), introduction of frivolous "social features", and removable of user-changeable options as part of the process of dumbing the browser down for the Apple Generation. Many options that used to be available in the options dialog (for example, disabling javascript) are now only accessible via about:config. But it gets worse. Mozilla has decided that the user is too dumb to understand what they are doing and even if they have gone to the effort of delving into the bowels of the browser and explicitly setting an option in about:config, so Firefox will now override them whenever it wants because it's "better" for the user. This includes ignoring options to disable functions (javascript, flash, etc), ignoring options not to update the browser (the latest version is forced down your throat regardless of setting Firefox NEVER to update), ignoring cookie options, ignoring cache options, etc. Mozilla clearly yearn for the modern, empty-head hipster user base and have shunned the original power users. Time to change to Pale Moon (web browser), OP. 117.173.108.38 (talk) 11:16, 16 August 2014 (UTC)

Since 2012, 90% of Mozilla's royalty revenue is derived from "a search engine provider" (there's a good chance that is Google, because Google is the default search engine selected by Mozilla, and the two organizations have corporate offices literally down the street from Each other). Accounting for the Mozilla foundation's grants, corporate partnerships, assets, and history, at this time it's my opinion that Mozilla Foundation (and its profitable partner, the Mozilla Corporation) is almost a wholly-owned subsidiary of Google, though legally distinct for tax and accounting purposes. But it stands to reason that the creative choices made for the Firefox browser are heavily influenced by said "search engine" who sponsors its development and marketing.

If you actually care about free software, perhaps GNU IceCat is worth a shot. It's derived from the free software that goes into Mozilla's browser, but it does not include nonfree add-ons. It works on most GNU/Linux systems.

Nimur (talk) 14:08, 16 August 2014 (UTC)

As the Wikipedia article mentions, the Mozilla Foundation has been primarily funded by Google search revenue since 2005. Google presumably makes money from this arrangement as well. If Google ever decided to cut off Mozilla, Microsoft would probably be happy to get all the extra Bing users. Google management doesn't tell Mozilla management what to do. -- BenRG (talk) 19:43, 16 August 2014 (UTC)

Addressing Trovatore's original question: the "about:config interface is one of several backdoors that are built in to Firefox. I mean this term in the literal sense of the word - with and without its negative security connotations. Basically, "about:config" is one of several methods by which you can change the software's behavior, using feature sets that are built in, but for which no user-interface exists:

• Some such items have no UI because the creative directors do not want to expose such a UI. An infamous example that caused uproar a few years ago was the removal of certain popular "Disable Feature checkbox", which was widely discussed across the development and user-community.
• Other features have no UI because these features are temporary, experimental, or outright broken. Worse yet, most such features are undocumented anywhere - not on developer forums, not in source code, and certainly not on easy-to-digest tutorial blogs.
• Waxing conspiratorially: still other features have no UI because you aren't supposed to talk about them loudly or in public. For example, even when you visit a secure website using secure protocols, your traffic is reported to aforementioned search engine - but it's only monitoring your traffic to to keep you safe.

When you use "about:config" or any other method to modify the program's behavior, you are explicitly asked to accept responsibility for the outcome - which is a perfectly fine thing to do, as long as you understand it.

Now, as somebody who has attempted to compile Firefox from source, I can attest: nobody understands all the complex interactions in this very large piece of software. The program has several hundred thousand "moving parts." A handful - say, a few ten thousand of those - have "configuration options" that can be set by the "about:config", "prefs.js", or other methods. Such preferences allow you - the "power user" - a bit more flexibility without implying that you can (or want) to modify the software at the source-code level. Yet, by using these features, you are taking a few steps down the road towards "developer" - which means that you can (and want) to understand the complex interactions of your changes. Nimur (talk) 15:38, 16 August 2014 (UTC)

---

Editing about:config is like editing a textual configuration file, or the Windows registry. Any part of Firefox, or an extension, can put any information it wants in these configuration variables, and use it however it wants. It can be useful to edit it following instructions from someone who understands Firefox internals, but you shouldn't edit it based on your own guess about the meaning of a setting. I suspect the reason that changing the dictionary language didn't work is that you don't have the en_US dictionary installed, so it fell back on one that was installed. It could have downloaded the appropriate dictionary in the background, I suppose, but that would have required them to add code specifically to support changing the dictionary via mucking around in about:config. Instead you should do it through the UI, specifically the Languages submenu of the context menu for a text box. I don't know the status of plugins.click_to_play; it may be obsolete, or overridden by another setting. Check the per-plugin activation settings in about:addons, or search a Firefox-specific forum for help.

