Wikipedia:Reference desk/Archives/Computing/2007 June 12

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June 12

OpenGL without a graphics card

I'm running Ubuntu 7.04 in parallels, and is it possible to have my processor do the graphics processing, (making ubuntu 'think' i have a graphics card) because parallels doesn't do graphics emulation. Thank you everyone.--67.181.167.227 00:35, 12 June 2007 (UTC)

I'm not that in the know with 3D on linux, not doing much 3D rendering or gaming, but the Mesa 3D library could accomplish this using software rendering, I believe. -M^ask? 02:23, 12 June 2007 (UTC)

Don't bother using that to run Beryl though, or basically anything except for glxgears unless you have a super fast CPU (one of those eight-core Mac Pros would probably let you play something like CS on lowest settings). --antilived^{T | C | G} 05:19, 12 June 2007 (UTC)

Thanks for the responses. How would I set Mesa up? And is a CPU reeally that bad at 3d? I have a 2ghz intel core duo.--67.181.167.227 14:43, 12 June 2007 (UTC)

I can't compile it with Ubuntu (7.04)! Make just gives me 'error'.--67.181.167.227 16:01, 12 June 2007 (UTC)

There are already Mesa libraries already built for Ubuntu, for example, libgl1-mesa. -- JSBillings 16:21, 12 June 2007 (UTC)

Actually, he can use libgl1-mesa-glx, the same one he would use with hardware accelerated rendering, since it falls back into the Mesa software renderer when hardware rendering isn't available (in fact, it falls back into AIGLX, which itself can fall back into software rendering on the X server AFAIK). --cesarb 00:32, 13 June 2007 (UTC)

Connecting RCA cables to a computer

If I were to try to connect a VCR (for example) to a computer because I don't have access to a TV, would those RCA to S-video adapters be the best idea? How much signal deterioration would there be? And how would I go about converting the audio signal as well? Thanks, --MagneticFlux 02:58, 12 June 2007 (UTC)

Are you trying to record your computer screen or watch TV on your computer? The former you need a video card with a video output or dual-head and use a VGA -> RCA cable and set your second head to clone the first. If you want to watch TV on your computer, please get a TV tuner card instead, your current configuration will not work (OK it MIGHT work if you have a TV capture card, but that's more expensive than a TV tuner card a). --antilived^{T | C | G} 05:30, 12 June 2007 (UTC)

You could capture your screen using one of those software video capture apps or Fraps if you're capturing DX. Splintercellguy 05:42, 12 June 2007 (UTC)

Actually, I'm trying to watch things with RCA outputs (like VCRs) on my computer. --MagneticFlux 19:14, 12 June 2007 (UTC)

Well then you will need a video capture card. --antilived^{T | C | G} 20:10, 12 June 2007 (UTC)

A RCA -> S-Video adapter won't work? I think my computer has an S-Video input. --MagneticFlux 00:22, 13 June 2007 (UTC)

I really doubt that, it's most likely a S-Video OUTPUT, unless you have one of those Radeon home cinema cards (forgot what they are called). --antilived^{T | C | G} 06:11, 13 June 2007 (UTC)

Teaching IT to children

I've just been made IT coordinator in my school and am looking to update our curriculum for next year (for 9 to 11 year olds). It's OK at the moment but not great. I intend to ask for a whole heap of cash for hardware, (that'll teach them to put me in charge of something) so would like to locate some free software (beer, but also speech if possible) to soften the blow.

He is what we need:

• Simple vector graphics creation. Inkscape? Are there any alternatives?
• Save images with different sizes, resolutions, and formats. Gimp seems overkill but MS paint isn't advanced enough for what I want to do. Are there any alternatives?
• Web page design. Last year I used microsoft notepad but I'd like something better. I don't want WYSIWYG but is there something simple out there that will highlight errors and colour code HTML so that it looks different from content?
• Email. The children need to learn email, but we need to consider safety. I'd like to set up an email system where the kids can email each other from within school but nothing coming in or going out to the outside world. Is this possible?

