Wikipedia:Reference desk/Archives/Computing/2010 February 22

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February 22

Double directorys

When unpacking/opening compressed sets of files eg .rar I often get file paths like this:

C:My_Computer\My_name\My_Documents\peter\peter\actual files here

when unpacking a file like this:

C:My_Computer\My_name\My_Documents\peter.rar

when the packed file was called peter - the relevent files are in the second peter - why is a nested peter directory created that contains nothing but yet another peter directory ? Is there a reason for this?87.102.67.84 (talk) 01:06, 22 February 2010 (UTC)

Some programs that extract files will create a folder with the same name as the compressed file, then extract all the files into it. Some people that prepare compressed files put a single folder in the root of the compressed file that contains all the other files. If both happen, then you'll get one folder in another. --70.129.132.244 (talk) 02:23, 22 February 2010 (UTC)

Makes sense, thanks.87.102.67.84 (talk) 02:25, 22 February 2010 (UTC)

In the world of Unix, it's traditional to create archives that extract into a directory with the same name as the archive. This is so you can drop the archive into, say, your home directory, and extract it without creating a huge mess. You can check the documentation of your extractor to see if it automatically creates those directories, or if the people who made the .rar files are doing things the Unix way. Paul Stansifer 14:09, 22 February 2010 (UTC)

Thanks - I'm using 7zip in windows - an experiment confirms that it creates a folder when extracting to contain the files compressed even when the original file was not 'folderised' - this explains it.

Simple when it is explained to you. Thanks both.

Resolved

Sega Master System cartridges

How can you tell the difference between a European (PAL) and a US (NTSC) Sega Master System cartridge? Daram.G (talk) 02:08, 22 February 2010 (UTC)

According to the same article you linked, there is no physical difference between the US and European cartridges. The only physical differences are between Japen/South Korea and the rest of the world. Likewise the console doesn't have any region coding so all US/EU games will run on the SMS with only a few exceptions because of the technical problems with the games themselves. ZX81 ^talk 02:33, 22 February 2010 (UTC)

Are the European versions of the carts adjusted to play at 50 Hz? Will the US version of a game at 60 Hz play at the same speed as a European version of a game at 50 Hz? Daram.G (talk) 03:40, 22 February 2010 (UTC)

Also, are there no obvious label differences? Daram.G (talk) 03:44, 22 February 2010 (UTC)

I have no source for this, but as far as I understand it with the SMS games it's nothing to do with the cartridge, but the console that's playing it (a US SMS runs the games at 60Hz, an EU SMS runs the games at 50Hz). Because there is no region coding and the cartridges between US and EU are fully interchangeable, I don't think there is any differences. As for the labelling though, I'm unable to tell you that I'm afraid, but since they haven't put in any region information it would make sense that the labels are all the same too. Sorry for not being able to give you a full answer, but I hope this is of some help! ZX81 ^talk 03:57, 22 February 2010 (UTC)

There will have to be a reference for ZX81's speculation, I am afraid. US console programmers always had to do a lot of crap work at the end of every project for the dreaded PAL conversion. Video resolution is different and the 50/60Hz difference is a pain, too. I don't know anything personally about the Sega Master System, but to my knowledge, the first console that supported a worldwide console release, where the same SKU (a disc, in this case) could work on any system was the first Xbox. Comet Tuttle (talk) 05:16, 22 February 2010 (UTC)

Normally I'd completely agree with you, but with the Master System it was a bit of a weird system because they really didn't bother. PAL versions of the console literally squashed the screen to fit the native resolution and ran slower as well, there was no adjustment done by the actual developers to handle PAL conversion. A lot of owners therefore "modded" their SMS to put in a switch to convert between 50Hz and 60Hz so they could play the games as intended. Links to this here and here. ZX81 ^talk 23:59, 22 February 2010 (UTC)

This is great information, everyone. Thank you for your help. Daram.G (talk) 04:24, 24 February 2010 (UTC)

daily/weekly PHP code problems?

Other than browsing StackOverflow, is there a way I could get daily or weekly PHP code challenges/problems to think about in my freetime and (hopefully) introduce me to new aspects of the language? I'm imagining a blog/email list or something where they post short challenges & answers on a regular basis... Thank you! 218.25.32.210 (talk) 06:54, 22 February 2010 (UTC)

thedailywtf.com is pretty funny. If you just want programming challenges, rubyquiz.com has a big collection of them, though not PHP-specific. They're intended for Ruby but lots of them are worth doing in other languages. PHP itself is not that complicated and in my perhaps snobbish opinion it's not worth messing with its weirder corners instead of just doing stuff straightforwardly. It -is- worth looking over other people's PHP code to figure out what it's doing. MediaWiki (mediawiki.org) is a big PHP application that we here all use, so it's a possible place to start reading. And of course bugzilla.mediawiki.org has tons of real-world problems that you can work on and for which your solutions would be gratefully received by the wikipedia community. Lots of the open requests aren't terribly difficult, it's just a matter of somebody finding the time for them. Maybe the somebody is you ;-). 75.62.109.146 (talk) 11:33, 22 February 2010 (UTC)

