Wikipedia:Reference desk/Archives/Computing/2007 April 19

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April 19

Folding@Home

Can I limit the times of day during which Folding@Home can access the Internet, while allowing it to run an already downloaded work unit anytime? NeonMerlin 00:22, 19 April 2007 (UTC)

Is that a BOINC-driven application? If so, look at the Projects tab of the BOINC Manager window, highlight Folding@Home and see if a Your preferences button appears at the left. —EncMstr 00:33, 19 April 2007 (UTC)

It is not BOINC-driven. -- Consumed Crustacean (talk) 00:58, 19 April 2007 (UTC)

It can be configured to ask you every time it needs to access the internet, otherwise if your internet is physically unavailable I don't see the damage of leaving it as i is. --antilived^{T | C | G} 08:46, 19 April 2007 (UTC)

To add to the orignal question, is there any way to get a portable BOINC, like, say, for a usb stick? Think outside the box 11:38, 19 April 2007 (UTC)

IP adresses

Why do IP adresses change almost every single day and then stay for about a month, then change again? (Yes, I know I am very inquisitive) Teak the Kiwi 03:05, 19 April 2007 (UTC)

Basically, it depends of your ISP, the type of connection, and the DHCP leasing. In most cable connections the IP address is stored in the modem, so as long as you keep the modem on, you will keep the same address. Sometimes, your internet service provider can assign you an ip address for a determined amount of time (minutes, hours, days or weeks). Personally, my ISP assigns me a different ip every 22 hours, so every 22 hours I get a micro disconnect (lasts around 15 seconds). In certain configurations, like AOL, you change your ip basically every time you load a new page, that is because the computer does not have an external ip, but instead use a different AOL proxy to access page requests. -- ReyBrujo 03:30, 19 April 2007 (UTC)

Ok, I know there was a time that I didn't have the modem turned off. Lately, however I have been turning it off every night. Teak the Kiwi 02:36, 20 April 2007 (UTC)

Try leaving the modem on for some days to see if that changes. You could also contact your ISP provider, asking them if they reset your ip every time you turn the modem on, or if there is a leasing time (which may be a day) after which your ip is changed. -- ReyBrujo 02:13, 23 April 2007 (UTC)

Proxy settings

Could someone please direct me to a program (hopefully free) that displays the proxy settings on a computer. Thank you 195.194.74.154 08:37, 19 April 2007 (UTC)

What operating system?

Proxys are usually set per program, not system-wide. Usually. It really depends.

Magnetic Stripe Writer

Hey, I was wondering about making magnetic stripe cards for my business, and I found what looked to be a good deal. I found what looks to be one for really really cheap, but I'm finding it referred to as a reader only and a reader/writer in different places. The part number is ST1044UB. I've found it referred to as "Cherry ST-1044U, Smart Card Reader/Writer with USB interface." and "Cherry ST-1044U Magnetic Stripe Credit Card Reader" on the same page! Can anyone tell me if this writes cards or not? Also, if not, can anyone suggest a writer in the $100-ish range? Thanks! Koriar 08:39, 19 April 2007 (UTC)

MD5Summer For Context Menu

What program do I use so that I can right click on a file and select the MD5SUM option and get the MD5SUM? It has to be in the context menu - no drawn out "wizard" nonsense or commandline whatnot. Thanks :) --Seans Potato Business 14:34, 19 April 2007 (UTC)

If you're using GNOME, then adding the file below to your Desktop will give you an icon you can drop files onto to see their md5sums. Otherwise, you'll have to tell us what system you use. --TotoBaggins 15:11, 19 April 2007 (UTC)

[Desktop Entry]
Version=1.0
Encoding=UTF-8
Name=Md5summer
Type=Application
Exec=bash -c 'md5sum $@; read' $@
Terminal=true
Name[en]=Md5summer

Sorry, should have said, Windows XP. Thanks though. --Seans Potato Business 19:24, 19 April 2007 (UTC)

Here you go — Matt Eason ^{(Talk • Contribs)} 21:30, 19 April 2007 (UTC)