Everything else on the new curriculum, we have pretty much covered.Does anyone have any recommendations?The operating system is windows 2000 Theresa Knott | Taste the Korn 07:54, 12 June 2007 (UTC)

Maybe have a whole computer lab with Edubuntu installed instead? :p These uses shouldn't require too much computer resource, what's the current specification anyway?

• And also try Xara Xtreme(free version is Linux only though), but Inkscape should be enough for them.
• No raster image creation? Then why do you need to resize and things like that? I think Gimp would be good for things like simple image enhancement and maybe some fancy effects.
• Bluefish (text editor) (Linux) is a pretty good HTML and general multi-purpose text-editor with tag highlighting, but otherwise good old Notepad++(Windows) or Gedit(GNOME) or Kate(KDE) would do fine.
• This would require you to set up an mail server which is not THAT hard, but I think something more along the line of instant messaging would be more suitable in a classroom environment, but that's just me. --antilived^{T | C | G} 09:23, 12 June 2007 (UTC)

Fedora is free. It has Inkscape for vector graphics. Gimp is good for working with pictures because you can also teach the kids about layers. Until they understand that concept, they will be stuck using programs like MS Paint. You can use Kate for web page design - it has context sensitive highlighting. Also, each desktop can have httpd installed (apache) so the kids can save to their local public_html folder and view their pages on their own mini web server. You can install sendmail on a Fedora box and only have it handle local mail - no inbound or outbound. I suggest getting one big box as the fileserver. Have all the desktops nfs mount the home partition on the fileserver. Then, it doesn't matter which computer the kids sit at. Have the fileserver handle accounts to through pam. So, all kids have the same login/password at each computer. You can take advantage of SELinux to really lock the boxes down so the script-kiddies won't have much luck messing with things. --Kainaw ^(talk) 12:47, 12 June 2007 (UTC)

If you're considering buying a whole bunch of new computers, then switch to linux and set up your lab with very cheap ($100?) thin clients. It'll leave your budget committee or whatever at your school much less dumbfounded at your bill :) --froth^t 14:18, 12 June 2007 (UTC)

Also it'll be really easy to set up a lab-only mail server since all mail is stored on the same server as what's running the thin clients --froth^t 14:21, 12 June 2007 (UTC)

And, now that I think of it, it will be easier to monitor the kids. All their home dirs will be on the fileserver, which you can mount. You can monitor what files they have. You can also place files in everyone's home dirs as a "starting point" for some assignments and then collect their finished results with a simple script (assuming they are smart enough to save a file with a proper file name in a proper directory). Of course, you can create a read-only public area also that is symlinked into everyone's home.

As for security - by simply not connecting this to the Internet, you can ensure that the kids can't get out on the net and do bad things. Also, since it is Linux, they can't bring all their programs from home (likely Windows stuff) and install it. --Kainaw ^(talk) 14:32, 12 June 2007 (UTC)

I would love to switch to linux,I've looked at edubuntu and want it, but the number of computers we have here is limited, and the staff use the kids computers all the time, and I do not have the time to retrain the staff (many of them barely know how to use windows) and I don't think the IT support guy has any linux experience whatsoever, so it's a no go for the time being. I am looking to buy new hardware, but it will not be computers (yet). The children are expect to learn to control external devices like floor turtles, traffic lights, and to be able to use data logging devices like thermometers and we need to buy those urgently. Any software you recommend has to run on windows. Theresa Knott | Taste the Korn 14:56, 12 June 2007 (UTC)

Unless you have a lot of chemistry or physics hopefuls in the class, lessons on using those instruments will be useless, and in any case basically unrelated to IT. They're mostly plug-and-play and the kids will just be learning to use the data capture programs, which are easy to learn if the kids have other foundational computer skills in the unlikely case that they ever actually have to use the programs in real life. --froth^t 17:49, 12 June 2007 (UTC)

• Not sure of a decent one that isn't bloated and therefore "harmful" to children.
• Paint.NET? The newer versions are tending towards GIMP but the one I used to use used to be dumbed down. Failing that, pixel art programs might be useful.
• Text editors like TextPad can use various highlighting syntaxes, but TextPad doesn't support Unicode (ugh). But it is quite useful, although nowhere near the standard of various Linux programs.
• It might be possible to set up something like a firewall that filters out all email traffic not being sent to a whitelist of addresses. x42bn6 Talk Mess 01:30, 13 June 2007 (UTC)