If you want some general programming challenges, Project Euler is a fun resource. The problems are mostly mathematical and computer science oriented in nature, so it may not be what you're looking for, but it will definitely help you become a better programmer. Start with the early ones, the last ones can be crazy difficult. Belisarius (talk) 22:12, 22 February 2010 (UTC)

Hardware Diagnostics

Please see [1]. Is there any way to run diagnostics to see if there is a hardware problem? TresÁrboles (talk) 08:39, 22 February 2010 (UTC)

You could try memtest86.com but from your description, I don't see anything suggesting hardware problems. 75.62.109.146 (talk) 11:38, 22 February 2010 (UTC)

I agree. OR here but I have seen my computer freeze thousands of times over the years, and only rarely is hardware at fault. Comet Tuttle (talk) 19:06, 22 February 2010 (UTC)

I really hope that is the case, but I'm worried. I've had the PC freeze up on me on rare occasions before, but it's been happening consistently these last few days now. At first, I thought it might be ads on websites, then Firefox itself, but then I had the problem happen when I was playing a Flash game not on a website (the swf file was on my drive) using Internet Explorer, so I then thought the recent Flash update was the problem. But then I got the problem while watching a DVD and not using any other app (besides PowerDVD). Therefore I don't think the problem is Flash by itself anymore. I'm pretty sure it's exacerbated by Flash though; I was browsing the web all day yesterday without problem, then last night I enabled Flash to browse Youtube, and bam! PC frozen after only 15-20 minutes! My current hypothesis is hardware related to video is flaking out, but works until irritated by Flash or video- or graphics-intensive stuff. Sorry if that's a silly idea; I don't know too much about hardware. TresÁrboles (talk) 01:02, 23 February 2010 (UTC)

videogame processor design idiocy

The Playstation series, of late, has seemed hell-bent on basing itself around "hard to design for" processors. Prior to that, the Sega Saturn was a famous pain in the ass. My question is simple: how is this possible? Processors are not designed overnight by one monkey - they take years and teams of engineers. How could "the system" possibly end up with something difficult to use? Logically, the fact that that processor was chosen implies that other options were found to be less acceptable. It baffles the mind. Isn't usability paramount here? How can you build something to be "fast" if no one knows how to use it? It's like making a bicycle that is allegedly phenomenally fast, but virtually unbalanceable, and then blaming the rider! This makes no sense to me... 218.25.32.210 (talk) 08:55, 22 February 2010 (UTC)

I'm not able to source any of this by the way, this is just put together from things I remember reading, but anyway... The Saturns (unique at the time) dual processor design apparently was actually a very quick decision. The console was going to have a single standard processor for quite a long time during its development, but then Sony released the specs for its Playstation, and sega decided that they needed more power, so added an extra processor or something, making it apparently difficult to program for. The PS3 uses the Cell Processor which is at least partially made by Sony, and because of this it allows sony to make them cheaply. Lots of components in both the PS2 and PS3 are made by Sony themselves if I recall correctly. The cell seems to have been designed for rendering and server applications, and massivly multithreaded things, and does pretty well. I guess this makes it hard to program games for, at least if you're making a game with the intent of making it multiplatform. Gunrun (talk) 09:09, 22 February 2010 (UTC)

The oft-repeated hard to program issue is overblown. It's just that having a single multipurpose processor (such as an x86) is easier to use.

The processors have maximium power for a specific task - in the PS2 (and PS3 cases) this is mostly vector transforms and similar - an 'easy to program' x86 processor of similar power would have been expensive, and full of a lot of extraenous processing ability that wasn't useful, and have a larger die size.

You're analogy is a little overblown - both playstation processors are perfectly workable and stable for the task.87.102.67.84 (talk) 13:20, 22 February 2010 (UTC)

See also http://forums.sega.com/showthread.php?t=313485 (the main Hitachi SH4 processors used in the saturn are simple, easy to use and straightforward RISC processors )

Most of this comes from people who don't really know what they are talking about - eg Saturn - what's so hard about a two processor system? Is a core2duo hard to program?

