Wikipedia:Reference desk/Archives/Computing/2007 April 14

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April 14[edit]

Business Network Layout[edit]

How is the network layed out in a school or business? Whats in the runways and what sort of switches or Hubs do they use. Where does their internet come from? That sort of thing. What type of servers are required? or are none required?Iownatv 00:52, 14 April 2007 (UTC)

Which school and which business? Every one is different - depending on what they wanted to purchase and how they felt like putting it together. --Kainaw (talk) 01:03, 14 April 2007 (UTC)

Convert VCDs into iPod format[edit]

Hi I have a massive collection of VCDs, is there any free way to convert them into iPod format so I can put it into my iPod? —The preceding unsigned comment was added by (talk) 01:45, 14 April 2007 (UTC).

VCDs store video in MPEG1 format. It's easy to extract a VCD into an MPEG file with free utilities (Isobuster is one) and all you need then is something able to convert these into an iPod friendly format Nil Einne 18:34, 14 April 2007 (UTC)

Look on this website this has a converter for almost anything i've ever tried to use and it's free so just look into it. i use it for the .3g2 format on my cellphone i'm sure iPod is on here 21:58, 16 April 2007 (UTC) Ag for MemTech
The standard iPod Video format is MP4, so I'd be surprised if a converter that handles most major filetypes wouldn't handle that. If you want to save space, set the resolution to 320x240 (I believe) or else you're keeping resolution your iPod screen won't show (of course if you plan to plug your iPod into a TV screen or something, ignore that advice). Confusing Manifestation 06:57, 18 April 2007 (UTC)

intelligent batch process of mp3 files[edit]

There are some routinely-downloaded podcasts for our organization that are useful, but is there a way to "batch-process" them so that the "introductory theme music" and the "closing credits" can be deleted from all the podcasts in our archive? They are extremely annoying when listening to multiple episodes of a particular podcast in one sitting. Also nice would be the ability to cut out portions at arbitrary time points, where "bumper music" usually occurs.

What tools and scripts allow for "batch processing" so the mp3 files do not have to be opened one at a time, by hand. Please include anything you know of, python, java, audacity, whatever. Thanks. NoClutter 04:28, 14 April 2007 (UTC)

( may help...ny156uk 09:05, 14 April 2007 (UTC)
The link ny156uk has given you points to a shareware program that does batch-mp3 edits, which has quite a few interesting functions, but, I *think* ultimately when batch-processing your mp3s you will have to enter in the times you want cut for each mp3 - is that what you were after? Unfortunately, as computer savvy as I am, I've never delved into podcasts and don't know what you're talking about. Even if you did want to batch-process mp3s, how would it determine when an 'introduction' ends and when the 'credits' begin - especially if it differs from mp3 to mp3 - by implication you'd have to specify this for each mp3 and say "Cut". Just in case you're interested, I know of one freeware program called "mp3directcut" (one word I think) - which will load in your mp3, and allow you to 'select' exactly what you want cut - do a search for that if you like. Good luckRfwoolf 02:35, 15 April 2007 (UTC)

I've used Sonic Foundry Batch Converter before to cut out a lot of intros from Anime episodes to put them all together without intros onto a sure this can help somehow xD 22:00, 16 April 2007 (UTC) Ag for MemTech

Want to find Hide Files[edit]

I used on software(Hide Files) to hide my personal files it is normaly open by pressing Ctrl+Alt+H. But I choose one option in that software i dont no exactly.... and it was not opened normaly by pressing Ctrl+Alt+Del. And also I cannot find that files.... Any one can Help me because all my files are in that folder which i collected for long time(3 years).... —The preceding unsigned comment was added by (talk) 04:41, 14 April 2007 (UTC).

Are you using Windows? If so, open the folder where you put the hidden files, then click Tools → Folder Options then click the tab that says View and in the section called Advanced settings:, under Files and Folders → Hidden files and folders there is a radio button and you want to click the one that says "Show hidden files and folders". − Twas Now ( talkcontribse-mail ) 23:31, 14 April 2007 (UTC)
They won't show up if he is running Hide Files — the program doesn't just hide them by flagging them as hidden, it runs at some sort of API level and won't let them in.
If you list processes (Ctrl+Alt+Del) you should be able to find Hide Files there but under an abbreviated name, like HF or something like that. If not, start up in safe mode, remove it from the startup section of the registry. -- 12:45, 15 April 2007 (UTC)

video/computer game[edit]

Hi, I don't know if this is the right ref. desk, but hopefully it is. On the Gamecube version of "the sims 2 pets", i can't seem to have kids. is it possible on this specific game? if so, how- thanks much!