Firefox gives you far, far more control than Chrome over all kinds of things. I doubt that will ever change: Google has no apparent interest in adding that functionality to Chrome, and Mozilla would lose too many of its loyal supporters if it tried to remove it. -- BenRG (talk) 19:43, 16 August 2014 (UTC)

Firefox 30 is one of the worst browsers ever. It's unstable (it crashes even without user input), and its RAM footprint is huge; it gets into the 10-digit range with less than 15 WP articles (even text-only) and never seems to get back down. Somebody at Mozilla obviously forgot that Firefox is free software... - ¡Ouch! (^{hurt me} / _{more pain}) 06:28, 18 August 2014 (UTC)

Disk Usage Analyzer has stopped working

I've used Disk Usage Analyzer (previously known as Baobab) on Fedora Linux to have a graphical view of how much space my folders are using on disk. But now it has suddenly stopped working. The process starts up, and keeps running, but doesn't seem to actually do anything. It never even opens a window. I don't see any error message either. The funny thing is, it used to work all OK on Fedora 20, but then just suddenly stopped working. I didn't even update or upgrade the operating system. How can I see what is the reason here? JIP | Talk 15:46, 16 August 2014 (UTC)

It probably exited before even getting to displaying a window and therefore might have writen someting in a logfile. Take a look at the files in /var/log/ If not, maybe running it from a terminal will be more enlightening. The program might still be 'baobab' (like it is on my system). Astronaut (talk) 16:33, 16 August 2014 (UTC)

The thing is, it doesn't exit. It just keeps running all OK, except it doesn't actually do anything. JIP | Talk 16:39, 16 August 2014 (UTC)

If you run it under ltrace, strace, or ptrace, then you might get some clues as to what it did before it locked up. CS Miller (talk) 21:34, 16 August 2014 (UTC)

August 17

Very large sets of permutations and their application in contemporary music theory

Twelve-tone music is based on an ordered set of 12, unique, pitch classes notated in music set theory as integers 0 … 11. Therefore there are 479,001,600 possible twelve tone rows (permutations of the ordered set). Even if it took just a millisecond to calculate each permutation it would still take about 326 days to perform that calculation, correct? Is there any hope at all that a searchable database of all twelve-tone rows can be constructed? --50.46.100.76 (talk) 00:31, 17 August 2014 (UTC)

Modern computers can do calculations far quicker than a millisecond. They can do more like millions or billions of calcs per second, depending on the complexity of the calculation and the computer used. But, even using your mere thousand calcs per second, I still get 5 and half days, not 326 (12!/1000/60/60/24). It looks like you forgot to divide by either the 60 seconds in a minute or the 60 minutes in an hour.

Also, I don't see any point in creating such a list. If I understand you correctly, there would be 12 notes in sequence, and the first could be any of the 12 notes, while the next would be any of the remaining 11 notes, etc., giving us 12! possibilities. If you really wanted a list of all those possible sequences, it probably already exists online, but what use would it be ? StuRat (talk) 03:00, 17 August 2014 (UTC)

Thanks for the reply, and sorry for my arithmetic error. My interest in having this kind of collection would be to search and/or sort the resulting database for desirable characteristics such as certain kinds of symmetries in the hexachords, all-interval tetrachords, etc. For students of 20th-century music theory this actually has great importance and practical application. I'm not aware of a readily available tool to do this online. (In addition, it would be a proof of concept that I would want to expand into other, more interesting applications in the study of algorithmic composition.)

I know that finding all the permutations is probably the most brute force of many available approaches, however I would want to allow for very broad flexibility in what the user specified as a search criteria. Could a database of this kind be indexed in some way so as to make the search more speedy than the initial calculation by which it was created? And is there some way to split up a calculation of this kind over a number of computers to speed up the process? Finally, how can one calculate the memory size for a database from the number of sets generated? Thanks! --50.46.100.76 (talk) 04:38, 17 August 2014 (UTC)

I don't understand why you're searching. If every possible permutation of notes is in your hypothetical database, why do you need to search it? Every conceivable combination is in there - so the answer to every search is "YES!" - so why search?!? SteveBaker (talk) 05:05, 17 August 2014 (UTC)

Steve, as a composer myself, I frequently want to see a selection of sets or chords with certain properties. This database would provide an analytical means of reviewing an inhumanly large data set and selecting appropriate musical material. Remember, we're talking about music represented by numbers. Perhaps the twelve-tone example is a bit obscure, but consider the set of all natural harmonics up to the 9th partial in the string section of the classical, western orchestra (also a set with close to half a million members if we only go up to hexachord-size subsets). Generating every combination of these harmonics reveals every possible chord in that set, each with its own expressive properties. That would be incredibly valuable in the field of contemporary sound art and algorithmic music composition. So, --50.46.100.76 (talk) 05:49, 17 August 2014 (UTC)

Yeah - but that list would also contain every possible jarring, grating, iharmoneous squawk. I'm no expert, but I bet there are 10,000 horrible sounds for every good one. If you have an algorithm for making "useful" chords - then just generate those rather than all of them. How are you going to search this list anyway? The point is that STORING a predictable series is pointless when you can generate the Nth element of the series trivially easily. It's kinda like saying: "I need to divide a bunch of number by 3 - so I'm going to generate a database of the first 100,000,000,000 multiples of 3 and search it to find the number I want to divide into." - there is simply no point in making the list.

