Wikipedia:Reference desk/Archives/Computing/2010 April 12

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

April 12

Touchscreen technology and human health

Touchscreen#Capacitive (permanent link here) says the following.

As the human body is also a conductor, touching the surface of the screen results in a distortion of the body's electrostatic field, measurable as a change in capacitance.

Does use of touchscreen technology pose a risk to human health? -- Wavelength (talk) 03:51, 12 April 2010 (UTC)

Touching anything results in a distortion of the body's electrostatic field. I don't think it can possibly have any effect on health except in the obvious case of very high fields. Even several million electrostatic volts from a Van der Graaf generator is usually considered harmless. Dbfirs 07:24, 12 April 2010 (UTC)

You probably meant the Van de Graaff generator though ;) --Ouro (blah blah) 08:38, 12 April 2010 (UTC)

... oops! So I did! I missed off the second "f" and saw it was a red link, so my subconscious must have thought of the band and made the wrong correction. Thank you. Dbfirs 13:34, 12 April 2010 (UTC)

I examined http://www.touchscreenguide.com/index.html without finding an answer. -- Wavelength (talk) 01:44, 13 April 2010 (UTC)

Whats the best website where i can learn Javascript language fully?

Im making my website but ive seen that there is many ccool things i can do with javascript not only with my html knowlege, so i decided to learn javascript, ive been trying to find normal Site where i can learn javascript, but i havent found any, so can any1 help me please?

check out my works: www.aodgx-club.ucoz.org and my newest www.godzilla.ucoz.co.uk what is made specially for my aliance, so if u have any advice say it nopw ;)

I don't think you can expect to learn any modern mainstream programming language fully, unless you design it (and even then it's unlikely, given the process that makes it mainstream). I found http://www.quirksmode.org/, http://www.w3.org/Style/CSS/learning, http://www.w3.org/standards/webdesign/script and http://www.w3.org/DOM/faq.html useful. None of them is about JavaScript alone, though. --Stephan Schulz (talk) 08:21, 12 April 2010 (UTC)

Douglas Crockford's book JavaScript: The Good Part is very good. -- Finlay McWalter • Talk 09:11, 12 April 2010 (UTC)

Actually there's more than one good part :) AndrewWTaylor (talk) 10:42, 12 April 2010 (UTC)

I have some advice which I will say now. First, your website does not explain its purpose very succinctly; you might want to put a quick summary to explain the website and its purpose. From what I gather, it's an enthusiasts website for a videogame or role-playing game, but your main page should specify. You don't need javascript to do this; it is just proper website design to explain your purpose. Nimur (talk) 17:49, 12 April 2010 (UTC)

non profit association / donations

Hello, I wonder if you can help me. I am a trustee of a non-profit organisation (not a charity) based in the UK. We are currently trying to set something up in order to receive donations online from people who wish to donate to the organisation. However, all the sites I have looked at (such as justgiving.com, etc) seem to be aimed around charities rather than non-profit organisations. We are very short of funds and cannot afford to do very much that will cost us money. It seems like justgiving and others rely on taking a 5% cut of gift aid on donations. Does anyone know if there is a site which can deal with donations to a non-profit organisation, or a v. cheap / free way of setting up a donation box on our wordpress site?

Many thanks, Handy2010 (talk) 10:06, 12 April 2010 (UTC)

Paypal has a scheme for accepting non-profit donations - see here. Their partner MissionFish has a scheme for registered charities and exempt organisations (as variously defined in complicated ways) - it's here, but I don't think it covers non-charity nonprofits. You can always ask them. -- Finlay McWalter • Talk 10:17, 12 April 2010 (UTC)

Paypal charges 2.2% + $0.30 per-transaction for nonprofits, assuming that the transaction volume isn't huge. I believe that that's about as low as the fees can get, unfortunately, because it mostly reflects the credit card fees. (according to interchange fee, it averages out at 2%). I thought that Amazon FPS might be cheaper, if harder to implement, but it turns out that I was wrong, unless a heck of a lot of people transfer from their bank accounts directly. Paul (Stansifer) 12:12, 12 April 2010 (UTC)

In one of the previous WMF fundraisers it was claimed Moneybookers fees were generally lower then PayPal. I don't know if this is still the case, a quick search suggests it's somewhat complicated so I didn't bother to compare it myself and I couldn't find any specific rates for non profits. It seems Moneybookers does tend to put more of the fees on the sender. I believe Moneybookers is also more focused on the European market and is a UK regulated company, whereas PayPal has a more of an international focus and PayPal's European operations are regulated as Luxembourg bank. I believe PayPal does allow people with a credit card to make payments without an account. Of course you could offer more then one option.