You should ask on the entertainment ref desk. Just kidding. I saw you referred here from the misc desk already. You mean human kids or kittens/puppies, btw? --Wirbelwindヴィルヴェルヴィント (talk) 06:02, 14 April 2007 (UTC)

sorry i forgot to mention which kind- human kids.

Did a search for it, but unfortunately people say no, you can get abducted by aliens but not have alien babies, because the Sims in the Gamecube version of Sims 2 Pets cannot get pregnant. --Wirbelwindヴィルヴェルヴィント (talk) 18:36, 14 April 2007 (UTC)

Oh, ok. thanks for searching for it!

RedDot Web Content Management System[edit]

RedDot's Official Website What is the purpose of RedDot? And what are the vulnerabilities of using RedDot? --Shines8 04:50, 14 April 2007 (UTC)

This code fragment confuses me.[edit]

open("/", 0); // 0 == O_RDONLY
execl(shell, shell, runc, (char *)0);

Can someone explain in a little more detail? (see for context). —The preceding unsigned comment was added by (talk) 05:07, 14 April 2007 (UTC).

Those are all system calls. See open(), dup(), and execl(). If you have more questions, feel free to ask. --Wirbelwindヴィルヴェルヴィント (talk) 06:01, 14 April 2007 (UTC)
I know they're system calls. I want to know what the fragment does. 06:21, 14 April 2007 (UTC)

It confused me too: V7 UNIX is a lot older than //-style comments. Turns out the comment was added by the person who posted it here.

I thought I'd mention that, by the way, in case people didn't know what O_RDONLY translated as. 06:21, 14 April 2007 (UTC)

First, runc[] is initialized to the filename "/etc/rc", which is the script that runs when the system starts up. This function's job is to run that script. execl() causes the current process to be replaced by a new one, with the same file descriptors open. (This is the normal way that any process gets started: the parent process first forks itself with fork(), then one copy sets up the file descriptors and uses execl() to mutate into the thing that needs to be run.) In this case that process is a shell whose argument is "/etc/rc", so it will run that script.

I know this. Why is it "/bin/sh /bin/sh /etc/rc" instead of "/bin/sh /etc/rc"? 06:21, 14 April 2007 (UTC)
That's how execl() works. The first argument is where the program to execute is, the second one is where you tell it it was (i.e. what goes in argv[0]). You're allowed to lie to it. --Anon, April 14, 07:44 (UTC).
Oh! Okay. Thank you very much! :) 08:59, 14 April 2007 (UTC)

The other lines are there to make sure that when this shell starts running, it has the usual three file descriptors open -- standard input (fd 0), standard output (fd 1), and standard error (fd 2). But /etc/rc isn't actually supposed to read anything from stdin, or produce any meaningful output that would go to stdout or stderr. Consequently it doesn't really matter what file the file descriptors point at. So the file that gets opened is "/", the root directory -- the one file that we can be absolutely certain must exist. A directory on traditional UNIX is just a file and can be opened as an ordinary file (you can read the bytes, although you can't write them), and that's what's happening here. Now, because this is the very first file opened after the system came up, it must be file descriptor 0. The two calls to dup(0) now copy file descriptor 0 onto the next two available file descriptors, 1 and 2. So now all three are open, and there we are.

Great, thanks! I was a bit confused as to why we'd need to open / for, that explains it. 06:21, 14 April 2007 (UTC)

At least, that's my interpretation of the purpose. I'm not 100% sure why it was felt more desirable to have stdout open to an unwritable file than to have it closed; perhaps it affects the way things would fail if there was an attempt to write to it.

--Anonymous, April 14, 2007, 06:16 (UTC).