87.102.67.84 (talk) 13:29, 22 February 2010 (UTC)

The other reason may be lack of easy to use middleware rather than something intrinsically wrong or hard with the architecture; which is designed with a specific task and purpose in mind, and not to be easy to program by untrained persons.87.102.67.84 (talk) 13:32, 22 February 2010 (UTC)

Keep in mind who is claiming the PS3 is hard to program for. Is it someone who purchased Sony's development API or is it someone who didn't get the API and is trying to poke through it manually? Imagine trying to write a program for you PC without any compiler of any kind. It would be a pain in the ass. -- kainaw™ 14:27, 22 February 2010 (UTC)

This is the reason game engines and middleware exists, so that the obscure task of writing machine code to drive the graphics chip, or do collision detection doesn't have to be written every time a new game is made. This I think relates to the reference to Yu Suzuki in the link I gave above - out of a development team of 100 only 1 person will actually need low level understanding of the architecture, and be writing code for it the rest will be concerning themselves with graphics assets, scripting, and programming that can sit on top of the 'hard coding stuff'. The days of the single lone programmer are pretty much dead.87.102.67.84 (talk) 14:34, 22 February 2010 (UTC)

87's claims (that this is all exaggerated) are not correct. It is apparent that he or she does not work on these systems. Every single coder in the video game industry bitches about the difficulty of programming for the PS3 architecture, and before that they all bitched about the PS2 architecture, and before that the few who worked on Saturn games really let you have an earful, all of the time. All three really have been pains in the ass. Video game coders — not one low-level guy, but all of them — are always leaned on hard to squeeze out the maximum performance possible, because the content guys always want to cram more data into every frame — larger and more textures, geometry, animation, particle effects. It's true that using the Unreal Engine, or whatever, helps a lot, but you still need coders to do specific low level stuff necessary for your game, because in the quest to become optimal — in order to accommodate more of the demands of the content guys — you're doing plenty of low level coding and optimization for all the systems you do have to write. Anyway, to speak to the original poster's question of why, I heard a similar story about the Saturn, that its extra processors were thrown in hastily and at the last minute. As for the Sony architectures, these came from Ken Kutaragi and his team. He loves high performance and for the PS2 and PS3 was willing to follow a path that got him some interesting high performance, even though it be hostile to programmers on his systems. The PS2 architecture with the vector units was introduced because some benchmarks were promising — although a slower system overall than the (later and more expensive) Xbox, the PS2 can beat the Xbox at certain narrow tasks because of them. And as for the PS3, Mr. Kutaragi stood in front of everyone at his GDC keynote speech a year or two before the PS3 launch, and showed some benchmarks of a prototype system with eight PS2 motherboards operating in parallel. Parallel computing seems to fascinate Mr. Kutaragi, and the PS3 is the result. Comet Tuttle (talk) 18:09, 22 February 2010 (UTC)

The PS3 is really a gaming machine. The end-use begs for parallel processing and (especially) vector processing. A scalar processor simply won't do. It is an architecture argument, not a programming argument. So, as you said, the programmers get left out of the argument and complain about it. If I were to design a gaming system, I'd use a vector processor with a heavily pipelined and parallel floating-point math unit along with associative memory instead of addressable memory. It would be completely beyond the norm for programmers, so they would hate it. -- kainaw™ 18:26, 22 February 2010 (UTC)

Internet service after power cut

Resolved

Is there likely to be a delay in the resuming of internet services after a small, localized power cut? —Preceding unsigned comment added by 82.43.89.27 (talk) 13:35, 22 February 2010 (UTC)

The internet may not actually be affected by a localised power cut since it usually runs off the telephone systems set of wires (depends on situation).

Otherwise if the local internet did lose power during a power cut - you could expect a delay whilst it restarts - anything over an hour would suggest to me they screwed up their recovery system. Sorry I can't be more specific. I wouldn't expect a notable delay in general.87.102.67.84 (talk) 17:20, 22 February 2010 (UTC)

. References please? Comet Tuttle (talk) 19:05, 22 February 2010 (UTC)

Last time our power was cut off the telephones and internet still worked - sorry that's the best I can do.87.102.67.84 (talk) 19:43, 22 February 2010 (UTC)

Thanks for the answers. The internet comes via fiber optic cable, not a phone line. Would that make a difference or do they use the same system? —Preceding unsigned comment added by 82.43.89.27 (talk) 20:45, 22 February 2010 (UTC)

Fiber optics mean you definitely won't get service during the power outage (since fiber optics only transmit data and rely on wall power to operate). After power is restored, it's a crap shoot and depends on what caused the outage, whether the ISP also lost power, etc. If both the fiber optic and power cables were cut, and only one was fixed, you'll need to wait until they fix the other. If the power outage was caused by a lightning strike, or there was some other source of power spike before the outage (or they caused a spike when turning the power back on), it may have damaged electronics at either end, and they'd need to be replaced before it would work. Aside from those circumstances, I wouldn't expect a significant delay restoring internet service after power was restored. —ShadowRanger ^(talk|stalk) 20:55, 22 February 2010 (UTC)

