Wikipedia:Reference desk/Archives/Computing/2010 November 18

= November 18 =

Post compile array size definition in Pascal
I'd like to create an array such as the type: truthtable : array [1..n,1..x] of boolean; in pascal after having used readln(n), and x:=n-1 to get the variables.

As far as I can tell the compiler only allows constants in the definition. Excluding creating a block of memory at run time and not using an array is there a work around ? 83.100.237.223 (talk) 01:41, 18 November 2010 (UTC)


 * You should use a dynamic array:

var truthtable: array of boolean; begin SetLength(truthtable, n, x); // Now you got truthtable as an array[0..n-1, 0..x-1] of boolean end;
 * --Andreas Rejbrand (talk) 08:29, 18 November 2010 (UTC)
 * Thanks . Actually worked with

var truthtable : array of array of boolean; ...etc 83.100.237.223 (talk) 18:17, 18 November 2010 (UTC)

Programming language
So I'm thinking about learning a more "hardcore" programming language.

I work on a Mac (so no Visual Studio products). I am pretty proficient with PHP, Javascript, VBScript, and Actionscript. I can meddle with VB.NET but I haven't used it as much as I could. I pick up things pretty quickly and have a fairly good programming mind. I know the basics of programming logic and object oriented programming. Of the languages I know, I find PHP the most straightforward and VBScript the least straightforward. What I like about PHP is I find it very easy to translate the logical structure in my head into the code on the page, without having to jump through too many jargony hoops, if that makes sense.

What's a good next step? I'd like whatever language I use to not involve too much meddling with the nuts and bolts of computer memory. I'd like it to be cross-platform enough to develop on my Mac, but to make programs that could theoretically be ported to PCs. I'd like it to be able to create GUI programs that look pretty good. The programs it make ought to be easily distributable as binaries.

I'm not 100% sure what I'd use it for at this point — I make lots of little things, and find that obviously having the capacity to use the language inspires me to have ideas as to what to make with it. My general model will probably be to get a "how to learn language X" book and work through it first, whatever the language.

I'm leaning towards Java. It seems to allow more portability than most others, seems to be relatively flexible and popular, and seems like it would open up opportunities for using it, say, in conjunction mobile apps.

Any other suggestions, thoughts, warnings? I understand this is entire subjective. --Mr.98 (talk) 01:57, 18 November 2010 (UTC)
 * If you are programming applications for "PC users," I would vote for Java as the best all-around power and tradeoff between portability, functionality, performance, and (this is critical), quality of free tools and documentation. If you decide to program embedded devices at a low level, there's no substitute for C.  But nowadays, many "mobile" devices like phones and ipods provide platform-specific programming environments - so you often have to target a specific brand/technology and use that set of tools.  Nimur (talk) 02:12, 18 November 2010 (UTC)