If you're planning to generate every possible set of (say) 6 notes - then we can write you code that runs in a billionth of a second that'll produce the N'th element of that series. Pre-generating and storing makes NO sense whatever. SteveBaker (talk) 21:22, 17 August 2014 (UTC)

The thing is, twelve-tone rows are not chords. They're never or hardly ever heard in any perceptible form in a final composition. Instead, they are a kind of tool which could be used to construct an infinite number of compositions. The row imparts certain qualities to the resulting work, but is fairly unimportant to the sonic result. In other cases, such as the set of all natural harmonics up to the 9th partial in the string section of the orchestra, remember that the point of music is not to create "nice" sounds. Like all other arts, the point of "art music" is to express something. (That's debatable of course, but certainly the desire is to do SOMETHING beyond creating pleasant sounds.) What one composer finds ugly, another composer will find beautiful. Since the purpose is to make this tool available to all, it must be flexible enough to sort for any quality at all in the resulting sets. --50.46.100.76 (talk) 17:32, 18 August 2014 (UTC)

Sounds to me like what the OP is asking about is more of a sorting algorithm with the database (or else it'd be like assigning keywords or tags to certain combinations, like 'hex' and 'tetra' and so forth...) rather than simply a searchable database. And to add to the mix, s/he is sometimes using the term 'search' above when he seems to mean 'sort' -- or else 'search for the keywords as assigned previously...'. (I know he said 'search and/or sort,' but the conflation of terms after that is perhaps some source of confusion (?) though i can't pretend to know much about the music side of the question. El duderino ^(abides) 06:08, 17 August 2014 (UTC)

• This sort of thing arises all the time in database programming -- that is, situations where you have a database most of whose index values don't have any entries associated with them. The standard solution is to construct what is called a hash table, which allows the database to be searched efficiently. Looie496 (talk) 14:29, 17 August 2014 (UTC)

• As far as figuring out the size of the database table, take the number of records (479,001,600) and multiply it by the length of each record. To calculate the length of a record, since each of the 12 positions will hold one of 12 values, that takes 4 bits per position, since 2^4 = 16. If the DB system doesn't support 4 bit integers, then hopefully it supports 8 bit integers, or at least 16 bit. So, we have 12 times 4 or 8 or 16, for 48, 96, or 192 bits. Now, you'll probably want to add some more fields to label this record. These could be binary variables, noting whether this record is or isn't a certain type of combo. So, one bit each would do. If you have 8 of those, that's 8 more bits. So, we now have 56, 104, or 200 bits. Using an 8-bit byte, that's 7, 13, or 25 bytes per record. Now we multiple by the number of records, to get 3.4GB, 6.2GB, or 12GB. The lower two would fit on one side of a DVD, while the larger would fit on a two-sided DVD. All would easily fit on modern hard drives, flash drives, etc.

There's also possible index space needed. That's typically much less than the data space, but if you put an index on every field, it could actually be more, considering that each data record is quite short. To index each of 479,001,600 records, you'd need a 29 bit index, since 2^29 is the first multiple of 2 greater than that number. However, you aren't likely to be able to do that, and will need to go to a 32 bit (4 byte) index, instead. So, you multiply that by the number of records, and the number of indexes. If you had an index on all 12 notes and 8 labels, that's 20×4×479,001,600, or over 38GB for the indexes. You probably don't want to do that, but you could, if speeding up the searches is far more important than the space on the hard drive. So, worst case scenario, we're at 50GB total, for data and indices. You could also be more conservative and only put indices on the label fields, which would lower the index size to 15GB, and the worst case total size to 27GB. If you need fewer than 8 labels, you could lower it even more. StuRat (talk) 18:27, 17 August 2014 (UTC)

Please help me buy the right wire

I want to connect my computer to my TV and be able to watch video/movies on it. I have no idea what connection/wire type I would need to do this or if it's even possible, so I was hoping someone here could be specific and tell me what I need: what type of wire/what type of connection/any adapters and so on.

My TV is a brand new Sony Bravia and it's specs including its ports are here. I want to run to it from my iMac (iMac11,3 Intel Core i5 2.8 GHz). After a bit of research, looking at the back and the searching for what they are, my iMac has four USB 3 ports, an ethernet port, a FireWire port, a mini DisplayPort, an audio out, an audio in and in fact is identical to this.

