Wikipedia:Reference desk/Computing

Welcome to the computing section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

January 28

PHP Login recommendation please?

Can someone in the know please recommend a good PHP login script for me? I don't want to roll my own because I'm still only getting my feet wet in PHP and am not confident I could produce a secure system. The Catch-22, though, is that I'm also hesitant to pick out a script from the wild because I'm not sure I'd be able to accurately appraise its security & quality... because I'm still only getting my feet wet in PHP. :-) Ideally, the script would allow for multiple levels of user privileges (basic/contributor/admin for example) and would have email confirmation/password reset ability. Failing that, I can always bolt on my own scripts for those features in the end. Thank you for any assistance you can provide! 218.25.32.210 (talk) 00:50, 28 January 2010 (UTC)

What backend do you want to use? PHP doesn't store any data. Are you going to store it in text files? Are you going to store it in MySQL? Are you going to store it in Excel spreadsheets? Do you have an LDAP server? Without knowing what you plan to do, it is hard to tell you what to do. In the end, a login script is rather straightforward. The common method is to store the user's password as a salted hash in a database. When the user logs in, you salt and hash the password they supply. If it matches what is in the database, you let them in. Use $_SESSION to store that they are logged in - as opposed to sending the password back and forth repeatedly. Anything extra is straighforward as well. Levels of security are nothing more than flags for the user in the database. A password reset will just change the hash and email a temp password to the user. -- kainaw™ 02:11, 28 January 2010 (UTC)

MySQL. 218.25.32.210 (talk) 02:33, 28 January 2010 (UTC)

Kainaw, a very simple log-in script is easy, but something that is a bit more bullet-proof, and has more features (like being able to reset the password securely), is a non-trivial endeavor, even for an experienced programmer. This is not what I would consider a "do it yourself" job unless you really didn't care if it was secure or not. --Mr.98 (talk) 22:07, 28 January 2010 (UTC)

Resetting a password is not complicated. Create a reset key. Email that to the user. User goes to reset page with reset key. If it is valid, allow the user to enter a new password. Done. Afraid people will automate the sending of reset keys just to be a pain? Add a captcha to the "I forgot my password" page and the reset page. Now they have to be humans. I do not see such a small algorithm to be complicated. -- kainaw™ 14:19, 29 January 2010 (UTC)

USB drive shrunk....

My USB drive is supposed to be 4GB... now it's only 385MB with 3.37GB of unallocated space for some reason! Windows won't let me add, delete, expand, or shrink any partitions on it either!! Why?? --76.221.146.179 (talk) 03:39, 28 January 2010 (UTC)

I've run into similar situations in the past. I think it had something to do with me deleting things off of it in Linux, and Windows not recognizing it correctly. I can't remember for sure, but whatever the case was it made absolutely no sense to me. In retrospect, Linux may have left deleted files in a hidden folder on the flashdrive... The way I got around that was formatting the flashdrive on Windows, which reset the space to the normal amount. Absolutely don't do that until you back it up, or decide that you don't care about what is on it. You will lose all the data on your flash drive in the formatting. I can't guarantee it will make any difference, but it may be worth a shot. Falconus^{p t c} 05:28, 28 January 2010 (UTC)

I think windows also keeps a "Recycle" folder on flash drives. If you have recently deleted lots of stuff, it might still be lingering on the drive. Try reconnecting it to the PC where you deleted the stuff off it, then empty the recycle folder. Astronaut (talk) 15:45, 28 January 2010 (UTC)

Backup your files then format the usb drive. Should fix the problem. —Preceding unsigned comment added by 82.43.89.14 (talk) 18:30, 28 January 2010 (UTC)

Since someone else asked... I formatted an 8GB PNY flash drive to install Dell's Bootable Utilities Partition. As I did it, I was informed that it will format in Fat16, and the rest of the drive will be unusable until I reformatted it. The problem is, any time I try to reformat it, the max size I get is 1.99GB, even in Fat32. (I tried Windows and Glary Utilities.) Any ideas? Mxvxnyxvxn (talk) 18:20, 29 January 2010 (UTC)

You need to re-partition the flash drive first. Otherwise, you will simply keep re-formatting the 1.99GB partition that the Dell tool created. -- 78.43.93.25 (talk) 13:41, 2 February 2010 (UTC)

EXCEL short cut

Frenz, this is Lawrence. i need to know whether there is any short-cut key to scroll from one sheet to other in ms-excel. can anybody help me? thanks —Preceding unsigned comment added by Johndlawrence (talk • contribs) 03:46, 28 January 2010 (UTC)

CTRL+PAGEUP, or CTRL+PAGEDOWN. More here --Tagishsimon (talk) 04:34, 28 January 2010 (UTC)

Facebook question.

Hello all. I was wondering, do any of you know if it's possible for me to deactivate/remove my Facebook account and still keep the fan pages I created running normally? If I hand over control to someone else, will they still get deactivated along with my account, seeing as I'm the creator? 202.10.94.125 (talk) 04:39, 28 January 2010 (UTC)

A New Undertaking

I`d like to make a site that approximates this:

WARNING: Medical pictures that may be not safe for work, or may be unpleasant to look at - it's a medical "guess the disease" test from the "new england journal of medicine"
http://image-challenge.nejm.org/?ssource=rthome#09172009

in its structure and function.

What would be the easiest way to go about it? Should I learn Javascript? Should I learn flash? or Both?

Or should I give up? I have a basic knowledge of HTML and CSS and a bit of time on my hands!

-Cacofonie (talk) 04:40, 28 January 2010 (UTC)

Forgive me for editing your post, but I clicked your link and just had a lovely picture of a diseased penis appear on my workstation. 218.25.32.210 (talk) 05:09, 28 January 2010 (UTC)

Sounds like you were unlucky - all I saw was a slightly bruised leg..(I modified the warning)

You want to make a site that is similar in layout and style to the site you linked ? if so you need html, css, and yes javascript - that's what the site uses.87.102.67.84 (talk) 13:46, 28 January 2010 (UTC)

You need to learn a back-end scripting language (PHP, Perl, Ruby, etc...) if you want to completely mimic a site like that. -- kainaw™ 14:26, 28 January 2010 (UTC)

Ah! I`m sorry about that! I purposely picked the tamest picture so as not to bother people. I`ve modified the link to a much tamer set. I hope no-one was traumatized. All I would really want to mimic is the zoomable picture, the multiple choice questionaire, and the easy scrolling between questions. Would I need to learn PHP for that? or can I do that all with javascript (including the animated scrolling?).

--Cacofonie (talk) 14:53, 28 January 2010 (UTC)

If you attempt to do it all in JavaScript, it will be a nightmare. Doing it with a backend script (like PHP) will be very easy - assuming you know how to program. I'd also use a database (like MySQL) to make it even easier. Once you have the backend, the content is not part of the page. It is added in dynamically. So, you create the user interface with JavaScript and CSS (the scrolling and such). You will in the pictures and questions with the backend script. You can load a bunch of different picture/question sets by just changing the query for the database. -- kainaw™ 15:06, 28 January 2010 (UTC)

Here's what's going on in the page and what's responsible for it:

• The general layout and appearance: HTML structures the elements, CSS determines how they look.
• The animated bits, zooming, etc.: all Javascript
• The database of images, the recording of votes: a server-side script, like PHP, probably in conjunction with a database, like MySQL.

Now you can cut out some things if you simplify it a bit—e.g., if you are content with a less flashy site, you can drop Javascript. (It could still load up images and look similar, but you'd lose the slick effects.) You could maybe skip out on CSS, and do it all in pure HTML, though the idea makes accomplished web designers squirm. But if you want to record votes, and have dynamically-updated content, you're going to need something like PHP. --Mr.98 (talk) 21:56, 28 January 2010 (UTC)

Strictly, you can write server-side stuff using almost any programming language - I have web pages that are generated on-the-fly in C++ for example. However, I strongly agree that this would be a hard task for anyone who is not a programmer. Step #1 in the process is to learn how to program...if you can't already do that then step #2 starts about a year later! SteveBaker (talk) 05:59, 29 January 2010 (UTC)

Safe Keylogger

Where can I download a free, safe keylogger for personal use? I want to let it run on my computer so that I can create a log of all the keystrokes I enter. Since I will not be using it maliciously or installing it on other people's computer, discretion is not important and its ok if the keylogger runs visibly in the tray or something. Acceptable (talk) 06:10, 28 January 2010 (UTC)

Family KeyLogger, found here. If I remember right, it has a limited trial period, but will continue to run with limited features past that point. It will be visible in the system tray; you will need a paid registration if you ever decide to hide it. If you like it, I would recommend purchasing it, even if you don't need the extra features, to support the company/developers. And it's a deal at only $28 USD. Hope this helps. -^Avicenna_sis @ 10:05, 29 January 2010 (UTC)

Not to doubt Avicennasis, but WOT reports that site to have a "poor reputation", and their website has comments alleging spyarsenal.com hosts malware. See [1]. Thanks, gENIUS101 20:45, 29 January 2010 (UTC)

Just Google Family KeyLogger for several other (possibly safer?) sites for downloading. Dbfirs 07:03, 30 January 2010 (UTC)