BTW note that the rates you are quoting are "To be eligible, you must have documented 501(c)(3) status or you will not receive the reduced nonprofit transaction fees". Since we're discussing a UK based non profit, it seems unlikely they will be registed in the US. The fees for UK registered charities are here [1] (1.4% + 20p) however since the OP specifically said the organisation is not a charity, it seems unlikely they will qualify.

Interesting enough, Google has no fees until 2011 at least for non profits who are also part of their Google Grants program [2] however it appears to only be valid for US registered non profits [3] even though they do have a Google Grants program in the UK [4]. There's also a Youtube linked program [5] which again is apparely offered in the UK however it simply uses Google checkout so I presume again has nothing extra for UK registered charities let alone non profits.

Nil Einne (talk) 17:12, 13 April 2010 (UTC)

Those of us who use e-banking might be happy to make donations directly from our own bank accounts to yours if you publish your bank details. Obviously, it would be wise to set up an account that accepts only in-payments. For those without e-banking you could provide bank credit slips. You might be no better off if your bank charges you for setting up or for in-payments. Dbfirs 20:15, 13 April 2010 (UTC)

Is there something like snapshot.debian.org for Ubuntu releases?

Hi, Debian recently started to offer a snapshot service at http://snapshot.debian.org/ - making a local mirror for large-scale, tested patch roll-outs obsolete. Is there a similar service for Ubuntu, and if not, are there plans to implement this in the near future? -- 78.43.60.58 (talk) 11:29, 12 April 2010 (UTC)

Thoes Small Icons What Are In Line With The Title

this is also on the Miscellaneous page

like on protected, spoken and featured pages

when mediawiki:sitenotice is being used, they stay in line with the title

on my wiki, they dont stay in line (see here)

iv coppied

• Common.js
• Monobook.js
• Common.css
• Monobook.css

to my wiki but it just wont do it, i dont want to use "demospace" because i want to use my own custom icons

how do i get it to work?

-Sghfdhdfghdfgfd (talk) 12:15, 12 April 2010 (UTC)

It's being transluced from a template. You need to copy the template and any translutions the template uses for it to work. 82.44.54.83 (talk) 12:56, 12 April 2010 (UTC)

Disappearing Ink(jet)

Hi Refdeskers, I bought an HP Inkjet printer last fall. I've barely used it since then, maybe 20 pages or so, and those mostly black. However, lately I've been getting these "Ink Alert"s popping up, and sure enough, when I check the ink status, its been dropping steadily since I bought it, and pages I print now do in fact back up that the ink has run out. Is this a normal think for inkjets to do? Where does all that ink go?

See this link, which claims that the ink cartridge that came with your printer probably has a "G" at the end of the cartridge number, meaning HP skimped on their quality by shipping you a "starter cartridge" containing about half the normal amount of ink. Comet Tuttle (talk) 18:20, 12 April 2010 (UTC)

Well, thats a bit of a chapper, isn't it? Even still, given my minimal use of the printer, would the ink level just decline over time like this?

