Wikipedia:Reference desk/Archives/Computing/2006 December 3

From Wikipedia, the free encyclopedia

Computing desk
< December 2 << Nov | December | Jan >> December 4 >
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.


Contents


[edit] December 3

[edit] Freeware Audio Recording

I am looking for a freeware program that can record music playing in another program on the computer. I don't mean I want a program that records from a microphone. I am hoping there's a program out there that would record music playing in another program even if my computer was on mute. I plan to record, for instance, live concert songs from youtube or music blogs - stuff I couldn't buy anywhere but would like to have in my music library. Any suggestions? Thanks a lot, 71.252.11.5 02:59, 3 December 2006 (UTC)

Yep, try Audacity --frothT C 03:03, 3 December 2006 (UTC)

Oh. I (same person signed in now) just downloaded this. I can't figure out how to do that function, so I figured it wasn't included. What's that function called? How do i get it to work? Thanks a lot. Don't take forever on this. If i know what it's called i can just look it up in the help file. 71.252.11.5 03:20, 3 December 2006 (UTC)

Find a drop down box next to the volume sliders. Is there a Stereo Mix in it? Select that. --Russoc4 04:18, 3 December 2006 (UTC)
Hit the big red record button :) You might want to turn off the mic input for better quality --frothT C 04:57, 3 December 2006 (UTC)

There isn't. The drop box next to the volume and mic sliders (on the same line) has Wave/MP3, Line In, CD Audio, Microphone, Auxiliary, and TAD in. There are two other drop boxes, which i don't think you're refering to, one next to a sound icon and the other next to a mic icon. They both have this drop-down list: Horizontal Stereo (I can't select this - it's gray), Vertical Stereo, linear, dB (can't select), Monitor Input, Disable. ThanksSashafklein 05:03, 3 December 2006 (UTC)

Wait. I think I figured it out. Wave/MP3 seems to work. That's so cool. Now I can get all those live Tom Waits songs/ramblings :) Sashafklein 05:07, 3 December 2006 (UTC)

One more thing. This shouldn't record a bad quality song, should it? Sashafklein 05:08, 3 December 2006 (UTC)

What do you mean by "shouldn't"? Do you want to know if it's recommended? No, I don't recommend it. Can it record anything though? Yes it can. If you can find an original mp3, that would be the best way to go. I doubt I'm supposed to do this, but maybe this link will help. --Russoc4 05:36, 3 December 2006 (UTC)

Thanks. I've got another question. this seems to work on my pc but not on my laptop. On the laptop, the dragdown menu wont even give me the option of choosing wave/mp3, only mic or line in. Am i doing something wrong? Is there any way I can fix this, or am I doomed to have to record on only one computer? 71.252.11.5 06:22, 3 December 2006 (UTC)

Not sure. But I'd advise against re-recording content. Although it's possible, it won't be at nearly the same quality due to compression artifacs. Same with using modified directdraw/mp4 drivers. For non-DRMed content the best bet is to extract the audio stream with audacity (not sure if it's possible but it should be) or virtualdub. You may need to use this tool to download the flv if it's youtube and mencoder to convert it. You can either specify the audio as uncompressed (wav) in mencoder and then use virtualdub to compress it (mp3) when you rip the audio stream, or specify the audio as compressed (mp3) in mencoder and then use virtualdub to directly rip it ("direct stream copy"). Both ffmpeg (mencoder) and virtualdub use mp3lame so it's the same I guess. --frothT C 17:36, 3 December 2006 (UTC)

Yeah. The quality does seem low. Is there anything I should do to change this? Does higher or lower Hz mean anything in terms of quality? Higher or lower "bit float"? How about Sinc interpolation? And I want the most narrowband, right? Any other settings I should change for best recording quality? Sashafklein 19:57, 3 December 2006 (UTC)

Download the songs from the websites using a download tool, like unplug, keepvid, etc. Then use the latest vlc or ffmpeg to extract just the audio with 100% quality. Note: before you do this, please make sure you have permission from the copyright holder (eg, a creative commons license). --h2g2bob 01:24, 6 December 2006 (UTC)

That sounds so useful. You just made my day. Thanks so much. Sashafklein 04:13, 6 December 2006 (UTC)