Ah. I was not aware of that that, gENIUS. I only remembered this particular program because I myself used it years ago, after seeing as a download of the day on The Screen Savers. OP is probably safer looking elsewhere, but at least I was able to point them in the right direction. -^Avicenna_sis @ 09:16, 30 January 2010 (UTC)

I wonder what exactly you mean to "log" all the keystroke? If you want to just log how many keystrokes you type (and the frequency of each key) and not concerning with what exactly you are typing at an particular moment, Whatpulse is probably what are you looking for. SYSS Mouse (talk) 02:19, 2 February 2010 (UTC)

about the racing car engine

where can i get the details of a racing(F-1)car? I need to know the whole engine working in detail and in simple language —Preceding unsigned comment added by Rohit100 (talk • contribs) 09:41, 28 January 2010 (UTC)

If it's Formula 1 in particular that you're interested in, try this article. You might get a better answer to your question on one of the other reference desks, like Science, Misc or maybe even Maths. CaptainVindaloo ^{t c e} 12:43, 28 January 2010 (UTC)

A formula one car is basically a high performance version of a normal car - for the engine "internal combustion engine" try these [2] [3], for more specific details on F1 try http://www.howstuffworks.com/auto-racing/motorsports/formula-one.htm 87.102.67.84 (talk) 16:51, 28 January 2010 (UTC)

bash filenames and redirecting output

If i run a bash script say, Script [Some Options] Input > Output, is there some way for me to make Output=Input.txt, without me having to know what the input name is, for instance i might want to run sort -un *.dat > (Whatever the *.dat matched to).sort , where the output has been piped to a file named like the input was named but with a suffix at the end (or any other string manipulation i may want to do), Thanks --137.205.124.72 (talk) 14:19, 28 January 2010 (UTC)

What would you want it to do if there were more than one .dat file present? You can sort each such file separately with

for t in *.dat; do sort -un "$t" >"${t%dat}sort"; done

(and that would work fine if there were exactly one). The quotes are to handle file names with spaces etc. There are several modifiers like % that you can use on a variable's value: %#/ are the most useful. --Tardis (talk) 16:20, 28 January 2010 (UTC)

Google Earth

How often does the radar update? Or how do I get it to update?Accdude92 (talk to me!) 16:52, 28 January 2010 (UTC)

If you mean the terrain altitude (relief) information, I believe that all comes from the Shuttle Radar Topography Mission, which is over. So I don't know if they ever update the radar info, other perhaps than fix bugs or plug obvious gaps ion the dataset. -- Finlay McWalter • Talk 17:43, 28 January 2010 (UTC)

No, there is a weather layer, and a subgroup "radar"Accdude92 (talk to me!) 17:45, 28 January 2010 (UTC)

On my copy, it says that it is updated every 5-6 minutes. (Click on Weather -> Information) Titoxd^{(?!? - cool stuff)} 10:35, 29 January 2010 (UTC)

TrueCrypt Recovery Disk

I wish to use TrueCrypt on a system partition. The program requires that a "recovery cd" be made, however the computer I wish to encrypt does not have a cd drive. The recovery disk isn't necessary, it's just a backup, yet the program simply will not continue unless one is made. How can I bypass this step? —Preceding unsigned comment added by 82.43.89.14 (talk) 18:29, 28 January 2010 (UTC)

With the "official" installation, basically you can't bypass it because it's a failsafe. You would need to either plug in a USB optical CDROM drive or download the source code and modify and recompile it not to require the check. Using the USB CDROM method would be the best idea though (you can burn the iso image on another computer, but it needs to be able to "read" it on your computer) and the recovery disk is for your own protection. You say it's not necessary, but it's there in case you ever have a problem with it and using the recovery CD you'll be able to unencrypt the drive (assuming you know the password still). Without that recovery CD, in the event of a problem, there's literally nothing you can do to get the data back. ZX81 ^talk 19:06, 28 January 2010 (UTC)

Won't work, each disk is different. You can't use another computers recovery disk, the headers and password hash will be different

Mounting the ISO file using a virtual CD mounting tool will fool TrueCrypt, I think. If you don't burn a recovery CD right away, you should at least keep the ISO file in a safe place where you will be able to burn a copy if you ever do need it. (The encrypted partition is not a safe place, needless to say.) -- BenRG (talk) 08:03, 29 January 2010 (UTC)

What ISO file?

It makes an ISO file in a temporary directory; you can mount it with a virtual CD utility, or burn it using a different computer as ZX81 suggested. I seem to recall that it displays the ISO file's location in the format wizard. I couldn't remember the details, so I looked in the documentation, and it turns out there's a /noisocheck command-line option that does what you want. You should have read the documentation before asking here, and I should have read it before replying. I still recommend saving the ISO file, though. -- BenRG (talk) 05:29, 30 January 2010 (UTC)

Threat detected and quarantined but site in history

I got a pop-up message from Norton saying it had found and removed a threat. I think the word "quarantined" may have been used. When I looked at the Norton security history I found a series of numbers and letters which I also found when I went to my history to look for a site I had gone to. I never intentionally went to Google-Analytics and yet there it was. Never have I found any site in the history that I didn't go to by clicking on a link or typing where I type the URL. And at home I'm careful where I go. I'm not at home now. By the way, I deleted the history just as a precaution, though by tomorrow the history would have been gone anyway.

What should I tell Google?Vchimpanzee · talk · contributions · 18:36, 28 January 2010 (UTC)

Google Analytics is a web statistics tracking tool. Anyone can embed a GA tracker into their website so that when you go to their website you ALSO connect to the GA server so that they can count the hits, collect data for traffic pattern graphs, etc.

It's perfectly harmless unless you're more than normally worried about privacy. APL (talk) 18:46, 28 January 2010 (UTC)

Well, Norton considered it a threat and I had a false alarm when a company told me I had viruses and demanded I download their software, so these days I'm overly sensitive.Vchimpanzee · talk · contributions · 18:58, 28 January 2010 (UTC)

By the way, those alerts that pop up while web surfing which claim "YOU HAVE A VIRUS! DOWNLOAD OUR SOFTWARE IMMEDIATELY TO CLEAN YOUR COMPUTER!" are all fake, and install malware, or at least install difficult-to-uninstall ad-vomiting software. You can safely ignore them all. Comet Tuttle (talk) 19:23, 28 January 2010 (UTC)

User:Comet Tuttle is referring to WinFixer like pop-ups. Although WinFixer was shut down a little over a year ago, others are still lurking. PCHS-NJROTC ^(Messages) 23:48, 28 January 2010 (UTC)

I know not to download anything unless it's a respected site. The pop-ups in my case came from scan-and-secure07.com.Vchimpanzee · talk · contributions · 18:51, 2 February 2010 (UTC)

Wierd attempts to access port 44281

I noticed today that a DSL IP from Mexico has been trying to access port 44281 on my network, and I'm kind of puzzled why. I'm guessing it's a virus, but why after it continues to fail? Anyone hear of any viruses that behave in this way? I've already contacted the abuse contact for the IP. PCHS-NJROTC ^(Messages) 23:33, 28 January 2010 (UTC)

It may be part of a botnet trying to contact a zombie, or a zombie trying to contact its master. Either way, assuming you're not infected (and the issue is caused because some previous user of your IP address) then there's nothing to worry about. Or it might be a peer-to-peer filesharing program (which occasionally run on weird ports, in part to try to evade blocking) which again is trying to connect to another p2p client which was run by some former user of your IP. Either way, it's probably nothing to worry about. 87.112.52.108 (talk) 23:42, 28 January 2010 (UTC)

I figured it's botnet, I'm just curious which one. I over 50 attempts a week at NAT level, usually coming from residential IPs around the world, but I rarely see any given IP keep trying besides those annoying port 445 attempts on my own CIDR range. PCHS-NJROTC ^(Messages) 23:52, 28 January 2010 (UTC)

January 29

micro-SIM

It looks like that any 3-year-old can use a pair of scissors to make a micro SIM card from an ordinary SIM card.

http://apcmag.com/images/micro-sim.jpg

Do they put the electric circuits under the "fingers"? -- Toytoy (talk) 01:18, 29 January 2010 (UTC)

As you can see in this photo - the actual circuit is a really tiny bit of silicon. It's about the size of the central contact patch on the smart card. SteveBaker (talk) 05:53, 29 January 2010 (UTC)

It appears to me that what you are calling "fingers" are the electrical contacts. The size of those are limited by the ability to get an acceptable connection between the card and the reader. That has nothing much to do with the circuit used for memory storage. -- kainaw™ 17:57, 29 January 2010 (UTC)

Regular expression - write n at nth match

Is there a way to use sed in order to replace the n-th match of a pattern with the number n? E.g. if the pattern is "xyz" and the file's content is "abcabcxyzuioxyzasdf" then the output should be "abcabc0uio1asdf". Thanks in advance. Icek (talk) 06:09, 29 January 2010 (UTC)

sed is Turing-complete, so it can be done, but not easily, I think. For what it's worth, you can do it in Perl like this: perl -pe 'BEGIN{$n=0} s/xyz/$n++/eg' -- BenRG (talk) 08:18, 29 January 2010 (UTC)

Careful there: do you mean the nth match within the same line, or the nth match in the whole file? If it's the second meaning, that Perl code is correct (and can be shortened by removing the BEGIN{$n=0} part). For the first meaning, where the count resets for each line, put $n=0; without a BEGIN. Either way this must be far easier than any solution involving sed, which does not have numeric variables. --Anonymous, 00:11 UTC, January 30, 2010.