Thanks much in advance, even if the answer is that I can't.--108.46.97.218 (talk) 01:15, 17 August 2014 (UTC)

Hmm, it looks rather incompatible. The inputs to the TV include HDMI, composite, and component video. Both devices have USB ports, but I don't think you can send streaming video over that, it's used more for displaying stills, playing music, etc. (Although maybe USB 3.0 can handle video, I'm not sure on that.) I'd think your best bet would be to get a device to convert the mini display port output to HDMI format, but let's see what others have to say about it. StuRat (talk) 01:40, 17 August 2014 (UTC)

They could get a mini display to HDMI adaptor. Dismas|^(talk) 01:46, 17 August 2014 (UTC)

Cool. So if I got this, and ran an HDMI cable from my TV to it, would it be as simple as (after changing the input on the TV to that HDMI connection) just turning on AVI/Quicktime/Wondershare, and playing the movie?--108.46.97.218 (talk) 02:30, 17 August 2014 (UTC)

There could still be some annoyances. For example, does the movie you are playing match the aspect ratio of the TV ? If not, then you will have letterboxing, stretching, or part of the movie will be off the edge of the screen. You can probably select which option you want using your TV remote. Also, the iMac might not send the full 1920x1080 resolution the TV can display. The TV may then create a smaller pic, or it could try to interpolate to "upscale" the image. Again, the TV remote may have options for which approach it takes.

Also, you will want to switch to a full screen display of the movie on the iMac, or you will get all the window frame and other junk displayed around the edges on the TV. Note that you won't be able to use the iMac for anything else interactive while the movie plays, because anything you do will also display on the TV. (You could run things in background mode, but they might cause the video or audio to pause or get out of sync.) StuRat (talk) 02:47, 17 August 2014 (UTC)

Interesting. Worth a shot considering what a pain it is to burn movies to DVD which take up a lot of time (especially now that I always want 1080p).--108.46.97.218 (talk) 03:56, 17 August 2014 (UTC)

On a side note, you don't have to buy brand name retail, which includes huge markups. There are perfectly good adapters out there for under $5 ([1]) if you don't mind waiting a few days for delivery. Same for the HDMI cables. You can find 25 foot HDMI cables for under $10 ([2]). -- Tom N talk/contrib 06:07, 17 August 2014 (UTC)

The specs for the TV say that it supports WiFi and Ethernet. Why not just network it and watch the videos directly from the TV, rather than via the iMac? --Phil Holmes (talk) 10:16, 17 August 2014 (UTC)

I am pretty sure that screen mirroring on Sony Bravia TVs is using a thing called Miracast which seems incompatible with Macs. ny156uk (talk) 12:29, 17 August 2014 (UTC)

Oh, that's interesting too! I really don't know where to begin though. So, um, it's a mac, so it only broadcasts via bluetooth right? I thought wifi and bluetooth were not compatible? Any suggestions on how I would "ask" the mac to send a movie that I have on it, and in a way a wifi capable tv would understand it--108.46.97.218 (talk) 12:10, 17 August 2014 (UTC)

I think Phil Holmes assumed that everything you want to watch is streaming video from the Internet, such as Hulu, Netflix, YouTube, etc. If that's the case, your TV wouldn't be connected to your Mac but to your router, using WiFi or an Ethernet cable. In other words, your TV would be like another computer in your home network. TVs that have that capability provide a way to connect to the desired site and start the video, using the TV's remote control and on-screen menus. That should all be in the documentation for the TV.

If you're talking about other video sources such as files on your Mac and DVDs, etc., then the TV's networking support is of no value to you. That is, unless there's some kind of Mac app that I'm not aware of, that would allow you to send a stream from your Mac to the TV through your router.

Bravia is a family of television models. If you could provide your TV's model number, we could be referring you to specific pages in specific manual(s) on the Web.   Mandruss |talk  12:41, 17 August 2014 (UTC)

Thanks Mandruss. It's a 48w600b. Yes, I am not thinking of using content from the internet directly, but videos on my computer. I have ordered the adapter and HDMI cable, for a grand total of about $14 (thanks Tom N!); thanks all!--108.46.97.218 (talk) 13:50, 17 August 2014 (UTC)

Cool. I'll mark this Q resolved for now, but please come back and tell us if it worked (repost if the Q has been archived by then). StuRat (talk) 17:09, 17 August 2014 (UTC)

Resolved

Automated accepting of cookies in EU

The EU passed a moronic law requiring each and every goddamned website to ask for permission to store cookies on my computer. I would like to grant permission once and for all - is there some way I can communicate this through a browser mod or user agent or some such thing? 129.215.47.59 (talk) 15:23, 17 August 2014 (UTC)

I think P3P does this, but it's not widely implemented.--Shantavira|^{feed me} 06:08, 18 August 2014 (UTC)

XML support in databases

I wonder what FREE databases provide XML support. I know PostgreSQL does. What others are in this league? Thanks, --AboutFace 22 (talk) 16:04, 17 August 2014 (UTC)

