Wikipedia:Reference desk/Archives/Computing/2006 October 7

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives

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Mozilla search engines

So, I used to use the Mozilla search engine bar all the time, having added a lot of good ones. But one day, I found they were all gone. I can go to the "Add engines" link on the bar, which takes me to their page. But when I click on one, it asks me if I want to add it, I say ok, and it doesn't get added. The Javascript console says

Error: [Exception... "Component returned failure code: 0x80570016 (NS_ERROR_XPC_GS_RETURNED_FAILURE) [nsIJSCID.getService]" nsresult: "0x80570016 (NS_ERROR_XPC_GS_RETURNED_FAILURE)" location: "JS frame :: file:///C:/Program%20Files/Mozilla%20Firefox/components/nsSidebar.js :: anonymous :: line 174" data: no] Source File: file:///C:/Program%20Files/Mozilla%20Firefox/components/nsSidebar.js Line: 174

I've tried re-installing Firefox, but it doesn't work. Does anyone know what's gone wrong, and how I can fix this and get my search bar back? -LtNOWIS 00:54, 7 October 2006 (UTC)

Most times these problems are related to your profile, which isn't cleared when reinstalling Firefox. Try temporarily disabling all extensions with the Safe Mode, or using a blank profile with the Profile Manager. --cesarb 21:15, 8 October 2006 (UTC)

What do the parts of an email address mean? Can the date or location it was sent from be deciphered from it?

Whenever someone prints out a hard copy of a hotmail, the bottom of the page has, for example, a string of letters and numbers like this:

Http://by119fd.bay119.hotmail.msn.com/cgi-bin/getmsg?=5A6F0A5E-9874-4958-…

How much about the email is obvious from the address? Can you prevent this from being printed when you print the rest of the email? Is any part of it a code?

Thank you to any and all who wish to answer this for me, especially if you can give examples.

You can use scissors and cut off the bottom of the paper althrough I don't think it matters because you would need a password to get to your email adress.Taida 02:15, 7 October 2006 (UTC)

Don't print sensitive information directly from your browser. Copy the information and paste it into your word-processor (e.g. MS Word) before your print it.  freshofftheufoΓΛĿЌ  04:22, 7 October 2006 (UTC)

Turn off the footer, to remove the link! Do this with Page Setup from Print Preview (or elsewhere) in either browser. Dysprosia 04:37, 7 October 2006 (UTC)

Http:// means retrive using Hyper Text Tranfer Protocol (HTTP).

by119fd.bay119 is the specific computer to obtain the information from.

hotmail.msn.com is the domain the computer is located within.

cgi-bin is the directory (folder) within the computer to look in. Note cgi-bin usually contains programs that generate web pages rather than just static files.

getmsg is the name of the file to retrieve (or in this case, the program to run on the server)

? means send the rest of the line to the program as an input parameter.

=5A6F0A5E-9874-4958 is a parameter to be passed.

The information above simply asks the web server by119fd.bay119 at hotmail.msn.com to to run the program getmsg in its cgi-bin folder with a parameter of 5A6F0A5E-9874-4958-… and show the result in the web browser. The information above does not contain an e-mail address, or any information about a user. E-mail addresses are in the form 'username@computername.domain' or sometimes just 'username@domain'. --Dave 07:40, 7 October 2006 (UTC)

I've got a rediculously long counter-answer Dave. The URL follows this form:

PROTOCOL://SUBDOMAINS.DOMAIN.TLD.(implied dot)/PATH?QUERY_STRING

The protocol is the way the data transfer is handled. After the protocol the rest of the URL can be divided up into two parts: the DNS requests and the file request. The file request information is everything after the root zone (the implied dot). First the root nameservers are called to give the IP address of the TLD nameservers that correspond the the TLD in the request (in this case .com, which are verisign servers). Then the nameservers at that IP address return the IP address of the domain. That domain's nameservers return the IP of the subdomain. Then that subdomain's web servers are given the file request (PATH?QUERY). It opens (or executes depending on server settings- in this case executes) the file at PATH and makes QUERY available to it. Convention (used by most browsers and web scripting languages for handling GET) dictates that the query string be arranged like ?VAR=VALUE&VAR2=VALUE2&VAR3=VALUE3 though a simple string can often be used instead of all that syntax. The = in front is meaningless, though it may be a hack for interacting with whatever web software they're running. --froth^{T C} 18:38, 7 October 2006 (UTC)