There seems to be some confusion here. Unless you have some sort of uninterruptible power supply or a laptop with a built in modem which you use to connect to the internet thru the phoneline without relying on any external device, you will lose internet access since you have no power for the devices on your end (it would work if your laptop has a built in Optical Network Unit that connects to your local fibre connection as well although I doubt such devices exist particularly since most fibre connections to the ONU aren't likely to be designed to be removable). I would hope this should be obvious to all, the same way your TV or microwave oven won't work. While normal corded analog phones can operate without any extra external power (getting power from the phone line), others including all data equipment (obviously something like a laptop has internal power so doesn't always need external power) can't no matter whether they connect to the phone line or fibre optic cables.

However the internet service itself may not be affected you just need to provide power to the modem and routers on your side to use it. If you have some sort of UPS for the ONU or modem and routers (if needed) then as long as that has power, your end should be fine (whether you can use it of course will depend on whether you have a UPS for connecting equipement or battery powered devices like a laptop).

It is of course possible that there may be problems on the other end. However most network providers should have decent UPSes and often backup generators too so provided it isn't too long and there isn't some other issue (like cut lines or lightning strikes) the network provider shouldn't go down or at least not for long due to a power failure. (Of course shit happens [2])

If you want to stimulate a power cut on your end and have access to the power supply for the modem or ONU, then just cut the power for a while and bring it back. It usually won't take long for service to work again.

Incidentally, if you rely solely on VoIP for your phone line, you may want to consider installing some sort of UPS for emergencies during power cuts.

Nil Einne (talk) 02:42, 23 February 2010 (UTC)

Thanks!

"Hex-based"?

I just stumbled upon the Systemsoft article. What does "hex-based" mean? I guess that it either means that the user has to input a large number of hexadecimal numbers during gameplay (not probable), or that the user interface is based on a hexagonal tiling, as in this screenshot (more probable). --Andreas Rejbrand (talk) 14:43, 22 February 2010 (UTC)

For company, hex refers to the map. It uses hexagons to avoid strategy faults in a standard grid map. -- kainaw™ 14:55, 22 February 2010 (UTC)

I have linked hex map in that article. -- Finlay McWalter • Talk 16:36, 22 February 2010 (UTC)

Make clickable links to HD in a text file or similar?

Is there anything that will allow me to click on for example C:\my docs\mytext.txt in a text file or similar and have mytext.txt open? The freeware notepad-like Metapad will do this with URLs but it does not work with references to the HD as far as I've found. A simple database with this facility would be useful too. Thanks 78.147.192.66 (talk) 16:29, 22 February 2010 (UTC)

Have you tried the file: notation? That is used by most web browsers. -- kainaw™ 16:32, 22 February 2010 (UTC)

http://techie-buzz.com/softwares/metapad-free-notepad-replacement.html for an example of using the "file:C:\blah" notation in metapad.

Found better answer ignore ... Notepad doesn't do it, Wordpad sort of does (for certain file types, as OLE objects), openoffice does it properly - use insert>hyperlink and select "document" then select your file - and give a text name as you wish it to appear in the document (annoyingly you need to use CTRL-click to open, not double click).

In general search the documentation or help page of a given program for "hyperlinks".87.102.67.84 (talk) 16:52, 22 February 2010 (UTC)

Strange Internet problem

My computer is connected to my d-link router and my modem. The internet on my host computer was working fine, but stopped all of a sudden. My laptops can still connect to my internet and I can browse the internet from there. My host computer cannot browse the internet and I have no idea why. I checked with ipconfig and saw that the dhcp is not enabled. I would really appreciate any help. If you need more info, just ask.--68.210.32.244 (talk) 17:23, 22 February 2010 (UTC)

You could set the IP address to use manually for this simple wired connection - in (windows) network places - select the connection, the open the properties window, then Internet Protocol (TCP/IP) properties - you can then enter the address - though the same window gives you the option to turn on DHCP anyway which should also fix it. (You'll probably need to go through a restart or maybe flush the DNS stuff - if you are using ipconfig in cmd.exe then "ipconfig /?" gives the switch to type to do this.