Google Chrome - How to remove the white boxes

There are 8 white boxes in Google Chrome that are obstructing the theme I've chosen. Can I remove them and leave everything else the same? I've tried what you can do from Settings and a number of apps. The apps can remove them, but they also remove the background picture. Starfsmanna (talk) 16:53, 17 August 2014 (UTC)

I don't think so. However, there is a great extension called "New Tab Redirect". When you click on a new tab, instead of going to the boxes, it goes to the homepage of your choice, which can be a website or even a homemade html page on your hard disk. Mine is an html page with a bunch of links I use all the time. So, it is just like the 8 boxes, but I can choose what is there and what is not. Anna Frodesiak (talk) 16:59, 17 August 2014 (UTC)

Thank you, with your help and a continued search for a solution, I managed to come up with a workaround.

https://answers.yahoo.com/question/index?qid=20140817094306AAw8dmg

Starfsmanna (talk) 18:00, 17 August 2014 (UTC)

August 18

Priming/initial charging a lithium-ion battery?

Is it even necessary? Some claim that I should give them an initial charge for like six hours to even a day, while others don't. In the case of a just-purchased tablet with a Lithium iron phosphate cell, do I really need to initialise it? Blake Gripling (talk) 01:21, 18 August 2014 (UTC)

I've never heard of this and I've been using LiPo batteries with remote controlled helicopters and airplanes for years. Did your device come with instructions? That's usually covered in the manual. As far as I know, Lithium batteries do not suffer from memory effect, but that might not be the only reason to charge a battery for that long. Also, lithium batteries are very sensitive to OVER voltage, so any device that's designed to charge them should STOP charging them when they hit full charge, so I can't see how leaving it plugged in for 6 or 24 hours would make any difference. But, like I said, I'd read what it says in the manual and stick to that. Vespine (talk) 03:35, 18 August 2014 (UTC)

It did come with some documentation, but there's nothing in the manual that suggests leaving the device charged for hours to prep a battery for first use. Also, during the time when I bought a Lenovo smartphone, the only advice the saleslady told me (at another store) was not to drain the battery at too low a voltage to curb any damage. Blake Gripling (talk) 04:47, 18 August 2014 (UTC)

Bitmap Header Field - Importance?

A while back I made my own image enhancement software (just to tinker with), I was going over it and decided to change the header it uses to the standard windows one (it's just for tinkering, so it assumes a certain structure). At any rate, what actually uses the biXPelsPerMeter and biYPelsPerMeter fields? As in, if I left them 0, would the image display differently anywhere? I understand what the values mean, but I can't find anything indicating if they need be correct - and I know that not all bmp headers have them. Just curious. Thank you:-)Phoenixia1177 (talk) 06:30, 18 August 2014 (UTC)

My own, rather limited experience, with generating bitmap (BMP or otherwise) headers from scratch is that physical specifications (DPI, DPM, PPI, etc.) are ignored for all but a few print-ready formats (TIFF, PS, EPS, PDF) and even than any actual print job being done, a designer or operator will still check (print-preview, essentially) what's to be printed before starting a job, to avoid nasty surprises - caused by mad suggested-size values in vector media (like SVG) or page size variances in page-aware formats (A4/letter/legal). Back when BMP had some currency as an interchange format, pretty much "what Windows does" was the nearest you'd get to compliance with its rather hazy specification (given that's it's just an old OS/2 "barf your internals into a file" type format). A corollary of your question is surely "if you don't know the physical dimensions of your bitmap, what values should bi[XY]PelsPerMeter have?". If you can, it's surely better to be silent (to not have the entry at all) than to lie. If you have to lie, it's better to lie with a sensible-ish guess than a definitely wrong value like 0 or NaN or -1 - because if some code somewhere does honour it, it'll surely do something like width_in_metres = width_in_pixels/biXPelsPerMeter - and your 0 value will either make the decode fail silently or with an error. Better, surely, to have a default that shows the image (at a wrong but recognisable size) than have the image not appear at all. These days I'd only add "what does libbmp do" and "what does libmagick do" to "what does windows do". Personally, if I were writing my own graphics software now and I wasn't going to use standard formats like JPEG or PNG, I'd probably use Netpbm format (with any of my own info in comments) as a path-of-least-makework. If I needed fancier features like alpha, gamma, compression, or progressive rendering I'd probably use libpng (with my custom data in PNG custom chunks). -- Finlay McWalterᚠTalk 12:21, 18 August 2014 (UTC)

• I'm a strong advocate of following standards in every possible respect, regardless of whether you know why they are written that way. I've never worked with that particular file format, but you can find documentation for the header structure at http://www.herdsoft.com/ti/davincie/davp3xo2.htm, where it states: "biXPelsPerMeter DWORD Specifies the horizontal resolution of the target device in pixels per metre. Applications often use this value to select the resource bitmap that best matches the characteristics of the current device.". In other words, you should specify the device resolution that makes your bitmap look best -- neither too large nor too small. Looie496 (talk) 13:11, 18 August 2014 (UTC)

Preventing Spam

Apparently that advice about ignoring internet trolls and cyber-bullies doesn't always work, since mine is now threatening to send a flood of spam against my twitter account, emails and most likely anywhere else he can find. I am wondering if anyone can recommend some way of blocking him from doing this, pre-emptively protecting myself in case he comes through with his threats?

