Wikipedia:Reference desk/Computing

Wikipedia:Reference desk/headercfg

September 8

Slow down animations

I use MSIE7 in WinXP. Is there a way to slow down animations such as to, say, 1/10th the speed? -- SGBailey 08:34, 8 September 2007 (UTC)

Yes, but it will take GIF editing software. Basically what you want to do is to increase the amount of time per frame by 10X. I would use Adobe ImageReady for that but I'm sure there is also a free way to do it. --24.147.86.187 12:31, 8 September 2007 (UTC)

Oh — do you mean, "is it possible for me to have GIF animations play slower in my browser?" If so, the answer is probably no, unless there is some sort of outrageously clever Firefox addition that takes care of it. --24.147.86.187 13:27, 8 September 2007 (UTC)

The latter is what I meant. Ah well. Thanks. -- SGBailey 21:44, 8 September 2007 (UTC)

One possible way is to have a seriously slow PC that does not have enough CPU power to keep up with the speed! Graeme Bartlett 00:27, 10 September 2007 (UTC)

BBC News 24 live online

I live in South Korea and I want to watch BBC News 24 live online. However, every time I try, the stream is not loaded.

I tried http://www.bbc.co.uk/newsa/n5ctrl/tvseq/n24/bb/wm/video/news24_bb.asx . However, my computer can't access to that asx.

Four addresses inside that asx also failed:

• mms://wmlive-acl.bbc.co.uk/wms/news/news24_bb_s1
• mms://wmlive-acl.bbc.co.uk/wms/news/news24_bb2_s1
• mms://wmlive-acl.bbc.co.uk/wms/news/news24_bb_s2
• mms://wmlive-acl.bbc.co.uk/wms/news/news24_bb2_s2

Now, what can I do?--JSH-alive ^(talk)_(cntrbtns)^{(mail me)} 10:23, 8 September 2007 (UTC)

What browser and OS are you using? --24.147.86.187 13:28, 8 September 2007 (UTC)

Windows XP and both Firefox and Explorer.--JSH-alive ^(talk)_(cntrbtns)^{(mail me)} 13:51, 8 September 2007 (UTC)

I just tried that address (IE6,XP,WMP 11.0), got the WMP, but after awhile it gave up trying to find the content. I live in USA. I doubt that your location matters. David 11:30, 9 September 2007 (UTC)

Works fine here - I'm in the UK. That link may be to the UK-only stream (see here). Try going to news.bbc.co.uk and clicking the 'Watch' icon in the top left. — Matt Eason ^{(Talk • Contribs)} 18:57, 9 September 2007 (UTC)

It does not works.--JSH-alive ^(talk)_(cntrbtns)^{(mail me)} 05:13, 13 September 2007 (UTC)

usage of lattice constants in automotives and information about quantum computation

Hi, i want to know about the usage of lattice constants in automotives and quantum computers so please help me. —Preceding unsigned comment added by Sankar sudhan (talk • contribs) 11:53, 8 September 2007 (UTC)

game consoles

why do game consoles have processors in it when computers themselves have processors anyway? do I get any free games when consoles are bought? How much does a game cost? —Preceding unsigned comment added by 59.92.119.141 (talk) 14:50, 8 September 2007 (UTC)

The Wii is the only current console i know of that comes with a game, and games for the wii usualy cost around $40. —Preceding unsigned comment added by 71.195.124.101 (talk) 16:02, 8 September 2007 (UTC)

1) Game consoles are, essentially, specialized computers. 2) Depends on the console. Sometimes special bundles are offered at a discounted price than if you bought the console and game seperately. 3) Varies from free to very large amounts for "Special Edition" versions. -- 68.156.149.62 16:47, 8 September 2007 (UTC)

Processors just run program instructions. Games are just types of programs. Consoles are just computers made to do one specific task (play gmes). --24.147.86.187 17:01, 8 September 2007 (UTC)

Are you asking why game companies don't just write games for general-purpose computers? One reason is homogeneity. All the consoles of a certain type have exactly the same computational hardware, so they don't have to worry about dealing with different vendors' buggy drivers and providing a low-detail mode for low-end computers and so on, which saves development time. Another reason is intellectual property. Console vendors like proprietary systems because they can charge royalties on every game sold, and game companies like proprietary systems because they make piracy harder. -- BenRG 23:42, 8 September 2007 (UTC)

Nintendo’s Wii costs US$250 and comes with a game: Wii Sports. New games for the Wii generally cost US$50 each.