I'm assuming that the fix is simple (above) - though I don't understand the cause.(below)

What IP address is the connector currently trying to use, and what is your routers address?? (did you connect manually before, and was DHCP on before?) - My guess is something has caused the IP address on one or both to reset - but why - this isn't normal? Hopefully someone else can explain if this is a worrying development..(Any new programs or other odd behaviour)87.102.67.84 (talk) 17:43, 22 February 2010 (UTC)

Windows 7 screen saver issue

Is there any way to adjust when the screen saver turns on with Windows 7 Starter Pack? I'm using a Spanish version and I thought I'd changed it under the energy saving menu but nothing really changed. It's set at 2 hours for everything but still there's a 1 min delay before it turns on again... It's very frustrating to try and watch a video on Youtube when the screen saver turns on constantly. Thanks for any help 87.111.102.76 (talk) 17:36, 22 February 2010 (UTC)

I do not know what "Windows 7 Starter Pack" is. Perhaps you mean "Windows 7 Starter"? The amount of inactivity before the screen saver starts is adjusted where you choose the screen saver. Right click on the desktop and select "Adjust" followed by "Screen Saver". Alternatively, you can open the same window by searching for "screen saver" in the Start Menu. --Andreas Rejbrand (talk) 17:43, 22 February 2010 (UTC)

Sounds like you are adjusting the amount of time it takes for the screen itself to turn off (in energy settings)

ie the energy settings turns the whole screen off , but doesn't affect the screen saver.

For screen saver properties http://www.sevenforums.com/tutorials/2109-screen-saver-change.html (scroll down to Here's how) .. right click on the desktop - select "personalise" then click on the screen saver part, and adjust the time it takes to come on (or off?)

To have no screen saver at all see http://www.sevenforums.com/tutorials/2111-screen-saver-turn-off.html

Did it work?87.102.67.84 (talk) 17:52, 22 February 2010 (UTC)

OK, so "Adjust" in my response above should be changed to "Personalize". Why can't everyone use the Swedish version of Windows?! --Andreas Rejbrand (talk) 17:55, 22 February 2010 (UTC)

For the benefit of the spanish version using poster - it's the option at the bottom when you right click on a blank area in the screen.87.102.67.84 (talk) 18:23, 22 February 2010 (UTC)

Thanks for your replies but the big problem is I don't have a 'personalise' feature on the right-click drop down menu... I believe it's mentioned in several places on the net that there is no 'personalise' feature on Windows 7 Starter... But surely there is something that can be done because it seems ridiculous to not be able to watch something for longer than a minute without it switching to screen saver 87.111.102.76 (talk) 18:52, 22 February 2010 (UTC)

ooops - sorry I had no idea the starter edition was that locked down - you can try start>>control panel>>display>>screensaver - but according to some reports the change screensaver dialog appears - but has no effect afterwards - just reverts to default - it's worth trying anyway.

If it's true that you can't even change the time limit for screensaver in the starter edition there might be a solution worth trying (no idea if it will work - it might generate a pop-up error) - and that is to delete the screen saver file so that it can't run at all..

Not sure what it's called but searching for "*.scr" in the hard disk should turn up all the installer screensavers - you could try moving them to a different location, and seeing if that has the desired effect. Hope this works.87.102.67.84 (talk) 19:21, 22 February 2010 (UTC)

According to the above link the files are in C:\Windows\System32 eg C:\Windows\System32\Bubbles.scr

If removing the .scr file works (not sure it will) then you can create the effect of a blank screen saver using the power options to turn off the screen after whatever time you can enter.87.102.67.84 (talk) 19:31, 22 February 2010 (UTC)

I see. But if Windows 7 Starter does have a screen-saver feature, then there must a dialog where the user can choose her screen saver? In the Swedish version of Windows 7 Home Premium, it looks like this. "Vänta 10 minuter" means "Wait 10 minutes", i.e. "do not start the screen saver until the computer has been inactive for ten minutes". --Andreas Rejbrand (talk) 19:22, 22 February 2010 (UTC)

If everything else fails, you might want to try an application that simulates cursor motion, such as my own CursorMotion.exe application. But this is a very ugly solution - surely there must be a way of inactivating, or delaying, the screen saver even in Windows 7 Starter? --Andreas Rejbrand (talk) 19:26, 22 February 2010 (UTC)

(People are calling windows 7 starter the evil edition...) I wonder if there is a command line switch there could be used to set the time out in the bubbles.scr program - someone else with have to tell since I have no idea - could the bubbles.scr program be replace with a shortcut of the same name incorporating the switch.