If the number of computers is a problem I think there is a way of running SUSE on one PC and having lots of Monitors and Keybords/mices coming out so one tower acts like four or five pcs, I'll see if I can find more info. --Lwarf ^Talk! 01:35, 13 June 2007 (UTC)

There is a freeware photo editing program for windows that I use call photo filter, it's realy good and much easyer to use than the gimp. --Lwarf ^Talk! 01:40, 13 June 2007 (UTC)

Try Kolourpaint - it's a little bit more advanced than MS Paint, so might do. The alternative is GIMP. Kate does notepad with syntax highlighting (or notepad2 for windows). --h2g2bob (talk) 17:29, 13 June 2007 (UTC)

"Save images with different sizes, resolutions, and formats." If this is all then the sweet freebie for windows "IrfanView" does such easily even in bulk!

Thanks everyone. Theresa Knott | Taste the Korn 05:49, 18 June 2007 (UTC)

Use Case Analysis-Software Requirements & Analysis

i would like to make a library system.can you assist me in listing the minimal set of use for the following actors in the particular library system:Borrower, Checkout, Clerk, Librarian, Accounting System

This sounds terribly like a homework problem. See use case. All you need are generic descriptions of the generic functions of the generic actors. Note that "Checkout" appears to be a function, not an actor. --Kainaw ^(talk) 12:42, 12 June 2007 (UTC)

Operating Systems

i recently installed windows vista on my PC and after that the performance of the computer went down.please advise on how to upgrade my computer & what are the best specifications of a computer to install windows vista

Ram, graphics card, CPU, and harddrive, in that order. Post your spec here and we can have a look and tell you more, but generally that's the order to upgrade if you find your computer struggling (graphics card is only for Aero and games though) in Vista. --antilived^{T | C | G} 09:27, 12 June 2007 (UTC)

I disagree, RAM, CPU, graphics card, in that order. Absolutely no reason to upgrade your hard drive unless it's a 900 megabyte 1200rpm beast from the early 90s :) If you dont want to run aero there's no reason to upgrade your graphics card other than gaming, and if you have a significantly terrible cpu then the better cpu will help more with that anyway --froth^t 14:15, 12 June 2007 (UTC)

Well you've upgraded the 3 major components and all that are left are the motherboard (likely to be replaced with new CPU), the PSU (also likely to be replaced with the new equipment) and hard drives. Last time I installed XP on a 10gig system drive it filled it up within 2 months, so I will not be surprised if Vista does the same to a 20gig system drive. With all these HD stuff coming up and newer and bigger games I would suggest them to get a new harddrive and maybe have daily backups of important stuff on the old drive. --antilived^{T | C | G} 20:07, 12 June 2007 (UTC)

The Windows Experience Index you can run on Vista will tell you what area should be your priority for upgrading. Neil ╦ 14:22, 12 June 2007 (UTC)

I don't really agree with the order of RAM, CPU, graphics card myself.... Going from 1 gig to 2 gigs of RAM is not going to have as big of an impact as going from 4 meg to 8 meg back in the days of Doom 2. --Wirbelwindヴィルヴェルヴィント (talk) 21:06, 12 June 2007 (UTC)

He just installed vista, which implies to me his machine is older. I guarantee going from 512MB to 1GB would have a tremendous effect on my current machine, and I'm not even considering Vista at the moment. Root⁴(one) 04:53, 13 June 2007 (UTC)

Well, for reference, I built my computer in 2003, have 1 gig of RAM, and no Vista still (and won't ever). I think the standard nowadays is 2 gigs, no? --Wirbelwindヴィルヴェルヴィント (talk) 05:29, 13 June 2007 (UTC)

The standard is 1GB or slightly less- there's not quite much of a push yet to put down hundreds of dollars more on another gig when 1GB is more than adequate for even Vista if you're not gaming --froth^t 13:59, 13 June 2007 (UTC)

Minimal encoding form results

I want to take the results of a html form and turn them into a string of minimal length. So, for example, if my form asks users to pick 1 out of 26 options, I want to be able to encode their answer as a lowercase letter a-z. Similarly, if my form has 26^2 potential options, I want to be able to encode it as two lowercase letter. If I want to send the results of my question to someone else, I can just send them a link to http://whatever.com/testresults.cgi?result=aa . Sorta like tinyurl, but using some sort of algorithm, rather than a database.

