Wikipedia:Reference desk/Archives/Computing/2007 February 6

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February 6

My compuer broke

how can i fix my broken computer.

Can you tell us more? What exactly is broken? What happens when you turn it on - for example, does nothing turn on, does text appear (if so, what), does Windows / OS X / Linux start up? --h2g2bob 01:12, 6 February 2007 (UTC)

Have you tried taking it to a computer repair shop? If you don't know how to be articulate about it you are probably not going to be able to fix it on your own. --140.247.250.21 17:39, 6 February 2007 (UTC)

MP4

Hi. Does anyone know of a free or open source app which I could use to convert the files from a DVD into MP4 or something that would be compatible with a PSP? Alternatively does anyone know how to do it with Nero or Media Player or something? thanks Mix Lord 01:20, 6 February 2007 (UTC)

This is a good looking guide to using DVD Decrypter and PSP Video 9 to do exactly that. For most other video types, using PSP Video 9 on its own is fairly easy. -- Consumed Crustacean (talk) 01:45, 6 February 2007 (UTC)

Okay thanks. I'll try thatMix Lord 06:44, 6 February 2007 (UTC)

If you use a Mac, you can use MacTheRipper to rip the DVD, remove encryption, etc., and then use Roxio Popcorn 2 to convert it to a PSP-compatible format. MacGuy^{(contact me)} 16:26, 14 February 2007 (UTC)

Adding Harddrive space to a laptop

So I've been looking into buying myself a laptop, and I want the best 15" laptop out there in pretty much every aspect other than graphics. I don't play games or anything, but I have enough music (about 100+ gigs right now and growing quickly) that I'll want a LOT of harddrive space (2 or 300g maybe?). But I also want the computer to be really fast, because I've consistently worn down the speed of every computer I have had through constant use of music, video, and innumerable strange programs. I've noticed that nearly every computer offering that much harddrive space is a) usually larger than 15", and b) that if I do buy, say a 120 gig harddrive laptop, the only drives available cap off at 5400 rpm, which, I take it, isn't as fast as 7200 or higher rpms, available with smaller hardrives. I have seen online, however, internal harddrives for individual sale that can hold 300 gigs and run at ridiculous rpm speeds. The question is whether I could buy one of these drives and an otherwise nice laptop with a small harddrive and then hire a computer guy to put the two together. Would this work? Would overheating be a problem? Physical size of the disk? Are these extra internal drives PC-specific? Will it really work so fast? How would you suggest I solve my conundrum? Thanks a lot, Sashafklein 03:48, 6 February 2007 (UTC)

No, that won't work. I suggest getting a small external HD. --Wooty Woot? contribs 04:02, 6 February 2007 (UTC)

You don't get fast speeds at anything past 150gb. 5200rpm is fine. And you won't find that size in a small HDD for a laptop. --froth^T 05:42, 6 February 2007 (UTC)

RPM is only one factor of the speed of a harddisk. Seek time and latency need to be taken into account aswell, but having said that, maybe we are getting too technical. Assuming the laptop has a S-ATA (Serial ATA) bus check the speed of that bus (S-ATA starts at 150MBps and goes to 300, 600 & 1.2GBps) and the amount of disk cache the harddrive has. The more the better. The speed of the bus only gives you what is known as the burst speed and can only be maintained as long as there is data in the harddrive cache. The harddrive fills this up pre-emptively using complicated algorithms based on what previous data has been asked for.

What ever harddrive you are getting another tip is that if you are only going to be storing large files on it, like music and/or video, rather than "strange programs". you could increase the cluster size. This optimises the seek function of the harddrive, thus making it quicker.

So, the spin speed is not the only thing that matters, although you can get harddrives with a faster speed than 5400rpm for laptops at very large capacities, you should make sure that the drive you buy is physically compatible with the laptop you buy, but do not forget the disk cache size when buying or the cluster size when formatting the drive.