Question about wikipedia search engine

I was searching for Dina Babbitt, and got 2.7% relevance for Josef Mengele. The two are in fact related, but Dina Babbitt is mentioned no where in the article. How did a search for her turn up Mengele, then? Thanks --01:35, 7 October 2006 (UTC)

http://www.google.com/search?q=cache:MD8iy5iNgScJ:www.nyu.edu/classes/siva/archives/2006_09.html+Dina+Babbitt+wiki&hl=en&gl=us&ct=clnk&cd=9

he painted some pictures for him.

gooogogoggooggoogogoggggggggggglelleeelelellgogogo

http://thomas.loc.gov/cgi-bin/query/z?c106:S.CON.RES.54.IS:

I would guess there was some mention in the version used to build the search engine, and it has since been deleted. I often get Google hits that are apparently to content that used to be there, but is gone now. StuRat 21:25, 7 October 2006 (UTC)

Yeah, that's what I thought, but I couldn't find any trace of it after going through several page histories. --02:38, 8 October 2006 (UTC)

african watering hole

is this really a live african watering hole or just some hoax?

mms://live.wildlife.wavelit.net/nk1957

Do you have any reason to think it is a hoax? It seems like a really stupid thing to make a hoax out of.  freshofftheufoΓΛĿЌ  04:10, 7 October 2006 (UTC)

Erm, things are actually starting to get a little weird now.  freshofftheufoΓΛĿЌ  04:14, 7 October 2006 (UTC)

what happened!? ? I've been watching and nothing but exotic noises !

A large number of bison-like grazers (that's not cool that I don't even know my African animals) and zebras came out of nowhere to take a sip. It's probably just a "popular" water hole, but I wasn't really expecting a whole bunch of them to appear so soon.  freshofftheufoΓΛĿЌ  16:28, 7 October 2006 (UTC)

t-rex tissue

is this a hoax?

http://www.calacademy.org/science_now/headline_science/T-rex_soft_tissue.html

I think you should ask these sort of questions at the Science desk: WP:RD/S. Anyway, see Tyrannosaurus, especially the bits about "B-rex". --Kjoonlee 04:05, 7 October 2006 (UTC)

There is mention of T-rex "soft tissue" being preseved inside bones, I think that article is just incredibly misleading. No dates are given (a few months ago and Montana are the only things that are explicitly stated) and no references, sources, links, or other relevant details are given. The images, I must remind you, show a 3mm section of bone. Putting the specimin under high magnification creates strange results.  freshofftheufoΓΛĿЌ  04:08, 7 October 2006 (UTC)

If the article really mentioned "soft tissue" instead of "soft matter resembling tissue" then it would be an example of bad journalism. Anyway, read the Tyrannosaurus article for links that properly describe what was found. --Kjoonlee 06:08, 8 October 2006 (UTC)

Under "Sexual dimophism" our article states, Only a single T. rex...has been...shown to belong to a specific gender. ..."B-rex," the...oldest known specimen, demonstrated the preservation of soft tissue within several bones. Some...has been identified as medullary tissue, a...tissue grown only in modern birds as a source of calcium...during ovulation.  freshofftheufoΓΛĿЌ  09:31, 9 October 2006 (UTC)