I could just write the thing, but somebody has to have written this before. Anyone have any suggestions for the easiest way to do this? --Alecmconroy 13:18, 12 June 2007 (UTC)

This is a rather simple algorithm. As you said, each item is a binary option (0=unselected, 1=selected). Turn them into a binary number, ie: 01101001001101001011010001. Then, cut that into 7-bit chunks: 0110100 1001101 0010110 1000100 (note the zero-padded last entry). Finally, get the ascii value for each 7-bit chunk: 52=4 77=M 22="SYN" 68=D. Now, if you don't want ALL the ascii codes to be possible, you can break it into 6-bit chunks and append a 1 to the beginning of each one so you have codes 64 (@) through 127 (DEL) possible. --Kainaw ^(talk) 13:26, 12 June 2007 (UTC)

Simple, but annoying to code out. I'd hoped there was some code out there to do this for arbitrary forms. --Alecmconroy 13:54, 12 June 2007 (UTC)

The serializing code (which is what you are trying to do) isn't as compact as you are asking for. Most modern languages have a function to serialize data objects and then get them back as unserialized objects. Maybe if you just make the binary string and serialize that you will get something nice. --Kainaw ^(talk) 14:28, 12 June 2007 (UTC)

The serialized form will not be compact either. If you need a minimal encoding, then you'll need to do some work. But if you don't need a minimal encoding, you don't have to use it!

Nintendo DS USB troubleshooting

I have a DS and want to connect it to the Interweb but it won't. I'm using a Nintendo Wi-Fi USB connector. It works fine until it comes to the connection test which fails and gives me error code 52203. What should I do? Nowhere is very helpful. Vitriol 16:45, 12 June 2007 (UTC)

Did you make sure to open the ports on your router to allow the Wii to have access?--GTPoompt(talk) 17:03, 12 June 2007 (UTC)

Er... I said DS, dude. Vitriol 17:04, 12 June 2007 (UTC)

I can't access any site remotely "games" related from my work PC, but a Google search for Nintendo DS 52203 returned 1340 results. Surely one of those will tell you something. --LarryMac | Talk 18:29, 12 June 2007 (UTC)

Whoops, my mistake. I must have been confused and thought them to be the same thing :(.--GTPoompt(talk) 19:46, 12 June 2007 (UTC)

When I did it recently (with a Datel WiFi Max), I got the the 5220x messages also. The x signifies which setting you have, so the 3 in 52203 means setting 3. You get to 5220x, which means it detects the access point, but it has no access to it. You need to open up your firewall/ports for the USB dongle. For example, if the computer that connects to the USB dongle has ZoneAlarm, you can add it to the trusted list, add the MAC address filtering, whatever else your computer requires to give the dongle access. Here's a thread with 52200-52203 error codes, and this one is for the Wii, but they actually share the error codes, afaik. --Wirbelwindヴィルヴェルヴィント (talk) 21:04, 12 June 2007 (UTC)

TCP/IP Question

If I send out a request for a web page, the server sends it back to my IP address. The NAT article says the router lets it through and gives it to the right client by remembering the outgoing request.. my question is what port does the server send it back to and if 80 why does the browser pick it up instead of the web server daemon also listening on 80?