Thank you

82.132.212.22 (talk) 12:04, 18 August 2014 (UTC)

As previously advised...ignore trolls. They crave attention - they delight in causing you grief. So, don't react. Don't acknowledge that there is a problem. "Dont Feed the Trolls" is excellent advice. SteveBaker (talk) 02:28, 19 August 2014 (UTC)

yes, random trolls feed on attention, but this concrete case seems much more like stalking by someone the OP knows in real life. Maybe this is a case to be reported to the police, if it gets to far.OsmanRF34 (talk) 16:04, 19 August 2014 (UTC)

I'd say it's time to change your accounts. Only give the new names to people you trust not to pass them along. StuRat (talk) 16:41, 19 August 2014 (UTC)

ISTM that the term "Troll" has changed or extended in popular meaning since the advice of "Do not feed the Trolls" was formulated. Back then it was applied merely to those who tried to provoke arguments – preferably between others rather than with themselves – by subtly provocative comments, and of course derived from the angling term "trolling" (often for "newbies"). For such provocateurs, the advice frequently worked.

Latterly the term seems to have been misunderstood as deriving from to the ugly mythological monsters, and is misapplied particularly by the mainstream media to people directing often crude or obscene attacks or continued harassments against other individuals. This sort of behavior is significantly different and the advice will often not work.

This has resulted in people who are suffering the latter type of attacks being additionally seriously distressed by the inapplicability of the advice, not realizing that it refers to a different sort of troll.

It might be desirable to establish consensus for a different term for the latter behavior – "Cyber-bully" is one possible example – and convince the media to use it appropriately. How this could be achieved, however, is beyond me.

Apologies for side-tracking rather than addressing the OP's problem {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 13:51, 20 August 2014 (UTC)

Label printers

I'm in need of printing a bunch of shipping labels for my wife's business (http://renm.us) - and it's clear that using our inkjet printer isn't a good option because you have to print an entire sheet of labels at one time.

I see that there are a bunch of devices by different manufacturers that take a roll of stickers - so (presumably) I can print to them one at a time.

My question is how those devices interface to the PC. Are they (in effect) just tiny inkjet printers as far as the operating system is concerned...or do I have to use some horrible (probably!) software that comes with the printer itself?

We use an SQL customer database, with custom web interface software - and I'd like to use our standard query software with a "PRINT ADDRESS LABEL" button. I can write the code to do that if the interface to the label printer isn't something exotic.

Does anyone have any experience with these machines? (Also, if you can recommend a good one, that would be nice).

TIA SteveBaker (talk) 20:06, 18 August 2014 (UTC)

Brother, Seiko and Dymo make affordable thermal label printers but they use special software. Zebra makes higher end printers with a higher price that you can create a print file in ZPL language. --  Gadget850 ^talk 01:30, 19 August 2014 (UTC)

Are there significant problems with the thermal-printed labels fading in strong sunlight and 100 degree Texas days? They won't experience any of those things when they're in our control - but we ship packages around the world. SteveBaker (talk) 02:32, 19 August 2014 (UTC)

For the lengths of time that your packages would see those temps, I don't think you should have an issue. Dismas|^(talk) 06:05, 19 August 2014 (UTC)

There are basically two types of thermal printing: direct and indirect. Direct thermal uses a print head to essentially burn the label in a controlled way to print. Cash register receipts are often printed this way. They tend to have low operating costs because there's no ribbon or ink, but they do tend to be thermally sensitive. I would definitely request samples and/or specs if you're thinking of going that way. Indirect thermal printing uses a wax/resin ribbon that gets burned onto the label by the print head. They tend to have higher operating costs (but the amount of ribbon you'd need would be negligible) and, IIRC, are somewhat pricier off the shelf as well. In my experience, they do not fade with heat, but you may experience cracking if you print to poly labels (the plastic expands in the heat and cracks the printing). I don't think that would happen if you printed to paper labels. I use a Datamax indirect thermal printer which has done yeoman's work for many years. The software is ridiculously priced, but it can marry up with standard DBF files and so forth. Matt Deres (talk) 17:15, 19 August 2014 (UTC)

I have never seen the term "indirect thermal" used— this is thermal transfer (TT) as opposed to direct thermal (DT). If you need durable labels, then you need thermal transfer with coated paper, vinyl or poly labels and a resin ribbon. The more popular label applications are Neat Label, LabelView and BarTender. --  Gadget850 ^talk 22:39, 19 August 2014 (UTC)

August 19

Hard disc I/O error

uTorrent can't download to one of my hard discs. It used to be fine. Now, it downloads for a while, then all the downloads stop and say "Error: WriteToDisk: The request could not be performed because of an I/O device error."