Adsl Sharing

I have a dlink dsl-g604t modem/router connected to an adsl conection. recently i churned to a new isp (WiltIT) and found that although i could access the internet through the wireless connection, i could not access it from a desktop connected to the router directly by an ethernet cable. Before the churn i was able to access both ways with no problems. how can i get the desktop to access teh internet through the cable? 02:36, 7 October 2006 (UTC)

Perhaps the network settings on the desktop are misconfigured? Maybe DHCP settings on the router are incorrect? A little more specifics would help. Splintercellguy 07:58, 7 October 2006 (UTC)

Wireless network adapter on Acer laptop

Howdy, fellow Wikipedians! I'm having a puzzling problem working with wireless networking. I've got an Acer Aspire 5000, which has a Broadcom 802.11g network adapter, and I'm running XP Service Pack 2. I'm able to find wireless networks, and the connection process partially works, but I'm unable to actually connect to the networks. I don't actually know exactly how long this has been a problem, or what I did that could have caused it as I infrequently use wireless, but I'm spending a few days at my mother's house, and I'd like to use her network. (Which is working properly -- I'm posting this on her computer -- and I have the password for, etc. I've logged in here before. I've also logged in previously on unsecured networks, but can't now, so I don't think it's her security.) What happens, step-by-step as I attempt to "repair network connection", it disables and re-enables my adapter, and connects, but it has problems renewing the IP address. It reports the network connection details with a physical address and IP address, a subnet mask of 255.255.0.0 and blanks for default gateway, DNS server and WINS server. I've searched the Acer site; they have a simple guide that covers everything I've already done, and according to them, I have the most recent driver (3.100.46.0, which I can't roll back, so I assume it was factory installed). I can't do a system restore, because my restore points don't go back far enough. (Only a month, and I know I had the problem a couple of months ago). Any suggestions, requests for more info, etc. would be gratefully appreciated. Thanks! --ByeByeBaby 02:44, 7 October 2006 (UTC)

I'm just guessing, but it might be that your mother uses MAC address filtering, ie it limits access to only a set number of MAC-addresses (every network card has a unique number that identifies it, a MAC-address, sort of like a serial number). Try logging on to your mothers router configuration and see if it is on. If it is, either add your own MAC address or simply turn it off while you are there. It could also be that the router is using static IP addresses, and not DHCP. Again, check the configurations and see if you can turn on DHCP Oskar 18:06, 7 October 2006 (UTC)

Hot laptop

I got an old thinkpad for free and I'm having trouble with it overheating after a couple hours of use (plugged in). The fan works fine, though it doesn't seem to help much. I've already elevated it, and I use it in a rather breezy place, but is there any half-assed solution that I can pull out of a dollar store to help me get a few more hours of constant use out of it? I'm thinking along the lines of putting it on a cushion of styrofoam, tilting it at a 20 degree angle, etc.  freshofftheufoΓΛĿЌ  04:19, 7 October 2006 (UTC)

Can you open up the laptop to get access to the CPU and heatsink? My old Sager laptop had an issue with overheating. It turned out to be the area where the fan was blowing air across the heatsink was clogged up with dust and crud. After removing it, the problems were gone. I'm betting your problem is the same. —Mitaphane _talk 04:38, 7 October 2006 (UTC)

Actually yeah it could be just that simple. It's a 5 year old lappie and I'm sure the guy who used it before me wasn't nearly as careful with it. I'll go get my hacksaw and give it a shot.  freshofftheufoΓΛĿЌ  16:25, 7 October 2006 (UTC)

Unfortunately almost all older laptops have heat problems.. and 5 years is way past the life of a laptop. If you can stand the heat, you could just let it overheat- I read somewhere that old thinkpads are surprisingly good at operating in extreme heat. As for the comfort of your skin, you could try that fire-resistant oily foam --froth^{T C} 18:24, 7 October 2006 (UTC)

Styrofoam isn't a good choice, as it's a thermal insulator. Instead, place it on metal "rails", so that air can pass underneath it, then point a fan at it. The metal will also help to draw away some heat. Old metal stacking inboxes might work well. StuRat 21:12, 7 October 2006 (UTC)

