Wikipedia:Reference desk/Archives/Computing/2007 June 21

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[edit] June 21

[edit] Buying a Computer

Hey, Im looking into buying a new computer. I was wondering what some tips for what I could be looking for. Like, what are some new things that might be good to have on the computer. Im looking into a PC laptop. No Macs.

What will you be using the computer for? Gaming? If so, you'll want a good video card. Simple web browsing and maybe writing an email or letter or two? Then most any laptop will do. Lots of number crunching? Then you'll want to max out your RAM. Dismas|(talk) 02:54, 21 June 2007 (UTC)
Hate to be commercial but I think the dell.com site is pretty good for checking out PC laptops, to see what's there and what the prices are like. You don't have to buy a dell but the website is a good benchmark for decent laptops at a decent price. From memory all the dell prices include a 2 year warranty which I highly recommend over the standard 12 months most other places offer, it's usually not very cheap to upgrade the warranty. Vespine 03:23, 21 June 2007 (UTC)
It would be helpful if you said exactly what you want to use the computer for. A mac might suit your needs better than a PC, believe it or not. Or heck, even something like System76 might be good if you don't need to run Windows apps. You might not even want a full computer at all, an N800 might be better suited to your needs. We won't know unless you're more specific than "I want a computer". -- Phoeba WrightOBJECTION! 05:34, 21 June 2007 (UTC)
Why not a Mac, they are "idiot proof", even I use one!--88.109.177.178 05:58, 21 June 2007 (UTC)
I argree, Mac's are "idiot proof", however, I preefer to think of them as simplfied Linux. Lapot wise look for somthing with an AMD chip, they tend to give more bang for buck. OS wise, get Win XP if you must have windows but I recomend getting Linux; Fedora 7 and Ubuntu are both good distros. for good priced pc's take a look on price watch. Good Luck. --Lwarf Talk! 09:43, 21 June 2007 (UTC)
I use a Mac, and remember that they can boot into almost all of the other operating systems.--67.181.167.227 13:02, 21 June 2007 (UTC)
If you want Windows Vista, make sure your dream computer can support it. --Mayfare 15:13, 21 June 2007 (UTC)
If you want Windows Vista, buy a Mac. (^_^)Gzuckier 17:04, 21 June 2007 (UTC) (windows user)
Save yourself the money and just buy the huge steaming pile of dog crap direct from the manufacturer. --frotht 02:32, 22 June 2007 (UTC)
Harsh yes, but fanboyism is unavoidable on tah inteerw3bz --frotht 02:33, 22 June 2007 (UTC)
Laptops have a much shorter expected lifetime than a desktop. Optomistically it will be another few years before Vista is used everywhere, until then XP will remain the most common. You need a significantly more power to run vista than XP, laptops are not well known for having oodles of power.... rather they will always be underpowered when compared to a desktop PC at the same price point. All of these add up to an even strong case of why you should get XP if you are buying a laptop. Mathmo Talk 02:25, 3 July 2007 (UTC)


Its not that hard to B.I.Y (build it your self) and then istall linux, i'll take a look for a wikibook on it. --Lwarf Talk! 08:28, 22 June 2007 (UTC)
If the person is asking here about buying a computer, then it probably isn't a good idea to build it themselves. Even though in my opinion it is very easy to to, because it won't be for them. Another factor to take into consideration is they want a laptop, which isn't quite as straightforward to build from scratch as a desktop is. Thus, even though I hate that I'm recommending this.... it probably is a good idea for them to consider a dell. Here is a good little article for you to read. [1] I wish I could give the advice to build it themselves to everybody. Mathmo Talk 02:22, 3 July 2007 (UTC)

[edit] Image effect

What is the name of the effect used to change an image into regions of white and black, looking perhaps not unlike a Rorschach inkblot test, yet in which the subject of the image is still immediately recognizable due to our interpretation of the black regions as shadows? A good example is the alternate album cover of U2's Boy ([our picture of it]), and also one of the two pictures of Bob Dylan in the opening sequence of VH1's program (the name of which escapes me) which plays two consecutive songs from the same artist. I would like to process some of my photos this way. Many thanks in advance. Baccyak4H (Yak!) 03:11, 21 June 2007 (UTC)