The disc works fine otherwise. I'm running and old version of XP. If you have an suggestions, I'd be most grateful. Anna Frodesiak (talk) 02:12, 19 August 2014 (UTC)

Try running CHKDSK, run "chkdsk /f". I think you run a command prompt "as administrator" and reboot your computer to start it. It may take a couple of hours. Bubba73 ^{You talkin' to me?} 02:31, 19 August 2014 (UTC)

Thank you very much. I'll give that a try. One thing I did is close uTorrent and start it again with a lower download speed. This is working. I recently renewed my ISP deal and they gave me much greater speed. Anna Frodesiak (talk) 08:58, 19 August 2014 (UTC)

Wording: "ID must be numeric"

Situation: A website has an admin search menu with several IDs to look for. Some IDs are numbers, others are strings; and some of the strings are with digits only (with leading zeros added by the search function, if necessary), others with mixed characters. If someone looks, say, for a shop and enters letters in the shop ID search function, while a numeric shop ID is required, an error message is helpful. Is "Shop ID must be numeric" a perfect wording? Can it be used both for numbers and purely numeric strings? If it is suboptimal for any reason, what would be better? --KnightMove (talk) 13:46, 19 August 2014 (UTC)

I might prefer "ID must contain only numerals" -- that way it doesn't matter if it's considered as a number or a string of numerals. I suppose you could even include something like "(0-9)" to make it more clear what is allowed. SemanticMantis (talk) 15:53, 19 August 2014 (UTC)

Null Zero Deletion in MS Word

How to delete all Null Zeros in Saved MS Word Document?--Tenkasi Subramanian (talk) 14:07, 19 August 2014 (UTC)

Movie quality

What would be better quality for a movie - an itunes download in 1080p or a 1080p "mastered in 4k" blu ray? — Preceding unsigned comment added by 176.251.149.21 (talk) 15:33, 19 August 2014 (UTC)

All other factors being equal (bitrate, source), the 4K Blu-ray will be higher quality. Simply because iTunes 1080p uses h264 encoding, while 4K Blu-rays use its successor. However, in the real world, it's really a case-by-case comparison, because the bitrate, source, and what's being encoded all affect quality. --Wirbelwind(ヴィルヴェルヴィント) 18:36, 19 August 2014 (UTC)

Did the hardware logic been?

Did the hardware logic (instrument logic) been or it been only the program logic?--Alex Sazonov (talk) 17:39, 19 August 2014 (UTC)

Could you try rephrasing the question? I'm not really sure what "instrument logic" is. Are you trying to ask about physical logic gates versus software logic, e.g. conditional statements? --Wirbelwind(ヴィルヴェルヴィント) 18:34, 19 August 2014 (UTC)

Could the math physical logical of material crystals of chips beening, is it a program (software) logic? I think that, the program (software) logic is simple section of chips, is it right? I seen that, the program (software) logical is been definite of all logical of computers, is it right?--Alex Sazonov (talk) 09:42, 20 August 2014 (UTC)

It seems me, that the static memory of structure of materials proves that hardware logic been.--Alex Sazonov (talk) 11:14, 20 August 2014 (UTC)

I'm not sure what your asking, but maybe Hardware description language will give you the answer. -- Q Chris (talk) 11:41, 20 August 2014 (UTC)

Thanks much. In simply case, I interested in that, did the logic been without program languages?--Alex Sazonov (talk) 14:13, 20 August 2014 (UTC)

Alex, can I make a specific request that you go and learn how to conjugate and use the English verb to be, please? You really can't just use the past form ('been') indiscriminately for everything. AlexTiefling (talk) 14:23, 20 August 2014 (UTC)

Well. I suppose that, the crystal structure of all materials always is mobile, however it had a static memory, that’s why the simple logic without program language be.--Alex Sazonov (talk) 15:09, 20 August 2014 (UTC)

Do you realise that your response has nothing to do with what I said? AlexTiefling (talk) 15:12, 20 August 2014 (UTC)

When using a VPN, do web-pages know their users are connecting to it through one

If yes, do web-sites like online banks or ecommerce sites care or at least raise a red flag due to it being a potential fraud? (in a scenario where a user connect both through a VPN when on public spaces and to the same page without said VPN from home or from the office).OsmanRF34 (talk) 19:51, 19 August 2014 (UTC)

Silverlight - What Does It Do?

