Wikipedia:Reference desk/Archives/Computing/2007 May 10

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[edit] May 10

[edit] Robotic Vacuum

Is there a R/C-like version of a vacuum which is like a R/C toy car but it vacuums and can be driven around??????--66.53.231.189 02:07, 11 May 2007 (UTC)

The Roomba comes with a remote control (excepting the 1st generation model), but usually people just let them roam about on their own. -- Consumed Crustacean (talk) 02:13, 11 May 2007 (UTC)

The company also has a kit that lets you experiment with robotics --69.70.21.10 16:27, 11 May 2007 (UTC)

[edit] CMOS settings

Is there a way to reset CMOS setting from the operating system after bootup or can this be done only at startup from the BIOS? 71.100.2.43 00:11, 10 May 2007 (UTC)

Usually it can only be done from BIOS (or by a jumper on the motherboard). Some board/chip manufacturers make programs that will allow you to edit the BIOS inside of the OS - usually it is a Windows-only program. --Kainaw (talk) 00:22, 10 May 2007 (UTC)
Though the user doesn't seem to be asking about modifying the BIOS (the name of an IBM-compatible PC boot firmware program), but rather the contents on non-volatile memory where the BIOS program accesses some configuration information. Most OSes provide some means of modifying this memory. In some OSes it's unprotected memory space that you can just write to, though most large modern OSes will require some system-level privileges to access it. You just need to find software that will do what you're after. A crude way I used to do this is to write some random bytes to the memory, which will cause its checksum to fail upon the next boot. Almost all BIOS programs will reset the non-volatile memory on POST if its checksum fails. -- mattb 05:15, 10 May 2007 (UTC)
What I am trying to accomplish here is to reset the BIOS CMOS settings for scheduled alarm startup after the computer shuts itself down for the evening so that it will start iteslf up at a slightly altered time in the morning. I can do this now of course simply by rebooting and doing it from the BIOS CMOS setup program but then its a manual task I would rather the computer do for me. If CMOS setting are stored in memory that I can access and write to from the OS then that is all I need. 71.100.2.43 01:29, 11 May 2007 (UTC)
Sure, but you'll also have to figure out where/how the particular setting you're after is stored. Hopefully someone has already done this for you, but if not it may be time to break out a hex editor... Neat idea you have, though. -- mattb 05:22, 11 May 2007 (UTC)
Actually I've found more clues which may allow me to do this. I post it here whatever the method turns out to be. 71.100.2.43 18:01, 11 May 2007 (UTC)

[edit] VLC and Microphone/Camera

Is it possible, with VLC, to open a camera or microphone and "listen" to it like any other file? This means it could be "read", but also streamed and transcoded. Does anyone know of a way to make this happen on a Macbook pro? Many thanks!--Ryan 00:37, 10 May 2007 (UTC)

Why in VLC? You could more easily do this, I am sure, in other programs. --140.247.242.215 14:53, 10 May 2007 (UTC)
What other program can do these things?--Ryan 23:30, 10 May 2007 (UTC)
My brain's not working very well today, so I dunno whether I've understood your question properly, but have you tried Audacity? --saxsux 10:53, 12 May 2007 (UTC)

[edit] Processors

Which of the following is not a Processor Model?

  1. 8081
  2. 80486
  3. UltraSPARC
  4. K7VT4A —Preceding unsigned comment added by 122.167.115.24 (talk • contribs)
I could tell you, or you could look up each of those on Wikipedia or Google and have the inner satisfaction of finding the answer for yourself (don't worry, it's very easy). -- mattb 06:46, 10 May 2007 (UTC)
I've linked the two CPU's that Wikipedia has an article for, K7VT4A doesn't look like to be a CPU but a motherboard [1]. 8081 doesn't turn up anything is well. --antilivedT | C | G 08:40, 10 May 2007 (UTC)
The 8081 was an early microprocessor, but Wikipedia doesn't appear to have an article on it. However, we do have an article on the earlier 8080. StuRat 15:13, 10 May 2007 (UTC)
According to the BogoMips article, there is a Motorola CPU called the 8081 - but a quick google [2] doesn't show anything. Davidprior 17:51, 13 May 2007 (UTC)

[edit] Download From YouTube

How could I download video content from YouTube? Once I did, what software would I need to play it? (To head off a few timewasting replies, by section 4 of the Terms of Use, "If [I] download or print a copy of the Content for personal use, [I] must retain all copyright and other proprietary notices contained therein." I'm given express permission to create purely personal archives of their best stuff, as long as I don't file off the serial numbers.) Any help is greatly appreciated. Black Carrot 06:52, 10 May 2007 (UTC)