I don't know how you could replace a match with an arbitrary string using only POSIX regex. Using a programing language of course would work, but I don't think it's possible with a typical regex alone. There may be some work around I don't know about in either of those, but if there is I don't know it if it's part of the general spec. Keep in mind that sed and grep use a better (as in more efficient) regex engine when it comes to non-recursive patterns than does perl and nearly every other reg ex out there. Shadowjams (talk) 11:58, 29 January 2010 (UTC)

The stupid way would be to have a sed script that looked like

s/xyz/0/
s/xyz/1/
s/xyz/2/
#...

...since it replaces from left to right and (without g) will replace one at a time. Is that good enough? (It won't be if it's possible for there to be confusion between replacements and things to replace, like if "xyz" is really "000"; you can do some sort of byte stuffing to work around that.) You could even run sed in a loop; write out each iteration and stop when two are the same. --Tardis (talk) 17:25, 29 January 2010 (UTC)

Where to get a capture card?

Any of you gamers out there making videos with capture cards or what not, could you text me back and tell me where you can get a capture card? Can you get them in Australia? Originally posted in article namespace by Jyejonah (talk) 10:21, 29 January 2010 (UTC)

Do you mean capturing video from a video game console, or capturing what happens on your PC's screen while you play a PC game? If the latter, I recommend FRAPS. If the former, lots of PC video cards have a video-in option so you can use them as a capture card. Be sure you choose a card that supports the video signal that you want to capture — PAL or an HD signal (presumably 720p; and make sure the cabling inputs match what's coming out of your console, so you don't get an HDMI input board only to find your console has no HDMI-out video connector). There are also USB devices that capture video; I expect these to be worse in quality than a solution built into your graphics card — though I don't have a specific recommendation; I'd search for "video capture" at Newegg (I know, it's a USA retailer, but the user reviews are great for locating which product you want to start actually shopping for) if you can't find any actual recommendations in this thread. Comet Tuttle (talk) 18:20, 29 January 2010 (UTC)

Laptop Problem

If I put my laptop on hibernate after connection to the WiFi in my college, when I return home I can't connect to my home network without a reboot. Getting DNS problem and also it says something about keyports. My usual solution is to sign into MSN and use the inbuilt repair with MSN to connect. But it is getting to be a pain now any suggestions? Thanks. BigDunc 11:28, 29 January 2010 (UTC)

I had similar trouble with a Centrino laptop from IBM. The issue turned out to be a faulty ACPI driver (not the wireless card driver! Go figure). The "hibernate" feature in particular caused a variety of improper hardware shutdowns, which the system did not know how to recover from on wakeup. This caused instability, blue-screen crashes, and generally required a regular reboot to fix.

Unfortunately, without very specific details about your laptop make, model, including the wireless card type, drivers, and operating system, we can't really begin to diagnose what's causing your trouble. The conventional approach is "update all your drivers," in the hope that this problem was fixed in a newer version. Nimur (talk) 18:33, 29 January 2010 (UTC)

In Windows XP and Vista, I think you can right-click on the wireless icon and choose "repair" (somewhat fewer clicks are needed in XP, I think). This would still be a rather inelegant fix, but somewhat simpler than what you are doing now. In the same vein is opening the command shell and typing "ipconfig/release" followed by "ipconfig/renew". Just some suggestions, I'd try the things suggested in the previous reply first... Jørgen (talk) 19:13, 29 January 2010 (UTC)

Cyberarticle 4.364

Does anyone know where I can get this last-freeware-version without using Torrent please? All the sites I can find that may host it also appear to be in Chinese or Japanese. I am looking for 4.364, not 4.363. Thanks 78.149.174.141 (talk) 12:39, 29 January 2010 (UTC)

Why not use BitTorrent? Get a copy of uTorrent or similar, and download it that way. Dedicated servers aren't cheap, not everything gets hosted in perpetuity. —ShadowRanger ^(talk|stalk) 15:02, 29 January 2010 (UTC)

Screensaver or program showing progression of night and day across the atlas

Where can I find one of these please? Similar things I've seen before show a world map which is light where daylight is, and dark where night is. The dark/light border is like a "S" shaped wave. 78.149.174.141 (talk) 12:43, 29 January 2010 (UTC)

Pick one. --LarryMac | Talk 14:37, 29 January 2010 (UTC)

Just providing a link to Google is not a helpful answer to the question, nor is it clever. I should have added that I'm looking for a freeware one. 78.149.174.141 (talk) 14:56, 29 January 2010 (UTC)

(ec)The link in his response lists several such screensavers in the first few lines. How exactly is that not helpful? Do you expect someone to test and evaluate each of them for you? —ShadowRanger ^(talk|stalk) 14:58, 29 January 2010 (UTC)

I cannot see any. I have been through every link on the first page. Most of the links are to irrelevant webpages that mostly look like automatic compilations of other web material. After going through two or three clicks through to other websites I did find one freeware program but which is not a screensaver, and which does not work. 78.149.174.141 (talk) 15:11, 29 January 2010 (UTC)

Following up based on your addition to your comment: Several of the links are shareware, which is better than nothing. Sometimes you have to pay for software you like though; someone does have to write it after all. —ShadowRanger ^(talk|stalk) 15:00, 29 January 2010 (UTC)

No need to be so aggressive, gentlemen. I was hoping that someone who had used one or knew of one could suggest one they were familiar with. If every question was answered with a Google link, what would be the point of this Reference Desk? If you do not want to be helpful but just macho, then let's consider this question cancelled. 78.149.174.141 (talk) 15:08, 29 January 2010 (UTC)

Then you should have asked "Can someone recommend ..." or "Has anyone used ..." rather than "Where can I find ...". Of course we can't help you if you don't explain what you really want. Gandalf61 (talk) 15:21, 29 January 2010 (UTC)

78, you are the only one that has leveled any criticism in this thread. Comet Tuttle (talk) 20:16, 29 January 2010 (UTC)

To be honest I couldn't find a useful one in the links myself - there was http://3d2f.com/programs/2-995-earthview-download.shtml which uses a globe not an atlas I think they want something like this - http://www.iris.edu/seismon/html/june15th.html - maybe someone could at least suggest better search terms? (is there a technical name for this shadow - that would help) How about http://www.brothersoft.com/earthwatcher-64155.html (free) or http://www.freemap.com/geoscreensav.htm $59 - but do they work?or http://www.osxplanet.com/ 87.102.67.84 (talk) 12:49, 30 January 2010 (UTC)

I use http://www.mapmaker.com/shadowfacts/v65/index.htm 's sunzip which has a freeware version. -- SGBailey (talk) 23:11, 30 January 2010 (UTC)

http://hewgill.com/xearth/
http://images.google.com/images?q=xearth ¦ Reisio (talk) 23:35, 30 January 2010 (UTC)

Automating downloading a page after a menu choice

There is a webpage with a drop-down menu. The menu offers twenty or thirty choices. After each selection of the menu, a page of information is shown, which I want to save to disk. What would be the easiest no-cost way to automate the downloading of these pages please? The problem is getting past the drop-down menu and going through all its choices. Actually there are three menus right next to each other, but I think going through just one menu gets all the information. Thanks. 78.149.174.141 (talk) 15:20, 29 January 2010 (UTC)

If you look at the page source, you might be able to figure out what logic it uses to determine the page to visit, then use wget or the like to iteratively retrieve each page. This would require some basic HTML and scripting knowledge though. Menus can be implemented many different ways, so it's not trivial to pull every page linked from one menu. —ShadowRanger ^(talk|stalk) 17:45, 29 January 2010 (UTC)

Also, while I've never used it, you might try DownThemAll. It might be a bit overzealous (you may get more than you want), but it should be easier than the manual solution I suggested. I'm a scripting geek, so I think everything is solved better with Perl one-liners, but I recognize that not everyone is in the same boat with me. —ShadowRanger ^(talk|stalk) 17:48, 29 January 2010 (UTC)

how do I use a networked printer

Okay, this is really dumb. I use dsl with a router, it has yellow lan lines and stuff, but also wireless. If I just plug in one of the yellow lan lines into the networked printer, will I suddenly be able to print from my netbook which is connected to the same router on wifi? Or, do I have to configure it or something? I'm using windows 7 on the netbook, and the printer is an hp. color laserjet... thanks for as much information as you can give me. 84.153.238.207 (talk) 16:28, 29 January 2010 (UTC)

All the computers (and networked printers, and any other Internet-ready gadgets) "behind" the router should be able to see each other, whether you're connecting to the router via cables or via the wireless connection, without having to configure anything special on the router. Comet Tuttle (talk) 17:26, 29 January 2010 (UTC)

thanks! 84.153.213.154 (talk) 09:52, 30 January 2010 (UTC)

