Wikipedia:Reference desk/Archives/Computing/2008 October 19

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

October 19

Research Project

I need to know about: Monolithic Systems, Layered Systems, Microkernels, Client-Server Systems, Virtual Machines and Exokernels,this work is due for October 22, 2008. Teacher told me last Wednesday, but I started looking for these, and I can't find anything in this or another address, thank for your help. —Preceding unsigned comment added by 76.109.82.91 (talk) 00:13, 19 October 2008 (UTC)

Try searching for lower-case singular in Wikipedia. For example: monolithic system. I'd also suggest searching the index of your textbook. -- Tcncv (talk) 00:58, 19 October 2008 (UTC)

Err... It's not that hard to find stuff on Wikipedia; most things don't have plurals and have uppercase only on the first letter... Monolithic system, Layered system, Microkernel, Client-server system, Virtual machine and Exokernel. Now do your own homework. Astronaut (talk) 04:39, 19 October 2008 (UTC)

How to make a glossy computer screen matte?

Greetings,

Do you know of any film that one may apply to a glossy LCD screen in order to make it matte?

Thank you,

--Anon 00:35, 19 October 2008 (UTC) —Preceding unsigned comment added by 88.189.248.66 (talk)

I thought glossy screens attract a premium price (they look better in my opinion and the image is often brighter). See if you can sell it and get a cheaper matt one. Astronaut (talk) 04:31, 19 October 2008 (UTC)

Yes. Its called greaseproof paper or tracing paper--GreenSpigot (talk) 19:46, 21 October 2008 (UTC)

New phone, crap battery life

I bought the Samsung E-530 off Ebay recently and it's supposed to have 8 days standby but in my experience it wont even last a full day at school in my pocket. It only seems to last about 3 hours fully charged and thats without bluetooth activated. What am I supposed to do with this phone? --124.254.77.148 (talk) 01:38, 19 October 2008 (UTC)

(POV alert) My first reaction is caveat emptor, or "that's E-bay for you". As a general rule, if a bargin is too good to be true, then it probably isn't. Seriously though, you could try contacting the seller or if that doesn't get you anywhere try leaving them some crap feedback on E-bay, but I honestly doubt you would get very far. Instead, try to get a new battery - your local mobile phones shop might have a battery (not a major service provider's shop but one of those street corner places). Astronaut (talk) 04:28, 19 October 2008 (UTC)

Yeah, my guess is a dodgy battery - in my experience there's a big variation in quality control for the batteries in phones and music players, with some unfortunate examples rapidly losing their maximum charge. You can probably find a new one reasonably cheaply. ~ mazca ^t|c 09:42, 20 October 2008 (UTC)

Modem Problems

Something is wrong with my modem. All the connections are right, and under Network Connections it says its fully connected and working. but when i start the browser, it says there is no connection. I never had this problem before. Do i need to reset it or anything? i just moved the computer to a different room, but it started doing this the day before i moved it. the juggresurection ^{(>-.-(Vಠ_ಠ)} 04:43, 19 October 2008 (UTC)

Reboot the modem and your computer. Check your browser settings. Check your modem's settings. If it's wireless, make sure the signal is strong enough. Finally, maybe it's something like the problem I think I have - the modem chipset being vunerable to line noise - causing me to have to reset it every few days. Astronaut (talk) 04:57, 19 October 2008 (UTC)

Well, how exactly would i go about resetting the modem? i dont mean turning it off and then on again, i mean resetting the configuration or whatever. sorry, im not very knowledgeable with this kind of thing. the juggresurection ^{(>-.-(Vಠ_ಠ)} 05:17, 19 October 2008 (UTC)

I just turn mine off and on then the saved settings come back. However, you might need to reenter the username and password and all the other settings given to you by your ISP. The usual way to do this with your broadband modem is to use the web interface at http://192.168.1.1/ (though I did read somewhere that some modems use http://10.?.?.?/ instead - maybe someone else know this one). More complete instructions should be in your modem's manual. Astronaut (talk) 06:17, 19 October 2008 (UTC)