Ok scratch the foam then. I've actually got it propped on some metal hangers now, but I'd probably get better results with something with more surface area, and more room for air to pass through. To Froth, I can't let it overheat. It's not that it's so hot I can't touch the surface (the keyboard is relatively cool, actually) it's that my OS starts stuttering after a couple hours of use, and eventually completely locks up if I don't turn it off or put it to sleep. I guess not all thinkpads are so wonderful!  freshofftheufoΓΛĿЌ  04:13, 8 October 2006 (UTC)

Guess it was a false rumor. What are you doing with it during use? Web browsing? Gaming? --froth^{T C} 05:54, 8 October 2006 (UTC)

Nothing too hardcore. I have it propped up on a couple of water bottles now, and I put a big 2L bottle of gatorade on the keyboard when I'm not typing. Doing that extended my uptime another 30 minutes or so. Hah! Liquid cooling rawks.  freshofftheufoΓΛĿЌ  09:27, 9 October 2006 (UTC)

It's not just a problem with older laptops - my Acer laptop also has a tendency to overheat, especially if the ambient temperature is high. In addition to elevating it, I strongly recommend you get yourself a can of compressed air and liberally squirt it through the various openings on the laptop. Laptops (unlike desktops) have many very tight spaces inside, and these will get clogged up with dust surprisingly quickly, severely inhibiting airflow and cooling. Even better, open the case up (if possible) and continue blowing air through the innards to try and clear out as much of the dust as possible. For me this helped enormously, my laptop went from operating at near 80°C to under 50°C. Note that you'll need to repeat this every couple of months. — QuantumEleven 12:03, 9 October 2006 (UTC)

Laptops, unlike desktops, are not designed to be "user serviceable". Thus, they are difficult to open and you may very well damage them if you try. I ended up with a torn paper cable (leading to the trackpoint) on my IBM ThinkPad, when I tried. StuRat 01:42, 11 October 2006 (UTC)

Hey I ripped that thing out too but fortunately it had a nice plug instead of a direct wire so the plug just came unplugged :) --froth^{T C} 05:13, 12 October 2006 (UTC)

Latex help - Section headings

Hi all. I'm creating a document in latex and I wanted to create a section that didn't have a number (ie. one that said "Introduction" instead of "1. Introduction). I used the \section*{} command I found on the web, but the problem with that is that it doesn't add that section to the table of contents. So I was wondering if there was anyway to have a non-numbered section that also appears in the contents. I am using the "article" document class. Thanks - Akamad 06:30, 7 October 2006 (UTC)

You might be able to get away with using \addcontentsline{toc}{section}{whatever} along with \section*{whatever}. A bit clunky, but it should work. --Pekaje 15:16, 8 October 2006 (UTC)

Thanks for that. It does the job well. - Akamad 09:10, 9 October 2006 (UTC)

icons in computers

ther are 4 main types of icons. Resemblance icons,exempler icons,symbolic icons,arbitrary icons. what are the difference among the 4? which are used in windows? what are the advantages of each?

Perhaps you could look at the article Icon, or look up the meaning of Resemblance, Exemplar, Symbol and Arbitrary? This is not a place to get homework answers. —Daniel (‽) 10:21, 7 October 2006 (UTC)

Odd task manager window

File:Task manager odd.jpg

Here it is

My task manager Ctrlaltdel recently went like this. What can I do to put it back to normal?--Keycard ^(talk) 13:46, 7 October 2006 (UTC)

Double-click the gray area to return it to normal. --Pidgeot (t) (c) (e) 13:49, 7 October 2006 (UTC)

Replace it with Process Explorer ;) It's much better~, it's free, and easier to use. Oskar 17:25, 7 October 2006 (UTC)

You mean the "NO INFRINGEMENT INTENDED"? ;-) —Bromskloss 17:32, 7 October 2006 (UTC)

java

is there any way to find how many times a particular class has been instantiated using programming logic not by manual counting.