 * At first sight there doesn't seem to be much choice for languages with good GUI support, (no .NET on the mac). As you don't want nuts and bolts C++ sounds like a non starter - the main difference is the need to do memory management yourself - depending on the scope of your programs that might not be a big issue, or you might find you enjoy the task. There are some other options though, notably Ada and Lisp which can be used with the Qt widget toolkit amongst others.
 * I guess that when you say 'hardcore' you mean faster. Ada is fast, and a nice easy language to read, unfortunately it doesn't have a total feature set on either GTk of Qt widget toolkits according to the wikipedia articles. Lisp is well supported (in terms of GUI stuff etc) and is a totally different kettle of fish, it's just something you'd have to look at yourself to see if you think it'll be useful to you. There are also some other ALGOL descendents that have 'rapid gui development tools' - such as pascal + Lazarus (software) or other gui builders. Pascal is a bit old though, I'm not sure how well it would adapt to a network type setup. None of these would be of much use on a mobile device though as far as I know.
 * The page Comparison of integrated development environments might be useful - not all the IDE's listed will have the features you want - but it's a good place to start browsing.83.100.237.223 (talk) 03:35, 18 November 2010 (UTC)
 * I'm not really sure what would constitute a "hardcore language"...especially since you don't want to learn pointers. Java/.Net would be pretty good... REALbasic also has cross-platform support. You might also want to see Comparison of C Sharp and Java.Smallman12q (talk) 15:10, 18 November 2010 (UTC)
 * I just want to note that I've played with REALbasic before and found it too primitive for my needs, and not cross-platform enough where it counted. It's like VB6 that works on a Mac, basically, which will get you so far but what I'm hoping for is something that lets me not rely on third parties to write plug ins and things like that so heavily. There are things it can't do at all (like adequate PDF support, or even the ability to use standard PDF viewer plugins) that are kind of musts for anything I want to invest a lot of time in. --Mr.98 (talk) 01:52, 19 November 2010 (UTC)
 * C, Perl. Java™ isn't remotely hardcore, it's what they teach kids at university instead of Pascal, because after a long time people figured out Pascal wasn't hardcore, so they had to switch to something else, and they'll have to again, eventually. ¦ Reisio (talk) 19:11, 18 November 2010 (UTC)

Thanks for the suggestions. I think I'm going to go with Java, or at least give it a gander. I appreciate your taking the time to try and make sense of my notably subjective terms and requests. --Mr.98 (talk) 01:52, 19 November 2010 (UTC)

External SATA + operating system
About 8 months ago, I bought a used computer which came installed with Windows XP or Vista (I can't remember which; probably the latter). You can actually read about it here (although I ended up buying a d620 not d520). As such I have two SATA hard drives:
 * One 250MB, which I use primarily and run Ubuntu on
 * One ~80GB, which is collecting dust in storage

I have a few questions about this setup: Magog the Ogre (talk) 05:28, 15 November 2010 (UTC)
 * 1) If I place my secondary hard drive into an external USB like this, will it work?
 * 2) Is it possible to run Windows from a USB while I have the first hard disk still attached? Windows is pretty pissy about sharing a computer with another OS. And is it wise to run Windows from a USB? I'm only doing it because there are games that can't play on Linux (Wine is utterly resistant to fixing the bug plugging up Sims 2, and I don't have enough knowledge of remote programming - let alone modern 3D graphics - to fix the bug for Wine).
 * 3) Will I run into any sort of issues with the Software Protection Platform locking me out because the hardware configuration has changed (the product key was activated by the vendor before they shipped me the laptop)?


 * For Question 1 : While yes it seems to work (All SATA drives) Are you sure it's two drives or is it just 2 separate partitions? Just check if you are not sure (Seems you don't have XP. If you do, go to Disk Management)
 * For Question 2 : Yes, but it may be laggy. It depends on the disk speed (most likely 7200 rpm) of the hard drive, but I don't think there would be any problems. Just make sure the hard drive is not one of those eco ones that just go to standby and takes a few seconds to spin again, or you may see lag. But that's unlikely.
 * No idea for Question 3, sorry. Good Luck! General Rommel (talk) 06:01, 15 November 2010 (UTC)

Well, considering that the other disk is collecting dust in the basement, yes, I'm quite sure it's not a virtual drive. ;) Magog the Ogre (talk) 06:05, 15 November 2010 (UTC)

Also some searching finally turned up, but I don't think I have the CD. Magog the Ogre (talk) 06:34, 15 November 2010 (UTC)