Sony’s PlayStation 3 60GB version costs US$500 and comes with no games, the 80GB PS3 costs US$600 and comes with a game: Motorstorm. New games for the PS3 generally cost US$60 each.

Microsoft's Xbox 360's three versions cost US$279, $349, and $429 respectively. None of them come with a game. New games for the Xbox 360 generally cost US$60 each.

Sony’s PlayStation 2 costs US$130 and does not come with a game. New games for the PlayStation 2 generally cost US$30 -$40 each.

Microsoft’s Xbox and Nintendo’s GameCube are no longer in production and the prices of the consoles vary widely if you can find them at all. New games for these consoles are rare, but games for them are generally priced similar to, or slightly lower than the PS2’s games.

Hope that helps. 69.205.180.123 00:03, 9 September 2007 (UTC)

I hate the idea of game consoles (these people are still living in the pre-Amiga days..) but I'll admit one major advantage to them is the lack of operating system overhead. You do have to have a pretty good API to outperform directx and the like, even if you're running on a dedicated system, but theoretically you can get much better performance by trusting the game software and totally forgoing memory protection and other performance-draining features necessary to a real OS. I won't go into how undesirable it is to own a non-programmable computer or the ethics of signing "licensed" games and similar DRM (it's wrong.). --froth^t 22:18, 10 September 2007 (UTC)

Turn off the touchpad

In Linux, how do I turn off the touchpad on my Toshiba Satellite 5000, preferably only while a USB mouse is connected? NeonMerlin 15:15, 8 September 2007 (UTC)

I'm taking a guess you are using Windows XP and not Vista, 2000, etc. You can find the directions here [1]. Keep me posted. Monkeynoze 19:41, 8 September 2007 (UTC)

It'd help to read his question. He uses Linux. First two words. OP: I don't know, though only turning it off when the USB mouse is in won't be an easily found feature. JoshHolloway 20:38, 8 September 2007 (UTC)

Ummm he clearly said he's using LINUX? It would help to state your distribution, and it's better to ask on their forums than in here. --antilived^{T | C | G} 23:59, 8 September 2007 (UTC)

It's Kubuntu 7.04. NeonMerlin 02:41, 11 September 2007 (UTC)

Some laptops have a button (near the touchpad) or a key combination (e.g. Fn + F7 or something like that) that turns the touchpad on or off. Your manual will tell you. --141.156.250.167 23:48, 8 September 2007 (UTC)

My thinkpad lets you control it via Fn+F8 (though those drivers aren't installed right now) and via the BIOS configuration utility. Look through your bios configuration. --froth^t 22:09, 10 September 2007 (UTC)

I use syndaemon(1) in Linux to disable the touchpad while typing. Assuming you have the synaptics touchpad driver (it's pretty ubiquitous), you should already have syndaemon; check out its man page. If you want to disable the touchpad completely (all the time, not just while typing), there seems to be an option value of the synaptics driver which you can stick in the relevant InputDevice section (look for 'Driver "synaptics"') of your xorg.conf:

       TouchpadOff (Integer)
              Switch off the touchpad.  Valid values are:

              0   Touchpad is enabled
              1   Touchpad is switched off
              2   Only tapping and scrolling is switched off

A good heap of further information is on the synaptics(5) man page, so take a look. -- Daverocks (talk) 13:00, 11 September 2007 (UTC)

Both laptops I own have buttons somewhere on them that disable the touchpad. Have you tried looking for one? Luigi30 (Taλk) 14:20, 13 September 2007 (UTC)

Detecting removable hard drive

I recently bought a removable hard drive(USB 2).When I plug it to the USB port of my PC, it is not detected by the explorer.How can i solve this problem.Thank u. —Preceding unsigned comment added by 202.70.64.15 (talk) 17:51, 8 September 2007 (UTC)

What OS version are you using (Windows XP, Windows 2000, mac, etc.) What brand computer do you have? Do you have a laptop or desktop. Thanks. Monkeynoze 19:43, 8 September 2007 (UTC)