Right. It's important to have 0, 1, and 2 open so that if/when a later (i.e. child) process opens its own files, they end up on fd's 3 and above. Really strange things can happen if they're not, though I can't quite remember the details. (With that said, it's also odd if fd's 1 and 2 aren't writable, though so few processes check the return values of e.g. printf and fprintf that this is rarely that much of a problem. The somewhat more usual thing to do is to arrange that fd's 0, 1, and 2 are open on /dev/null, though this does indeed assume that /dev and /dev/null both exist. But typically, by the time a real end-user process is open, the three canonical fd's have been opened on something else, either /dev/tty or /dev/null.) — 07:07, 14 April 2007 (UTC)
[P.S. Though in V7 Unix you could and had to open and read from directories, in some more modern Unices reading from a directory ist verboten and yields an error; you're compelled to use the more abstract getdents or readdir to read from directories.]

Gigabit Ethernet Networks[edit]

What are the disadvantages and advantages of a gigabit ethernet network? —The preceding unsigned comment was added by (talk) 11:52, 14 April 2007 (UTC).

Now that sounds to me suspiciously like a homework question, and it does clearly say at the top of this page, Do your own homework. Look at the wikipedia entries for ethernet and gigabit ethernet and come back here if you have a specific question about any of the information there. Johnnykimble 12:05, 14 April 2007 (UTC)
One should probably assume good faith! Though you're probably right, so I'll just start him off. Advantage = fast. Disadvantage = very expensive. JoshHolloway 12:54, 14 April 2007 (UTC)
Hmm, yes. See the question I asked recently on the guideline page. Johnnykimble 13:04, 14 April 2007 (UTC)
Compared to what? —The preceding unsigned comment was added by (talk) 21:52, 14 April 2007 (UTC).

MIDI Wavetable Synth Question[edit]

I wonder if anyone could shed some light on this:

Whenever I open my favorite Midi program, I get a choice of MIDI Devices (Wavetable Synths) to use: The ever-present Microsoft GS Wavetable SW Synth and another one that probably came with the sound card which someone else installed, SoundMax Wavetable Synth. Using SoundMax I get better-sounding Instruments than using Microsoft. The question is: Can I install new Midi Devices so that in the end I can get a Midi Device with even-better-sounding instruments to appear in that Midi program (without installing any new Hardware, that is)?

I'd appreciate any feedback, since the Wikipedia articles on that particular subject are a bit vague...

Thanks, Danielsavoiu 12:03, 14 April 2007 (UTC)

There used to be commercial soft synths that would install as midi devices however these are now largely dead. You may still be able to purchase Yamaha's SYXG50 but you should not expect any more support as they've abandoned it. Most soft synths now AFAIK are either DX plugins, VST plugins or stand alone utilities. As far as I'm aware VST plugins and DX plugins can only be used in utilities like Cakewalk that support them. I don't know if there is any free utility that enables you to use DX or VST plugins to play midi files. However most of these plugins are not free in any case, they are designed for professionals in general. But two free standalone utilities you might want to try are Synthfont and Timidity [1].
You will need some sort of instrument samples for both of these as I'm prety sure they don't come with any. Soundfonts are the most common source for these. You would want a GM soundfont. There are many of these available. If you have 2gb or RAM or more, you might want to try the Crisis GM 3.0[2]. This is a 1.5gb soundfont. While size does not equal quality it's quite a decent SF IMHO (but I've never been an expert at music and am probably tone deaf). Technically you probably don't need 2gb of RAM as it's extremely unlikely a MIDI will use all instruments but I'm not sure if the programs I recommend can load on demand. There is also a smaller and older 300mb or so Crisis GM. And many other GM soundfonts are available, generally they are smaller. Creative/EMU has 2, 4 and 8mb GM SFs which are resonable quality which are probably fairly easily available albeit almost definitely illegally. Of course, personal preference comes into this a lot, and you may prefer some instruments in one soundfont and some in another which you can do. Cheers and enjoy your music
Nil Einne 18:28, 14 April 2007 (UTC)
I didnt really read the previous answers because this reminded me how much i should play Final Fantasy VII again on my computer (even though i have it on PS xD) but answer your can...i remembered Final Fantasy VII because it came with a nice midi synthesizer which was Yamaha something (maybe the one listed in the first answer because now i did read the answers jaja), from what i remember it was free search for that one it should give you excellent sound. 22:05, 16 April 2007 (UTC) Ag for MemTech