Other alternatives seem possible - I think .scr files might(?) just be .exe files by a different extension - perhaps it is possible to create a "bubbles.scr" file from another file eg create a .exe that simple exits rapidly, and rename it "bubbles.scr" don't know enough about their implementation to be sure.87.102.67.84 (talk) 19:41, 22 February 2010 (UTC)

Yes, a screensaver is an ordinary Win32 application (*.exe file) with an odd extension (and that responds well to some command-line arguments for "preview", "start screensaver", "show settings dialog", etc.). --Andreas Rejbrand (talk) 19:45, 22 February 2010 (UTC)

I've just been experimenting and noticed that the screensaver files in \system32 are fairly well protected - ie can't be straightforwardly deleted - if someone wants to delete them I think some registry editing would be needed - something I don't know how to do.87.102.67.84 (talk) 20:14, 22 February 2010 (UTC)

"Registry editing"? Wouldn't it suffice to run the file manager as an administrator? --Andreas Rejbrand (talk) 20:19, 22 February 2010 (UTC)

Something more odd is happening - I can delete the file eg ssstars.scr - no problem - but the deleted file is actually replaced by the system a few seconds later - similarily if I manage to rename another file to ssstars.scr (the starfield screensave) overwriting the old one - it automatically re-overwrites with the old file a few seconds later - I've never seen this behaviour before- and don't know what is doing it - try for yourself ???87.102.67.84 (talk) 20:36, 22 February 2010 (UTC)

Well, that doesn't surprise me. Windows doesn't want its system files to be altered (and most often that is good)... --Andreas Rejbrand (talk) 21:09, 22 February 2010 (UTC)

How to get rid of screensavers (doesn't work for me) found a possible answer should someone really need to delete a screensaver, as maybe the case here - quite why windows is so protective of an apparently non critical component is still a mystery though.87.102.67.84 (talk) 21:22, 22 February 2010 (UTC)

Perhaps Windows is as protective of all items in the System32 directory? --Andreas Rejbrand (talk) 21:24, 22 February 2010 (UTC)

It looks like it is - not sure if the delete bubbles.scr method will work after all, even with extra effort.87.102.67.84 (talk) 21:30, 22 February 2010 (UTC)

Anyhow, I still cannot accept the fact that you cannot disable or delay the screensaver in Windows 7 Starter. I wish I had a W7S machine to try... --Andreas Rejbrand (talk) 21:31, 22 February 2010 (UTC)

Does help [3]. Did you try searching in the control panel as suggested above [4]? Incidentally Windows 7 Home Basic lacks a personalise tab too [5] although it seems like it may come with more then one desktop background [6]. Incidentally does the Windows 7 Starter EULA allow installation in a VM? If so, someone with the proper MSDN access or whatever could just install it onto a VM and try. Nil Einne (talk) 04:07, 23 February 2010 (UTC)

This page from Microsoft leaves me with the impression that you cannot change your screensaver in Win 7 Starter (see "Applies to these editions of Windows 7" in top right). Further down, behind the "To install a screen saver" link, it says you cannot uninstall screensavers that came with Windows 7. Perhaps you could hack the registry, but then again maybe Win 7 Starter stops you doing that too. Anyway, in my Vista installation the "HKEY_CURRENT_USER\Control Panel\Desktop" node includes:

"ScreenSaveActive"="1"

"ScreenSaveTimeOut"="600"

"SCRNSAVE.EXE"="C:\\Windows\\system32\\Aurora.scr"

Seems ScreenSaveTimeOut=600 gives a 10 minute delay. Astronaut (talk) 10:00, 23 February 2010 (UTC)

The same values exist on Windows 7 Home Premium. This looks like a very promising solution for the OP. Try to change the number of seconds to the value you want (ScreenSaveTimeOut). Of course, it is possible that these registry values do not exist on W7S, or that theye are ignored, but my guess is that they are still there, and working. --Andreas Rejbrand (talk) 13:43, 23 February 2010 (UTC)

This vbs script turns on and off the screen saver it relies on the registry so it may not work if Windows 7 Starter won't let you edit the registry, but as long as it works he could run it whenever he needs to turn the screensvaer off. I'd recommend assigning it a hot key with AutoHotKey or something similar.

Dim WSHShell, RegKey, ScreenSaver, Result
Set WSHShell = CreateObject("WScript.Shell")
RegKey = "HKCU\Control Panel\Desktop\"
ScreenSaver = WSHShell.RegRead (regkey & "ScreenSaveActive")
If ScreenSaver = 1 Then 'Screen Saver is Enabled
Result = MsgBox("Your screen saver is currently active." & _ 
vbNewLine & "Would you like to disable it?", 36)
If Result = 6 Then 'clicked yes
WSHShell.RegWrite regkey & "ScreenSaveActive", 0
End If
Else 'Screen Saver is Disabled
Result = MsgBox("Your screen saver is currently disabled." & _ 
vbNewLine & "Would you like to enable it?", 36)
If Result = 6 Then 'clicked yes
WSHShell.RegWrite regkey & "ScreenSaveActive", 1
End If
End If