Good luck. Steve Edgington 10:06, 6 February 2007 (UTC)

Thanks everybody. I guess I'll keep looking around. Sashafklein 03:13, 7 February 2007 (UTC)

You could easily get a huge external drive for a fraction of the price it would cost you to get a totally souped up laptop. Surely you don't need all 100GB of music every place all the time? It seems smarter, to me, to get a 500GB external drive in the place where you actually use the music and just cycle what you think you might plausibly ever need at any given time onto the laptop as needed, but what do I know. --24.147.86.187 03:37, 7 February 2007 (UTC)

Indeed. An external hard drive is what you need. --Proficient 08:37, 7 February 2007 (UTC)

No one has pointed out but laptop hard drives are different from normal computer hard drives. Specifically they are smaller (2.5" vs 3.5"). Also laptop hard drives tend to be better designed to withstand the occasional fall etc. You cannot put a normal 3.5" into a laptop. As others have alluded to, drive speed is actually a very complex matter. Take a look at www.storagereview.com to learn how complicated it can be. It depends greatly on your usage patterns which drive is the fastest to you. However generally speaking a same generation 7200RPM 2.5" will be a fair bit faster then a same generation 5400RPM 2.5" 203.109.240.93 14:19, 15 February 2007 (UTC)

NC command

I was browsing the internet and came upon a command in mac os x terminal called nc. I've figured out how to use it (man pages), but what is the practical use? As far as I know, it just sends raw data to computers. Thanks!--Ryan 04:43, 6 February 2007 (UTC)

netcat --Spoon! 04:55, 6 February 2007 (UTC)

Can't change images on my web page

I can't change the images on my web page. I'm using a purchased template and tranferring my own images for the ones shown, following the instructions, but when I refresh the page I get a blank image space, with an icon (round,square & triangle) in one corner. I've emailed the template provider and they've said use photoshop which I already am using. I am being careful to make the photos the correct file size and even flattened them but to no avail. As I am very new to this type of work I am probably doing something really stupid so I hope you can help. Thank you.Sue latham 07:58, 6 February 2007 (UTC)

You either have to change the HTML so it uses the new images, or alternatively make sure your new images have the exact same names (and format) as the ones you want to replace and then simply upload the new images to the same location and overwrite the old ones with the new. I would highly recoment the first option though, getting at least some basic HTML understanding is not that hard and helps a lot. Try reading one of the many, many HTML tutorial's out there. --Sherool (talk) 08:41, 6 February 2007 (UTC)

The icon you describe sounds to me like Photoshop's default icon for PSD images. Are you sure you are saving them in the right file format? Typical web formats are JPEG, GIF, and PNG. Anything else is probably incorrect. --140.247.250.21 17:48, 6 February 2007 (UTC)

It also sounds to me a lot like a web browser's placeholder image icon. --cesarb 19:01, 6 February 2007 (UTC)

Thank you all. I've managed to get the small pics to show but not the larger ones.

Assuming you've correctly uploaded your image to the web, have you checked the path name to it is spelt correctly? If you directly type in the URL of the image into your webbrowser, does it display? If not, you've likely not uploaded it correctly, or it's not in a supported file format _└ ^UkPaolo/_talk^┐ 16:42, 11 February 2007 (UTC)

Bear in mind many webservers are Unix based and case sensitive too 203.109.240.93 14:39, 15 February 2007 (UTC)

PCI express (PCIe)

Having read extensively on this bus and also having included a discussion of it in the hardware courses I have tutored over the last few years I have still not been able to find out the Frequency (Hz) this bus runs at. We are told the Bandwidth, but this is a function of the hertz rating and the amount of conductors involved in the transmission. The EIA/TIA-644 specification says that the total bandwidth is 655Mbps on a single LVDS pair with a 100Ohm load. As the bus is a serial bus one can assume that the hertz rating is therefore 655MHz, but I do not like assumptions and would like to know the actual specific Hertz rating of this bus so that I can demonstrate how the bandwidth is worked out for one or more lanes to my future classes. Thank you Steve Edgington 09:43, 6 February 2007 (UTC)

From our PCI Express article: "At the electrical level, each lane utilizes two unidirectional low voltage differential signaling (LVDS) pairs at 2.5 Gbit/s. Transmit and receive are separate differential pairs, for a total of 4 data wires per lane." --antilived^{T | C | G} 11:27, 7 February 2007 (UTC)

ADSL Data usage Meter

Would you'll be able to provide a link for an accurate data usage meter on the adsl broadband connection that takes only the internet data traffic volume? Some of the freeware I downloaded even takes readings on normal browser and program execution.