[edit] parallel processing

What processor chips are desinged exclusively to be wired together to form a parallel computer using minimum additional chips? 71.100.6.152 04:27, 3 December 2006 (UTC)

Dual core processors? Intel core duo, etc. --Wooty Woot? contribs 08:55, 3 December 2006 (UTC)
I think he's trying to come up with something more scalable than just 2 --frothT C 18:34, 3 December 2006 (UTC)
Those processors can generally be used in far larger clusters than 2 CPUs. The most powerful (publicly known about) supercomputers are #1. an IBM Blue Gene system, which uses 131,000 PowerPC 440 processors (which each have comms, cache, memory controller etc built in - they are designed for system-on-a-chip, not exclusively for parallelisation) and #2 is a Cray Red Storm system using 26,544 AMD Opteron dual core processors. -- AJR | Talk 01:53, 4 December 2006 (UTC)

[edit] 3D Molecules

Are there any good free programs (Windows or Linux) for drawing molecules in 3D? ChemSketch is the de facto 2D program here, but it doesn't do 3D. At least not that I'm aware of.--Russoc4 04:27, 3 December 2006 (UTC)

You'd probably actually have better luck with this on the science desk. I think. Sashafklein 05:04, 3 December 2006 (UTC)

I thought so. But then I thought they would've pushed me off to here :/ Thanks. --Russoc4 05:38, 3 December 2006 (UTC)

[edit] Online Translations

Is there a good free online English to Vietnamese block text translator out there? Crisco_1492

[edit] Bittorrent question.

I paid for some webspace and FTP access to it. Is there any way I can use this space to seed a torrent file -- by pointing a torrent client at the space -- without it filtering through my home connection in any way? I'm trying to seed some torrents (legal ones of my own, not pirated stuff) but my home connection is horrible. Thanks.

Well, kind of. You can use your favorite bittorrent client (I think azureus and utorrent do this, and I know the official client does) to build a .torrent of the files you want to make available. Since you don't own the server and I highly doubt the host will let you run a tracker on his server, you'll have to use DHT so clients can find each other without a central server (DHT is an option when you create the torrent file). Host that torrent file in your FTP space and let people download it. They'll have to use BitComet, uTorrent, or the official client to download with DHT, so make that clear. Also you'll have to be running it (seeding it) for the content to be available --frothT C 18:09, 3 December 2006 (UTC)

[edit] Name of type of computer architecture

Is there a generic name for this type of computer architecture :

N processors share a main memory area (either using multiply ported RAM or just waiting), each processor has a separate (typically smaller) memory that it has exclusive access to. The Processor exclusive memories are paged at the most significant bit (eg 1xxxxxxxxx is a location in processor memory, 0xxxxxxxxx is a location in main memory) and there is a 'crossbar' or switch directing memory access to either main or processor exclusive memory. Typically programs are stored in the processor exclusive memory (to reduce main memory 'bandwidth' usage), but both types of memory can be used by the processor to store data or programs and both can be read/altered by the same instructions. (No 'L2 cache' is used. since it is not neccesary)

This seems to me to be different from Harvard architecture as described in the article since the program and data memories share the same data structure.. Or is it just a specific case of parallel processor harvard architecture? Thanks.83.100.253.140 14:23, 3 December 2006 (UTC)

Sounds like a very simplistic Non-Uniform Memory Access architecture to me, as implemented in most modern multiprocessor systems with processor caches. The Harvard Architecture is a hardware-level architecture that uses different pathways and stores for data and instructions, and would apply only to a processor where data and instruction caches are distinct (which is typical). Droud 18:37, 3 December 2006 (UTC)
Thanks (I probably would have never found that) Is NUMA an extension of Symmetric Multiprocessing by definition or can a system use NUMA with out having SMP? The system I described has SMP.87.102.9.4 21:02, 3 December 2006 (UTC)
I would say all modern systems are NUMA. Droud 01:43, 5 December 2006 (UTC)
Sorry didn't get that - is that a yes or no?87.102.32.250 10:44, 5 December 2006 (UTC)
NUMA practices are embodied in modern systems regardless of whether they have multiple cores, even at the cost of single core performance. Most modern processors have multiple FPUs and integer units as well, blurring the distinction. Droud 15:03, 9 December 2006 (UTC)

