Wikipedia:Reference desk/Archives/Computing/2008 February 22

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February 22

Odd DNS-related (maybe?) Internet problem

I'm on a university wireless network, and lately I've been having an odd problem. I'll be using the Internet normally, then suddenly I'll lose the connection - but my computer will still think I'm connected to the Internet through the network. I still can't visit or even ping any sites though, or use instant messengers, etc. Even stranger, sometimes I get a similar problem, but I will still be able to visit anything on the domain I was visiting at the time the Internet went down, and I can stay on instant messenger, but I can't visit any other site. Flushing the DNS cache does not fix this. Neither of these problems can be fixed by any method I have figured out (disabling and enabling the wireless card, disconnecting and reconnecting from the network, etc.), except by restarting my computer, and this happens frequently enough that having to do that every time is a major annoyance. Any ideas? -Elmer Clark (talk) 00:14, 22 February 2008 (UTC)

When this happens, can you access web resources by IP? F'rinstance, tracert www.google.com gives me the IP 74.125.47.147. Then, if you have IP connectivity but for some reason don't have DNS services, you can simply type that IP into a browser window. If you get Google, that's it. You can still pass packets back & forth, but don't get DNS services. -SandyJax (talk) 19:51, 22 February 2008 (UTC)

I also had this problem at my university. Running a DNS server on my computer fixed most of these issues (I used TreeWalk for XP; BIND is available for the Unices, I do believe) Washii (talk) 05:21, 24 February 2008 (UTC)

I confirmed that it is indeed a DNS problem - I could access Google via IP while the problem was occurring. I've tried using OpenDNS instead of the default DNS servers here, hopefully that will do the trick. If not, I'll try TreeWalk. Thanks a lot for both answers. -Elmer Clark (talk) 07:32, 25 February 2008 (UTC)

Windows Live Messenger on USB?

Hello,

Is there any way that I can run Windows Live Messenger off a USB. I've tried freeware like Pidgin, and Miranda IM, but I want Windows Live. How can I do this?

Perfect Proposal ^{Speak Out!} 01:24, 22 February 2008 (UTC)

I don't think that is possible unless there is a U3 smart drive version of Windows Live Messenger, which I don't think there is. Kushal 05:37, 22 February 2008 (UTC) Since this is a Microsoft product it hooks into the registry a whole bunch, so it probably isn't possibleTheGreatZorko (talk) 13:28, 27 February 2008 (UTC)

Hydra on ubuntu PPC

I am trying to build Hydra on my PPC Ubuntu box. This is the error:

hydra-ssh2.c: In function ‘start_ssh2’:
hydra-ssh2.c:34: warning: implicit declaration of function ‘options_new’
hydra-ssh2.c:34: warning: assignment makes pointer from integer without a cast
hydra-ssh2.c:44: warning: implicit declaration of function ‘options_set_wanted_method’
hydra-ssh2.c:44: error: ‘KEX_COMP_C_S’ undeclared (first use in this function)
hydra-ssh2.c:44: error: (Each undeclared identifier is reported only once
hydra-ssh2.c:44: error: for each function it appears in.)
hydra-ssh2.c:45: error: ‘KEX_COMP_S_C’ undeclared (first use in this function)
hydra-ssh2.c:46: warning: implicit declaration of function ‘options_set_port’
hydra-ssh2.c:47: warning: implicit declaration of function ‘options_set_host’
hydra-ssh2.c:48: warning: implicit declaration of function ‘options_set_username’
hydra-ssh2.c:50: warning: passing argument 1 of ‘ssh_connect’ from incompatible pointer type
hydra-ssh2.c:50: warning: assignment makes pointer from integer without a cast
hydra-ssh2.c:82: warning: implicit declaration of function ‘ssh_error_code’
make: *** [hydra-ssh2.o] Error 1
  —Preceding unsigned comment added by 75.31.170.32 (talk) 04:19, 22 February 2008 (UTC) 

I added <br>s to make your post readable. It sounds like you're not including some required header file, or have the wrong version of one. Unfortunately, the only suggestion that occurs to me would be to search for the undeclared identifier in the source you obtained: "grep -r 'KEX_COMP_[CS]_[SC]' .". Does that turn up anything? --Tardis (talk) 18:30, 22 February 2008 (UTC)

Reformatted. --Kjoonlee 09:02, 23 February 2008 (UTC)