If you use Microsoft Windows 2000 (any version) or XP (again any version) try using the 'Network Monitor' tool that is shipped with the Operating System. This tools monitors ALL the traffic on a particular network LAN segment, so all of the traffic coming in through your broadband connection to any of the computers in your local LAN, if you use a router, or just to your PC if you have only a broadband modem.

Here is an example of what it looks like below;

[[]]

Good luck Steve Edgington 18:14, 6 February 2007 (UTC)

Wireshark might do the job, though I could be wrong. Splintercellguy 00:50, 7 February 2007 (UTC)

PUH-LEESSS.... use PNG --antilived^{T | C | G} 11:24, 7 February 2007 (UTC)

X_X yes please --froth^T 22:17, 7 February 2007 (UTC)

Someone might also want to add that to an articel or it'll be Fair Useless. 68.39.174.238 15:32, 10 February 2007 (UTC)

Hypertext as cultural phenomenon

what might be the ramifications of the hypertext on culture? The hypertext transforms a text, which no longer has a set meaning, but how can we look upon a text as a unit when it is led into different directions by "links". There are no authors any more(in the sense that nothing new or amazing can come from an online publication), only writers and users, most of whom do not write very well. What is the future for culture when it is being degraded as it is? Also, does anyone know of any idea of where we are headed with the hypertext? What's next? Thank you for any comments on this you might have, it would be greatly appreciated. Henry Adams

Actually, some of the best journalism and writing I see comes from online sources; and yet I also don't see traditional book sales decreasing. Some writers like Cory Doctorow are embracing this new distribution method of the internet, while out of copyright works can be obtained for free (archive.org, Wikisource, Project Gutenberg etc). What hypertext does do is change non-fiction from a linear story where concepts are explained in turn, into a web of interconnected ideas. What's next - tags, which is really just more of the same. --h2g2bob 13:30, 6 February 2007 (UTC)

Hold on there - I think you are getting a bit carried away.

"The hypertext transforms a text, which no longer has a set meaning" - not really true - a text still has a set meaning - all the hypertext does is make it easier to link to other texts.

compare the above with this

" "The hypertext transforms a text, which no longer has a set meaning" - not really true - a text still has a set meaning - all the hypertext does is make it easier to link to other texts" Here I've hyperlinked several words - so you can click on them to look at what the wikipedia page says about them - the meaning of the sentence hasn't changed.

Quote "..how can we look upon a text as a unit when it is led into different directions by "links" " - my answer would be to simply read it as a unit - the links are optional - you don't have to click. Personally I only click if I think a hyperlink will be useful or interesting.

You seem to be dissapointed with the standard of writing on the internet - this is unaviodable - many people can now publish electronically their thoughts and thesises - it is off course unlikely that all of these will be of the highest quality. But I don't see any reason to believe that nothing good will come from the entire body of electronically published work.

As for the future of hypertext - I think it will stay an integral part of the 'web experience' - I've never had any major qualms about it - I see it as being similar to having many books on my desk at once with the indexed references at the back all at easy reach..87.102.13.26 15:01, 6 February 2007 (UTC)

Thanks for the response... but I think you've proved my point. The note that I started with was mine (as its author, and as a "user") and it has now changed. Anyone can come along now and read the entire thing (including this), instead of just my piece that got this started. To the "new reader", this section is not just a question about hypertexts, but a discussion about them...you have changed my identity, yours, ours, and his/hers... a bad example, but hopefully you get my point. No identity is secure. When you read a page in a book, you are free to establish your own reading, but online, a text can be edited... meaning is not stable. Although I agree that links are optional they are also prompts by which to contaminate the readers reading. Any thoughts? Henry Adams

Surely it's clear to the reader and to you that this is a place for questions and answers - I fail to see how responding to you proves a point - you confused me there with your reasoning - I assumed it was an open question and that an answer would be expected..

As far as I can see your identity is secure - this page is like a transcript of a conversation - my comments are labelled separately from yours - I think it is plainly clear what you have written, and what has been written by me.

