Wikipedia:Reference desk/Archives/Computing/2008 April 18

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April 18

Is wireless encryption secure from other users?

Hi, I know that unsecured wi-fi traffic is unsecure because anyone with a wireless card can sniff all the data you are sending and receiving. If I am on a secured wi-fi network, but there are others who are allowed to use the same network (they know the shared encryption key needed to access the network), can they read my data? Thanks, --131.215.166.106 (talk) 00:05, 18 April 2008 (UTC)

If you use such encryption as WEP, then you aren't secure from anyone, as it's easily crackable.

If you use WEP or WPA, then other users have the same key, and so they can see the traffic. (It's symmetric encryption: if one has the key, you can't prevent him to use it.)

To be secure, you need to use such encryption programs as PGP/GnuPG (for e-mail), or encrypted protocols like SSL (HTTPS) or SSH.

--grawity ^{talk / PGP} 11:50, 18 April 2008 (UTC)

It's not necessarily as simple as that. WPA uses TKIP, which creates new keys for each user and session (and indeed, each packet), which would mean that it is not as simple as using the same WPA key to decode every packer. Our article on TKIP is a little fuzzy on the subject, but it says that if you use a pre-shared key, the session base-key will always be the same; but I'm not so sure that's true. I mean, it would be trivial (well, ok, not trivial, but fairly easy) to add something like a Diffie-Hellman key exchange to generate a new completely new key each session for each user, so I find it highly suspect that the bad-boys who designed WPA would overlook such an obvious problem (with an equally obvious solution). Does anyone know the exact details of this? --Oskar 14:08, 18 April 2008 (UTC)

With due respect, I believe the question at hand isn't being addressed. A http://en.wikipedia.org/wiki/LAN grossly simplifying, works on the idea that everyone on its network shouts to it, and that it shouts to everyone on its network. "People" - computers - just ignore things that aren't relevant to them. Or, if there were a classroom, Jenny shouting she loves Jeremy is ignored by Tom, Dick, and Harry; presumably this request generates a response from Jeremy. This is not different for wi-fi, except that the classroom now isn't bound by physical wires between the "desks", to go with the metaphor. Now for your actual question - "securing" a wifi network (and the above responders' comments about security here are relevant) just mean that someone has to say the magic word before wireless treats them like they're in the "classroom." Once they are, again, everyone is shouting everything to everyone, so dad can have a traffic monitor and know you're visiting badcowsandthekittenswholovethem.example.com.

So, short answer: Directly and immediately, yes.

Is there Orthodox Islam?

Question moved to Humanities Desk.

Sony NWZS515B

I'm contemplating buying this MP3 player, but can't seem to find any mains chargers that are definitely compatible with it. Could someone direct me to one, preferably on Amazon UK? Thanks. —TreasuryTag—t—c 07:26, 18 April 2008 (UTC)

The product is available on Amazon.co.uk. The details indicate that the battery is rechargeable but no mains charger is provided. Presumably, that means that it is recharged through the included USB cable. So if you just leave it connected to your computer, it will charge itself. If you really want a mains charger, how about one of these (results of a search for "USB charger"), which provide a powered USB port directly from the mains supply or the lighter socket in your car. Most/all of these are "market place" sellers, but there are probably plenty of other suppliers with proper shops/warehouses in the internet. Astronaut (talk) 09:27, 18 April 2008 (UTC)

Thanks for that; do you think the type you listed would work... as in, not damage the player, be too low voltage/ampage or whatever? I definitely need a mains one - I'm on a trip to the Israeli desert where USB ports are in short supply!! —TreasuryTag—t—c 09:33, 18 April 2008 (UTC)

My neice has a Sansa MP3 player and the charger is just like one of those. She has had no problems. The USB specification says 5V is all that should be supplied across pins 1 and 4 (see our USB article) - I imagine that you could test any charger to see if it does that and only that. However, what I've said is no guarantee. Perhaps it would be better to try Sony's website to see if they sell a charger or you could ask their tech support. Astronaut (talk) 09:46, 18 April 2008 (UTC)

"what I've said is no guarantee"... Oh, no, I'm holding you fully responsible :-) No, thanks, good advice! —TreasuryTag—t—c 09:50, 18 April 2008 (UTC)

Installing OS from a USB

Just wondering if it would be possible to install an OS from a USB (i.e. the installation files are on the USB) and if anyone has any good links/advice. I ask because my DVD drive is not working. This is probably not easy, and i figure the first thing to do would be to create a boot disk. Next I'd have to somehow get the OS installation CD onto the USB. Then, prior to re-booting, i'd have to set the USB to load first, and go from there... am i on the right track?

Appreciate the help.