The only place it would go is if it were dripping out of the bottom of the cartridge — take a look inside the printer underneath the cartridge(s) to see if there's any leak. (Personally, I don't remember ever seeing an ink cartridge leak that was not caused by me in some way.) If not then I guess HP gave you an even lower amount of ink than is discussed in the article. I would expect that would be the problem, and would expect that the sensor system for detecting the ink level is just pretty inaccurate. Sorry! Comet Tuttle (talk) 18:34, 12 April 2010 (UTC)

Wait a minute, there's more. Someone smarter than I will have to elaborate on this point, but I recently opened an ~8 year old factory-sealed box with a brand "new" HP color ink cartridge in it. It refused to print anything. No ink came out. The ink doesn't just evaporate or disappear, so I assumed that it had congealed / solidified within the cartridge or something. Since you were able to print with your cartridge, this was probably not what occurred to you, but I mention it as a possibility. Comet Tuttle (talk) 18:38, 12 April 2010 (UTC)

I believe a typical ink cartridge contains a sponge full of ink. It's not perfectly sealed, so the liquid portion slowly evaporates and the solid portion plugs up the sponge. Considering how freaking much they charge for ink cartridges, they sure are junk. StuRat (talk) 18:42, 12 April 2010 (UTC)

Current HP starter cartridges contain only about 20 pages-worth of ink (depending on page density, of course). This forces the user to pay the extortionate price for a new cartridge soon after the purchase of the printer. Many retailers in the UK warn the purchaser about this and use it to sell replacement cartridges (on which they make much more profit) along with the printer. From personal experience, I suspect that HP also sabotage the starter cartridge to cause problems if an attempt is made to refill it! Dbfirs 21:49, 12 April 2010 (UTC)

The inkjet article and in particular the Inkjet head design and following sections all provide some possible explanations for what you have experienced here. In my experience, inkjet printers are sold at remarkably low prices, yet replacement ink is incredibly expensive (so much so, it seems almost worthwhile buying a new printer each time the ink runs out). On the other hand, I have used the same laserjet printer for over ten years and never replaced the cartridge - there is little sign of it wearing out even after some thousands of pages. Astronaut (talk) 11:58, 13 April 2010 (UTC)

I have a 14-year-old laserjet printer that is still printing, but it has used many toner cartridges (and refills). I seem to get only a couple of thousand pages at the most. You must have a magic cartridge, Astronaut! (or possibly you print low-density pages) Dbfirs 20:02, 13 April 2010 (UTC)

Inkjet printers also have warm-up and head-cleaning routines that waste a surprising amount of ink. (I don't know exactly how the HP ones work, but the Epson ones have a little sponge to the side of the paper track that the print heads squirt ink into to flush out any gunk in the print heads.) APL (talk) 15:46, 13 April 2010 (UTC)

The old cartridge mentioned above that would not print might be due to it being deliberately time-limited. I refill black ink cartridges - after much practise I can now do it quickly and without getting ink everywhere. 89.240.34.241 (talk) 22:43, 13 April 2010 (UTC)

Yes, some cartridges have an inbuilt chip, but I don't think it stores the time. (I was wrong - see below - it can store dates.) How would it know the current time unless it asks your computer? (and you could tell it lies). I agree that refilling saves much cash, but sometimes print quality deteriorates. Dbfirs 01:50, 14 April 2010 (UTC)

I doubt if the chip kills it, but it may be designed to clog with dried up ink after a certain time period. Just normal evaporation will do that, provided they "accidentally" forget to seal the cartridge properly. Planned obsolescence rears it's ugly (printer) head again. StuRat (talk) 03:43, 14 April 2010 (UTC)

Actually some catridges do expire [6] [7]. While not something the manufacturers yell and scream about, these things aren't big secrets and the error message you get will always tell you the catridges has expired AFAIK. They can get the time from the computer but those which expire the catridges also often have an internal battery backup clock [8]. As you may notice that's mostly HP. Epson catridges don't expire by date, but they do monitor the ink levels (well so does HP) and will sometimes/usually? completely refuse to print if the ink is out or the catridges are refilled (although some companies have designed resetters although I believe you have to reset before the ink runs out otherwise it might not be possible). Canon catridges also monitor the ink levels but they will generally print if the ink is out or the catridges refilled if you overide the monitoring (which is recorded in the printer EEPROM and may create warranty issues). (As with the rest, Canon won't work if the catridges don't have the chips at all.) In all cases although some may be worse then others, the ink monitoring isn't that great and some tests have shown upto 50% wastage or something IIRC.

Incidentally HP and Epson in particular also seem to more vigiriously pursue manufacturers of alternative catridges and chips. Oh and from memory all of them also have region coding for some of their catridges and printers. I've discussed some of this before with more references if anyone is interested.