IE7 peculiarity

There was a discussion regarding Template:Collapsible list which died out a couple months ago, but never came to a solution. Is there anyone that can figure out why the show/hide link displays differently in IE7 than every other browser? Assuming it hasn't expired yet, this page shows the screenshots of the different browsers. Thanks, MrKIA11 (talk) 16:46, 29 January 2010 (UTC)

Have you tried asking this question at the Village Pump "Technical" page? That page is frequented by Wikipedia hackers, and is much more likely to get you a response than this Reference Desk, which does deal with computer related questions but isn't Wikipedia-specific. Comet Tuttle (talk) 17:27, 29 January 2010 (UTC)

Yeah, I also posted there, just trying to reach a wider audience. MrKIA11 (talk) 17:39, 29 January 2010 (UTC)

I would hazard a guess that Internet Explorer is an awful browser. —Preceding unsigned comment added by 82.43.89.14 (talk) 22:35, 29 January 2010 (UTC)

template talk:collapsible list#Overhang_section_break^* ¦ Reisio (talk) 09:58, 30 January 2010 (UTC)

Graphics card question

My mother is buying a new computer. She has figured out what she wants, but the company she is buying from (Dell) has a number of graphics card options, and she doesn't really know which one to pick. I don't either, but I suspect they are all overkill for her needs. Her most graphically-intensive activities are to edit large photos in Photoshop, occasionally watch DVDs, browses the web and watches YouTube. She does not play games or do anything with 3D (and she is the only one who will ever use this computer). Is there any reason to go beyond the basic option here? Is she going to notice any kind of real improvement?

• nVidia GeForce 310 512MB GDDR3 [Included in Price]
• nVidia GeForce GTS 240 1024MB [add $130]
• ATI Radeon HD 5770 1GB GDDR5 [add $180]
• nVidia GeForce GTX 260 1792MB [add $230]
• ATI Radeon HD 5870 1GB GDDR5 [add $330]

I've had a hard time researching this because all of the discussions about the merits of said video cards are about their abilities as gaming cards or 3D rendering cards, which are irrelevant for this purpose. She won't be overclocking, obviously. Does she really need more than the basic card? All I know is that it seems much more powerful than my current card, and I'm able to edit photos, movies, what have you without much difficulty, but I haven't bought PC parts in ages. Any thoughts? (And spare me the "Dell hell" lecture and any related ones... I know, but it's what she wants to do.) --Mr.98 (talk) 17:57, 29 January 2010 (UTC)

The baseline card should be *more* than sufficient. A card half that powerful would do for what she is doing; unless she takes up 3d gaming, CAD work, or video editing, it will be more than enough. —ShadowRanger ^(talk|stalk) 18:01, 29 January 2010 (UTC)

OK, that's what I thought. She was scared because the Dell site helpfully explains that if you have the low-end card, all you can do is Instant Messaging and E-mail, which I am sure is not true, but of course she wanted me to double-check. --Mr.98 (talk) 18:10, 29 January 2010 (UTC)

Of course the Dell site says that. Dell is trying to up sell. The only thing she does that requires even a modicum of power is Photoshop (and running the OS), but any of the cards listed will kick Photoshop's ass, metaphorically speaking. She should make sure she has at least a couple gigs of RAM, and going up to 3 or 4 won't hurt (newer OSes are RAM hogs, and programs like Photoshop and Lightroom often benefit in responsiveness when provided additional RAM to cache images), but I can make a guarantee that no photo editing software worth the name released in the next five years (and more than likely, the next ten) will even remotely tax the resources of the "low end" graphics card you describe. —ShadowRanger ^(talk|stalk) 18:15, 29 January 2010 (UTC)

Does the GeForce 310 actually use a 300-series GPU? It seems like it does not, and uses a G80 processor. More details at GeForce 300 Series. This is an unfortunate and confusing bit of marketing-ese. (I almost choked on some coffee over here seeing a GeForce 300 OEM that cost less than a GTS240!) Nimur (talk) 18:50, 29 January 2010 (UTC)

If that's the case, it would make it a bit more power hungry for the performance, but not underpowered. I'm running an 8800GTX (768 MB of RAM) at home and can run Fallout 3 (and several other graphics intensive games) without issue. 98's mother will do just fine, G80 core or no. —ShadowRanger ^(talk|stalk) 19:30, 29 January 2010 (UTC)

If your assessment of her needs is correct then even the cheapest of those systems is probably a hundred times more powerful than she needs. I would stick with an nVidia board because their drivers are better. I'd avoid anything by Intel because they are junk. Aside from that, aim for the low price point. SteveBaker (talk) 05:15, 30 January 2010 (UTC)

General Purpose GPU

I heard that graphics cards are super powerful processors. I have a bog standard graphics card that came with the computer, and except for basic display of the desktop and firefox etc I don't use it for graphics (games, movies etc). Can I harness it's power for computing tasks? —Preceding unsigned comment added by 82.43.89.14 (talk) 19:41, 29 January 2010 (UTC)

See our article on GPGPU. Short answer: If your graphics card is old (more than two or three years) it's likely not useful. And even if it is, the programs have to be coded to take advantage of it. You can't just shift processing from CPU to GPU for arbitrary programs. —ShadowRanger ^(talk|stalk) 19:48, 29 January 2010 (UTC)

For example, when I'm not gaming, I run Folding@Home on my GPU. It produces results for the project that are (according to the points given by the project) roughly 10-15x more useful to the project than that produced by a single core on a CPU. The results are different (GPUs are good at floating point calculations, CPUs are good at integer calculations), but sometimes it's useful to get the faster but somewhat less precise results a GPU can give. —ShadowRanger ^(talk|stalk) 19:54, 29 January 2010 (UTC)

Thanks for the links. So I can't just wave a magic wand and double my computers processing power, seemed to good to be true :( —Preceding unsigned comment added by 82.43.89.14 (talk) 22:34, 29 January 2010 (UTC)

No, you have to go to great lengths to find useful applications for the GPGPU outside of the realm of technical computing (CAD, numerical physics, and so on). The GPGPU is not very useful for things like web surfing - although regular GPU acceleration can be useful for things like accelerated web-video decompression, 3D maps like those on Bing Maps, etc. Nimur (talk) 23:01, 29 January 2010 (UTC)

The GPU is a very strange beast. It contains a heck of a lot of extremely simple computers that all have to run the same program at the exact same time and (more or less) all run the programs together in lockstep. These little computers are crazy-fast. This makes them very useful for doing bulk processing work where some simple operation has to be done a heck of a lot of times with slightly different data each time. That's why they are so good at doing graphics where there are maybe a million pixels that need to be drawn, all with essentially the same algorithm but with slightly different data at each point. The GPU can draw graphics hundreds of times faster than the CPU could possibly hope to do. That also makes them good for things like movie compressing or weather forcasting. However, these little machines don't have much memory each, they have no access to the hard drive or the network or even the mouse and keyboard, and they find it hard to communicate with each other. They also have their own fairly weird programming languages. So you can't run something like a browser on them (although you could use them to draw pictures on behalf of the browser). It all depends on what you want to do.

If you are a programmer and you're (say) writing a chess playing program - then you could probably do some restructuring of the software that tests out every possible move that you and your opponent can make for the next few moves of the game and get a massive speedup by using the GPU. But as an average non-programmer, you can only get out what the people who wrote your software designed their product to do. Right now, not many of them use the GPU for anything other than graphics.

SteveBaker (talk) 05:11, 30 January 2010 (UTC)

Thank you everyone for the informative answers! :) —Preceding unsigned comment added by 82.43.89.14 (talk) 12:48, 30 January 2010 (UTC)

January 30

Cannot delete user accounts

I'm trying to delete a user account on Windows XP, but each time I click on the "Delete Account" button, the program freezes, I have to end the process, and as a result the account is never deleted. What do I do about this? 24.189.90.68 (talk) 00:42, 30 January 2010 (UTC)

I hate it when I am told to try this, but without knowledge of any known bugs in this area, I have to suggest re-booting the PC. In other words, shut it down and turn it OFF.(maybe even at the power point) Wait a minute, turn it on and try gain. --220.101.28.25 (talk) 04:12, 30 January 2010 (UTC)

You can try removing it from the command line. For example, simply typing net user bob /delete will delete the account named bob. -^Avicenna_sis @@09:28, 30 January 2010 (UTC)

All I get is: NET USER

             
[username [password: *] [options]] [/DOMAIN] 
              username {password: *} /ADD [options] [/DOMAIN]
              username [/DELETE] [/DOMAIN]
 

And the account isn't password protected. 24.189.90.68 (talk) 00:40, 31 January 2010 (UTC)

OK, never mind the above, I found a way to delete the account through Computer Management with no problem, but thanks for the suggestions anyway. 24.189.90.68 (talk) 00:48, 31 January 2010 (UTC)

Java bytecode vs. machine bytecode

I've always heard that compiled-then-interpreted languages like Java run slower than machine code, but I've never heard by how much. I know it probably depends on many factors, but I'm just interested in an estimate of how many times faster machine language would perform a task, say, repeated manipulation of a large text file, over Java. Does using the Java Native Interface to do work-intensive operations make a big difference, or to truly utilize the sped-up benefits of machine code, do you have to avoid a Java implementation altogether? Thank you!--el Aprel (^facta-_facienda) 03:34, 30 January 2010 (UTC)

The traditional rule of thumb was that a bytecode interpreter cost you a factor-of-ten slowdown. But if the bottleneck is the network or the disk rather than the CPU then using bytecode makes no difference, and if the bottleneck is loading or caching code (which it actually can be in some large applications) then bytecode may be faster than native code because it tends to be more compact.