NAT is intended to be transparent to the things on either side of it- otherwise nothing would work with it. TCP connections have ports on both sides- your client sent the request to port 80 but from some unused port it selected. The "netstat" command (which exists on windows too I think) would show you the ports on both sides. Friday (talk) 17:50, 12 June 2007 (UTC)

Ah, ok thanks --froth^t 19:01, 12 June 2007 (UTC)

When you send an outgoing packet, it contains some port to where the recipient can respond. This outgoing port is a random one with a high number (not 80, that's only the port on the recipient computer, yours is completely different). So when the router sees a packet going out to address www.google.com (it uses the IP, not the domain name, but you know what I mean) with outgoing port 45432, it remembers what computer on your network sent it. When the response comes from www.google.com to port 45432, it knows to what computer it is headed. That's how NAT works. --Oskar 23:00, 12 June 2007 (UTC)

Right, to add to what Oskar said, Imagine you've opened a connection to google behind a NAT. As there are two IPs associated with each IP packet, there is also two ports, the source port and the destination port. Local machine assigns it local port 19932, outgoing port 80, and your machines IP is 192.168.3.15. At the NAT, it see s that machine 192.168.3.15 wants to communicate with 216.239.51.104 (some google server). Lets say the NAT has IP Address (on the outside world) of 66.230.200.100. It translates that request from 192.168.3.15 to a request from itself, with a new local port number, say 15003. When google responds, it will respond to that source port. When the packet arrives from google, the NAT then back translates that packet into a response from 216.239.51.104 at port 80 directed to 192.168.3.15 at port 19932. This is all off the top of my head... so there may be some technicalities missing (and I don't mess with network technologies alot), but I think the gist is there. Root⁴(one) 05:08, 13 June 2007 (UTC)

Browsers apparently not sending HTTP_USER_AGENT

Hi all. My friend's computer does not seem to be sending out the HTTP_USER_AGENT (what browser she is using). She used Internet Explorer to try access Facebook and Gmail and both told her she must use either IE, Firefox or Opera. Strange, as she was using IE. She tried with Firefox, and then Opera, and the same thing happened each time. I sent her to a test page to see what her user agent is (thinking she may have some adware or something changing it) and it printed nothing but her IP. So, from what I can conclude, the HTTP_USER_AGENT is not being sent. Is my conclusion right? What can I do to fix it? What else could it be? Help! Thanks. JoshHolloway 18:45, 12 June 2007 (UTC)

Perhaps some toolbar has interfered with normal browser behavior? I would suggest switching to Firefox regardless, and that seems like it would likely fix this issue. Oh, except it didn't (duh). Is she perhaps going through a proxy server? Friday (talk) 18:51, 12 June 2007 (UTC)

Maybe a long shot, but this post says it might be caused by a Norton firewall. --LarryMac | Talk 18:56, 12 June 2007 (UTC)

Thanks for the replies. I'll look into it being Norton - it is the firewall software she uses so it could very easily be that. As for using Firefox, I'm more of an Opera fanboy myself :p. No proxy server, already checked. I think Norton is my best bet. Thanks, will edit again if it didn't work! JoshHolloway 21:44, 12 June 2007 (UTC)

Opera? My friend swears by opera but I don't like that they charged for their software when far better alternatives were free.. and it strikes me that the only reason they made it free was that nobody was buying --froth^t 04:35, 13 June 2007 (UTC)

Squid, a common web cache, can be configured to strip useragents.

This or the firewall is most likely. It would have to be a very stupid firewall tho. Firefox doesn't care what IE's user agent settings are --h2g2bob (talk) 17:21, 13 June 2007 (UTC)

Graphics Acceleration in Qemu

Is it possible to set up graphics (opengl) acceleration for ubuntu inside qemu?--67.181.167.227 20:46, 12 June 2007 (UTC)

Web Designing on Microsoft Word

Hello. I am designing a website using Microsoft Word 2000's Web Page Wizard. When a surfer accesses a hyperlink, I would wish to know how to bold that hyperlink to let the surfer know where he or she is as he or she is on that particular hyperlink. --Mayfare 21:51, 12 June 2007 (UTC)

Oy, Word is a pretty scary program to do web design in. But anyway: I'm not 100% sure what you want, you might have to describe the site layout a bit better. If it is, say, a number of pages with a common menu, you just bold the hyperlink on each page separately. If it is one big page, then it really depends on how the page is put together (it can be done, but it probably needs javascript, and I would be totally scared of trying to do that with Microsoft Word). --24.147.86.187 22:48, 12 June 2007 (UTC)