Nil Einne (talk) 06:00, 14 April 2010 (UTC)

Yes, you are correct (again)! I'd forgotten that modern printers have processors with backup batteries. Dbfirs 08:06, 14 April 2010 (UTC)

The solution may be to buy an old second-hand printer that uses simple cartridges - which is what I do. 89.242.91.98 (talk) 10:52, 14 April 2010 (UTC)

Config file keeps "vanishing"

Is there anything which would cause a WinXP computer to lose track of its system configuration file, and what can be done to correct it? —Jeremy ^{(v^_^v Dittobori)} 20:30, 12 April 2010 (UTC)

To clarify: I have both Pro and Home editions on my rig. Whenevcer I try the Professional one, I get a warning message that it can't find the system config file, and if I try the Home edition it can't find my C: drive. —Jeremy ^{(v^_^v Dittobori)} 20:37, 12 April 2010 (UTC)

What's the exact text of the message, and when does it appear? —Korath (Talk) 21:47, 12 April 2010 (UTC)

It appears whenever I try to boot. For Pro, it's "The system cannot start because the following file is missing or corrupt: WINDOWS/SYSTEM32/CONFIG/SYSTEM You can attempt to repair this file by starting Windows Setup using the original CD-ROM. Select 'r' at the first screen to start repair."

For Home, it reads "Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware. Please check the Windows documentation about hardware disk configuration and your hardware reference manuals for additional information." —Jeremy ^{(v^_^v Dittobori)} 22:07, 12 April 2010 (UTC)

The first looks like a corrupt registry. This should allow you to boot, at least. —Korath (Talk) 23:36, 12 April 2010 (UTC)

That's a no-go on this rig since I turned off System Restore. Any other suggestions? (As an aside, I'm able to load it using a boot disc, and will be moving my essential files off of it tonight so that I can reformat and reinstall.) —Jeremy ^{(v^_^v Dittobori)} 03:55, 13 April 2010 (UTC)

Just a guess, but could the two keep the config files in different places in an otherwise shared directory structure ? StuRat (talk) 22:00, 12 April 2010 (UTC)

Benchmarking AWB's typo fixing

I'm interested in quantifying the processor use / run time of AWB Typo rules. Really this is an attempt to see if we need to be more cautious about rules that aren't used much in practice for the sake of increasing speeds. Ideally I'd like to be able to say that "rule x adds y milliseconds to each 1,000 characters of page processing" or something like that.

AWB uses the .net implementation of regex libraries, and there may be other overhead in there for the plugin too. Obviously different expressions will have different time, and the word's they're checking will vary. I'm just looking for some general idea about how to benchmark these with some precision. Shadowjams (talk) 23:00, 12 April 2010 (UTC)

Not to side-step the issue, but I'd be very surprised if the bottleneck wasn't the data transfer (over the 'net) rather than any processing. 94.168.184.16 (talk) 11:31, 13 April 2010 (UTC)

Not really. I'm asking only about the length of time it takes to process a page, not the whole experience of AWB scanning. But even if you include the AWB scanning time, for longer pages (even moderately longer), the processing takes a significant amount of time... perhaps longer than the download. That's mostly because the download is pure gzipped text and it's done through the API. Even a large page is at most a few 100k.

This is even more significant if the selection of the page is sometimes done intelligently... after scanning a database dump offline, or perhaps at random, or from a selection of pages from a category or new, etc. There are over 3,000 AWB typo rules and the processing on a long page can take a few seconds on my machine (not cutting edge, but not too old). Shadowjams (talk) 00:54, 16 April 2010 (UTC)

Excel to VBA to VBScript

Excel macros are written in VBA so thee must be a way to convert a simple spreadsheet entirely to VBA and then to VBScript. Where can I find a reference to doing it? 71.100.3.207 (talk) 23:03, 12 April 2010 (UTC)

Your logic is faulty. Excel macros are indeed written in VBA, but the behaviour of Worksheets (calculation of formulas etc) and other objects is not. AndrewWTaylor (talk) 15:23, 13 April 2010 (UTC)