 * Here at work, I use Ubuntu as my primary desktop environment. The machine also came with a separate partition with Windows XP installed, and GRUB gives me the choice to boot into Ubuntu or Windows.  That's fine, but I have need of more regular access to Windows XP without leaving Ubuntu (mainly because the company's Exchange server works so much better with the Microsoft Outlook mail client than, say, Thunderbird), so I have switched from the dual-boot setup to running XP in a virtual machine, and I must say it is pretty seamless.  I would recommend you give it a go, and you can always delete the virtual machine if you find it's not for you.
 * As for potential problems with SPP, I think you would encounter some problems but you should be able to simply re-activate it (though you might have to call the activation helpdesk and explain you have shifted it to a virtual machine). 212.123.243.220 (talk) 12:30, 15 November 2010 (UTC)
 * Come to think of it, if you don't have an XP/Vista installation CD and you don't have the Microsoft Certificate of Authenticity still attached to the machine, you might not be able to install Windows in a virtual machine. 212.123.243.220 (talk) 12:41, 15 November 2010 (UTC)

No, I use VirtualBox, but it has no support for DirectX. Virtual OS's are not good for gaming. Magog the Ogre (talk) 12:42, 15 November 2010 (UTC)

I'm moving this section back to the bottom to get more input. Magog the Ogre (talk) 02:18, 18 November 2010 (UTC)

Samsung Syncmaster 797MB monitor OSD
What does NP, PP and NN means in following context?

81. 3k 100 hz NP

60. 0k	75 hz PP

56. 4k	70 hz NN

Jib-boom (talk) 04:44, 18 November 2010 (UTC)
 * 81.3k is 81.3kHz the frequency of the signal the monitor receives through the VGA cable
 * 100Hz is the monitor refresh rate
 * NP refers to the polarity of the input signal (eg N negative, P positive)
 * If you follow this link you can read what it say in the manual (page 33) - though it doesn't say a lot.83.100.237.223 (talk) 05:13, 18 November 2010 (UTC)

How to reset game in old Xbox
How do I delete game memory in my Xbox so that it resets to default? —Preceding unsigned comment added by 220.255.2.65 (talk) 08:49, 18 November 2010 (UTC)


 * Go to memory, select the game slot and click delete.

No add/remove programs in my settings folder!! what can i do to uninstall?
it's win 2003 srv std ed. thanx --217.194.34.103 (talk) 08:56, 18 November 2010 (UTC)
 * Perhaps discuss it further? Has this occurred recently, has other strange things happened? Perhaps there is a virus? General Rommel (talk) 11:17, 18 November 2010 (UTC)

(e/c)
 * Is the icon itself missing or is the problem that when you click on the icon, the add/remove programs pane does not appear or is not populated with programs? If the first, searching suggests these possible solutions:
 * Make sure you are logged in as administrator
 * Make sure the icons are not appearing out of order (ie. the add/remove programs icon is there, but the icons are not sorted alphabetically)
 * Run "appwiz.cpl" (no quote marks). Does the Add/Remove programs dialog start? - some other options there, although it is not aimed at Windows Server 2003.


 * If the second, consider this. Also consider rolling back any changes you have made recently. Depending on your setup, it could also be caused by a group policy setting. -- Kateshortforbob talk  11:29, 18 November 2010 (UTC)

Count valid English vocabularies
10,000+ strings consisted of a-z are generated randomly, and all of them are shorter than 5 letters. Now I want to count how many strings are valid English vocabularies, so I need a method or a program to do this work, could you help me?-- Merry Rabbit 09:16, 18 November 2010 (UTC)
 * There are many. First you need a list of valid words - see e.g. this page. The simplest solution then is to just read the word list into an efficient data structure (a Python dict or set would do fine), and then check for each of the generated words if it is in the word list. If your data structure is O(1), the word list has n elements and your test set has m elements, overall performance is O(n)+O(m) (n for loading the dictionary with the n words from the list, m for checking each of the m words). Here is an example implementation for recent Linux/Python systems using the normal /usr/share/dict/words list as the source and a hard-coded file name for your candidates:


 * --Stephan Schulz (talk) 13:48, 18 November 2010 (UTC)


 * If no string appears twice in the list, you can make do without any programming. Let a be the file with your strings, one per line, and let b be a reference list of English words in the same format, such as /usr/share/dict/words suggested above. Count the number of lines in a, in b, and the number of distinct lines in their union:

$ wc -l a 10000 $ wc -l b 479625 $ sort -u a b|wc -l 487576
 * Then the number of English words in a is the sum of the first two numbers minus the third number (in my example, 10000 + 479625 − 487576 = 2049).—Emil J. 15:00, 18 November 2010 (UTC)
 * Now that I had a look on the first few pages of my /usr/share/dict/words, I wouldn't consider most of the garbage listed to be actual English words, so this is not a particularly reliable source to obtain a meaningful answer.—Emil J. 15:07, 18 November 2010 (UTC)

Encryption master key held by the Chinese
New York Times informs that the Chinese rerouted much of the Internet traffic through Chinese servers on 2 occasions last spring. The article notes that "While sensitive data such as e-mails and commercial transactions are generally encrypted before being transmitted, the Chinese government holds a copy of an encryption master key, and there was speculation that China might have used it to break the encryption on some of the misdirected Internet traffic." What key is that? What's the point to encrypt secret military emails with a code that could be broken by the Chinese government??? 93.172.63.225 (talk) 10:43, 18 November 2010 (UTC)
 * While "the Chinese government holds a copy of an encryption master key" is most likely true in the literal sense, it's also irrelevant. The internet is an end-to-end network, and all really sensitive data should be encrypted directly by the participants, using trusted encryption methods which do not have or require a "master key". Most protocols use asymmetric public key cryptography to transmit one-time session keys, and something like AES for the actual data. The NYT article seems to be badly confused, as it speaks about "web traffic routes" - there is no such thing. They probably mean IP routes. --Stephan Schulz (talk) 13:16, 18 November 2010 (UTC)


 * It's not at all clear what that means. I suppose the following might be what they mean is that, in addition to being able to route all traffic, read and change unencrypted traffic, a government-backed attacker can also compromise a certificate authority based in that country (something that's very very difficult for anyone else to achieve). That could, kinda, lead to some capacity to "intercept" SSL traffic, but at a cost.  The report talks about China, which would entail compromising China's CA, and as there isn't a shred of evidence that that has happened, I'll write an explanation for the imaginary country of Brobdingnag, whose top-level name is .bro, and in which BROBNIC is the country's domain registrar and certificate authority. Here we go:


 * agents of the dreaded Brobdingnag intelligence service hack into ISPs and force traffic to be redirected via a datacentre in Brobdingnag
 * you visit gmail.com (with unencrypted http)
 * the server in Brobdingnag sends your browser (again unencrypted) a redirect, making it go to googlemail.co.bro (a server they operate) on an https connection
 * your browser tries to verify its SSL key with one of the certificate authorities it knows about a priori (e.g. Firefox's list is https://www.mozilla.org/projects/security/certs/included/) - you'll have to imagine BROBNIC is also listed there
 * for that domain the certificate authority is registered with a certificate authority: BROBNIC
 * as BROBNIC has been leaned on by the Brobdingnag intelligence service, it confirms the SSL certificate and says the certificate is owned by "Google Inc."
 * your browser then establishes an SSL connection with that service, which acts as a man-in-the-middle proxy between you and the real google mail; they're one end of that connection, so they can read (and change) your gmail traffic.


 * But that article says it's all "speculation" (twice) and that there's "no evidence" of any of this actually having happened. If the above happened, lots of network admins would have noticed that the wrong CA was being asked for sites, and big sites like Google would have noticed (by dint of their own automatic testing) that stuff that should have been going to gmail.com was going somewhere else entirely. This would have immediately implicated the compromised CA.  So browser manufacturers would remove BROBNIC from their list of trusted CAs. That would mean no-one would be able to establish a verified SSL connection with any .bro domain. This ruins the reputation of BROBNIC and the entire internet industry of Brobdingnag.   Note this all holds for the public-key infrastructure that allows you, a regular person, to find out the SSL public key for Google using your web browser (it does entail you trusting the CAs). A more secure network (which surely any decent military operates) can rely on clients having more a priori knowledge and using clients that insist on connecting to an IP address they know with a key they already have (in practice they'd have a VPN to a specific IP with a specific key, which can't be fooled by the above mechanism). -- Finlay McWalter ☻ Talk 13:18, 18 November 2010 (UTC)
 * Thank you very much! Your answer is excellent and clear 93.172.57.34 (talk) 13:35, 18 November 2010 (UTC)

PPP connection with Ubuntu II
Follow-up to: [] above.