OK, I ran the grep command menioned above, I get this:

./hydra-ssh2.c: options_set_wanted_method(ssh_opt,KEX_COMP_C_S,"none");
./hydra-ssh2.c: options_set_wanted_method(ssh_opt,KEX_COMP_S_C,"none");
—Preceding unsigned comment added by 75.31.170.32 (talk) 16:25, 24 February 2008 (UTC)

KEX_COMP_S_C is defined in the libssh documentation here, but it doesn't appear in the libssh2 headers on my ubuntu machine or (as far as I can tell) in the libssh2 documentation here. I can't find a list of dependencies for Hydra, but I'd guess that (being a bit old) it depends on version 1 of libssh, and you have libssh2 installed (that's what's in the Ubuntu repositories) [Note that that "ssh2" in the filename probably refers to the version of the ssh protocol, not the library]. So I'd guess that you don't have v1 of libssh installed (either you have no libssh or you have libssh-2-dev). In most current programs the autoconf script should have noticed that you don't have the requisite headers in place, but Hydra's build may not. You could try to manually install libssh (v1) from somewhere (and make sure its location is on the include and lib paths). -- Finlay McWalter | Talk 17:09, 24 February 2008 (UTC)

Quicktime in the site www.nveil.com

I need to get feedback on the video quality and usage issues in a site I designed with quicktime. The site is www.nveil.com The videos are in the signage and video art pages. I used 386KB/sec encoding on Sorenson. How do you like/ dislike the experience? —Preceding unsigned comment added by 76.126.110.79 (talk) 04:53, 22 February 2008 (UTC)

It was pretty good with a wired broadband Internet connection. Great job! Kushal 16:29, 22 February 2008 (UTC)

PDFs

Hi

I am trying to check whether a PDF is accessibleor not the PDF was saved as my own from another source but when i try to make it accessible it comes up with This direct object already has a container what does this mean/

thanks —Preceding unsigned comment added by Gmcgregor (talk • contribs) 10:02, 22 February 2008 (UTC)

Are you using Adobe Acrobat Professional? Which version? Kushal 16:21, 22 February 2008 (UTC)

auto variables(local variable)

what is the actual part of any program when local variable get memory allocation? 1. at time of declare or 2. at the time of use in program?

124.30.211.128 (talk) 13:14, 22 February 2008 (UTC)sankalp

Relocation may help. It depends on the language, I believe. x42bn6 Talk Mess 13:44, 22 February 2008 (UTC)

If you really mean "automatic variables" in the way that the C language means them, automatics are usually allocated on the processor's stack. So the storage for them comes into existence as the containing subroutine is called and goes out of existence when the containing subroutine returns.

Atlant (talk) 13:52, 22 February 2008 (UTC)

Windows XP - Password

A friend got an old PC from a wife of a friend who passed away. Now he has the PC but can't log in, as it requires a password. He also has no back-up disks or any windows disks, What is the best thing to do? Is there a way that a new account can be made at the login screen? --ChokinBako (talk) 13:39, 22 February 2008 (UTC)

If see the Welcome screen pop-up, press Ctrl-Alt-Del to get the alternate log-in dialog. Enter "Administrator" in the user field and nothing in the password field and see if you can log in. Many people don't set an admin password (however, I think it prompts you to do so when you install Windows, but it is worth a shot anyway. 206.252.74.48 (talk) 13:56, 22 February 2008 (UTC)

You could try this site, which seems to provide a tool to recover lost Windows XP passwords. Also have a look at this site, which provides a utility to (re)set the password of any user that has a valid account on a Windows NT/2000/XP/2003/Vista system. Think outside the box 16:02, 22 February 2008 (UTC)

Just to note that I've used the utility on this site (which is free) many times in the past with great success. Don't pay money for it—they're likely giving you the same software but making you pay for it. --98.217.18.109 (talk) 22:43, 22 February 2008 (UTC)

Try Active Password Changer to just clear the password flag. It's on the Hiren's livecd, google it :D\=< (talk) 16:23, 22 February 2008 (UTC)

Note that Hiren's boot CD is a massive copyright violation. There are free-software alternatives, like this one (already linked by Think outside the box). Another option is ophcrack, which actually reveals the current password instead of changing it. The commercial site linked by Think outside the box is probably running it on their server. Also, you didn't say how old the system is, but if it's running Windows 95/98/Me, you should be able to just click Cancel at the login dialog. -- BenRG (talk) 22:06, 22 February 2008 (UTC)

Digital Camera TYPE

I've seen some people outdoors taking some pictures. They do this quite often. These People! This isn't a lot of info here, but out of all the cameras that I've seen, I like one. But I'm not sure the brand/type. Here's a brief description:

Small size. Maybe marketed for teens. I'm not sure what the front looks like. But the back, LCD fits the entire back end. It's like the back of the camera is an LCD.