I should probably find that. :P the juggresurection ^{(>-.-(Vಠ_ಠ)} 06:42, 19 October 2008 (UTC)

I was wondering, do you only have a modem, or do you have a modem AND a router? If you only have a modem, that means that you only have one computer connected directly to the internet with a cable. If you have a router, then you can have many computers connected to the internet, using either cables or wireless. It would be easier to help you if you could give us those details :) Belisarius (talk) 07:17, 19 October 2008 (UTC)

Two notes:

• If it's a dial-up modem, things are different, but if it's cable/DSL, there is possibly a "reset" button on the outside. I have a 2Wire DSL modem that occasionally stops working (but only websites, HTTP port 80) and I use a paperclip to hold down the reset button for 30 seconds, then everything works peachy. But definitely know how your account works before you try this! Might be worth a call to customer service, despite the wait time, because you really should have that stuff written down somewhere. (Account ID if needed, password if needed, email account name and POP3 password, DNS server addresses).
• And it is possible that your DNS server information has gone bad. In Windows, open a "command shell" (same thing in Linux) and try "ping en.wikipedia.org" and "ping 208.80.152.2" - if the first one doesn't reply and the second one does, it's a DNS server problem. End result though will be "call your ISP" I guess :( Franamax (talk) 22:50, 19 October 2008 (UTC)

"Ask your network administrator"?

Quite often when installing an operating system, I get to the networking setup and the installations notes will say something like "if you are unsure what to provide here, please contact your network administrator". Well I am the only one here so I suppose I'm my own network administrator, and I still don't know what info to provide. Any suggestions on how I could learn how to administer my own home network? Astronaut (talk) 04:51, 19 October 2008 (UTC)

That message often comes up when you have to enter specific information for your network setup (like IP-address, subnet-mask, standard gateway, etc.), but when you are just setting up a home-network, you shouldn't have to enter that stuff. It should be configured automatically. Just hook up your router, configure your wireless settings if you are using wi-fi (for help with this, look at the manual for the router) and then just connect the computer (either with an ethernet cable, or by using the connect to wireless network function of windows). If you have any more specific problems, we'd love to help :) Belisarius (talk) 05:23, 19 October 2008 (UTC)

Trouble is, my network has grown from a modem/router and one old PC, to the modem/router, a print server, four PCs of various ages, and now a server. In the early days it was easy - just plug in and away I go. Now I want to share stuff in a mixed Windows XP, Vista and Linux environment. I want the server to have the same name and IP address all the time so I can try out running a small web server and maybe have it carrying out a proper backup policy for the shared docs and photos, and maybe doing all the user authentication (like at work). The only thing I've got working satisfactorily is the print server. Unfortunately, I don't know how to make most of it work properly and the only help provided by the OS's is: "ask your network admin". I suppose what I'm really asking is for some guidance on network admin training - books, online, classroom even. What kind of titles/descriptions/keywords should I be looking for? Astronaut (talk) 06:44, 19 October 2008 (UTC)

As for how to set up the server so that it has a static IP, that's pretty easy. Go into your router-configuration, where you should be able to configure static IPs from the device's MAC-address. On my router, it's under the "DHCP" settings (where I can also see all the MAC-addresses of the devices on the networks), not sure where it is on yours. It should be pretty easy to do though, just look around for "Static IP" somewhere. Then you can also set up port-forwarding so port 80 always gives you the server. It's not a terrible idea to do that with all devices that are permanently connected to the network, that way you can access each and every one of them using their IP and not worry about it changing.