What does Silverlight do? The only times I have ever seen anything about it on my computer (ANY of my computers) is when I get a message on my browser saying it has stopped working. What exactly is it supposed to do? KägeTorä - (^影_虎) (Chin Wag) 21:59, 19 August 2014 (UTC)

Our article Microsoft Silverlight gives a basic description of what it is and how it is used. --Mark viking (talk) 22:10, 19 August 2014 (UTC)

For the most part, it's an Adobe Flash substitute. Netflix, for example, uses Silverlight to stream their content. Without Silverlight, you'd see a blank page. They do have some HTML5 support, but it's in the infancy. --Wirbelwind(ヴィルヴェルヴィント) 22:13, 19 August 2014 (UTC)

This site claims that only 0.2% of websites use Silverlight. Other than the very notable example of Netflix, which Wirbelwind mentioned, I can't remember ever finding a site that I wanted to use which needed Silverlight to work. 87.112.89.107 (talk) 22:35, 19 August 2014 (UTC)

Microsoft provides a list of Silverlight features. Among these, I find the video streaming technologies to be the most interesting and useful, because the feature-set for streaming video is significantly richer than that available in the HTML5 specification. For example, Silverlight supports adaptive streaming from multiple sources at variable bitrates, using client-side cooperation built into the Silverlight plug-in to monitor streaming performance and adjust the server-side parameters accordingly. This would be very difficult to re-implement using only HTML5 - so there's an immediate value-add for video-streaming providers who want a software solution that already works. Silverlight also provides state-of-the-art security and authentication, assuring integrity from the network layer all the way to the hardware layer - again, by relying on cooperative security provided by the client-side plug-in (addressing a very difficult problem, which is that content is consumed on machines that categorically cannot be controlled by the content-provider). This plug-in solution ranks among the more secure ways to execute digital rights management (digital restrictions management) - for better or for worse, this means that it's more difficult (prohibitively difficult) for users to save, copy, or inspect digital content in ways that the developers and providers do not authorize.

Nimur (talk) 23:27, 19 August 2014 (UTC)

Basically, Silverlight is only one case where "somebody else is innovative, and Microsoft makes an inferior knock-off product". (This sounds bad, but it isn't always a bad thing. In some cases, the MS product isn't too bad, and actually good enough for 90% of the users.)

The bad part is that Silverlight cannot possibly replace Flash, due to the popularity of Flash, which makes Silverlight a solution without a problem. If Silverlight becomes more popular, internet users are in big trouble; both products have quite a record of bad (browser-breaking) updates. - ¡Ouch! (^{hurt me} / _{more pain}) 08:11, 20 August 2014 (UTC)

A lot of Microsoft's products are better than the competition's. IE certainly was for a while, mainly because it worked while Netscape was so buggy it was almost unusable. (And don't forget that IE introduced DHTML and Ajax, which everyone else then copied.) I suspect Silverlight is better than Flash for similar reasons, but it's hard to know when no one develops for it. -- BenRG (talk) 19:00, 20 August 2014 (UTC)

Replacing RAM with old RAM still in the system

I have a set of 2x4GB ram running at 1600mhz. One of these sticks has gone bad, and it has been determined it is not a socket problem. The other one is not, so I'd like to get another stick of 4GB ram to replace the bad one. 2 questions here. Must it be the same model or manufacturer? (they are Patriot Viper 3s) Does it have to be the same speed? I'd run them in dual channel. KonveyorBelt 23:31, 19 August 2014 (UTC)

I find it prudent to swap it with the stick of the same speed, i.e. 800Mhz on a board that takes DDR2-800s. Not sure if mixing speeds would be bad but I bet it is. It should be alright to use different brands though. Blake Gripling (talk) 00:43, 20 August 2014 (UTC)

I believe the problem with mixing speeds is that they all then work at the lower speed. StuRat (talk) 23:03, 20 August 2014 (UTC)

It may be alright to use different brands, but if you can get the same brand and/or model, by all means do. One can occasionally run into serious problems with otherwise identical sticks by different manufacturers; I know I did a few years ago!—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); August 20, 2014; 19:32 (UTC)

August 20

McAfee Security Scan Plus

Hi there. One day I found this application installed on my computer. I never asked them to install it. I am surprised the application showed up, just like this. Roughly once a month it "runs" which takes about 30 seconds and declares that my computer is free of malware. I googled and found a few websites with mostly negative information. This is one of them. I wonder what people visiting this Reference Desk would say. I decided to ask here before I uninstalled it. Thanks, - --AboutFace 22 (talk) 00:46, 20 August 2014 (UTC)

It is offered with Adobe Flash Player- if you update, you have to opt out. I have a low opinion of McAfee security products. --  Gadget850 ^talk 01:14, 20 August 2014 (UTC)

It's so bad even McAfee himself hates it. Based on personal experience, yes it is indeed no better off than not having antivirus protection, as what I observed with a friend's laptop. Blake Gripling (talk) 01:21, 21 August 2014 (UTC)

A better way to restore files?

I accidentally deleted a directory and wanted to restore it using MozyHome, but I had to choose between restoring a single file and restoring everything. Is this the way it works with all the online backup services? --Halcatalyst (talk) 22:19, 20 August 2014 (UTC)