In any case, Java bytecode is usually compiled (JITted) to native code before being run these days, though possibly with less aggressive optimization than modern C++ compilers employ. There are also compilers that compile Java directly to native code, like gcj, which uses the same optimizing backend as gcc. I think performance problems with Java have less to do with the bytecode than with features of the language itself, like those I mentioned here. -- BenRG (talk) 06:18, 30 January 2010 (UTC)

As always, you have to benchmark in order to be sure of a particular speedup or slowdown - and it is highly situation-dependent. I can't tell you how many "super-optimized" FORTRAN codes I've seen that used unbuffered disk I/O. This particular detail, which entails less than a half of a line of Java code, could give break the execution bottleneck of a huge class of computer programs. But if you are comparing direct implementations and execution time of native code vs. Java bytecode that are otherwise implementing identical operations, the native code will mostly execute faster. Nowadays, even this is not necessarily accurate - more instructions is not equivalent to longer execute time, because the CPU can do intelligent prefetching and branch prediction if the instructions are well-ordered; various instructions and operations of the x86 pipeline have different execution times; and as always, memory locality and cache performance will dramatically affect execution - probably more so than instruction count. So, I'd go for a compiler that is cache-aware, and a language which permits the user to ignore those details and let the compiler optimize them. Lately I've been mixing FORTRAN90, C, and Java with JNI. All I can say is, I wish the F90 would disappear. (Disappear__(), rather). I'm unconvinced by my benchmarks that it provides a comparative speedup at all. Nimur (talk) 18:03, 30 January 2010 (UTC)

As to "possibly with less aggressive optimization than modern C++ compilers employ", Sun's Java compiler, called HotSpot, is a very aggressive modern optimizing compiler. Java code routinely runs at speeds comparable to statically compiled languages - sometimes a few percent slower, sometimes a few percent faster (artificial benchmarks will inflate to NN% slower to NN% faster). JIT compilation really works; writing out machine code to a disk file before executing it does not make it faster!

Static compilers like gcj typically produce less performant code as they can't do things like inline most methods -- rather an important optimization in object oriented code with many small methods. Dynamic compilers can do that, giving HotSpot an edge over static Java compilers as well as statically compiled other languages. 88.112.56.9 (talk) 04:53, 31 January 2010 (UTC)

I didn't mean to imply that bytecode makes Java slower. Any given optimizing backend will produce pretty much the same machine code from bytecode as from the source code "directly". But when you're JITting, the compilation time counts as part of the run time, which makes some expensive optimizations less desirable. That's why I thought that JITters tended to dial down the optimization a bit. I know there's academic research on deciding (quickly!) which methods are likely to benefit from extra optimization, but I don't know what the commonly used VMs actually do.

JITters benefit from having access to the whole program and to runtime call traces, but so do modern C++ compilers. Since VS.NET (2002), Microsoft C++ has supported link-time code generation, in which the .obj files contain not machine code but a serialized intermediate representation—bytecode!—which is then optimized at the whole-program level. Microsoft C++ also supports profile-guided optimization. Intel C++ has supported whole-program optimization for even longer. I don't know the status of whole-program optimization in gcc. I think it has been delayed by licensing/political problems: defining an on-disk format for the intermediate code makes it possible for third parties to add passes to the compiler that don't fall under the GPL. I would expect that to hurt Java more than C++, because in C++ the functions most suitable for inlining are often placed in header files where they're available for cross-module inlining even when separately compiling. -- BenRG (talk) 09:12, 31 January 2010 (UTC)

(addendum) One factor that isn't stated often enough is that java (and many others) do more error checking a runtime than C - (of course you really should know how big your arrays are anyway..) - this puts most languages at a disadvantage in the computer language benchmarks game with respect to C (OCAML allegedly also does well).87.102.67.84 (talk) 09:43, 31 January 2010 (UTC)

Thank you, all, for the interesting and thorough information!--el Aprel (^facta-_facienda) 17:22, 1 February 2010 (UTC)

Getting Office 2007 Student on my eeepc

Hey all. I recently bought (well, won actually) an Asus eeepc, which, as you will know, does not have a CD/DVD drive. I'm looking to buy a copy of Office 2007 Student edition to put onto it, but I'm worried that I'll just get a disk through the post. On the other hand, it came pre-installed with a trial edition - can I just buy a licence key somewhere online? What's the easiest way of doing this? - Jarry1250 ^{[Humorous? Discuss.]} 11:33, 30 January 2010 (UTC)

Upon further research (putting my problem into words helped), I think it may come down to cost. I live in the UK, and can get a legit copy presumably on disc for £36 (approx $57) thanks to an RM/Windows partnership thing. Download sources seem vastly more expensive e.g. $150. Maybe I should just go ask the £36 source about getting a download version... - Jarry1250 ^{[Humorous? Discuss.]} 11:42, 30 January 2010 (UTC)

Actually, I must be going mad. Surely I can just buy the CD/DVD version, look at the packaging, grab the licence key and chuck it into my trial? Yes, that sounds sensible. - Jarry1250 ^{[Humorous? Discuss.]} 11:44, 30 January 2010 (UTC)

You can only do that with the same EXACT version of office that the trial is (I believe it should be Home and Student? I'm typing on an eeePC right now.) If you get a Basic or Ultimate key, it will not plug in. Mxvxnyxvxn (talk) 23:48, 30 January 2010 (UTC)

If it comes on a CD, just make an image file on a computer with a CD drive, copy the image file to usb drive then on your ASUS Eee PC mount it with magic disk or similar software. —Preceding unsigned comment added by Kv7sW9bIr8 (talk • contribs) 12:10, 30 January 2010 (UTC)

In Australia, I recall seeing a version that actually came on a thumbdrive! (My memory may need defragging! ;-) ) Otherwise an external USB DVD drive? The Student version DVD was available for A$99. --220.101.28.25 (talk) 12:23, 30 January 2010 (UTC)

MHTML VS HTML

When I save a web page, I have the option to save as normal html with images etc in a separate folder, or save as a single mhtml file. If I'm saving thousands of web pages, which is the better option for long term storage, viewing, searching etc etc —Preceding unsigned comment added by 82.43.89.14 (talk) 12:44, 30 January 2010 (UTC)

I think that a MHTML file is much more convinient. Then you get one file for the entire web page. I would definitely use this format if I were to save and archive a large number of web pages. But I suppose that the compatibility is slightly better for HTML + folder of images; I do not know if all major browsers can read .mhtml files. --Andreas Rejbrand (talk) 14:19, 30 January 2010 (UTC)

Not all can, but MHTML indicates that the big ones (Firefox, IE) can. I don't think it really matters either way. The upside of MHTML is that it results in fewer files to keep track of. But that's it. --Mr.98 (talk) 17:57, 31 January 2010 (UTC)

CSS question

I'm trying to whip myself up a simplified speed-dial type page. Using CSS, is there a simple way I can divide the window into four quadrants, with text centered inside each, both horizontally and vertically? I could try positioning text links, but I want the entire upper-right area to serve as a link, the lower-right area to serve as a link, etc -- the entire area, not just the text. I know I described it poorly, but yeah -- is there a way to do that using plain CSS? 202.10.95.36 (talk) 15:16, 30 January 2010 (UTC)

Here is kind of a crude way. The difficulty (and crudeness) comes from the browser trying to figure out whether you've hit the limit for needing a scrollbar or not. (You could put this off if you had this code launched by Javascript in a window with no scrollbars.) This also kind of breaks official HTML DOM order—you aren't supposed to put DIVs inside of A HREFs, I don't think, even though it works (and is the only solution for certain types of things, unless you want to use javascript OnClick's, which I think are worse).