One problem I had; I have some network drives which are disconnected. When I plug in a USB stick, Windows assigns it the drive letter of one of these drives - and proceeds to forget it's there. Maybe that's your problem, in which case you can view the drive in Disk Management and give it a different letter. Rawling4851 14:16, 9 September 2007 (UTC)

gps in cell phones

a coworker claimed that all cell phones in the last few years have GPS, but that it's not necessarily enabled. True/false? —Preceding unsigned comment added by 12.217.199.246 (talk) 23:02, 8 September 2007 (UTC)

See Wireless Enhanced 911. I'm not sure if they're required to have it, but a lot of them seem to. Essentialy, it's more than just a GPS, it also used the cell-towers themselves to pin-point you. Many phones seem to have an option to turn this on for all calls, or just on for E911.(Default) My old phone had an option to turn it off entirely, but I'm just now noticing my current one doesn't. APL 23:27, 8 September 2007 (UTC)

Accidentaly closed tab

I accidentaly closed a Firefox tab. Wikipedia in Portuguese was opened and I has just translated an entire article, and I didn't save anything. Is there a way to get the information back? A.Z. 23:14, 8 September 2007 (UTC)

I could find it! There's a feature called "recently closed tabs". It wasn't actually an entire article, since there's one section left. A.Z. 23:21, 8 September 2007 (UTC)

You can also right-click on an open tab and choose "undo close tab" from the menu. It's a great feature. --Sean 23:52, 8 September 2007 (UTC)

different connections for different applications

Hi. Can I have different applications use different network connections on my computer? For example, can I have my browser use my wired connection, and have my email client use my wireless connection to a particular wireless network, both connected to the Internet at the same time? Directions for Windows and/or Linux would be appreciated. Thanks. --141.156.250.167 23:51, 8 September 2007 (UTC)

Dual 12V rails on PSUs

If an ATX power supply has "dual +12V rails", does that mean that some number of connectors are on rail 1, and the others are on rail 2? Is there a way to figure out which connectors are on rail 1 or 2 if it isn't documented? Or do all of the 12V connectors pull from the same power source (then what's the point of "dual" rails..)? Thanks! --72.66.219.162 23:57, 8 September 2007 (UTC)

September 9

Microsoft Excel question, probably a dumb one

I have a Microsoft Excel spreadsheet, it's not for math or formulas, just to keep notes on something. Many of the cells have a lot of text in them (up to a paragraph) but I don't want all the text to be visible in the spreadsheet, as long as I can see it when I click on that cell. Does that make sense? This usually works fine, but occasionally Excel will automatically resize the cell for me, making the entire row taller so that I can see all the text in that row at once. I don't want this; it is annoying and frustrating that I don't know why it sometimes does it or how to fix it. I know that I can change it back by going to the Format menu and selecting Row and manually adjusting the height, but is there an easier way? Instead of fixing it like that each time, I'd rather just know why it's doing that so I can avoid the problem. Thanks in advance for any help you can give. --Grace 01:24, 9 September 2007 (UTC)

It's really hard to tell since we have no idea what you're doing with the spreadsheet. But there are several easier ways: Try selecting the cell, the column the whole sheet, or whatever you want to be displayed in this way and hit Ctrl+1 (the number one). This will give you the Format Cells dialog. In the Alignment tab, either unselect Wrap text or select Shrink to fit, whichever you like better. — Sebastian 09:17, 9 September 2007 (UTC)

Hey, that seems to have worked, thank you. --Grace 23:24, 9 September 2007 (UTC)

OS X Address Book and Default Email Address

Hello,

Is there anyway in OS X address book to set a default email address? I have many contacts with multiple email address and I would like to be able to specify one as the one to always send mail to.