Now, I am at list getting the IP and some traffic is flowing through the network.

GNOME PPP: STDERR: --> Ignoring malformed input line: ";Do NOT edit this file by hand!" GNOME PPP: STDERR: --> WvDial: Internet dialer version 1.60 GNOME PPP: STDERR: --> Cannot get information for serial port. GNOME PPP: STDERR: --> Initializing modem. GNOME PPP: STDERR: --> Sending: ATZ GNOME PPP: STDERR: ATZ GNOME PPP: STDERR: OK GNOME PPP: STDERR: --> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 GNOME PPP: STDERR: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 GNOME PPP: STDERR: OK GNOME PPP: STDERR: --> Modem initialized. GNOME PPP: STDERR: --> Sending: ATM1L1DP*99# GNOME PPP: STDERR: --> Waiting for carrier. GNOME PPP: STDERR: ATM1L1DP*99# GNOME PPP: STDERR: CONNECT GNOME PPP: STDERR: --> Carrier detected. Starting PPP immediately. GNOME PPP: STDERR: --> Starting pppd at Wed Nov 17 21:59:09 2010 GNOME PPP: STDERR: --> Pid of pppd: 7875 GNOME PPP: STDERR: --> Using interface ppp0 GNOME PPP: STDERR: --> Authentication (CHAP) started GNOME PPP: STDERR: --> Authentication (CHAP) successful GNOME PPP: STDERR: --> local IP address 212.169.177.2 GNOME PPP: STDERR: --> remote IP address 10.64.64.64 GNOME PPP: STDERR: --> primary  DNS address 85.62.229.133 GNOME PPP: STDERR: --> secondary DNS address 85.62.229.134 GNOME PPP: STDERR: --> Script /etc/ppp/ip-up run successful GNOME PPP: STDERR: --> Default route Ok. GNOME PPP: STDERR: --> warning, can't find address for `www.suse.de` GNOME PPP: STDERR: --> warning, address lookup does not work GNOME PPP: STDERR: --> Nameserver (DNS) failure, the connection may not work. GNOME PPP: STDERR: --> Connected... Press Ctrl-C to disconnect

But, I still cannot navigate. There's a problem (see above at the end) with the DNS and the browser cannot resolve any address.

My config file for wvdial is:

[Dialer CARREFOURINTERNET] Modem = /dev/ttyUSB0 Baud = 115200 Init = ATZ Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 Init3 = AT+CGDCONT=1,"IP","CARREFOURINTERNET" Phone = *99# ISDN = off Username = '' Password = '' New PPPD = yes Stupid Mode = 1 Dial Command = ATDT

I have the impression that the problem lyes in the init strings, since when I changed them, I also got an IP. By the way, what do this init strings mean anyway? Mr.K. (talk) 10:55, 18 November 2010 (UTC)


 * Solved, I added ,,0,0 at the end of Init3 = AT+CGDCONT=1,"IP","CARREFOURINTERNET". However, why did this ,,0,0 work? Mr.K. (talk) 13:39, 18 November 2010 (UTC)


 * It seems that CGDCONT thing sets up the PDP Context; this article shows the meanings of the values of its parameters, and this explains (a bit) more. -- Finlay McWalter ☻ Talk 15:36, 18 November 2010 (UTC)