I find hyperlinks useful in finding information and as an educational aid. I agree that I wouldn't want to see hyperlinks in the middle of a novel or poetry etc, or indeed in the middle of a quotation. In this respect I think we agree. I also hope that common sense would prevent most english speaking people from doing so.

So to summarise: in a an educational text, or an encyclopaedia I wholeheartedly support 'hypertext', in a technical document they may be useful, in other contexts I would not approve of their use.87.102.13.26 15:36, 6 February 2007 (UTC)

(By the way if you publish work on the internet it cannot be changed - unless you specifically allow it. Wikipedia is different in that it is a collective effort - though to alter someones comments on a talk page or here is considered vandalism ie wrong to do.)87.102.13.26 16:03, 6 February 2007 (UTC)

• Hypertext only transforms a text in the sense that it puts it into dialogue with other texts. In other words, hypertext is not something which alters the text itself but rather is a system to organize texts. I think there are definitely going to be cultural ramifications for thinking about information in this way — as always being embedded within a larger mesh of information — though this is primarily a technical change. From a philosophical point of view information is always embedded in a larger world of information — language itself necessarily and constantly involves reference to a world of meaning outside the text itself. Would a rose hyperlinked to any other flower smell so sweet? --140.247.250.21 17:44, 6 February 2007 (UTC)

• Stability and authorship are different questions. They are not necessarily linked to anything with hypertext. Perhaps here you are confusing hypertext with things like wikis, which allow easy multiple and simultaneous authorship. (Multiple and simultaneous authorship did not begin with the invention of a wiki, nor did a lack of stability of text, but it has made it significantly easier and allowed a far greater number of participants than any other mode of mass communication, so I'd say that is an important change.) --140.247.250.21 17:45, 6 February 2007 (UTC)

The question is rather invalid because it contains a lot of logical fallacies.

Weigand Output/Interface

I am looking for information or history of the Weigand output/interface used in RFID or barcode security readers. I did not find any information on wikipedia, and several various web searches just gave me vendors. Any information would be appreciated. Jaegendar 13:48, 6 February 2007 (UTC)

Source code website

Hi, Does anyone here know any website that provides source codes of its softwares. Thanks. Sara

Wikipedia (which runs on the MediaWiki software) is a good start, since you're here. It's free software, and it's used at a lot of other sites besides Wikipedia. --대조 | Talk 14:15, 6 February 2007 (UTC)

I am looking for the code of a specific software for my project, and I downloaded many softwares(commercial ones) for this purpose, but unfortunetely they are not coming with their source codes files. So Taejo are you telling me that I can find what I want on wikipedia?. Sara

What exactly are you looking for? If you're trying to find the source code for commercial closed-source software, you're out of luck. SourceForge is home to a lot of Free software projects that you can glean code from (assuming you can accept the terms of their license; mostly the GNU GPL or a BSD license). -- mattb @ 2007-02-06T15:13Z

You can pretty much find open source libraries for anything (especially on source-forge). If you give us more specifics (what exactly you need, what OS and what language), we can probably give you more help. Oskar 15:35, 6 February 2007 (UTC)

A tip: don't assume that people will have read your previous questions. Just to clarify: what I meant is that the source code for Wikipedia is a available. I read your question as you wanting to find the source code for some (any) website. --User:Taejo|대조 11:39, 8 February 2007 (UTC)

sourceforge didnt help me much, for more details you can check my first post [1]. Sara

I can tell you with almost certainty that this is impossible to do with pure java. Java is not designed to do that kinda stuff, it's designed to be portable and secure. At one point or another, compiled code must be invoked. I suppose you could do it with something like NativeCall that unloads the keyboard and mouse drivers. However, I wouldn't recommend it, this sounds like a very bad idea from the start. Oskar 22:24, 6 February 2007 (UTC)

Mounted disk icon on Ubuntu desktop

I'm dual-booting my system with Ubuntu and Windows. I have my windows partition mounted (using ntfs-3g) on my Linux system in case I need a file or something from it. It's not something I do often, but it is a nice convenience. However, now my otherwise clean desktop has this ugly icon on it that says "windows" under a small picture of a disk. It goes away if I umount it obviously, but I'd rather have it mounted and not have to look at that damn thing all the time. Can anyone help me? Oskar 15:33, 6 February 2007 (UTC)