Xor24 ^{talk to me} 21:05, 28 February 2010 (UTC)

The internet thinks my computer is a mac

Hi,

My laptop has many viruses, I recently tried to clean it up a bit and now it doesn't open random webpages and play me porn videos when I'm least expecting it - but it's also not completely healthy. I'm going to have to format it and all that, but one of the other symptoms it's now exhibiting (seemed to be caused by the virus scanners...) is that the internet thinks it's a mac - but it's really an off the shelf hp running vista. Sites include download.com, chrome download site, and youtube - they all give me suggestions or downloads suitable for macs. What could be causing this? As I said, I'm not so worried about fixing this problem, I would like to hear theories on how this could work.

Cheers,

Aaadddaaammm (talk) 18:56, 22 February 2010 (UTC)\

Most likely your browser's user-agent string has been modified. The Hero of This Nation (talk) 19:02, 22 February 2010 (UTC)

Probably done by the virus or whatever to make it more difficult to download solutions to your problems - good luck with the re-install ..87.102.67.84 (talk) 19:25, 22 February 2010 (UTC)

According to the ads, the internet now thinks you're much more hip than you used to be!-- Flyguy649 ^talk 19:27, 22 February 2010 (UTC)

If you have a bunch of viruses, I would use this free download to help clean things up. [7] I use this, and it scans, and deletes. I haven't had any problems with it. Moptopstyle1 ("I Feel Fine.") (talk) 19:45, 22 February 2010 (UTC)

Windows Defender, included in Windows Vista/7, is also good. --Andreas Rejbrand (talk) 20:01, 22 February 2010 (UTC)

"Get a Mac!" ;-). Or, more seriously, try Ubuntu. It is mostly virus-proof, reasonably friendly, and reasonably capable. --Stephan Schulz (talk) 20:13, 22 February 2010 (UTC)

I doubt it. MAC_address - Kittybrewster ☎ 20:17, 22 February 2010 (UTC)

Don't try to remove viruses. You will never get them completely gone. Buy a new hard drive, install it in the laptop, install your OS and software on it from original media, and copy your user files from the old drive being very careful about any file types subject to infection. Anti-virus software is useful because it can alert you to the presence of viruses. But it can never give you any assurance at all about their absence. 75.62.109.146 (talk) 20:26, 22 February 2010 (UTC)

I wouldn't go so far as to buy a new hard drive this IMO is a bit of a drastic action for a little infection. Try the link provided above by Moptopstyle1, I have used it myself with no problems. Mo ainm (talk) 20:34, 22 February 2010 (UTC)

I'm with 75; I would always do a wipe and a clean install. New hard disk is only needed if you lack a 2nd already (in order to store all your infected stuff before moving it onto the wiped hard disk). Comet Tuttle (talk) 21:33, 22 February 2010 (UTC)

Supervised and Unsupervised Learning

I was reading the supervised learning article. At the end of the overview section it says that the Gaussian Mixture Model is one of the most commonly used classifiers. But the Gaussian Mixture Model article says that a mixture model can be regarded as a type of unsupervised learning. Can something be regarded as both supervised and unsupervised learning, or are they mutually exclusive? •• Fly by Night (talk) 20:42, 22 February 2010 (UTC)

Oops missed your final question ... see Semi-supervised learning (or below for a long discourse that doesn't really answer it...)

Also by picking data associations you think (or know a priori) will be useful, without actually classfying any data sets is an example of a combination of the two - it's not truly unsupervised. eg you might want to classify alien language scripts based on things you already know about writing methods in general - not only does it simplify the process - but also by choosing the 'right questions' you can get answers (classifications) by the right type - eg a totally unsupervised learning method might end up just classifying scripts into those that were written big or small.. (stupid example).87.102.67.84 (talk) 00:27, 23 February 2010 (UTC)

It seems that the gaussian mixture model when used in supervised learning has labels attached to the different properties - without the labels it reverts to being unsupervised. For example in unsupervised learning a set of examples of arabic and chinese text could be separated into two distinct sets 1 and 2 (after much iteration of sets) - based on similarity of near features. In supervised learning the individual text examples are labled - thus a final text example should be classified into either chinese or arabic type. (without the iteration of sets required for unsupervised learning). Both can use (or assume) a gaussian spread of values (the values being association of nearby features).

In both cases the gaussian distribution is used as a statistical method to compare sets of data.