Yes, you're on the right track. Here's a tutorial on installing Windows Vista from USB, I'm sure there are other tutorials out there for Linux, etc. You won't need a boot disk if your BIOS supports booting from USB (I hear most new ones do). Good luck! Xenon⁵⁴ 10:36, 18 April 2008 (UTC)

See http://www.pendrivelinux.com/2007/01/01/usb-knoppix-510/. --212.149.216.233 (talk) 11:01, 18 April 2008 (UTC)

Here's a guide for Windows XP.--droptone (talk) 11:33, 18 April 2008 (UTC)

How to course on designing html websites

How to course on designing html websites I'm not too tech savvy but I would like to learn how to create html websites to promote the nationalist agenda. So far the only sites I know how to create are message boards, blogs, and pre-designed websites. But I've never made a website where I've actually designed the layout myself. Are there any good introductory websites that teach you how?--Gary123 (talk) 13:03, 18 April 2008 (UTC)

I don't know about web sites, but HTML for Dummies is a good book: [1]. StuRat (talk) 19:47, 18 April 2008 (UTC)

You should start by learning some HTML. In the beginning, you only need to know a few elements: paragraph, heading, image tag and link. Most of the necessary functionality of web page can be done with these four elements (but don't forget to add a title). However, the most important are the contents. Contents is the reason why people will come to your web site. You could start by writing the text as plain text with a text editor. The HTML coding and CSS formatting can be added later. --PauliKL (talk) 11:24, 19 April 2008 (UTC)

Getting different results from hash-programs

I was idling and doing nothing in particular just now, and by chance I happened upon this page that details how you can commit your user to a specific hash (which I think sounds like a very good idea), and in there I read something I didn't know: that there comes a whole lot of hash-functions with GNU core utils (which I guess is pretty obvious when you think about it, seeing as how the OS needs to hash passwords and such). "How nice", I thought, "let's try it out!". So I typed "echo "" | sha512sum" into the command line, and it did indeed spit out a hash. However, when I compared it to the list of reference hashes on wikipedia, I saw that it had hashed to a different value. I found this most strange, and on a whim I typed in "sha512" instead (instead of "sha512sum", that is), knowing that ubuntu helpfully informs you about packages you need to execute programs you don't have yet. Ubuntu recommended the package "hashalot", and I installed it, and unlike "sha512sum", the newly installed package did indeed give the right hash.

What's going on here? I mean, why does the standard GNU program give a different hash than the "hashalot" program? Does it do something else, except just creating SHA-512 hashes? Does it add a salt, or something? I assume that the other program was the more accurate one, because it gives the same value as wikipedia does. Can someone enlighten me? --Oskar 13:47, 18 April 2008 (UTC)

When you do

echo "" | sha512sum

you're not calculating SHA512(""), you're calculating SHA512("\n"), because "echo" outputs a newline. Try:

sha512sum < /dev/null

and see what happens. -- Coneslayer (talk) 13:52, 18 April 2008 (UTC)

Ahh! I figured it would be something silly like that! Thank you! --Oskar 14:03, 18 April 2008 (UTC)

With GNU's echo, you can say 'echo -n "" | sha512sum' to suppress the newline that echo usually tacks on. --Sean 18:29, 18 April 2008 (UTC)

Snes Emulator editor

does anyone know of a good site where i can find one of those?the juggresurection ^IstKrieg! 13:49, 18 April 2008 (UTC)

ehrm... www.znes.com - best SNES-emulator nowdays...

i have zsnes, but im talking about actually editing the levels themselves, i have seen it done before.the juggresurection ^IstKrieg! 15:33, 21 April 2008 (UTC)

You've asked the wrong question, I think. An emulator acts like the console - in this case, ZSNES acts like the SNES. Since you want to modify levels, you're probably referring to a specific game - which would be stored on a ROM. So you're looking for either a ROM patcher or a ROM editor. Be warned, the data is all stored in whatever format (style, language) the game's developer felt like using, there's not really a standard across ROMs (although, predictably, the same developer will probably use the same format across games). More popular games may have many and/or technically skilled enthusiasts who de-crypted the format of said games and created a tool for editing maps "directly", bypassing the great gulf of technical knowledge and research required. I don't think there's more to it then a good google using those terms. Good luck. Ironmandius (talk) 00:23, 23 April 2008 (UTC)

OMG. Duh. I am a dumbass, why didnt i think of Lunar Magic in the first place? someone please slap me, i deserve it.the juggresurection ^IstKrieg! 13:37, 23 April 2008 (UTC)

Well..while im in the area...