Not sure how to set up backup policies, but if you want to enable file-sharing between the Linux-machines and Windows, you can fairly easily set that up using Samba. Here's a guide for Ubuntu, and more can easily be found by googling. Vista and XP should work just fine together, I think, and Samba should extend that cooperation to linux. As for network admin training, I can't really help you, Google is my teacher :) (and a bad one at that!) Belisarius (talk) 07:04, 19 October 2008 (UTC)

I think I understand the question - you want to understand what all this stuff means so that it's not just a black art and trial-and-error. That's a good aim. I don't know off-hand of a single good treatment of the subject at an appropriate level - the nearest O'Reilly might perhaps be this one? I was going to also suggest that the basic Linux networking-HOWTO might be suitable, but after a quick glance I think it's almost certainly not. Have you had a good read of Wikipedia's own stuff on TCP/IP, and all that's linked from it? 81.187.153.189 (talk) 11:22, 19 October 2008 (UTC)

Using an AirPort Express as a wireless bridge for a NAS-device

My dad has a NAS-device he bought from D-Link that I set up, which he uses for storing all his music and photos and things (it's a RAID 1 device, and he likes the idea that his data is automatically backed-up), and he likes it very much. The problem is that it is quite noisy, and his router is in his living-room. The NAS-device doesn't have wireless built-in, you have to connect it using an ethernet-cable, so he can't just put it in a closet.

He does, however, have three different AirPort Expresses from Apple which he uses to stream music throughout his house. I'm thinking that I could configure one of the AirPorts as an ethernet-to-wireless bridge (that connects to the router), and then put it and the NAS in a closet somewhere, where no one will hear it. Is this possible? Or is it just utter foolishness? The only reservation I have is that if he wanted to play a song using another one of the AirPorts, he'd be sending the data from the song over the wireless network six times! First from the NAS to the router, then from the router to the computer and iTunes, then from iTunes two streams to the router which the router forwards to the two AirPorts. Is this just to much strain on a lowly home-router? On the other hand, if I can get this working fine, it would be worth it just for the story to tell (seriously, that's one bitchin' home network). Does anyone have any other ideas for how to solve this, or do my poor papa just have to live with a noisy living-room? Belisarius (talk) 06:24, 19 October 2008 (UTC)

I just realized that the way he has it set up right now, it's transferring the song even more, seven times wirelessly across the network (once wired from the NAS to the router, then from the router to iTunes, then three streams from iTunes to the router, and three streams from the router to the AirPorts). So I guess it wouldn't be a problem with capacity. So, back to my earlier question: would this be possible to do with an AirPort Express? Belisarius (talk) 06:29, 19 October 2008 (UTC)

I don't think putting noisy (therefore hot) hardware in a constrained place such as a closet is a good idea... Rilak (talk) 08:21, 19 October 2008 (UTC)

It depends how tight the closet is. In this case, "in a closet" seems to just be shorthand for "somewhere in the house that isn't right in the middle of the living room". I have a cupboard containing router, phone base station, power-use-monitor, NAS/automation/etc box and so on, and I don't give heat a second thought because they're laid out on a board on the wall with plenty of space.

As for the proposed wireless solution, I don't see why this shouldn't work. Especially since it doesn't involve buying any new hardware, why don't you just go ahead and try it?

If it doesn't work, my preference would be to stick with a wired connection, but rearrange things so that the NAS can be tucked away. Obviously the details will depend on the layout of your house, but you can either run a cable from the existing router location, or (perhaps better) move the router to the "closet" as well. Having the router in an odd, on-display location like the living room just because that's where the phone socket is as always seemed sub-optimal to me - phone wiring is not hard, and, at least here in the UK, is perfectly legal once you're downstream of the BT entry point ("master socket"). 81.187.153.189 (talk) 11:09, 19 October 2008 (UTC)

I stored a download computer in my bedroom closet. It's survived for over a year with mostly 100% uptime. It is however an old computer and I don't store anything on it I can't afford to lose. Nil Einne (talk) 14:23, 20 October 2008 (UTC)