That's the EXACT one I had mind! Thanks Matt! How did you find it? --Seans Potato Business 07:54, 20 April 2007 (UTC)

No problem. I Googled for Windows XP MD5 "right-click" and got this page, which links to digestIT 2004. — Matt Eason ^{(Talk • Contribs)} 08:50, 20 April 2007 (UTC)

Random numbers in bash

What's the deal with the $RANDOM function (is it a function? Not sure what it is) in bash? Does it have a memory? I mean if I do "echo $RANDOM" twice in a row, will the result of the first affect the result of the second? Just curious. Thanks. --130.88.52.54 19:24, 19 April 2007 (UTC)

Interpreted languages will often have magic variables that are computed specially, rather than just storing a value. $RANDOM is one of these. Echoing $RANDOM will show two (hopefully) unrelated random values. Other magic values in bash are $DIRSTACK, $FUNCNAME, $GROUPS, $HISTCMD, $LINENO, and $SECONDS. Perl lets you make an arbitrary variable magic with its "tie" mechanism, as below. --TotoBaggins 19:57, 19 April 2007 (UTC)

sub TIESCALAR { bless [] }
sub FETCH     { rand }

tie $my_random, "main";
print $my_random;  # really calls FETCH()
print $my_random;
print $my_random;

As for whether calling it twice in a row affects it, it depends what you mean. Most pseudorandom number generators that are built in to a language are quite poor in terms of true randomness, and in many cases the answer before does affect the answer after it — it is often the basis of, or simply is, the seed which is then run through the algorithm again the next time you call it. Hence many languages have ways of manually resetting the randomizer seed in order to make the order unpredictable, though it doesn't necessarily make it any more "random". I don't know bash but I'd be surprised if it were different in this respect — many built-in generators are just based on the rand function in c, which has been demonstrated many times (notably by Donald Knuth) to be a poor pseudorandom number generator (poor in this sense meaning "bad for really serious simulations, probably OK for many less serious tasks"). --24.147.86.187 00:52, 20 April 2007 (UTC)

Own Valid Windows Key - Don't Own Windows Disc

A long time ago, Microsoft decided to stop supplying OEM discs in a bid to combat piracy (don't really see how that should work). I had to pay an extra £70 to Time Computers Ltd (rip off, I know) for a "Restore Disc". On the second use, it failed to work and I was left with an inoperable computer. A friend got me a copied disc but when I tried my key, it wouldn't work. This is perhaps because it was a Pro CD whereas it ought to have been Home? Can I use any old pirated XP Home CD with my key or will it need to have come from Time Computers? I don't feel that what I'm doing is very illegal since the key has been paid for. I gave up with contacting Microsoft when they cut me off about 20 minutes or so into my call. --Seans Potato Business 19:32, 19 April 2007 (UTC)

You should be able to use your key on the first release (build 2600 i think) of WinXP home and yes the key does affect which version you are installing. Make sure you key is in proper format though, sometimes the OEM key's that companies give are for modified install discs that require a much shorter key. Another suggestion is you install WinXP Home as a 30 day trial, and then follow the proper steps to Validate your copy of Windows with your valid key. Hope this helps. 200.35.168.129 19:52, 19 April 2007 (UTC) Ag for MemTech

Belkin Wireless Router uninstall

We have a Belkin router for our PC and we think its crap, how do we uninstall it? --Hadz^Talk 19:48, 19 April 2007 (UTC)

You should not have to uninstall anything, routers usually are not installed on a computer, unless they provide some sort of software to access or modify the router and it's settings. What you are referring to i think is getting rid of the connections it made on your computer, to do this just use the Network Wizard if working in Windows to replace or modify the connections you made to get hooked up to your Router. Also to get connected to the internet if your router provided IP Addresses without DHCP, then you need to change the TCP/IP settings from manual to automatic in order for your ISP to assign you your IP address, so you can have acccess to the Internet. if you have any further questions let me know, please be more specific to your computer hardware and setup though (OS,Netork Adapters,etc) Hope this helped 200.35.168.129 19:57, 19 April 2007 (UTC) Ag for MemTech