First choice would be whatever describes emboss in the 2D sphere. Second, and probably more correct, is reticulation. --Wirbelwindヴィルヴェルヴィント (talk) 04:04, 21 June 2007 (UTC)
Actually, on second thought, I don't think either of those are correct. However, in Photoshop, the stamp filter gets the most similar effect. --Wirbelwindヴィルヴェルヴィント (talk) 04:07, 21 June 2007 (UTC)
I'm pretty sure you can acheive this affect with most Posterisation filters if you set them to 2 tone black and white and fiddle with the settings. Vespine 05:26, 21 June 2007 (UTC)
Try Threshold in Photoshop (Layer > New Adjustment Layer > Threshold...). I prefer a different technique which results in an effect similar to the cover of Regina Spektor's Begin to Hope (mainly black and white, but with shades of grey in between). Desaturate the image, add a Brightness/Contrast adjustment layer and drag the Contrast slider to around 80. You can use a Levels adjustment layer in place of the Brightness/Contrast if you want more control over the effect. It works best on images with a white or light-coloured background. — Matt Eason (Talk • Contribs) 12:26, 21 June 2007 (UTC)

(outdent) Posterization does indeed look like the effect I want. I do not have Photoshop, but have GIMP and Graphic Converter (yes, I use a Mac). The former should have this for sure... The Begin to Hope effect is not what I am looking for, although it is a nice one in its own right. Thanks again, and I would still be open to hints/tips. Baccyak4H (Yak!) 14:06, 21 June 2007 (UTC)

It's under Colour/Threshold, and I would load it into Inkscape or something and use the auto tracer to trace it so it's no longer aliased (or just use the auto tracer on the original image and set the threshold there). --antilivedT | C | G 06:20, 22 June 2007 (UTC)
In Corel Draw (or I suppose similar programs) you would go Bitmap -> Convert to Bitmap (sic) and click "Black and White" (not to be confused with "Grayscale"). Before you do this I would fiddle with the contrast a bit. Rfwoolf 10:36, 23 June 2007 (UTC)

[edit] Firefox find

The Firefox find function doesn't search within edit boxes, making it difficult to use when trying to edit a wiki page. Any way to change this, or is the solution to use an external editor? Jooler 07:45, 21 June 2007 (UTC)

At least for me (Firefox 2.0.0.4 on Ubuntu), if you use Ctrl+F, it does search within the edit box. --cesarb 09:55, 21 June 2007 (UTC)
  • If you decide to use an external editor, you can boost functionality to make up for the lack of quick buttons. (I use the Vim syntax plugin) -wizzard2k (C-T-D) 15:20, 21 June 2007 (UTC)
It works for me, with Firefox 2.0.0.4 on Mac OS X. Maybe try clicking in the box first? Abeg92contribs 21:40, 4 July 2007 (UTC)

[edit] Two Computers

Can the motherboards of two seperate computers be connected so that one operating system (from a single hard drive on one of the computers) can use both its host motherboard and the connected one; including all the ram, processors, cd drives etc? Think outside the box 09:20, 21 June 2007 (UTC)