Define a static variable in the class, and increase it every time you initiate a new class. Observe

public class ExampleClass {
    private static int numberOfInstances = 0;
    
    public ExampleClass() {
        //Initiate class
        numberOfInstances++;
    }

    public static int getNumberOfInstances() {
        return numberOfInstances;
    }
}

cheers! Oskar 17:24, 7 October 2006 (UTC)

Is that thread-safe? This has of course to do with how the Java system handles the humberOfInstances++. Is it atomic? —Bromskloss 17:44, 7 October 2006 (UTC)

Honestly, I'm not entirely sure whether it's thread safe or not. It's been a couple of years since I programmed Java seriously, and even then I didn't use much threads. This should be fine, I think. I guess one could create a counter-class which has two functions called increaseInstanceCount() and getInstanceCount() that are both synchronized. Still, it is a bit overkill. Oskar 17:52, 7 October 2006 (UTC)

Java makes no guarantees of atomicity (for anything other than the operation of synchronized sections and the new atomic variables in java.util.concurrent). Depending on the implementation that ++ operation might be MT safe, but its certainly not MP safe. From java 5 onward, if you wanted it to be MP safe and wanted to avoid the clunky synched sections, you could AtomicInteger.incrementAndGet() instead of ++. -- Finlay McWalter | Talk 18:10, 7 October 2006 (UTC)

Could you make the constructor a monitor to ensure thread safety? - Rainwarrior 15:33, 9 October 2006 (UTC)

The standard way to do this is to define another, synchronized method:

  public ExampleClass() {noteInstance(); /*...*/}
  public static synchronized void noteInstance() {numberOfInstances++;}
  public static synchronized int getNumberOfInstances() {return numberOfInstances;}

(The reader must also be synchronized, of course!) Of course, a static synchronized method just synchronizes on the Class object for its class, so the constructor could just do that itself:

 public ExampleClass() {synchronized(ExampleClass.class) {noteInstance();} /*...*/}

but not

 public ExampleClass() {synchronized(getClass()) {noteInstance();} /*...*/}

since the constructor is called when subclass objects are instantiated and then you could have conflicts between an ExampleClass object and a SubExampleClass object being constructed simultaneously. (Rainwarrior: it would be useless to make the constructor a monitor in the method sense, because each constructor call would lock a different object.) --Tardis 14:49, 10 October 2006 (UTC)

binary to decimal or hexadecimal

if a binary number has n digit then what is the number of bits and digits of its equivalent decimal number or hexadecimal number or vice-varsa. can anyone help me by telling the logic and theory for solving this type problem.

This is easily solved with logarithms. Assuming a number n is written in base b. Then the number of digits is

$\log _{b}(n)$

rounded down to the nearest integer. Then conversion between different based logarithms is easy, see Logarithm#Change of base. You should be able to work from there yourself, but if you want more detail, you should probably ask at the mathematics reference desk Oskar 17:21, 7 October 2006 (UTC)

You are supposed to round up, actually. Hmm, mabye it's even more accurate to do $(\log _{b}n)+1$, and then round down. Anyone agrees? —Bromskloss 17:39, 7 October 2006 (UTC)

Ahh, yes, silly me. You are of course correct, round up, not down. Oskar 17:46, 7 October 2006 (UTC)

As far as binary to hex, it is well known by most computer programmers (and computer graphics people) that four binary digits equal one hex digit. That is why hex is used so much to represent binary data. --Kainaw ^(talk) 18:57, 7 October 2006 (UTC)

If you just want a rough extimate, note that 2⁶³ is a 64 bit binary number, or a 19 digit decimal number, so it takes about 3.4 bits to represent 1 digit. --Gerry Ashton 21:09, 8 October 2006 (UTC)