Yeah, you'd be much better off learning how to make a page in raw html, or at least a proper web program. If nothing else, learn the basic tags for bolding things, and add it to the html export from word. -- Phoeba Wright^OBJECTION! 22:59, 12 June 2007 (UTC)

It sounds to me like he wants to have a menu of links and bold the one for the page he's on. Just highlight it and click the bold button on each of the pages you are making. Gotta warn you though - your pages are going be bloated and messy. Youth in Asia 23:36, 12 June 2007 (UTC)

Vmlinux

Is VMlinux or VMlinuz the default name for a compiled kernel? I just compiled it (first time) and Vmlinux was a file that was outputted. If this is one, how would I put it on a usb memory key, ready to boot?--67.181.167.227 21:55, 12 June 2007 (UTC)

vmlinuz is a compressed version of the vmlinux kernel image. Here are instructions for booting from an external device. --TotoBaggins 23:52, 12 June 2007 (UTC)

Editing your custom dictionary in Firefox?

I just accidentally added a typo to my Firefox dictionary, is there any way for me to undo this?--VectorPotential^Talk 23:32, 12 June 2007 (UTC)

I just added the word "sneeeeef", so I could find it (because I've been wondering the same thing myself). looks like the first google hit for "user dictionary Firefox" probably will work. [1]

I remember adding the other that are currently listed in persdict.dat, but I don't see "sneeeeef", Firefox probably needs to be shut down for me to see it. Root⁴(one) 05:16, 13 June 2007 (UTC)

Thank you, worked like a charm--VectorPotential^Talk 13:07, 13 June 2007 (UTC)

Another Mac OSX Question

I asked this question some time ago. Sorry to ask it again, but the answer I got, while very helpful and appreciated, did not actually solve the problem I have, and led me to find another, unrelated problem that I had but did not know about. I'll come to that problem after I have solved this more pressing problem. Anyway, my problem is that I have installed OSX 10.4.9 on my G3 iBook PPC, and have ended up with only 3~4GB left out of a total of 20GB, even without downloading much extra software. I find it hard to believe that OSX would take up 10GB+, and am led to believe that there is something I have done wrong. The only two things I can think about are:

1. Should I have deleted a folder called 'Previous Systems' (in which there is another folder called 'Previous Systems 1', with lots of things like IE5, PostPet, and other things I never use and are not from OSX); and/or get rid of my OS9 Applications folder, in which are, again, older versions of Acrobat and IE, plus things like Outlook, and the like; and/or

2. Do I need the folder called 'Developer', which I suspect may have been an option when I put the OSX disc in for the first time?

Any help would be appreciated, but, please bear in mind, I don't have my old OS9 discs (they were lost), so anything I delete cannot be put back, unless it's on the OSX disc, which I still have. Manga 23:37, 12 June 2007 (UTC)

I don't know about this specific question, however: If you have no data you intend to save on your disk, there's nothing to be lost (except time) by reinstalling. You could always try deleting anything questionable, and re-installing with a minimal set of software and see where that gets you. Friday (talk) 23:41, 12 June 2007 (UTC)

Yes, delete Previous Systems if your computer is running well. That's where the old OS goes when you do an upgrade (in this case, when you went from 10.3 to 10.4). It does that in case you have problems with the new OS and need to revert. So long as your current system is running well, you can safely delete the Previous Systems, which should free up at least a couple gig. I'd leave "Developer" alone for now. You probably don't need the contents, but I don't know if removing it will break dependancies with what was installed. -- Kesh 05:00, 13 June 2007 (UTC)

• See if "Developer" is just the XCode program its files. If so, and if you are not a computer programmer, trash it. XCode takes up a huge amount of space and if you aren't using it you don't need it (and can always get it back from the OS X CD). I would be really surprised if there were dependancy issues (just don't start deleting things willy-nilly out of the Library folders). If you want to see where your hard disk space is going, I find tools like Disk Inventory X invaluable. --24.147.86.187 12:59, 13 June 2007 (UTC)