Have a look at http://ubuntuguide.org/. I have 6.06 (http://ubuntuguide.org/wiki/Ubuntu_dapper), and I used that to mount my NTFS. Then you can create a link to it from anywhere. I hopde that helps. - Akamad 19:58, 6 February 2007 (UTC)

I don't think that's what (s)he wants. This should help if you want to eliminate the disk icons altogether. --antilived^{T | C | G} 11:17, 7 February 2007 (UTC)

OskarS sounds like a she-name? Dude... Anyway, thanks, that worked! Oskar 17:40, 7 February 2007 (UTC)

Yes and I am a little girl in some sort of twisted online fantasy game :p. You just never know... --antilived^{T | C | G} 23:37, 7 February 2007 (UTC)

One Huge pc power supply

Ok, so say your a pc enthusiast and you have a garage with, lets say 8 computers in it. would it be more effective to use one power supply in terms of efficancy?

Also, could we expect to see houses with built in +12V, +5V ect power rails to make homes more efficant?

I guess the transformer could always double up as centeral heating too :)

BenHowes 17:04, 6 February 2007 (UTC)

The main problem with distributing extra low voltage is that the power loss due to resistive heating of the wire is proportional to the square of the current. Higher voltages need less current to deliver the same amount of power. It's for that reason that high voltage is used for long distance electrical power distribution. So, distributing +12V, +5V, and other common power supply voltages, would be less efficient, not more.

You would have a related problem with your "common power supply" solution: as the distance to the power supply gets longer, the voltage drop gets higher, which could make the voltages fall outside of the specified range.

That said, it's common to have telecommunication equipment which runs on -48V DC, and there are proposals to use 380V DC in data centers[2]. In both cases, the computers still have their own power supplies; the difference is that, instead of the AC->DC->AC->DC conversion done by computer power supplies (see switched-mode power supply for the why of all these conversions), they only have to do an DC->AC->DC conversion. Since by using DC their UPS do not have to convert their output to AC (data centers usually have dual conversion UPS), at least two conversions are avoided, making it more efficient.

--cesarb 18:51, 6 February 2007 (UTC)

Thanks very much for that! I hadent thought about the voltage drop issues. theres always super conductors, but i doubt that there is any chance of saving money after installing coldheads all over the house to cool the liquid helium used in ceramic supercinductors :P BenHowes 19:25, 6 February 2007 (UTC)

Another problem is the evolution of power supply voltages. It used to be that there was only +5 and ±12. But ATX style power supplies now also have +3.3. (See page 37 of this pdf.) What will it be in 5 years? Probably something different. —EncMstr 03:31, 7 February 2007 (UTC)

The actual loads are already operating down at 1.8 and 1.2 volts. As someone above said, there's some benefit to distributing high-voltage DC, but there's nothing to be gained by distributing today's low voltages (in the hopes that they'll still be useful tomorrow). By the way, did you realize that many ordinary computer power supplies already will operate just as happily from high-voltage DC as they do from line-voltage AC? (But don't try it on my say-so!)

Atlant 13:29, 7 February 2007 (UTC)

However AFAIK most modern computers (as in A64s etc) now get a significant amount of the power from the 12V line (which the mobo and/or graphics card downconverts). Hence the 12V is becoming increasingly important compared to the 3.3V and 5V. (For example the 4 pin ATX+12V is starting to become compulsary and there is also the new 8 pin variant). Google in fact is trying to get computers to move to +12V only ([3])203.109.240.93 14:47, 15 February 2007 (UTC)

AFAIK, it's the 4 pin 12V plug which is the newer variant. The 8 pin 12V plug comes from EPS12V; the ATX version is half of it. There's also the 6-pin 12V "PCI Express" plug, which I don't know if comes from PCI Express or EPS12V. --cesarb 15:22, 15 February 2007 (UTC)

Any info about "exosort" sorting algorithm?