I know this doesn't answer your question but the first thing I would do is teach your dad that RAID is not a backup [1], [2], [3], [4] & [5]. You and your dad wouldn't be the first to confuse the two but it is vitally important you understand the difference. RAID 1 only protects your data against the failure of a single hard disk. It doesn't backup your data. There are many circumstances where you could lose data with a RAID array. For example accidental or malicious (viruses, malware etc) deletion, partition corruption (caused by the OS, NAS, RAID controller etc), loss of the array (due to theft, flooding, tornado, fire etc), the failure of two hard disks simulatenously or before you rebuild the array (this is not as unusual as it seems, it could be caused by a catrastrophic power supply failure for example or if both hard drives have sustained failure or have a similar defect which isn't as uncommon as as it seems when you've purchased the drives at or around the same time even worse in the event you continue to use the array while waiting potentially several weeks for the broken drive to be replaced). In other words, while RAID provides redudancy, it's not as backup. If your father has stopped good backuping practice because he has a RAID array, he should seriously reconsider. Nil Einne (talk)

Blown-Up Screen Display

I had a game that asked me to change something about the settings, and when I hit okay, and later when I turned the game off, everything on the screen seems blown up, or stretched. How do I get it back to the way it was? --Ye Olde Luke (talk) 06:24, 19 October 2008 (UTC)

It sounds like you changed the screen resolution! The new resolution probably don't match the aspect ratio of the screen, and that's why everything got stretched. Go into the game's settings (I assume you can still navigate the menus of the game, even if they look a little strange?) and change the screen resolution. It's often under the "Video" portion in the options-screen. Try a few out and see which ones look ok. If you look at the screen settings in windows, you can find out what resolution windows is using and try that. Remember though, the larger the screen resolution, the more resources the game will demand. If you have a slightly older machine, use lower resolution settings. It will make your screen look less sharp, but it will improve performance. Belisarius (talk) 06:35, 19 October 2008 (UTC)

It's not the game, it's the computer desktop. And any windows that open. The game was the only thing that looked normal, and now I can't get back in because my 60 minutes is up (it was a trial version of Escape the Museum). I guess I need a way to change resolutions without the game options available. --Ye Olde Luke (talk) 06:49, 19 October 2008 (UTC)

Ahh, sorry, I misread your question! Terribly sorry. Well, that's easy to fix too :)

1. For Windows XP: Right-click on your desktop and select "Properties" from the menu. Select the "Settings" tab. There should be a dial-thingy that you can drag back and forth to change resolution. Try different values (i.e. select a value, and press "Apply") until you find the one that you had before.
2. For Windows Vista, again, right-click the desktop and select "Properties""Personalize". It will open a window where you can configure a whole bunch of things. At the bottom there will be one called "Display Settings". Click it, and proceed in the same way described above.

Good luck! Belisarius (talk) 07:10, 19 October 2008 (UTC)

In Vista the option when you right-click on the desktop is called "Personalize". Astronaut (talk) 07:23, 19 October 2008 (UTC)

Thank you, correction appriciated Belisarius (talk) 07:38, 19 October 2008 (UTC)

That did it. Thanks both of you! --Ye Olde Luke (talk) 07:53, 19 October 2008 (UTC)

Good thing it was just a trial. My suggestion is that you do not buy that game now ... Kushal (talk) 21:17, 19 October 2008 (UTC)

Happens to me all the time, but restarting normally fixes it (althought I sometimes have to rearrange my desktop icons afterwards). DendodgeTalk^Contribs 19:13, 20 October 2008 (UTC)

Defination of diffrent words

Computer,E-commerce,calculator,modem,mobile phones,E-mail —Preceding unsigned comment added by 117.98.93.26 (talk) 09:53, 19 October 2008 (UTC)

Although computer related, this should really be on the language desk.--ChokinBako (talk) 13:45, 19 October 2008 (UTC)

Google has a dictionary function. Use it like this. There are many other electronic dictionaries as well, and I've even heard rumors that they exist in paperback form. Don't bother us with things like "define this list of (homework) words for me" unless you've tried other options. It's a waste of our time and it's something you could clearly figure out on your own. --98.217.8.46 (talk) 14:25, 19 October 2008 (UTC)

Oh comeon. Take a stab at it.