I was trying to install Linux on a computer that had been wiped clean. When i got to the hard drive partitioner, the box to select hard drives was empty. Is there something i need to do beforehand?the juggresurection ^IstKrieg! 14:20, 18 April 2008 (UTC)

I hate to stoop to the dead obvious, but exactly how wiped clean is it? Are you sure there's still a hard drive in there at all, and that it is still physically connected? Also, this might be stretching a bit, but you might want to do some research on SATA support in Linux. I think most new distributions/versions should handle SATA drives cleanly (though I recall there being some kind of issue with RAID). It might be worth a little searching. --Prestidigitator (talk) 18:58, 18 April 2008 (UTC)

well, and youre probably going to think im an idiot for this, but me and a friend tried to get it open to see if it was phisically connected. We worked at it for an hour and could not get it open. No screws, no holes, no sliding covers, NOTHING. he had never seen anything like it in the time that he has been fixing computers.the juggresurection ^IstKrieg! 19:51, 18 April 2008 (UTC)

One of those Chinese puzzle boxes, huh? What is it? Dell? Gateway? Sounds like an HP to me. If you can give us the make/model, there is a high chance that someone has opened one before. -- kainaw™ 02:34, 19 April 2008 (UTC)

Gateway.the juggresurection ^IstKrieg! 15:32, 21 April 2008 (UTC)

Oh Lord, Gateway. I have opened some of those (mostly ancient ones). In my recollection you have to hold some tabs on the front while sliding the front out so it slides out of its "shell" of a case. I never managed to get the hard drives out of one of those, they are buried in tabs that require at least 3 people to get working. What were they thinking? Well, good luck with that. 206.252.74.48 (talk) 20:29, 21 April 2008 (UTC)

Another computer changing question

Now that I have Office installed (see questions from 16 April), I'm setting up other features of Vista, including Windows Mail. Rather than checking email on the server, I download my email to Outlook Express on my old computer. Is there any way to transfer my emails en masse to the new computer? The only ways I can think of are (1) forward all of them to myself and download them onto Windows Mail, or (2) find them on the old computer's hard drive and copy them with my flash drive to the new one. Can I simply move them over, so that the emails from the old computer look as if they had been sent from the new one? Nyttend (talk) 14:38, 18 April 2008 (UTC)

It looks like this page is describing what you want to do. --LarryMac | Talk 15:11, 18 April 2008 (UTC)

Thanks, but one question: it seems like the page is describing migrating on a single computer. Do you think I could migrate through a flash drive onto another computer? Nyttend (talk) 16:04, 18 April 2008 (UTC)

Sure. Each of the first three steps (exporting addresses, accounts, mail) involves selecting a storage location for the file(s) to be written, so just select a folder on your flash drive. When you get to the import steps, select the appropriate folder on the flash drive and Bob's your uncle. --LarryMac | Talk 16:09, 18 April 2008 (UTC)

When I migrated to Vista, I found Windows Mail was able to import the .dbx files from Outlook Express without problems. I copied the .dbx files from my old PC (somewhere like C:\...\Application Data\Identities\{...}\Microsoft\Outlook Express\*.dbx) onto a CD, popped that CD into my new PC, and chose "import" on the file menu in Windows Mail. Very easy and quick enough. Also did the same for the Contacts.

In case you're interested, I was using Windows Mail as a route to import my mail into Outlook 2007 on my new PC. I'm still baffled why Outlook cannot read the .dbx files without them being linked to Outlook Express or Windows Mail.

Astronaut (talk) 17:00, 19 April 2008 (UTC)

Overclocking

I have been working on overclocking, but found it difficult to locate good sources for the article. Could anyone recommend some? Online sources are preferred but published books are welcome too. Thanks. --BorgQueen (talk) 16:08, 18 April 2008 (UTC)

A decent article came with my XFX card, let me know on my talk page how I should send the PDF file to you. Sandman30s (talk) 17:02, 19 April 2008 (UTC)

Google Groups won't let me post

I've subscribed to this group in order to ask a question, but Google Groups won't let me post. I've tried to post my message about 10 times, but it doesn't show up, and "My groups" keeps saying I have no recent activity. Am I missing something? --Lazar Taxon (talk) 16:13, 18 April 2008 (UTC)

How recently did you post? This is a Usenet group, which is very different from a web forum. Your post may not show up for days! -- Kesh (talk) 00:45, 19 April 2008 (UTC)

In my experience, articles posted through Google Groups show up almost immediately in GG. (Of course, they take longer to propagate to other Usenet servers.) Do you get an error message when you try to post? AndrewWTaylor (talk) 20:38, 19 April 2008 (UTC)

BTW, you don't have to subscribe to a usenet group to post Nil Einne (talk) 20:05, 20 April 2008 (UTC)

SATA transfer mode

I have a WDC WD1600JS-60MHB1 hard drive (that's how Windows reports it), on Serial ATA. In Device Manager > IDE ATA/ATAPI Controllers > NVIDIA nForce4 Serial ATA Controller > Primary Channel > Master Drive, the Transfer mode is set to "Serial ATA Generation 1". Would selecting "Serial ATA Generation 2" make it faster? If yes, is it safe to select it? --grawity ^{talk / PGP} 19:36, 18 April 2008 (UTC)

Yes, your drive is a SATA Generation 2, so it would be advisable to select that option. Whether it will run faster or not - highly unlikely or at most negligibly - read the SATA article for theoretical limits and limits of mechanical devices such as hard drives. Sandman30s (talk) 16:59, 19 April 2008 (UTC)