Yes, I understand. Thanks. Thanks.87.102.44.80 17:48, 11 December 2006 (UTC)

[edit] HELP? Windows Movie Maker Question

Okay Okay Let's Make this simple. I decided to make a movie on my laptop, which runs XP Media Center Edition, it was not there, so I downloaded it via CNET/Downloads. It was done, I went on it. I couldnt be on it for more than five minutes, and if I was an error report would appear. I would either lose all my work or only be able to work on it 4 5 more minutes. What's Wrong? 72.193.100.178 15:32, 3 December 2006 (UTC)

Try here instead of here since the first link is a newer version that CNet apparently doesn't have yet. Droud 18:40, 3 December 2006 (UTC)

[edit] Accessing a Linux Network Remotely

I have a dedicated server which backs up its files to an FTP server within the same network at its datacentre. The IP address it uses to transfer files to this computer is an internal one (within the 10.x.x.x range), but I want to be able to see the FTP server using something like FileZilla and perhaps also be able to download/upload files to this FTP server from outside the network (i.e. my home). I've heard of methods such as VPN, but I have no idea how to go about implementing this.

I tried forwarding a certain port available to the outside world on my server to the internal FTP server to no avail - my server refused the protocol. I don't want to have to edit configuration files to accept the FTP protocol for that port if possible. RevenDS 15:53, 3 December 2006 (UTC)

FTP isn't a safe protocol to be using over the internet, and its fondness for using a control socket and a data socket makes it complicated too. Open TCP port 22 and forward that to your server, and make sure its SSH server is running. SSH is, frankly, magic. You can run SCP or SFTP (which do your file transfer stuff - WinSCP is a nice client for windows), you can make in interactive SSH session (like telnet but better), and you can tunnel all kinds of things (VNC, X, rsync) over it. SSH is, surely, one of the most useful computer programs ever written. -- Finlay McWalter | Talk 16:28, 3 December 2006 (UTC)
I am aware of SSH and SFTP (I use the former all the time), but will a normal FTP server support SFTP? Does the FTP server even get an incoming SSH connection, or does the OSI model ensure that it only ever gets FTP? Thanks. RevenDS 18:16, 3 December 2006 (UTC)
No, an SSH server handles SFTP - see SSH file transfer protocol. Using FTP for the application you describe is an extremely bad idea: it's far too insecure. -- Finlay McWalter | Talk 18:43, 3 December 2006 (UTC)

[edit] Installing fonts with CMD

Is there anyway i can install custom fonts on a Windows XP without going into control panel and instead using CMD? Jamesino 18:17, 3 December 2006 (UTC)

Interesting question. Fonts are stored in c:\windows\fonts and registered in HKLM\software\microsoft\windows nt\currentversion\fonts. So just copy your font to that folder and add the entry to the registry with activex or a .reg script. In case you're not familiar with the format:
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts] "Name of the font"="filename.ttf"
Save it as a .reg file, and run it from the command line with
regedit whatever.reg
And that should do it! If using the "Copy" command to move a font into the fonts folder causes the folder to lose its special status, then you might want to do:
attrib +S c:\windows\fonts
at the end of the batch file to make sure it's recognized as a system folder. good luck --frothT C 18:33, 3 December 2006 (UTC)

I copied the fonts into the c:\windows/fonts folder. What do I do next? Do i make a .reg script in CMD or in Notepad? Jamesino 18:50, 3 December 2006 (UTC)

Notepad. copy those 2 lines and save it as a .reg --frothT C 20:35, 3 December 2006 (UTC)

Would this method work on school computers that removed my access to the installing fonts section of the control panel? Jamesino 21:13, 3 December 2006 (UTC)