<html>
<head>
<style type="text/css">
<!--
body {
	margin: 0;
	padding: 0;
}

.box {
	text-align: center;
	height: 49.9%;
	width: 49.9%;
	vertical-align: middle;
}

#topleft {
	border: 1px solid blue;
	position: absolute;
}

#topright {
	border: 1px solid red;
	position: absolute;
	left: 50%;
}

#bottomleft {
	border: 1px solid green;
	position: absolute;
	top: 50%;
}

#bottomright {
	border: 1px solid yellow;
	position: absolute;
	left: 50%;
	top: 50%;
}

.innertext {
	position: absolute; 
	top: 50%;
	width: 100%;
	text-align: center;
}

a:hover .box {
	background-color: silver;
	color: white;
}

a:link {
	text-decoration: none;
}

//-->
</style>
</head>
<body>

<div id="holder">
	<a href="#"><div class="box" id="topleft"><div class="innertext">topleft</div></div></a>
	<a href="#"><div class="box" id="topright"><div class="innertext">topright</div></div></a>
	<a href="#"><div class="box" id="bottomleft"><div class="innertext">bottomleft</div></div></a>
	<a href="#"><div class="box" id="bottomright"><div class="innertext">bottomright</div></div></a>
</div>

</body>
</html>

Hope that helps. --Mr.98 (talk) 16:09, 30 January 2010 (UTC)

The big problem right now is that CSS doesn't properly support vertical centering. If you omit the requirement for vertical centering, just make four divs. Make each one 50% height and 50% width in CSS. Set position to absolute. Set left and top for them using 0% and 50% as necessary. Set text-alignment to center to center vertically inside the div. For vertical alignment, you have to place a div inside each div. Then, set the top and bottom margin to auto. Then, hope that the user isn't using an old version of IE. Then, hope that new versions of IE don't break all the code you just spent days working on. Then, give up on CSS and just use a table with heigh/width at 100% and 4 data cells. -- kainaw™ 21:08, 30 January 2010 (UTC)

http://reisio.com/temp/speed-dial.html
This will work in all relevant browsers, uses standardized code, and is semantically correct. ¦ Reisio (talk) 22:55, 30 January 2010 (UTC)

how does an Intel Atom compare to an old Pentium III?

I can't for the life of me seem to get even the performance out of this netbook that I had on my old Pentium III, so my question is:

• how does an Intel Atom N280 @1.66 GHz compare with a Pentiumn III @ 999 MHz in terms of performance?

Thanks. 84.153.221.224 (talk) 18:40, 30 January 2010 (UTC)

What performance do you mean? For your reference, here's the direct specs for N280 and Pentium 3. Most of the way through, the Atom is at or above the specification for a Pentium 3. Perhaps the performance bottleneck is somewhere else (e.g. a slower hard-disk, or comparing wireless network to wired network?) It seems unlikely that the netbook has less RAM than the original P3 computer, but this could also contribute to performance issues. Perhaps you had a better graphics card in your previous computer - netbooks tend to have flaky, bottom-of-the-barrel graphics chips because they are intended only for 2D graphics and "web surfing". Finally, check if SpeedStep is enabled - the Atom may be scaling back its performance intentionally in order to preserve battery life. You can disable that option in the power management control interface. In closing, I would just ask that you perform a side-by-side comparison to verify your claim - a lot of performance issues are subject to user-bias. If you actually measure load or execution times with a stopwatch, do you actually see that the P3 is outperforming your Atom N280? Nimur (talk) 18:49, 30 January 2010 (UTC)

Thanks, I do mean ACTUAL processing performance. I heard like fourth-hand that the Atom architecture is about as well-performing as a celeron at half the speed. Now, is a Pentium III @ 999 MHz markedly better than a celeron at 833 MhZ (half of 1.66 GHz)? Was what I heard even correct? Thanks for anyhting like that you might know, I'd hate to actually have to go through the trouble of doing a benchmark myself... 84.153.221.224 (talk) 18:58, 30 January 2010 (UTC)

They probably meant an Atom at 1.66 GHz is comparable to a Celeron (the original?) at 3.32 GHz, which seems plausible to me. -- BenRG (talk) 08:01, 31 January 2010 (UTC)

There's some benchmarks here http://www.cpubenchmark.net/low_end_cpus.html

• Atom 280 @ 1.6GHz scores 316

There's so many pentium III's I don't know which to choose - there's Pentium III mobile @ ~1GHz scoring 193 up to about 228 . Higher figures are better. - it's not clear how they make the numbers - so I'm not sure if double = twice as fast..87.102.67.84 (talk) 20:19, 30 January 2010 (UTC)

Oh - your atom is dual threaded - I assume the old pentium was single core - for some applications the threading doesn't work very well - ie CPU activity doesn't get above 50-70% - if this is the case then this may cause the pentium III to appear better. Try a comparison in the task managers - and see if this is the case.87.102.67.84 (talk) 20:26, 30 January 2010 (UTC)

A dual-core CPU may peg at 50% instead of 100%, but a single-core hyperthreaded CPU like the Atom N280 can only peg at 100%. If the CPU usage is less than that then the CPU is not the bottleneck. -- BenRG (talk) 08:01, 31 January 2010 (UTC)

Is the N270 same as the N280? On a N270 I've seen various applications (eg ffmpeg) top out at 50% - opening a second instance increases this to 100% - As I understand it the atoms use hyperthreading to present 2 virtual cores to the machine.? Also the likely other factors preventing cpu over 50% include memory bandwith as well for anything with more than 1 (virtual) core?87.102.67.84 (talk) 09:04, 31 January 2010 (UTC)

Okay, admittedly my claim was not based on experience. Now that I think about it, a hyperthreaded CPU might well peg at 50% depending on how the OS measures things. But it's not actually half-idle in that situation like a dual-core CPU running a single execution thread. -- BenRG (talk) 09:21, 31 January 2010 (UTC)

Yes, Task manager isn't the best measuring stick. For a simple interpreted 'round robin' program a single instance takes 60s, two instances take ~85s each, beyond that (3 or 4 instance) the average times increase (slightly better than) roughly linearly with number (~10% base load) (ie as expected).

So the hyperthreading works ok - but might be a reason why single threaded programs (1 of) make the atoms seem slow compared to an old pentium III.87.102.67.84 (talk) 10:55, 31 January 2010 (UTC)

I remember similar complaints when the first core 2 duo's came out (@1.8 to 2.6GHz) - that they weren't as fast as a proper desktop pentium @+3GHz (despite being intrinsically faster in general) - nowadays standard core 2 duo parts run between 2.2 and 33 GHz so even applications that don't take advantage of the extra core work just as well or better.87.102.67.84 (talk) 11:03, 31 January 2010 (UTC)

This site is good in that it provides individual benchmark data (and a lot of it) - if you look closely you can see the effects of cache, processor speed, pipeline, and general architecture by comparing the individually listed benchmarks. This http://www.roylongbottom.org.uk/cpuspeed.htm is the best way in. You can get classic benchmarks to run as well from the same site if you wish87.102.67.84 (talk) 20:41, 30 January 2010 (UTC)

some of you said you didn't know which Pentium to compare with: it was a non-mobile normal Pentium III @ 933 MhZ (I had misremembered the 999 MHz). Now, that PIII scores 228 compare with my netbook's Atom at 316. Should be about a 38% speed improvement. Far from it. This thing is way, way, way slower.

There are two HUGE differences I can think of to explain this:\ 1) this is running Windows 7 whereas the PIII was running Windows 2000. 2) this thing has a Mobile Intel 945 Express Graphics Card, versus a dedicated NVidia in the old PIII desktop. Now this 945 Express is such a piece of junk, it's depressing. can anyone find benchmarks comparing this mobile graphics chip to old real graphics cards?

But this netbook is realy awful. It can't even play an MP3 while I browse without sometimes getting huge stuttering (I mean about 1000 milliseconds of it - that's 1 second of awful screeching) and other incredibly ugly artifacts. It's a total piece of shit! 84.153.221.224 (talk) 13:59, 31 January 2010 (UTC)

The 945 is about as low as you can go nowadays - but people have still compared it's performance with other things - http://www.google.co.uk/search?hl=en&rlz=1C1CHNG_en-GBGB363GB363&q=intel+945+graphics+benchmark&btnG=Search&meta=&aq=f&oq= it'll run Neverwinter Nights (medium). However you shouldn't be getting stuttering on mp3 no matter what.. Might be something wrong - (or maybe you have something like norton antivirus installed or some other performance hog). What does windows task manager tell you? I'm not sure about win7 but it might be a problem if you try to run the full aero thing. or maybe flash on browser sites is killing it? A usual atom+945 can just about do 720p video and doesn't have a problem with mp3 at all. Here's two of many places you can find 945 vs other video card numbers [4] [5] ~85fps on Quake3 (high).87.102.67.84 (talk) 17:31, 31 January 2010 (UTC)

Increasing the program priority of the mp3 program might fix it - all (single core) cpus will peak briefly to 100% utilisation when opening a web page - just right click on the process and select, not sure how or if this makes it permanently higher priority. If that helps there are ways to make the priority permanently increase.87.102.67.84 (talk) 17:45, 31 January 2010 (UTC)

The same site as before has a big list of video cards http://www.videocardbenchmark.net/gpu_list.php 87.102.67.84 (talk) 18:28, 31 January 2010 (UTC)

Another possible explanation (for audio problems) in win7 drivers - this page http://www.tomshardware.com/reviews/windows-7-xp,2339.html from a while ago suggests issues - I know that XP is fine on notebooks. New audio drivers?87.102.67.84 (talk) 19:07, 31 January 2010 (UTC)