Modem and Hyperterminal

I have just bought a new laptop and decided to plug my phoneline into it. I diealled out using Hyperterminal and itworked but there is a constant beep over the entire call, how can I stop this?

yours, Christopher

The beep is your modem trying to signal another modem. While some modems can indeed be configured as "voice devices" (essentially as sound cards rather than digital communication devices) HyperTerminal won't automatically do that. Instead you want to use a (rather neglected) application called dialler.exe (launch it from the run option), which (if your modem is of an acceptable type) will configure things so that you can use the modem as an ordinary voice phone (assuming you've got something like a headset plugged in to your soundcard). -- Finlay McWalter | Talk 18:22, 7 October 2006 (UTC)

Citing an acceptance speech with BibTeX

What is the BibTeX format for citing an acceptance speech for an award, for example a Nobel Prize lecture? —Keenan Pepper 17:51, 7 October 2006 (UTC)

Ooo, exciting! Are you going there? —Bromskloss 18:54, 7 October 2006 (UTC)

Um, no. I want to cite one from 1906, and it's not for the invention of a time machine. —Keenan Pepper 19:01, 7 October 2006 (UTC)

Nobody knows? —Keenan Pepper 02:32, 9 October 2006 (UTC)

Reading from a source and outputing it to standard out in linux

I'm fairly new at using linux and I had a question. What is the command for reading input from a specified source on a filesystem and outputing it to standard output in linux? Specifically, I wanted to read a number of random bytes from /dev/random and printing it to the console. Oskar 18:47, 7 October 2006 (UTC)

cat - so you could say cat /dev/urandom. But urandom is a binary device, so it'll chuck out a bunch of nonprintables that will probably drive your terminal insane. You could use od to turn it into something legible: cat /dev/urandom | od, which you can simplify to just be od < /dev/urandom. -- Finlay McWalter | Talk 18:52, 7 October 2006 (UTC)

Also, use head to stop the flow of random numbers at some point. --Kainaw ^(talk) 18:55, 7 October 2006 (UTC)

So like cat /dev/urandom | head -50 | od? Yeah, seems to work. Thanks! Oskar 19:00, 7 October 2006 (UTC)

I just realised that if you use head you don't really need the cat. Neat things, these unix terminals.... Oskar 19:03, 7 October 2006 (UTC)

od can stop itself - od --read-bytes=50 < /dev/urandom. By default od prints an address line, and the data in octal - a more useful invocation would be od -An -t x1 --read-bytes=50 < /dev/urandom which will display 50 one-byte random hex numbers. -- Finlay McWalter | Talk 19:06, 7 October 2006 (UTC)

url

how do you register a new url?

I assume you mean domain name. Just search for a "domain name registrar". Note: it is not free and whatever domain name you want is most likely already taken. --Kainaw ^(talk) 19:42, 7 October 2006 (UTC)

Haha, that's a bit of a generalization, don't you think? I have very unique wants.  freshofftheufoΓΛĿЌ  04:07, 8 October 2006 (UTC)

expanding opcode

can anybody help me by explaining the theory for solving this type problem

A certain machine uses expandind opcode.it has 16 bit instructions and 6bit addresses.it supports one address and two address instructions only.if there are'n' two address instructions,the maximum number of one address instruction is---?

if possible then please explain by solving this problem.then it will be easy for me to understand.

I am going to assume you paid some attention in class and you know that a 16-bit instruction with two 6-bit addresses is using 12 of the 16 bits for addresses. That leaves 4 bits for the function. You may have no 1-address instructions that begin with the same 4-bit sequence as a 2-address function. However, 1-address functions can possibly use 10-bits (16-bits minus the 6-bit instruction). That should get you to the point that you can calculate how many total 4-bit instructions there are. The 1-address instructions may use that total minus "n". But, each 4-bit sequence used by the 1-address functions may form many instructions (using the extra 6-bits). --Kainaw ^(talk) 23:18, 7 October 2006 (UTC)