There are some fairly clear explanations of the difference between the two using http://www.google.co.uk/search?rlz=1C1CHMA_en-GBGB367GB367&sourceid=chrome&ie=UTF-8&q=supervised+vs+unsupervised+learning

It's possible to explain more about the differences between the two learning methods and how they differ algorhythmically (the implementation) if you want.87.102.67.84 (talk) 22:32, 22 February 2010 (UTC)

eg consider text stored as the series of pen strokes required to express it: defined by length, curvature (1/radius of curvature), curve angle and start and end position - see how the two writing types will consist of a mixture (gaussian? probably) of lines of zero and finite curvature (in different proportions for the two scripts). (assume that curved strokes can be approximated by arcs of circles..) - clearly you would expect the range of values of curvature for arabic script to be gaussian about an average position (eg O B Q etc) - but not with chinese script. Noting that both will have data that has an average around zero curvature ie from L I F etc.

In both types of learning gaussian distributions are used - but in supervised learning the two sets are already described - it's a simpler averaging proceedure to find the gaussians describing each set. In unsupervised learning the sets are not known - so some algorhythm must be used to find the organisation of script examples into sets that produces sets with mimimum gaussian spread (variance). (Placing items in the wrong set will increase the spread) - one way is to iterate over all possible sets that can be constructed - but this is extremely compute intensive. 87.102.67.84 (talk) 23:29, 22 February 2010 (UTC)

Bondi Reader convert to epub?

I have the Rolling Stones Magazine collection, 'Cover to Cover'. Reading happens using the Bondi Reader, which is installed on my XP desktop, and came with the RS collection. Is there a way to convert material from the RS discs to EPUB, so that I can view them on my epub reader? It seems the RS files are in a format called .djvu . On my first try, Calibre did not easily convert the djvu file to an epub file. Thanks if you can advise. —Preceding unsigned comment added by 83.98.238.113 (talk) 22:15, 22 February 2010 (UTC)

Rolling Stone website

I can't access http://www.rollingstone.com/rockdaily . Is anyone else experiencing this or is it just me? 24.189.90.68 (talk) 22:30, 22 February 2010 (UTC)

Can't see it either.87.102.67.84 (talk) 22:32, 22 February 2010 (UTC)

I can see it, but "it" means "Error: Page cannot be displayed. Please contact service provider for more details. (5)". --Andreas Rejbrand (talk) 22:41, 22 February 2010 (UTC)

Amusingly, if you hit refresh, the number changes. I wonder what it specifies, exactly. --Mr.98 (talk) 22:49, 22 February 2010 (UTC)

Seems to be back up.Smallman12q (talk) 02:02, 24 February 2010 (UTC)

Running Pocket PC software on a Windows XP computer

I would like to run a particular program that is only available for the Pocket PC. I do not have a Pocket PC, only a WinXP desktop computer. Is it possible to run it on that please? If so, how is it done? Thanks. 89.242.98.70 (talk) 22:45, 22 February 2010 (UTC)

Try an emulator: [8] [9]. F (talk) 00:30, 23 February 2010 (UTC)

Ubuntu Hardy Heron, Kernel 2.6.24-27-server, trying to get module snd-pcsp to work

Hi,

I'm trying to play audio files through the PC speaker, as this should be possible with the module snd-pcsp.

I can load it with modprobe snd-pcsp without any errors, and aplay /usr/share/sounds/alsa/Noise.wav will output some noise. However, aplay /usr/share/sounds/alsa/Front_Center.wav sounds almost like the Noise.wav file - it shrieks like a Fax machine trying to use a Mickey Mouse voice changer for its connection handshake signal. In other words, I can't hear anything that would sound like the voice saying "Front Center" that I can hear when playing the file on my sound card. At first I thought that the 48kHz of that wav file might be too much for the poor little PC speaker, so I tried it with an 8kHz file as well - with the same result. :-(

I also tried alsamixer to change the setting labeled "BaseFRQ" from 18643 (default) to 37286 (the only other option), but that didn't help either. What else can I try?

I'd really like to be able to use that feature as it would allow me to notify nearby users of certain error situations when there is no screen or speaker set attached to the computer. -- 78.43.93.25 (talk) 22:59, 22 February 2010 (UTC)

Update: After setting the master volume to 100% using alsamixer, the voice can be heard, but there still is an ugly overlay of (white? pink?) noise - way louder than the barely audible voice. Any suggestions as how to fix that? -- 78.43.93.25 (talk) 23:19, 22 February 2010 (UTC)

Try converting the file to 8-bit samples (sox infile.wav -1 outfile.wav), that might help if it's a byte ordering problem. 98.226.122.10 (talk) 01:31, 23 February 2010 (UTC)

I followed your suggestion and tried an 8kHz mono 8-bit file. Sadly, the noise is still there. -- 78.43.60.58 (talk) 10:57, 23 February 2010 (UTC)