AnandTech compared Atom N270 with Pentium M (see [[6]]) and concluded that depending on task, the Atom is equivalent to a Pentium M at 800 to 1200 MHz. Atom N280 is a more advanced variant of a N270 and a Pentium M is a further developed version of Pentium III. Thus, a Pentium III at 999 MHz should be even at its best equivalent to an Atom N280, and more often slower. The conclusion is that something is probably wrong with your Atom system. Is there any chance that it has a solid state disk? Bad performance of budget SSD's was an industry-wide problem until very recently, and stuttering is a possible symptom. 85.156.64.233 (talk) 21:42, 1 February 2010 (UTC)

Ubuntu Dual Boot

I have an HP Mini 1000, Running Windows XP Home Edition. I have 3.63 GB of free disk space, and I'm not sure how much RAM I have. I want to dual boot it with Ubuntu 9.10. This will be the first time I have ever tried something like this, and need help. Thanks. MMS2013 19:51, 30 January 2010 (UTC)

• 3.63 GB disk space may not be enough; even wubi requires ~5GB. ----Zvn (talk) 19:57, 30 January 2010 (UTC)

No, you certainly don't have enough diskspace. The system requirements lists 4 GB for "bare minimum" operation and 8 GB for comfortable operation. The installer should allow you to resize your Windows partition if it has a lot of space that you aren't using. Just make sure you shut down Windows properly before fiddling with its partition, otherwise Ubuntu will refuse to touch it. Consider using Xubuntu (1.5 GB minimum, 6 GB recommended) or, if applicable, Ubuntu Netbook Remix. Xenon54 / talk / 20:05, 30 January 2010 (UTC)

And if you're not set on Ubuntu, there are a number of low-diskspace linuxes, such as Damn small linux and Puppy linux. See Mini Linux for more (or List of Linux distributions). However, depending on which one you choose, it may have less user-friendliness/community support than Ubuntu. -- 174.21.224.109 (talk) 20:24, 30 January 2010 (UTC)

It might be a bad idea to fill your free disk space with another OS - where would XP put new programs, documents, photos, etc.? Astronaut (talk) 13:57, 31 January 2010 (UTC)

It might be prudent to ask yourself whether you really really really need two OSes. I actually have Zenwalk and XP, but don't really use XP, because, y'know... ;) --Ouro (blah blah) 08:14, 1 February 2010 (UTC)

There is something you can do; Get a 4 gig usb drive, and install Ubuntu on that. The installation might replace your MBR/boot loader on your main HDD so it might be prudent to pull it out first. I have used this exact thing on my carputer. I have also used my flash drive to help me fix and recover virus infected windows computers for friends and coworkers. – Elliott(Talk|Cont)  14:33, 2 February 2010 (UTC)

Is an ATX psu suitable for 24vdc supply?

Resolved

I need at 24vdc power supply for a stepper motor I'm testing. I do not have anything here that can push 24v. If I used an old ATX psu and used the +12 as positive and -12 as ground, would I be able to get 24v out of this setup?

A quick googling yeilded this site showing a 17v supply created from +5 and -12. Before I blow anything up, I just wanted a second set of eyes to tell me go/no go before I start splicing. Thanks aszymanik speak! 20:26, 30 January 2010 (UTC)

Usually you'd be ok - one obvious mistake I can think of would be to use +12 and -12V lines rated at different currents (or Watts) - if you do this the lower powered one is likely to overheat (or something) under load.. There probably are other things that can go wrong as well but I can't think of them.87.102.67.84 (talk) 20:56, 30 January 2010 (UTC)

An ATX power supply is designed to be controlled by a computer motherboard. So, you will have to rig up some controls to make it work. I think it would be much easier and safer to simply purchase a 24vdc power supply. Depending on amp requirement, you can get them for under $10. -- kainaw™ 21:03, 30 January 2010 (UTC)

I agree with Kainaw. I'd definitely go for a cheap AC/DC power supply, or string up a couple of 6 or 12-volt lantern batteries. This will be generally safer and less likely to cause hardware damage. Your ATX power supply is designed to supply power to a motherboard, and your unusual, out-of-spec usage may result in undefined behavior, potentially dangerously. Really, what you want is one of these, a variable DC power supply (unfortunately, the cheapest I could find was $99). However, if you're seriously experimenting with electronics, you really can't live without one or two of those (or even better models). Nimur (talk) 01:44, 31 January 2010 (UTC)

(edit conflict)[7] page 21 table 9 - the -12V rail is usually rated at about 0.1 A (whereas the +12V rails can take/give over 1A) - so you can't use more than a fraction of an amp without overloading the -12V rail - ie don't take much more than 1-2Watts for a ~300W powersupply. [8] suggests a limit of about 0.5 A for the -12V rail - your powersupply probably has similar figures on the side - or you can look it up on the web - summary - try to take 1Amp of current (24W) and there will probably be smoke!87.102.67.84 (talk) 21:06, 30 January 2010 (UTC)

Ok, thank you. That is some wise advice. I hadn't considered the likeliness of overloading the bus and definately dont want any smoke ;). I've been debating on getting a proper benchtop power supply. Maybe now is the time. aszymanik speak! 06:53, 31 January 2010 (UTC)

I would point out it's actually quite easy to start an ATX PSU without connecting it to a motherboard. People do it all the time when testing them for example. You just have to short the power on wire to any of the ground wires. The article has more details However ATX PSUs are generally designed with the expectation they will have resonably loading on the 3.3V, 5V and 12V and the regulation may be poor if you are only drawing a few watts. So even if you are trying to use them for the 3.3V, 5V or 12V I would use caution when using them as a generic PSU Nil Einne (talk) 15:52, 31 January 2010 (UTC)

While there certainly is no substitute for a good variable output power supply, I can say from experience that a well made switching-regulated ATX power supply can be a *very* cost competitive way to do some basic electronics work. The nameplate limitations are good to follow but on major brand units these values are rated based on full output and high heat. I can suggest Antec as a brand that routinely outperforms it's nameplate (I have used them in this exact setting). Also, a well made unit will voltage limit itself before melting down, so its relatively safe to experiment with as long as you are mindful of the voltage and cut off the load quickly when the supply is overloaded. --Jmeden2000 (talk) 15:44, 1 February 2010 (UTC)

Accidental forks?

Are there any known cases where a branch of a software project became a fork only because attempts to reintegrate it with the trunk failed? (If the trunk was then abandoned, that doesn't count, because then the branch has become the trunk.) NeonMerlin 22:13, 30 January 2010 (UTC)

Mmmh (interesting) Microsoft's version of Java might count - though it wasn't exactly reintegrated (or supposed to be a branch) - more 'kicked out' - did that become c# I wonder? via Microsoft Java Virtual Machine Visual J++ and J# - dunno - I give up what's the answer? :) 87.102.67.84 (talk) 22:30, 30 January 2010 (UTC)

A rough approximation of the Unix lineage. Nimur (talk) 01:42, 31 January 2010 (UTC)

How about Unix? This has got to be the most well-known example of forks that become entirely new projects. You can also count the Linuxes, too, which are technically not a "fork" as the original kernel never shared a codebase with any Unix. At this point, it's best to think of a modern *nix operating system as a "mesh" which includes pieces of code from a lot of historical lineages. Aside from key utilities like the core kernel, the X server, and certain well-demarcated system utilities, it's very hard to say exactly where any particular component actually came from on any particular distribution. Often, the manpage or the source-code will document the lineage, and you can perform some technology archaeology of your own to trace back the versions. Nimur (talk) 01:42, 31 January 2010 (UTC)

I'm not sure that any of those forks were "accidental" in the sense that there was an intent to keep a unified codebase and then that attempt failed. APL (talk) 05:13, 2 February 2010 (UTC)

January 31

Connecting wirelessly

Or rather, not. I have a router which is working fine and connecting to computer #1. But #2 is not connecting. A bar chart bottom right is green and says things are excellent. 2 little tvs bottom right say there is a wireless connection albeit at a low strength. Clicking on it suggests mighty little contact has passed through it. Typing 192.168.0.100 into the url bar does not bring up the router start page on #2. What have I missed and what should I try next? Kittybrewster ☎ 20:05, 31 January 2010 (UTC)

Have you tried connecting on #2 (what OS) (ie wireless connection wizard or something similar) - does it fail (how) or succeed?

• If fail is it possible to bring #2 closer to the router (or the router closer to #2) and try again - if this works it might be a simple problem of signal strength - there are solutions for this.
• If succeed then - how does it not connect - what error messages? 87.102.67.84 (talk) 21:51, 31 January 2010 (UTC)

do I have to do something with my complex printer to turn it off, or just flick the switch?

I have a complex HP networked printer, it has a big LCD display and everything. Should |I try to shut it down in some special way, as with a PC, or should I just flick the on/off switch. I can't seem to find any shutdown in the menu system. THanks... 84.153.232.162 (talk) 22:08, 31 January 2010 (UTC)

The Power (On/Off) button/switch should do it (unless it is a physical switch on the back of the printer, in which case there probably is a more "soft" way of powering it down). A model number would help. --Andreas Rejbrand (talk) 22:16, 31 January 2010 (UTC)

February 1

What file compression format has the smallest minimum size?