Yes, but I'm surprised that it would give you access to the registry, the command line, and the windows directories if the control panel is restricted... can you open My Computer and browse to c:\windows\fonts? That's exactly the same as going to Control Panel > Fonts. If you can do that, open up the fonts folder and drag your font in; it'll take care of everything. If you can't... run cmd. Type
copy C:\path\to\font\blah.ttf c:\windows\fonts
regedit
If the registry editor opens fine, then browse to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts key and add a string value, following the pattern of the other entries there. And that's it. If the registry editor is restricted by insufficient windows user permissions, you can't do it at all with any method other than privilege escalation (granting yourself or getting a more-privileged program to grant you privileges you shouldn't have) or perhaps external registry editing with a linux livecd or something. And even then the school might have software running to restore it to the way it was. If regedit doesn't work you can go from mischeviously adding a font to serious trouble so don't pursue it any farther. Chance are you'll either find a way to do it and do it wrong or get caught doing it, or fruitlessly trying method after method before finally realizing that they're all blocked by the same lack of permissions. --frothT C 21:26, 3 December 2006 (UTC)
lol, alright. Thanks a lot for your help =) Jamesino 01:30, 4 December 2006 (UTC)

[edit] DHT

How does a node connect to a DHT network? I'm thinking of this specifically in relation to bittorrent. If there's no point of contact for connecting nodes, how do they get in the know of the location of other nodes at all? It seems to me that there has to be some static service connecting incoming nodes to at least one random existing node. --frothT C 18:22, 3 December 2006 (UTC)

Clients obtain addresses to connect to DHT networks in the following ways:
  • Remembering peers from previous runs of the software.
  • Monitoring peers and traffic on other protocols, such as BitTorrent.
  • Randomly trying addresses.
Droud 18:52, 3 December 2006 (UTC)
OK so in the case of bittorrent the first and the third options don't really apply.. so how does a node go from just sitting there, no incoming or outgoing traffic of any kind, because it doesn't know the IP address of any other nodes, to finding a node? Apparently gnutella used a centralized directory so you could look up other nodes who are identified by the hash of the file they're sharing. Freenet uses a routing table that stores the contact information of "neighbor" nodes. But what about bittorrent- you're not necessarily going to always be seeding so it would be useless to put hard-code your IP address in the torrent file when "Use DHT" is selected in maketorrent. And without a point-of-contact IP how do you get any data at all? Since bittorrent (even with DHT) is an overlay network it has to use traditional internet routing schemes- it can't just say "hm who has this hash" without another node to ask. --frothT C 20:33, 3 December 2006 (UTC)
The first and second apply to bittorrent (and the third is just an implementation away). The DHT works by having peers, on every torrent, participating in the same DHT worldwide. This makes it very likely that when you join a new torrent, at least one of the seeders or leechers is running DHT. Once you talk to them, they tell you about other DHT peers, and so forth. Once you're connected you can "see" the entire DHT, and thus find any hash (and the sources for it) that you're looking for. You only need one valid address for a node on the DHT, and as soon as you talk to that address you are integrated into the DHT. Such addresses can come from the sources I listed above, there's no magic addresses. Droud 01:40, 5 December 2006 (UTC)
Fundamentally my question is where does that first address come from? If you just installed bittorrent, eager to start downloading linux isos (yeah right :p), and you connect to a trackerless torrent, how do you find that very first address to get into the network. I can see that if you can connect to one person with some DHT information then you have access to the addresses and hashes of everyone on the network. What I don't see is how you can connect to that one person --frothT C 20:27, 8 December 2006 (UTC)
You usually see a small number of hard coded addresses (called a seed list) in an implementation of a DHT, although many support seedless startup. Seedless startup randomly tries addresses, which works remarkably well if the implementation considers IP distribution and there are a significant number of participants already online. Seed lists are updated for each new version and the boxes they point to are reliable and well connected. Sometimes these seed boxes are merely delegates, providing a list of DHT nodes but not participating in the DHT itself (a layer of separation, legally useful). Droud 15:12, 9 December 2006 (UTC)
Oh I see, I had no idea. Thanks a lot -froth

[edit] Running Multiple Anti-spyware programs

Hi, I have windows defender on my computer. If, I install additional programs, like spyware blaster?, will I have more protection, or will they interfere and mess each other up? 896y 22:38, 3 December 2006 (UTC)

You can, and you should. If you're not running a firewall, get one. Most users use a combination of Ad-Aware and Spybot Search And Destroy. These two programs, together, should catch anything, and they're both free. --Wooty Woot? contribs 01:08, 4 December 2006 (UTC)
Better yet, dump Internet Explorer and switch to Firefox. I haven't had to run Ad-Aware since I did. Clarityfiend 09:50, 4 December 2006 (UTC)

Or Opera.martianlostinspace 16:57, 5 December 2006 (UTC)