If it is possible, I doubt it's something you could do yourself. There aren't exactly "Motherboard SLI connectors". Why would you want to anyway? I have to imagine such a setup would be more costly and slower than an equal setup with a single motherboard, at least for the tasks you'd want such performance for. -- Phoeba WrightOBJECTION! 09:28, 21 June 2007 (UTC)
I doubt it's possible at all. It would be a lot easier if you just get a dual-CPU motherboard with lots of ram and IDE controllers etc. --antilivedT | C | G 09:34, 21 June 2007 (UTC)
Does network booting count? If not, then see above. --Wirbelwindヴィルヴェルヴィント (talk) 09:37, 21 June 2007 (UTC)
It's possible; what you want is a single-system image like openMosix (and you'll need network boot to boot the second computer, since you want to boot from a hard disk on the first one). --cesarb 09:54, 21 June 2007 (UTC)
I think the questioner would be better off setting up a Beowulf system. It allows you to work at one computer, but make use of other computer's processing power in the cluster. I have note a quote I heard from one of the Beowulf designers when they spoke at a conference I was at. It went something like, "I have been asked if I can turn a hundred or so old 386 computers into a cluster. I have to answer, yes, you can - if you want a hundred or so computers that overall will function slower than a single Pentium computer, but will produce about 100 times the heat and suck up about 100 times the electricity." --Kainaw (talk) 12:52, 21 June 2007 (UTC)
The IBM Blue Gene has a high speed interconnect between all its nodes as well. Check out the Supercomputer article about more of this technology. There are a variety of methods of achieving this interconnect, from NUMAlink with the SGI Altix to HyperTransport used in a variety of systems, and to a lesser extent, with Infiniband on Beowulf and other HPC clusters. -- JSBillings 13:40, 21 June 2007 (UTC)

[edit] Creating backups of dvds

Hi, i want to copy my dvds onto my computer. Not as disc-images, but as avis or mpegs etc... Can anyone reccommend the best freeware to do this?

A great, open source program to do this is Handbrake.--67.181.167.227 12:59, 21 June 2007 (UTC)

[edit] multicore vs. multiprocessor

Dear wikipedians:

What is the difference between a system with one multicore CPU and a system with more than one CPU (multiprocessor) in it.

129.97.225.195 14:34, 21 June 2007 (UTC)

With a multicore, you have one processor - so you have one connection between the processor and the motherboard. With a multiprocessor, you have multiple processors. So, you have multiple connections between the processors and the motherboard. With one processor, much of the handling of multiple code running at the same time can be handled inside the processor. With multiple processors, the motherboard has to handle the handoff between one processor and another - or, as is usual, just ignore one of the processors and waste resources. --Kainaw (talk) 14:39, 21 June 2007 (UTC)
Multicore CPUs are lower power and heat than symmetric multiprocessing designs and take up less space in the system. Since they're on the same die, that means faster communication between the cores. I believe they also share cache, which has some speed advantage but I think it reduces the total per-node cache overall. I think one of the biggest limitations now is that most apps aren't written to take advantage of multicore CPUs. -- JSBillings 14:46, 21 June 2007 (UTC)
The above sounds pretty right, I'd only add a couple bits: Multicore tends to be cheaper than multiprocessor, because it's cheaper to produce (essentially) two CPUs on one chip than two chips, and because the motherboard to support the processor is cheaper that way. It's true that many apps aren't written in a threaded way to take full advantage of multiple CPUs/cores. But, this should be improving as multicore chips become more and more standard. Even if a given app isn't taking advantage of it, the system still feels faster because it will slow down less under load. Friday (talk) 14:58, 21 June 2007 (UTC)
Sorry for hijacking here - how well do operating systems handle multiple/multiple core CPUs? If I have two processors and one application which needs loads of CPU time, will Windows give it exclusive use of one of the processors and put everything else through the other, for example? — Matt Eason (Talk • Contribs) 15:49, 21 June 2007 (UTC)
No. It is not that simple. You don't have two computers in your computer that can run side-by-side. You have two processors (or cores) that can handle very basic functions like shifting some 1's and 0's right or left. There is still only one overall computer that decides which programs can access memory, which can access the processor, which are in a waiting queue, which need to be killed off... --Kainaw (talk) 16:02, 21 June 2007 (UTC)
But it's not as complicated as you make it out. The processors can actually handle a bit more. The compiled code will talk to the OS to get permission to have exclusive access to a piece of hardware or memory, etc. A program written with threading in mind will be able to spread its load across multiple processors (whether in a multicore CPU or multiple chips, or in some cases, multiple distributed machines), see multithreading for more discussion. From the CPU's perspective it's all code. There will be periodic hand-offs between an application and the OS as resources are allocated/freed. But it's not uncommon in a 2-processor system to see one processor spiked while the other is mostly idle. Donald Hosek 18:16, 21 June 2007 (UTC)

Either way, a multi-core or multi-processor computer doesn't necessarily speed up processes. Most programs aren't designed to optimized performance with two cores or processors.