What file compression format has the smallest minimum size file? I'm not asking about the efficiency of compression, but rather the minimum "footprint" of an archive. For example, (these are made up numbers) a ZIP archive of a 100B file would still need 20KB of disk space just to create the ZIP container. --70.167.58.6 (talk) 00:20, 1 February 2010 (UTC)

Does it include the size of the program needed to de-compress the files as well?Shortfatlad (talk) 00:27, 1 February 2010 (UTC)

A trivial compression algorithm could be extremely small. For instance, converting any run of 3 or more words (words being whatever unit you're using in the algorithm, such as hex words) into some code of word plus repeat count.

I think what you want is what widely available useful compression algorithm would have a small footprint. This post might help you [9] for a practical example. From that discussion it looks like zlib family compression algorithms have good overhead properties. Shadowjams (talk) 00:50, 1 February 2010 (UTC)

There are compression programs with no overhead at all, such as bicom. It compresses a file of length zero to a file of length zero. -- BenRG (talk) 02:50, 1 February 2010 (UTC)

minimum qualification for post of lecturer in degree colleges

hi,

wheather it is mandatory for a person with M.C.A degree to become lecturer in degree colleges to pass NET/SLET/PHD ?

thanking u

bye Nagendra R —Preceding unsigned comment added by Siranagendra (talk • contribs) 05:50, 1 February 2010 (UTC)

This question has come up multiple times. It depends on the country. In the United States, a Masters Degree is all that is usually necessary, but most universities want PhDs. -- kainaw™ 05:56, 1 February 2010 (UTC)

DjVu file download

1) I would like to save a copy of the DjVu file from this page http://www.archive.org/details/tenacresenoughpr00morriala but right clicking and saving the DjVu link does nopt work, and the DjVu reader itself does not offer any means of saving it to HD. How could I save it please? I have tried using CacheViewer and PageInfo from Firefox, but neither of them show a DjVu file. 2) Why is the DjVu file so much smaller than the Pdf file? Thanks 84.13.23.254 (talk) 13:54, 1 February 2010 (UTC)

Click on "All Files: HTTP", then right-click, save-as the DjVu file at the top of the list. I don't know why, but the regular DjVu link is only set up to "stream", whereas the "All files" link lets you just download the individual files, no questions asked. --Mr.98 (talk) 15:11, 1 February 2010 (UTC)

Java to retrieve webpage source

Resolved

Hello again! Could someone please give me a Java code example that retrieves a source of a webpage given a web address, so that I can apply a Scanner to it to look for certain words? Thank you!--el Aprel (^facta-_facienda) 17:27, 1 February 2010 (UTC)

See the archives, where I did this (mostly for fun). --Tardis (talk) 18:19, 1 February 2010 (UTC)

(edit conflict) This page shows how to open a internet connection (for reading etc) http://java.sun.com/docs/books/tutorial/networking/urls/readingWriting.html as used in the above example, this one http://java.sun.com/docs/books/tutorial/networking/urls/readingURL.html is all you need if you aren't writing back.

This page (about 1/2 way down for the code) [10]- has another example of the same thing, and uses scanner class too - with emphasis on reading the whole page at once.

More info http://weblogs.java.net/blog/2004/10/24/stupid-scanner-tricks - this is probably the clearest and most concise. (though it's not clear to me why they use the \A instead of \Z regex to find the end of file.)

(or just save the web page as a .txt file to the hard disk and do as normal?) - do you want more glue? 87.102.67.84 (talk) 18:40, 1 February 2010 (UTC)

Good stuff—just what I needed. Thank you both!--el Aprel (^facta-_facienda) 21:59, 1 February 2010 (UTC)

Scan cancelled; no items to scan

I recently had error messages when I tried to visit Norton tech support, so I copied those messages and asked about them as a separate issue. I was told the exisitng software was corrupted and that I should download Norton's latest version. After I did, it wouldn't automatically do a full system scan like the old software did. I got a message worded essentially the same as the title of this section. If I clicked on the Norton logo and clicked on "scan", though, I could select a full system scan (the old software made that option harder to find) and it would do it. I asked Norton and couldn't get a straight answer or an obvious reason for this. There were no virus defintions when I first downloaded, and when I clicked on the Norton logo I got a red message saying I needed to take action, and over the next few hours I downloaded the virus definitions. That has not solved the problem of the scan not happening automatically, though the message telling me the scan was cancelled does pop up at the scheduled time to remind me to manually do the scan, which serves the purpose. It just seems strange.Vchimpanzee · talk · contributions · 18:44, 1 February 2010 (UTC)

Sounds like the new norton has inherited an issue from the old norton - maybe because the old norton wasn't fully uninstalled when you uploaded the new norton. (I believe norton has tools to fully uninstall an old version - did you use anything like that? eg[11] )87.102.67.84 (talk) 19:10, 1 February 2010 (UTC)

I'm not sure. I uninstalled the old version when it told me to. I have a couple of other Norton products that I downloaded free to help me with the problem I contacted them about (which most people say was a fake virus message anyway), but I think they operate independently. The one that does the scan is operating continuously, while the others just run when I tell them to.Vchimpanzee · talk · contributions · 19:23, 1 February 2010 (UTC)

If you want to start afresh there's a guide here - [12] - what it says is right - in that after uninstalling norton there's still a lot left. Is it right that you are getting the same (erroneous) popup from the old norton even though you've got new norton - if so I would recommend the total uninstall - both two links above, restart and then reinstall. (it's just a minor bug though isn't it?)87.102.67.84 (talk) 19:31, 1 February 2010 (UTC)

I never saw a message saying "Scan cancelled" until I got the new software. I'm not aware the error messages I reported had any effect on Norton's performance.

This is a copy of the message I sent to Norton that led to the downloading of updated software. I've replaced my real name with my name on Wikipedia.

I clicked on "Help and Support". At the end of the first step I got this message: "Autofix did not find any issues that affect your Norton Internet security and performance". But before that, a box popped up with the following error messages (my computer has no backslash key so I used the forward slash)

(01)6947=No Smartissue template file specified.

(02)6961=Invalid Smartissue template [13] -Parsing XML Error: no element found File C:/Users/Vchimpanzee/AppData/local/Temp/siA0B4.tmp Line: 1 Column: 0

(03) 536870914=Unable to copy file C;/Users/Vchimpanzee/AppData/Local/Temp_tf1E7.tmp->C:/Users/Vchimpanzee/AppData/Local/Temp/siF604.tmp

(04)2=The system cannot find the file specified.

When I clicked on "OK" and the first box disappeared, there was a new one: Function:startXMLIO.js.cfm Name: Error Message: (01)6951=Failed to open file []. Description: (01)6951: Failed to open file[].Vchimpanzee · talk · contributions · 20:19, 1 February 2010 (UTC)

Mac Program Similar to Notepad++ (Not XCode)

Is there anything for the Mac OS X that is similar to Notepad++ that is not Xcode, which I view as too complicated. I like the former because it highlights similar tags and also colors tags red when invalid. I am only trying to do HTML, XHTML, CSS, and maybe JavaScript, so I don't want something too complicated. —Preceding unsigned comment added by 128.54.237.250 (talk) 21:46, 1 February 2010 (UTC)

I really enjoy TextWrangler. It is in that wonderful sweet spot of light-weight but feature-rich (and free). Syntax highlighting, but it doesn't tell you when things are wrong, I don't think. (But it doesn't highlight them, which is an indication.) Here is a list of a few other Mac-specific text editors. (Of course, the cross-platform ones should work too in some cases.) Of those, the others that look like they might fit the bill (though I haven't myself used them) are TextMate and skEdit, both of which cost money. --Mr.98 (talk) 23:10, 1 February 2010 (UTC)

I love Komodo Edit. It has all kinds of languages that it supports natively, and anything you can jury rig too. Oh, and it's free and free Quintusπ ^talk 23:34, 1 February 2010 (UTC)

Emacs, of course. Your Mac actually is a useful Unix computer under all that glitter (typed on a MacBook Pro ;-). And, of cours Ed is the standard text editor. --Stephan Schulz (talk) 23:36, 1 February 2010 (UTC)

February 2

Removing an overlay

I'm led to believe for the most part that if something is on your computer, you have viewing access to it. For example on this one site, it requires that you pay a subscription in order to view the content, but the way it hides the information is by overlaying a black screen over it, but the text is still there. What I do is use my HTML editor and edit the black overlay out and I have full access to the text. Another example is online streaming music. All that needs to be done is download the source of the music using lovely Firefox addons and you don't have to pay a dime. Other methods include downloading the shockwave flash and decompiling it using your favorite flash decompiler. But the only one that is stumping me (and I hope you can help me) is this one here: http://www.cramster.com/discrete-math-and-its-applications-6th-problem-9-894932.aspx click view solution. What it is is a text being partially hid behind a white overlay (I can clearly see the text as the overlay isn't the same width as the text). But unfortunatly, it's embedded in a flash player. When I download it, I can only download the flash player and not the content it's retrieving from this site: http://www.cramster.com/solution-player.aspx?solution_problem_id=678347. Is there anyway this content can be accessed, I mean, the content is right on your computer. 198.188.150.134 (talk) 06:27, 2 February 2010 (UTC)