Saving Hotmail emails to hard disk
What is the best way to save Hotmail emails to hard disk? Not doing them manually, as that would take weeks. I only have Outlook Express available (but not used) as I deleted MS Office some time ago. I'd prefer some freeware gismo that would just do it without too much complication. I use WinXP. Thanks 92.24.187.23 (talk) 13:36, 18 November 2010 (UTC)
 * You could use Windows Live Mail to export the messages.Smallman12q (talk) 15:20, 18 November 2010 (UTC)

Easy script language to back up data to a pen drive
I use WinXP. I have a small pen drive pernamently stuck into the back of my computer. I would like to be able to copy c:/mydata to e:/backup. In fact I'd like to copy to backup2, then when that is copied without any problems to delete backup1; and then next time to copy from mydata to backup1 and then delete backup2. What would be an easy script language to write this in please?

I would like this script to operate as part of the closing-down procedure of the computer: how do I get it to do that please? Thanks 92.24.187.23 (talk) 13:42, 18 November 2010 (UTC)
 * You'd like to make a copy of your entire hard drive each time you shut down(this would be inefficient)? Or a specific directory?Smallman12q (talk) 15:17, 18 November 2010 (UTC)

Just the small directory mydata. 92.15.5.101 (talk) 17:05, 18 November 2010 (UTC)

OK, what script languages can copy directories and their contents easily (eg "copy c:mydata e:backup"), and would be suited to the above task? Thanks 92.29.125.34 (talk) 20:43, 19 November 2010 (UTC)
 * A Batch file, Shell script, or a macro language such as AutoIt. Smallman12q (talk) 14:31, 20 November 2010 (UTC)

Would FreeBasic be a macro language? Thanks 92.24.181.96 (talk) 23:14, 20 November 2010 (UTC)


 * I think there is a windows port of rsync. 69.111.192.233 (talk) 07:48, 21 November 2010 (UTC)

Camera timer capture and filenames
I want a Windows program which can take a picture with an attached digital camera every 1 hour. So far in my searches I've only found this which works perfectly except that it overwrites the image each time it takes a new one. I tried using %date% %time% as the filename in the save as dialogue box, so that each time the program takes a picture it doesn't overwrite the previous file, but it doesn't work sine %date% and %time% output using : separate the digits, and : is not allowed in Windows filenames. Are there any other programs which I could try, or perhaps a way to get a timestamp from Windows without : in it? The OS is Windows XP 82.44.55.25 (talk) 15:28, 18 November 2010 (UTC)


 * What you want is a webcam program. There are literally thousands of them.  You want one with archiving capability.  You won't be saving the image to a webpage (the webcam part), but you will be archiving it locally.  I use camE, but I use Linux, not Windows.  Searching for "webcam program with archiving" will locate more programs that you will want to look through. --  k a i n a w &trade; 15:35, 18 November 2010 (UTC)

what percent of the area of a 17" macbook pro scren does a 15" macbook pro screen have?
Thanks. 84.153.193.81 (talk) 16:01, 18 November 2010 (UTC)


 * This sounds like homework. You know that both screens are rectangles and that the width measurement is from one corner to its opposite at a 90º angle. Do a little trig and it should be no problem to figure out their areas and thus the percentages. --Mr.98 (talk) 16:11, 18 November 2010 (UTC)


 * No trig required, surely ? Just use area ratio = square of linear ratio (assuming screens have the same aspect ratio). Gandalf61 (talk) 16:23, 18 November 2010 (UTC)


 * I wasn't sure they wanted to make that assumption. (All Macbook Pros probably have the same aspect ratio, but not all Mac laptops.) It's worth noting that the 15" is really 15.4" when you get down to it. Of course, if you wanted to take the really easy way out, you can get the pixel counts from the MacBook Pro article. --Mr.98 (talk) 16:26, 18 November 2010 (UTC)

it wasn't homework, but I have mild mental retardation and am not able to do "trig" or other math like that, I just wondered what the screen percentage is. Thanks for your understnading. 84.153.193.81 (talk) 16:42, 18 November 2010 (UTC)