Kevinwong913 Speak out loud! 20:49, 21 June 2007 (UTC)

[edit] Accidental adding of a misspelled word to a dictionary

I accidentally added a misspelled word to the Firefox British dictionary, how do I undo that. PS: I tried reinstalling, and it didn't work. Thanks, Jeffrey.Kleykamp 16:02, 21 June 2007 (UTC)

Lifehacker has instructions on how to remove words from the dictionary here. If you're on Windows make sure you open it in Wordpad rather than Notepad - the latter messes up the line breaks. — Matt Eason (Talk • Contribs) 16:10, 21 June 2007 (UTC)
Thanks, that worked really, really well, so, again, thanks. Jeffrey.Kleykamp 16:15, 21 June 2007 (UTC)

[edit] HTML redirect

I have a domain but I don't have a main page yet. I'm setting up the forum right now, so for the time being, I'd like users to get redirected from the main page automatically to the forum. The forum resides in its own directory. What's the easiest way to get the users automatically redirected to this directory? Thanks, Dismas|(talk) 23:50, 21 June 2007 (UTC)

Make the main page for your domain (index.html on Apache machines) just contain <meta http-equiv="refresh" content="0;url=http://your.forum.address"> Youth in Asia 00:38, 22 June 2007 (UTC)
Cool, thanks! Dismas|(talk) 01:22, 22 June 2007 (UTC)
A better solution is to ridirect with http headers (in php it's header("whatever");)- Location: http://www.example.org/. An even better solution would be to make apache rewrite the location to the forum directory so it's transparent to the end user. Unless you actually want a "redirecting.." notice to be seen, refresh redirects are generally a terrible way of doing it. Be considerate of those using lynx! --frotht 02:37, 22 June 2007 (UTC)
Which part of that do I put in the index.html file? Basically, where do I start the copy/paste? Dismas|(talk) 03:34, 22 June 2007 (UTC)
That you need PHP, but isn't also possible to do <meta http-equiv="Location" content="http://www.example.org/"/>? --antilivedT | C | G 06:16, 22 June 2007 (UTC)
Froth's suggestions are fine if you have access to install PHP or change your Apache config file. For normal users, using a meta tag is best. Antilived's "meta location" suggestion is the proper one. Youth's "meta refresh" works, but it isn't the proper tag. You are abusing the refresh by saying "refresh in 0 seconds to..." instead of simply saying "change to location...". As for Froth's lynx concern, I use lynx regularly and it accepts meta tags. It will refresh or change locations fine. --Kainaw (talk) 12:04, 22 June 2007 (UTC)
Well, I put Antilived's in and it didn't redirect me at all. So back to Youth's I go. Dismas|(talk) 13:43, 22 June 2007 (UTC)
(de-indent) Hmmmm the http-equiv=Location way doesn't work at all, maybe because by that time the header is already sent and a Location header is invalid by then? The best way would be either header() or rewrite, but if you don't have PHP or don't know how to use Apache Rewrite (or don't have Apache), http-equiv=refresh is the only way to go... --antilivedT | C | G 01:30, 23 June 2007 (UTC)
Well, the forum that I put up is written in PHP and it's on an Apache web server, so I would presume that I have what you're talking about. Dismas|(talk) 01:56, 23 June 2007 (UTC)
Then just copy an paste <?php header("Location: http://www.example.org"); ?> into the very top of your index.php and you should be all set. Remember to delete index.htm or set Apache to go to index.php first though. --antilivedT | C | G 04:42, 23 June 2007 (UTC)
And to do it fully server side, put this between <directory /whatever/dir/you/want/> and </directory> tags in your httpd.conf:
RewriteEngine on
RewriteRule ^/directory/relative/to/the/one/above/filename\.html$ /another/directory/path/filename.html
--frotht 16:02, 23 June 2007 (UTC)