How do I get a dark background in Firefox ?[edit]

When viewing and editing Wikipedia on Firefox, I would much prefer light colored text on a dark background. Inverting the current colors would be ideal. How do I do this ? StuRat 15:07, 14 April 2007 (UTC)

You could take a look at User Style. You'll need experience of CSS if you go down that route though. I'm sure there must be an easier way than rewriting the standard CSS files though. Johnnykimble 15:38, 14 April 2007 (UTC)
The following perl one-liner takes the default wikipedia main.css and prints it out to new.css but with all the hex colours inverted:

perl -wple 's/#([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})/"rgb(".abs(hex($1)-255).",".abs(hex($2)-255).",".abs(hex($3)-255).")"/ie' <main.css > new.css

You could then run perl -wple 'if (/white/i) { s/white/black/i } else { s/black/white/i }' <new.css >final.css and copy the contents of final.css into your Special:Mypage/monobook.css page. However, as you can see, this doesn't really have the intended effect, as the main body of the articles are still in their original colours. I'll watch this with interest to see if anyone comes back with a full solution... Johnnykimble 17:21, 14 April 2007 (UTC)
Wow, I had no idea it was so complicated. Perhaps instead of focusing on Wikipedia colors I should instead look at inverting colors on Firefox or on the entire (Windows 98) PC. Any thoughts there ? I tried using Settings + Control Page + Display + Settings + Advanced Button + ATI Color, and this will let me adjust the amount of red, green and blue using a histogram. Unfortunately, these adjustments don't appear to allow inverting the colors (the histogram just won't move that way). StuRat 21:07, 14 April 2007 (UTC)
Get Opera (link). You can then View -> Style -> High Contrast (W/B)! JoshHolloway 21:25, 14 April 2007 (UTC)
One problem, that makes all text black, so I can't distinguish between broken links and active links. StuRat 21:04, 15 April 2007 (UTC)
Thanks, that works well for viewing Wikipedia, but the edit panels are still black on white. Any ideas on how to fix that ? StuRat 21:38, 14 April 2007 (UTC)
You just use textarea {background-color: black; color: white;} in your own monobook.css file. --Kjoonlee 22:40, 14 April 2007 (UTC)
I added that line, but nothing happened. Do I need to log out and back in or something ? StuRat 00:42, 15 April 2007 (UTC)
Wikipedia:Bypass your cache :) --Kjoonlee 03:52, 15 April 2007 (UTC)
If you want to use the same colours on all pages in Firefox, then you can use the same code in your userContent.css --Kjoonlee 22:43, 14 April 2007 (UTC)
Also, you could use div#bodyContent {background-color: black; color: white;} and so on in Firefox or monobook.css. If you want to extend this to other elements, you can use Firefox's Web Developer add-on to find out which elements to mention. Press control-shift-F and click on an element to get its details. --Kjoonlee 22:49, 14 April 2007 (UTC)

Good font viewer for Windows[edit]

Hi, I'm looking for a good font viewer for Windows. Here are my requirements:

  • Must not mess with my system when installing/uninstalling
  • Must have ability to view identical text in multiple fonts
    • Must be possible to change the text
    • Must support automatic ligatures (ffi to ffi, for example, for fonts that support the feature)
  • Must be free of cost

Your kind help would be much appreciated. :) Thank you. --Kjoonlee 15:09, 14 April 2007 (UTC)

I never did have too much luck with looking for this - but you can try - and then when you do a search, look at the top of your search results and click "Freeware" which will filter your results to only show freeware (after 3-4 sponsored results). As a graphic designer I wanted it to show a list of my fonts, with a changable 'sample text', but I wanted it to show the samples without my having to click on each font - with most apps you need to click on the font name to preview the font. Good luck Rfwoolf 02:25, 15 April 2007 (UTC)
X-fonter is one that I use. I use v4.5 which is a free version, v6.2, the latest, seems to be a trial version. I don't know about ligatures though. ( =Nichalp «Talk»= 06:17, 15 April 2007 (UTC)

TV card & freeview coverage[edit]

Hi, I'm considering getting a digital tv card for my pc but on checking the freeview site I see that my area isn't covered by freeview, & probably won't be till 2011. I take it that I won't be able to get any reception using the tv card but can anyone confirm this &, hopefully, suggest a way around this. Thanks. AllanHainey 15:31, 14 April 2007 (UTC)