Cheers, 17:35, 22 February 2008 (UTC)there will be OIL!

It would be a 'compact' or 'ultra compact' camera, with, by the sounds of it a 3" plus screen (presumably no viewfinder either?). I think that makes it similar to the Fujifilm Finepix F11 (an excellent camera) but there is a site that lets you compare cameras so maybe that will help. Here's one set for 3i-inch screen ultra-compact (http://www.dpreview.com/reviews/compare_post.asp) and here's one of just compact ones http://www.dpreview.com/reviews/compare_post.asp. You'd have to 'go into' the details to try find a back-shot of them. ny156uk (talk) 17:48, 22 February 2008 (UTC)

Standby and Hibernate Modes

I understand standby mode puts the computer into a low electricity mode so I can swiftly startup again but what is going on? What does "hibernate" mean on the computer? How can I start it up again if it's already on? I have DSL so in standby or hibernate am I still connected to the internet? Am I vulnerable to viruses if my virus protection isn't getting enough power? I understand I might want to put it into one of these modes if I'm only going to be gone for an hour or so but what about overnight, a day, a week or a month? What are the advantages and disadvantages of each and why use one and not the other? No one else has access to my computer and I pay a flat rate per month, not by time used. If an update or scan is scheduled to run while it's in one of these modes will it "turn itself on"? —Preceding unsigned comment added by 74.233.41.190 (talk) 20:04, 22 February 2008 (UTC)

It's possible that there's some variance in how manufacturers use these terms, but typically "hibernate" means "dump a copy of memory to disk, and turn off." This means when you start back up, instead of the OS booting and you starting all over, whatever you were doing is restored. All the stuff that was open before will still be open. In either standby or hibernate, the computer isn't really running- consider it to be "asleep", or perhaps "in a coma" for hibernate mode. Friday (talk) 20:08, 22 February 2008 (UTC)

First of all, you could turn off your antivirus indefinitely and you'll be fine. Also, hibernating is identical to shutdown except a dump of the memory is made and then restored on startup instead of following the normal boot sequence. There's probably other things going on too, like networking being disabled so it doesn't think it's still online when the memory is reimaged. I don't know exactly what's going on "standby".. I think it's just a low power mode where the CPU is just looping checking for the power button being hit, and all peripheral and output devices are shut down. Obviously in either of these states your computer's not "connected to the internet" in the sense that any daemons are running on the computer listening on ports. The cable's still connected, but the balls are inert. :D\=< (talk) 21:54, 22 February 2008 (UTC)

No, absolutely not! You should not turn off your antivirus. If you do that, your computer will soon become a zombie that spreads viruses, sends millions of spam e-mails or performs denial of service attacks.

Further, whether the computer is in stanby, hibernating or even fully turned off, it may still be awaken by network or modem if that option is enabled. - PauliKL (talk) 23:57, 24 February 2008 (UTC)

oh lord.... :D\=< (talk) 06:55, 25 February 2008 (UTC)

The advantage of standby over hibernate is that it's faster to come back to life. The disadvantages are (1) it still draws some current, though a lot less than when turned on, and (2) you'll lose unsaved work in a power outage just as though it were turned on. A hibernating machine is actually powered off and you can unplug it completely. For anything more than overnight you should probably use hibernate. Often you can choose whether to have the computer wake up to perform a scheduled task. In the Windows task scheduler there's a checkbox you can check. -- BenRG (talk) 22:40, 22 February 2008 (UTC)

Some, including Joel Spolsky, suggested that the sleep and hibernate functions can be integrated into one. The idea would be to dump the momory to the hard disk, (park the hard disk head), and set the computer on a low powered state for a predefined amount of time, and turn off the system.