I just discovered a company -- FAC Systems, run by Farid A. Chouery -- that's selling an implementation of a sorting algorithm known as "exosort". They seem to claim it offers significant time savings over quicksort in practical sorting problems, although they don't appear to claim that it performs better in asymptotic analysis. Anyway, Google and friends don't really seem to know anything about the algorithm, and I'm curious if anyone has any more information about this "exosort". Is it in fact a new algorithm? Is it described anywhere, or is it basically a trade secret? Are there any independent tests of its performance? --Ryguasu 17:05, 6 February 2007 (UTC)

First off all, it cannot have a better analysis than optimized quicksort, because optimized quicksort (unlike the regular kind) is computationally optimal for the problem of exchange-sorting. You can get better results using non-exchange sorts, like Radix sort, but that only works on limited kinds of data (most often numbers). Second, I doubt that this tiny company has outsmarted a whole world of academiacs that have long considered quicksort one of the best sorts there is for general data. Google shows all of three results. I call bullshit.

If they do have some sort of algorithm, it is most likely a slightly modified variant of another sort. The 60% (if it is even true) might come from a comparison using regular, un-modified quicksorts worst case (quicksort has a horrible worst case of O(n^2)) with their algorithm. I wouldn't believe them for a second. Oskar 21:59, 6 February 2007 (UTC)

I wouldn't say it's impossible. Quicksort is O(n log n); if their supposed algorithm is 60% faster, it would still be O(n log n) (it's just a multiplicative constant). That could be done, for instance, by somehow optimizing for cache behaviour (which can make quite a difference on modern computers); in fact, optimizing for cache behaviour is the only way I can see they could beat quicksort on the average. However, even if it's possible, I agree with you that it's very unlikely. Instead of something unproven like that, I would prefer to use an optimized version of the introsort algorithm (which retains quicksort's average speed but avoids its worst-case behaviour). --cesarb 03:03, 7 February 2007 (UTC)

It is possible to get decent linear speedups from sorting algorithms by careful consideration of cache issues for the specific sort of data concerned. I remember seeing a paper on this topic at a conference a couple of years ago. --Robert Merkel 03:24, 9 February 2007 (UTC)

Unlock Code For Samsung A707

hi, I've got a Samsung A-707 handset but a'm unable to find a permanent network unlcok code for it. Can you please help me out and send me one on my email address - <email removed> Thank You very much.

Poetry software

Does any software exist specifically for the purpose of composing verse. I was thinking of something along the lines of a word processor, but able to compute meter, rhyme, etc. Has anyone ever heard of such a thing? Thanks! Bhumiya (said/done) 21:11, 6 February 2007 (UTC)

Microsoft Word? --Proficient 08:38, 7 February 2007 (UTC)

Microsoft has hidden depths! Where is the "compute meter" command? I think the OP's best option is to find a rhyming dictionary. Don't know about a meter-computing tool (at least for English) --대조 | Talk 11:26, 8 February 2007 (UTC)

Well, rhyme was actually the least of my concerns, since so many rhyming dictionaries exist already, and rhyme isn't strictly necessary in poetry anyway. It occurred to me that a lot of poetic devices could be turned into computer functions, possibly within the framework of a word processor, or possibly as a stand-alone program. But I suppose its appeal would be very limited. Bhumiya (said/done) 03:15, 9 February 2007 (UTC)

Here's a book about computer-assisted poetry-writing: [4]. The author has a page with some software from the book here: [5]. Post back with some poesy you create! :) --TotoBaggins 19:53, 12 February 2007 (UTC)

Headphone socket on external DVD drive

I bought a new external dvd drive to sit on my desk as my box is behind the desk. I noticed today that in the back there is a headphone jack. I'd like to use this to listen to my headphones as an audio out but haven't been able to figure out the procedure. I've tried a few things including playing with the digital out under the drive's properties (Win XP), but I'm still coming up short. Any suggestions? —The preceding unsigned comment was added by 71.199.159.98 (talk • contribs).

Ah! A true engineer! When all else fails, read the instructions! --Zeizmic 02:59, 7 February 2007 (UTC)

Noticed the little button next to the eject button? Put a CD in and press that and you should have music... although the jack should be on the front not back. Normally it completely bypasses the computer, and as long as you got power, it will act like any other CD player. --antilived^{T | C | G} 11:11, 7 February 2007 (UTC)