 * If you look at MacBook_Pro, you'll see that that a 15.4 inch screen(1,440 × 900) has 73% of the pixels of a 17 inch(1,680 × 1,050).Smallman12q (talk)


 * ...or, in round terms, about three quarters. Gandalf61 (talk) 17:02, 18 November 2010 (UTC)


 * Hang on if you want to compare screen size by area, are you sure both have exactly the same Pixel density? Nil Einne (talk) 07:26, 20 November 2010 (UTC)


 * If the screen do not have the same pixel density, and you are comparing them by screen area, then the 15.4" screen has approximately 82% of the screen-area of the 17" screen. This is, of course, presuming that both screens have the same aspect ratio. Rocketshiporion ♫ 03:07, 21 November 2010 (UTC)

Flash ad archive
Is there a flash advert archive somewhere online?Smallman12q (talk) 17:00, 18 November 2010 (UTC)

Coloribus maybe? 92.15.13.70 (talk) 20:20, 18 November 2010 (UTC)
 * Interesting site, but it doesn't seem to have flash ads, only tv/print ads.Smallman12q (talk) 21:46, 18 November 2010 (UTC)

Restrict printer
I have a printer set up on my house PC but the kids keep printing out picture using up all my ink, is there a way I can prevent them from printing from their user accounts, their user accounts are not set up with admin privileges. Mo ainm ~Talk  19:21, 18 November 2010 (UTC)


 * Probably, but first you need to tell us what version of Windows you are using. XP, Vista, 7? --Mr.98 (talk) 19:33, 18 November 2010 (UTC)


 * Low-tech solution.... Take away network access from them. No Facebook.  No Twitter.  No games.  It won't take long for them to agree to stop printing just to get back online. --  k a i n a w &trade; 19:37, 18 November 2010 (UTC)
 * Tried a clip round the ear and that didn't work ;) Thought about removing network access but then they hit me with "I need it for school" so thats not an option. Using Windows XP. Mo ainm  ~Talk  20:59, 18 November 2010 (UTC)
 * Allow them to use it for school but nothing else? If that doesn't work you may have other problems, but a quick and dirty solution is just disable stuff they won't need for school like Facebook, twitter, Youtube, etc. Anyway as for your question, I would guess in most versions of Windows just click on the properties of the printer and disable all permissions for the printer for accounts you don't want to have access. Of course you need to have the security tab which may not show up in some versions of Windows. See or  for XP specific info. Nil Einne (talk) 21:15, 18 November 2010 (UTC)

Images not showing up
One my website, Leubantia Wiki, the flags of Republic of Macedonia, Paraguay, Honduras, Romania, Croatia, Nigeria, Belgium, Estonia, Slovakia, Peru, Republic of Ireland, Gabon, Costa Rica, USA, Algeria, Georgia (country), and many, many more images are not showing up. I do not have a clue why so many images are not showing up. My computer must, but maybe not, have a virus or something... Also, when I try to re-upload them, they still don't show up. There has got to be a bug. Also, my stupid compute is making TYPOS!!!!!! —Preceding unsigned comment added by Velociraptor888 (talk • contribs) 21:46, 18 November 2010 (UTC)
 * I can see the flags of the Republic of Georgia and Algeria perfectly fine, as an example. I'm not about to speculate on a cause if I can't reproduce the error, and I fail to follow the logic that leads you to conclude that your computer has malware. As for the computer "making typos" -- are you sure it isn't a problem with the entity between the keyboard and the chair? Have you tried cleaning the keyboard with a screwdriver and compressed air? Xenon54 (talk) 22:02, 18 November 2010 (UTC)


 * IMHO, I concur with the conclusion of PEBKAC, except for the possibility of a malfunctioning keyboard or (in some applications, such as word-processing) an AutoCorrect option being turned on in the wrong language (e.g. US English instead of British English). Rocketshiporion ♫ 03:13, 21 November 2010 (UTC)