They wanted this to happen in Windows Vista but I don't know if Windows Vista got the feature. Maybe in Service pack 2? Kushal 14:50, 23 February 2008 (UTC)

I think that if you have a desktop, you might just turn off the monitor when you leave, and let the computer run as usual. That would still be doing something and if you have autoupdate enabled, the computer will update itself with the latest Tuesday patches. Kushal 14:56, 23 February 2008 (UTC)

That is definitely not a good idea. A computer consumes some 150W to 250W of power. It may well be over 50% of all the electric power consumption in your household if you keep it running all the time. You should always turn off the computer, to save the World. - PauliKL (talk) 23:57, 24 February 2008 (UTC)

Hi Kushal, I'm the person who asked the question. After reading this I tried standby and hibernate modes with and without a program running. I also found the Windows task scheduler. After restarting I looked for the copy of memory which had been dumped on disc but didn't find it. It seems like it would take a lot of space on the disc so it should delete it after you come back on. Then could it reuse that same space the next time you went into hibernate? Could you have the copy of memory put on a removable disc and bring it to another computer and start that one just as if it had been the first one? But when you tried to restart the first computer it would look for the removable disc to read from and not find it unless you put it back in. I was thinking of running full scans while sleeping but I'll first do that while keeping watch on it to see if it turns itself off again. Thank you very much for all this very interesting information. Now I have a new toy to play with. —Preceding unsigned comment added by 74.233.118.98 (talk) 21:19, 23 February 2008 (UTC)

Hard disks are usually so much bigger than RAM (which is what must be written to it) that the lost space is insignificant. (However, one might consider it a serious security issue to have your RAM written to disk.) The space can certainly be reused for the next hibernation. You can't usefully transfer a memory image between computers -- even if they happen to have the same amount of RAM, the hardware is different and would disagree with the RAM image. (Even two "identical" computers will have different MAC addresses, hard disk serial numbers, etc.) If you did hibernate to a removed disk, the first computer would have no way of knowing that there was supposed to be a disk, and would probably start up in the normal fashion. (Note that booting in the normal fashion prevents ever using a memory image; the act of booting (in almost all cases) effectively makes the computer a different computer that can't share it. So you have to use the memory image the very next time you use the computer.) --Tardis (talk) 02:46, 24 February 2008 (UTC)

The "memory image" loading is handled by Windows, not any BIOS magic. When I restore from hibernation, it boots just like normal with the GRUB prompt.. I can even boot into xubuntu for days then next time I need windows --oh what a pleasant surprise I have a fast boot cause I hibernated the last time I shut down. :D\=< (talk) 10:05, 24 February 2008 (UTC)

I'm aware of that. Unfortunately, if your various OSes mount any of the same filesystems (read/write) then the cached information maintained by one will be invalided by the other(s). I left that detail out for the benefit of the OP, who probably does not use multiple operating systems or (if so) know off-hand which filesystems which OS mounts read/write automatically. --Tardis (talk) 19:25, 25 February 2008 (UTC)

HOLD ON - THIS IS WEIRD Up above BenRG said in shutdown the CPU is just looping waiting for the power button to be hit, all input and output devices are shut down. Well all I have to do is walk near my computer in standby and it starts up again! I don't need to touch anything! The floor is carpeted and very solid underneath and the desk is quite solid, so I don't think the modem is being shaken, and I don't have a microphone so I don't think it's picking up any sounds. HOW DOES IT KNOW I'M APPROACHING? Also, I set it up to run a virus scan during the time it was in standby mode and to turn itself on for this. I watched it and nothing seemed to be happening, no sounds, no lights etc. so I turned my desktop on and clicked on the virus program and it said that the scan was running and had been running for ten minutes. It hadn't come on the screen when I first turned it on.74.233.118.98 (talk) 19:56, 24 February 2008 (UTC)

It's possible that your computer has become sentient. Buy a webcam, plug it in, and talk to your friend in the next room about how you hate your computer and you're going to throw it out. Then see if it gives you any problems. :D\=< (talk) 01:41, 25 February 2008 (UTC)

That was a riot, I laughed till I cried! Now I'll tell my computer I love it and it's a good, sweet angel.

(Added by mysterious user: Try placing the computer case (your desk even) on an antistatic mat. Stray electrical charges (such as your walking across the floor approaching the pc) can play havoc. Fact: Your body needs to build up thousands of volts before you even sense static electricity. I understand a single spark can carry about 25,000 volts. —Preceding unsigned comment added by 74.233.118.98 (talk) 07:22, 25 February 2008 (UTC)