A computer is the milestone for the decline of western civilisation. E-Commerce is an opportunity for on line shopping, ordering, and SPAM. Calculator is a device that can do simple calcuations. Modem is a modulator-demoduator for sending and recieving data over Telephone lines. a mobile phone is one you can throw out a window. ( or is that a flying phone ). and Email is message that is sent from a computer to a mail server, that moves to the destination mail server, and then gets transferred to your computer by a mail program, or a broswer. It can contain simple text, or include pictures, viruses and social networking viruses. Which one is not true? $--~~~~$ —Preceding unsigned comment added by 99.185.0.29 (talk) 03:11, 20 October 2008 (UTC)

Jebus the homework questioners are really getting lazy if they can't even be bothered to type out the question and instead only type out the keywords and want us to guess what they want Nil Einne (talk) 11:11, 20 October 2008 (UTC)

Adblock Plus

Resolved

I went to the Adblock Plus website yesterday. It did not say anything about what software (Firefox or IE) or OS are needed, but I decided to risk it for a biscuit and download anyway. I'm on a Mac, using Firefox, and Adblock Plus downloaded and installed automatically. It works like a dream! Now, I am wondering, would it work on IE on Windows? I still know a few people who stick to IE and won't touch Firefox despite, well, everything, really. So, anyone know?--ChokinBako (talk) 13:26, 19 October 2008 (UTC)

Comment moved to correct section by IMSoP (talk):

(EC - and this has been transformed into a new question!) I must be getting old - one look at the website of Adblock Plus tells me it's for Mozilla products only! I should have known! The Steve Jobs article is here.--ChokinBako (talk) 14:26, 19 October 2008 (UTC)

End moved comment

I would sacrafice a large animal if it worked on IE, but there is so very many security problems with IE< and ActiveX in pitecular, ( I run only ONE active X Control ), I actually use HostXpert for blocking ads. I can start with Spybot Search and Destory's black list, and then ad to it. But thats for a lightly used IE. I dont use Adblock Plus, because of its interface, but use Adblock and Adblock Filterset G updater, and it works GREAT. ( Oh, and just for fun, I have banned *.ru, *.cn and *.nl, because some punk rooted my linux box from *.nl ). Any other suggestions on countries to ban? --99.185.0.29 (talk) 03:01, 20 October 2008 (UTC)

Steve Jobs

I want to know more about Steve Jobs,but i can`t find article about him in Wikipedia —Preceding unsigned comment added by 212.233.240.207 (talk) 14:07, 19 October 2008 (UTC)

If you had typed "Steve Jobs" into the search box below the Wikipedia logo at the left hand side of the screen, it would have taken you to the article you are looking for. --NorwegianBlue ^talk 14:24, 19 October 2008 (UTC)

I am glad I read 'The journey is the reward' and found it really good. I would recommend it far and above the article on Steven Jobs here. ( The article on John Skully, and John Lois Gasse are also not very comprehensive. ) —Preceding unsigned comment added by 99.185.0.29 (talk) 03:03, 20 October 2008 (UTC)

Well, you could write more for those articles if you like, but here isn't the best place to recommend books. My name is anetta (talk) 13:30, 21 October 2008 (UTC)

A reference to a relevant book is a good answer to a factual question, IMHO. --NorwegianBlue ^talk 19:42, 21 October 2008 (UTC)

Privacy: do emails reveal my IP address?

Could someone take a close look at my email and discover the IP address, and thus be able to see what text I had provided here and at other places? 78.149.192.49 (talk) 17:25, 19 October 2008 (UTC)

Yes, the headers of any e-mail message contain a set of lines beginning "Received:", which show the path the message has taken through the Internet, usually starting with the sender's connection to their ISP. You can see this for yourself: if using Thunderbird, just click View -> Message source; GMail I think has a "view original" option somewhere; Outlook hides it away somewhere I can never find, but it is there somewhere.

Using a webmail interface or service such as GMail or Hotmail would generally avoid this, I think.