Firefox has an extension you could download called "Download Video". Once it's downloaded, renamed it to whatever you want, but add .flv at the end. THen you can play it with quicktime or VLC.--Ryan 13:17, 10 May 2007 (UTC)
A Google search for "download from youtube" gives you, as the first result, a site that lets you download not only Youtube movies but a player for them as well. Enjoy :-) Rawling4851 13:23, 10 May 2007 (UTC)
I develop UnPlug which allows you to download youtube videos (among others). Videos are downloaded by all tools as FLV files, so you may need to use a media player like VLC to play them. --h2g2bob (talk) 15:00, 10 May 2007 (UTC)

We should put this question and its answer at the top of this page, or something. It seems to come up every few days... --Steve Summit (talk) 20:57, 10 May 2007 (UTC)

Thanks. I feel stupid, I should have thought of at least one of those. Re Steve Summit, though, it looks like the question has only been asked an average of twice a month over the past six months, with none at all for about the past month and a half. Not worth the space. Black Carrot 23:26, 10 May 2007 (UTC)
No problem, and sorry, I wasn't trying to give you a hard time. I must have seen the question somewhere else recently. (Maybe on the Miscellaneous Desk?) And I have nothing against frequently asked questions -- they've made me a certain amount of money! :-) --Steve Summit (talk) 23:51, 10 May 2007 (UTC)
Sweet man. [Mac Δαvιs] ❖ 05:43, 11 May 2007 (UTC)

Everything seems to be downloading fine, with one small exception: none of the systems I've tried can access password-protected content. Unfortunately, anything flagged as "inappropriate" asks you to verify that it's not their fault you're watching it, which requires a nominal membership, which requires a password. Each downloader says, in its own special way, that it can't deal with that. Any ideas? Black Carrot 07:48, 11 May 2007 (UTC)

If it's one or two videos, you could use Wireshark to monitor your internet traffic, using "http" as the filter. The video download is one of the requests in the list. This is tedious, but works.
I'm always looking to support as much as possible, so are there any example urls you can give? Or can you give more detail on what happens? Feel free to email (compunach@yahoo.co.uk) if you prefer. --h2g2bob (talk) 02:12, 12 May 2007 (UTC)

[edit] my qsn

If i want to take admission in BIT colleges without entrance exam , than what i have to do ?? —The preceding unsigned comment was added by 220.226.64.150 (talk) 20:02, 10 May 2007 (UTC).

I suggest phoning or writing to the college, and convince them that you are eager, dedicated, hardworking, etc. They may agree to decide on your suitability based on an interview; or they may not. --h2g2bob (talk) 02:26, 12 May 2007 (UTC)

[edit] Computational question

Let's say that I have a given set of nodes with x,y coordinates scattered around semi-randomly. What sort of computation should I do (that is, how should I approach this from a computational point of view) if I want to identify the outer-most nodes and to draw a line connecting them all (i.e. creating an outline of the entire node group)? Obviously this will involve stepping through them somehow but I'm having something of a hard time conceptualizing exactly how to go about doing it, what I would be looking for in each node's existing position vis-a-vis the other nodes in the set. (The language, if you care, is just Flash ActionScript, so it is a very javascript-esque syntax. I don't need it in a specific language, I'm just thinking through the problem.) I'm interesting in being able to identify which nodes would be a part of the "outline" and which would be contained within the outline, and then drawing a clockwise (or counter-clockwise) line through them all (creating the outline itself). Does this make sense? Let me know if I can try to clarify it. --140.247.242.215 20:49, 10 May 2007 (UTC)

Perhaps Convex hull will help. 84.160.220.235 21:09, 10 May 2007 (UTC)
Yes, that's very useful, thank you! I think I've been going about it wrong anyhow. My points are not randomly generated, in fact — I define them ahead of time. If that's the case then I should know the order they should go in, and for the purposes of my project I can make them maintain that order. So in fact my whole approach is ridiculous, trying to find a very complex and generalized solution to what is in fact a far more limited problem! But I didn't quite see that until I looked over some of the Convex hull examples and realized they were computationally overkill for what I was doing. Thanks! --140.247.242.215 21:27, 10 May 2007 (UTC)

[edit] Usb Webcam on linux 2.6.xx

What must be done to have an usb webcam working under linux 2.6.xx?

I plug in the device and /usr/sbin/lsusb lists an entry. Does that imply there already is a driver in the kernel for this? With 2.4.xx /var/log/messages showed information if the device was claimed by a module or not.

Somewhere below /dev/bus/usb (probably different for different linuxes) I find an entry appearing and disappearing when the device is pluged in or out.

Next, I guess that I should be able to use the streamer command on that entry to make snapshots and the like.

Is this correct (and deviceindependant) so far?

Now I get "no grabber device available". So whats missing?