Do you know anyone in close proximity to your location with Freeview? The online postcode checker isn't always accurate. For example, my street is apparently unable to receive Freeview according to the site, but in actual fact I can receive a fair number of channels. I think if I bought a better aerial I could receive them all. Your best bet is to borrow a Freeview box and try it out. Johnnykimble 17:28, 14 April 2007 (UTC)
Yes, that's probably best. Don't purchase without checking first, as you can't send it back as a "fault" when they've told you it might not work. JoshHolloway 21:22, 14 April 2007 (UTC)
I can't really borrow a freeview box as I don't have a tv and noone I know here has freeview, only sky. I'll try asking about but if it is the case that I can't get freeview is there anyway to get around it, like getting tv through the internet or using a stronger aeriel? AllanHainey 09:19, 15 April 2007 (UTC)

Artificial intelligence & Problem Solving Software[edit]

I Nead The Name Of Problem Solving Software . " Problem Solving is The Type of Artificial intelligence "

History of this software . Pricing . and advantige and Disadvantage. —The preceding unsigned comment was added by (talk) 18:33, 14 April 2007 (UTC).

This _really_ sounds like homework, and you're supposed to do homework on your own.-- 19:49, 14 April 2007 (UTC)
Verrryy good idea to give us details. Splintercellguy 20:04, 14 April 2007 (UTC)

Please This is not homework . I search too much in the internet . but problem solving software is Unlimited , Wide ? please give me one name Of problem solving software ? and i continue the other Topic

Request for clarification:
Please explain what you mean by 'problem solving software'. For example do you mean mathematics problems? There exists software that solves mathematic formulas and calculus for you. Of course there are various software applications that solve various other 'problems' like converting "wav" files to "mp3" files, or encrypting information. Just what do you mean by "problem solving software"? Rfwoolf 09:45, 15 April 2007 (UTC)
Perhaps your are talking about expert systems? Or maybe complexity classification, i.e. P, NP and NP-complete? Johnnykimble 10:34, 15 April 2007 (UTC)


Is there a way (in bash) to have netcat reopen every time someone diconnects? Thanks!-- 19:45, 14 April 2007 (UTC)

The below would work.
while true; do
     netcat -v -l -p 12345
     echo "Connection closed; listening again"
--TotoBaggins 23:09, 14 April 2007 (UTC)
Interestingly, someone else asked the exact same question last month; you might want to review that thread.
TotoBaggins's solution, though the obvious one, has a subtle problem. Safer is
while netcat -v -l -p 12345; do
     echo "Connection closed; listening again"
I'm surprised netcat -l doesn't reopen the connection automatically; it's clearly a frequent need. It ought to at least be a built-in option. Perhaps I'll find netcat's author and contribute this. —Steve Summit (talk) 14:34, 15 April 2007 (UTC)
I don't think that's what netcat is designed for. It is slightly cleaner to abstract some arbitrary functionality out elsewhere. —The preceding unsigned comment was added by (talk) 22:53, 15 April 2007 (UTC).

THese work great, but could someone explain the syntax? I want to be able to do this stuff on my own. And also, how do you get out of the loop?-- 15:40, 15 April 2007 (UTC)

Second question first: you get out by hitting control-C (and the potential difficulty of doing so is the "subtle problem" with the first loop).
First question: The Unix shells (including /bin/sh and its descendant bash) are more than just command line languages or script interpreters -- they are full-fledged programming languages. That is, besides simple 1-2-3 scripts like
you can also do things like
if command4
then    command5
else    command6
while command4
do      command7
In these cases, the "if" branch is taken or the loop is executed as long as command4 returns a successful exit status. In principle, command4 can be any command you want, although most of the time, in practice, it's a special-purpose command used mostly for testing conditions, such as test, or the degenerate do-nothing-but-always-succeed command /bin/true.
In the control-flow syntax used by sh, those words if, then, else, fi, while, do, and done are keywords, and must appear in their correct positions. There is also a mandatory newline, or equivalently a semicolon, after command4. So you will often see these rendered as
if command4; then
while command4; do
Steve Summit (talk) 16:33, 15 April 2007 (UTC)