And of course a lot of places, including Wikipedia, will only reveal your IP address publicly if you don't create an account. See Wikipedia:Why create an account? - IMSoP (talk) 17:53, 19 October 2008 (UTC)

Gmail hides the IP address of the original sender, at least when you send from its webmail interface - the originating address is the gmail server. Outlook and OE show your originating IP when you send out a mail - they are designed as host-based clients, so the originating IP has to belong to your ISP network, otherwise it gets rejected as a spam transfer. Hotmail used to show full email headers traced back right to your own PC, but I'm not sure now since I refuse to upgrade to the "full" version of Windows Live. Generally, when you use an email client on your own computer, your own IP address is visible at the other end. If you use web-based email, the visible address is the server you connected to in order to send your email. You can always send an email to yourself and find the "full headers" option to see how far back you can trace it. Franamax (talk) 23:27, 19 October 2008 (UTC)

And of course if you use a DHCP service from your ISP (as most people do these days) - then your IP address will probably change each time you power your computer down or disconnect from the Internet...so it may not matter that your IP address is leaked. SteveBaker (talk) 02:13, 22 October 2008 (UTC)

transient in Java

Hi,

What's the motivation behind the existence of this modifier? —Preceding unsigned comment added by 3sJJ0Itf (talk • contribs) 19:41, 19 October 2008 (UTC)

Do you even know what transient does? --71.106.183.17 (talk) 20:05, 19 October 2008 (UTC)

Transient marks data that isn't to be emitted when an object is serialised. Why, you might ask, would you want to serialise some data in an object and not other data? Some data, in certain objects, isn't meaningful if you reconstruct the object at some future time; so you wouldn't want to store that in the serialised object. Say for example you were writing a video game, and you had a PlayerState object, which kept things like the player's position and how much health they had. And so save the game you'd chosen to serialise that PlayerState object, save the resulting bytes on the disk, and you'd do the reverse when you wanted to load a game. But, for convenience, say you also store some stuff in that object like which keys the player is pressing on his keyboard. You wouldn't want to save that info, so you'd mark that data transient. Another example: say you were implementing a web browser, and you wanted to have a BrowserState object that you'd save when the user exists the browser, which you then reload if they restart it - allowing them to get back the tabs and tab histories they had when they closed the object. But say in that same object you also kept the cached contents of web pages; saving that would make the serialised BrowserState object very large, and slower to load, and would contain a bunch of stuff that the user wouldn't want to see anyway (if, say, they restarted the browser a week later). So you'd mark that cache object transient too. -- Finlay McWalter | Talk 20:24, 19 October 2008 (UTC)

Okay, so if it wasn't a keyword, you'd have to do a lot of messing around to achieve the same thing? I guess what I didn't understand is that actual serialization doesn't seem built in, it seems more like any other API but that this transient, which only makes sense in context of serialization is a keyword of the language, on the same level as old favourites like if, abstract etc etc. -3sJJ0Itf (talk) 20:40, 19 October 2008 (UTC)

Like modifiers such as "volatile" and "public", "transient" is per-item meta-information. Because classes can implement any number of interfaces, one can add such meta information to a class simply by making the class implement a special interface (e.g. Serializable, Runnable) and then test an instance with the instanceof keyword. There isn't a comparable way to designate a method or a field, so the Java designers chose to use keywords. These mostly tell the compiler to set a bit in a bitfield describing the member, which can later be inspected by native code or by inspecting the Modifier obtained via java.lang.reflect.Member (see the java.lang.reflect.Modifier docs). This is probably a bit clunky, as it would be nice to be able to tag members the same way we can tag classes and object, but this is the limited path the Java designers have chosen. If it wasn't a keyword you'd have to figure out some other way of tagging a field in this way, or remove automated serialisation and make every serialised class explicitly generate its own serialised form (with its own method, which knew which fields to store and which not to). Serialisation itself is part of the java.io package, which makes it "built in" (the implementation of the native bits of java.io is pretty tied up with the internals of the JVM, although less so than java.lang). -- Finlay McWalter | Talk 21:17, 19 October 2008 (UTC)