84.160.220.235 21:21, 10 May 2007 (UTC)

lsusb simply reflects the device self-identification. A device showing up in the list reported by lsusb is just an indication that the device and the Linux USB stack can communicate to some extent, not that there's any driver support for the device. I don't really know much about webcam protocols, but I don't think there's any de facto USB standard interface for them (as there is for things like mass storage devices, HIDs, and to some extent photos). You may need to ensure that your particular model of webcam is supported by a Linux driver and whatever software you're using for capture. -- mattb 05:19, 11 May 2007 (UTC)
From what I have found on the internet so far there should be a driver for that cam in all reasonably new distributions. But I didn't find neither the name of that driver nor any clue on how to check if it's active. With 2.4 kernel there were messages in /var/log/messages about what module/driver claimed a pluged in device or if it wasn't recognized by any. This has changed and I don't know where to look now. 84.160.220.235 15:02, 11 May 2007 (UTC)
Try checking the tail-end output of dmesg. -- mattb 15:55, 11 May 2007 (UTC)

[edit] Domain Name and DNS Management

Alright so I'm planning to buy a domain and setup a website. I've heard that it's best to get hosting and domain names from different companies. Is this true? If so, how am I supposed to tell the hosting company so that they can have the domain name point to the correct IP address? If I wanted two domains to point to the same IP, how would I arrange that? How do I prove that I own a domain and after that who do I talk to to change my DNS settings. DNS management is the only part that still confuses me somewhat. BrokenSegue 22:14, 10 May 2007 (UTC)

It's got nothing to do with IP Addresses, not to you anyway and it's a lot easier then you think. You hosting company will give you a URL, something like www.hostingcompany.com/~YourUserID where you stick your web page, then you buy a domain called www.MyDomain.com, then at the place you got the domain name there will be a very simple admin panel where you redirect www.hostingcompany.com/~YourUserID to www.MyDomain.com.. A hint I can give you is make sure when you are building your website, that the internal links refer to the MyDomain address not the hostingcompany one, otherwise people will see the real address of the page by viewing the links or the source. Vespine 22:44, 10 May 2007 (UTC)
Oh and you don't have to prove you own anything, you can redirect your domain name to anything you want. Vespine 22:46, 10 May 2007 (UTC)
I don't think he wants a web page. The original poster wants to set up a genuine host. —The preceding unsigned comment was added by 84.187.35.117 (talk) 22:55, 10 May 2007 (UTC).
What's the difference? I think you are right though. BrokenSegue 02:32, 11 May 2007 (UTC)
The reason to use two different companies is to ensure that you are listed as domain owner with the registrar instead of your hosting company. Only the owner of the domain can change the host it links to, and if your provider owns the domain you might be forced to chose a new domain when you want to switch providers and tell all your users the new address. This is a very bad but somewhat common business practice used by some providers to keep their customers. Good providers won't do that. Just check the whois entry on the domain right after you bought it and make sure that it lists you as owner. —The preceding unsigned comment was added by 84.187.35.117 (talk) 23:02, 10 May 2007 (UTC).
To make the domain name point to the correct host, tell the company that sold you the domain where you want it to point to. How that works may depend on the company but it is the basic service you pay for. The information you provide will be propagated across the dns system (that may take some time). The hosting provider is not involved in the process. You can have as many domains pointing to the same host as you like. —The preceding unsigned comment was added by 84.187.35.117 (talk) 23:10, 10 May 2007 (UTC).
Ah, thank you. And I will be pointing to an IP then? Or is it to the "www.hostingcompany.com/~YourUserID" thing mentioned by Vespine. Somehow I don't think I need to point one domain at another. Sounds inefficient. Also, what do I do if the whois says that I don't own it? BrokenSegue 02:32, 11 May 2007 (UTC)
Every website doesn't have it's own unique IP address, we would have run out of IP addresses a long, long time ago. Redirecting to a URL is not unusual or as inefficient as it may sound. If whois is not showing the correct information you'll probably have to talk to your domain name provider, it may be part of their conditions or something, but I'm pretty sure it populates from there. Vespine 04:51, 11 May 2007 (UTC)
Oh, alright then. That makes sense. Thanks. BrokenSegue 12:48, 11 May 2007 (UTC)
You need to tell the hosting company your domain name so they can set up their name server to point to the server holding your site. Once that's done they should give you their name server addresses (for example, ns1.example.com and ns2.example.com). You then need to tell your domain name registrar (usually through a control panel) these name server addresses. These changes can take up to 48 hours to propagate through the domain name system. — Matt Eason (Talk • Contribs) 09:11, 11 May 2007 (UTC)
I looked up my host's ns, you're right. Thanks! BrokenSegue 12:48, 11 May 2007 (UTC)
No problem. Actually the DNS article says I'm wrong about the 48-hour propagation thing. Just be aware that it may be a few hours/days before everyone can get to your site using your domain name. — Matt Eason (Talk • Contribs) 16:19, 11 May 2007 (UTC)