Thank you,

--Grey1618 11:02, 9 September 2007 (UTC)

Running a game in windowed mode

Hi, I have a game that I would like to run in windowed mode. None of the configuration files I have come upon so far seem to allow such an option to be turned on. The target is "C:\...\RomeTW-BI.exe", do I need to add anything to this to force it to run windowed? Thanks in advance. :)) 81.93.102.185 11:43, 9 September 2007 (UTC)

Some programs allow it, some don't. First see if the game has the option to run windowed mode through any of its in-game options. If not, go to the shortcut of the game (or create one) and try changing the target to have a " -window" (with a space) or " -w" and running the game - the two most common switches for windowed mode. Otherwise, you'd have to run an emulator or a sandboxing software that runs in a window to force it to be in a window - but that is often more trouble than it's worth. x42bn6 Talk Mess 12:40, 9 September 2007 (UTC)

Also, try ALT-ENTER while in-game. This is a common Windows shortcut for toggling between fullscreen and windowed modes. 68.183.218.134 15:13, 9 September 2007 (UTC)

Googling "Total War Windowed Mode" comes up with some options. Try running the application with the switch -ne; apparently that works for some versions. --24.147.86.187 21:35, 9 September 2007 (UTC)

No Emacs in Fedora 7?

I recently updated my Fedora system from version 5 to version 7. The new system boots up nicely, and even remembers my complete profile, but for some reason it doesn't seem to have Emacs installed. What the heck? How can there even be a Unix system without Emacs? JIP | Talk 17:08, 9 September 2007 (UTC)

It may not have been part of the default basic install. Just install it then. Go to Add/Remove Programs and it's listed in there somewhere. --Spoon! 17:34, 9 September 2007 (UTC)

I tried, but pirut said that pup was already accessing the update database. Pup has been doing that for half an hour now, clogging up my Internet connection, without showing any signs of actually installing anything. Well, it did say there were 165 updates available, so I guess downloading all of them is going to take a while. I'll have to see tomorrow morning at the latest. JIP | Talk 17:47, 9 September 2007 (UTC)

I don't use any gui package managers. I install it from the command line: yum install emacs. -- kainaw™ 22:08, 9 September 2007 (UTC)

Unfortunately, if pirut is updating packages in the background, it's possible that the RPM database will be locked, or that there will be a yum lock. Annoying for the first boot, until you can disable it. -- JSBillings 13:43, 10 September 2007 (UTC)

Emacs is not a standard Unix program, so you can't just expect it to be there by default. —Preceding unsigned comment added by 129.78.64.102 (talk) 22:29, 9 September 2007 (UTC)

Now why would you expect Fedora to include a competing OS in its default install? :) --froth^t 22:08, 10 September 2007 (UTC)

cost of cell phone plans

Is the cost of cell phone plans expected by analysts to decrease in a year? —Preceding unsigned comment added by 12.217.199.246 (talk) 20:34, 9 September 2007 (UTC)

I know my comment is grossly off course but this thread reminds me o0f my rebellion when our english professor shunned the use of passive voice. --Do not click me! 20:23, 13 September 2007 (UTC)

Difference between Mirroring, Failover, Clustering and Load balancing?

What is the difference between Disk mirroring, Failover, High-availability clusters (a.k.a. Clustering?) and Load balancing?

It would seem that Load balancing is different in that it involves a server that redirects traffic to an array of servers which then handle the traffic from there, and each of the servers in the array may be slightly different.

Mirroring / Failover / HA Clusters seems to be multiple servers that [may or may not?] have identical disk images that each act as a backup ready-to-go in case the primary server failed.

Perhaps Mirroring / Failover / HA Clusters may not actually have identical drive contents? Maybe they are all server data in unison, just without another server acting as a Load Balancer?

Help?

--Eptin 22:09, 9 September 2007 (UTC)

That's a lot of questions. Did you check into each of the articles you linked? Keep in mind that many of these look and act the same. Or, you may use multiples of them at the same time. That is, if you have a number of web servers fronted by a load balancer, you could call that a high-availability cluster of load-balanced servers, exhibiting failover. If a web server fails, the load balancer fails over to the remaining ones. There is a cluster of them, and when they are not in a failure state, you can balance the load across them.

Mirroring, in my mind, just means that you've got two identical drives, and you always write the same thing to each. If one drive fails, you still have the other drive -- you can fail over to it. --Mdwyer 04:06, 10 September 2007 (UTC)

Smells like homework; however; disk mirroring is generally on a single machine (setting aside remote mirroring provided by SAN clusters.) failover is when you have a hot standby machine, with the master writing data to a shared drive (NAS or SAN) and is brought up after the master fails, load balancing is where two or more machines run at the same time and requests to them are split between machines (with the machines synchronising between themselves if the requests actually change things), high-availability clustering is a combination of load-balancing and failover (where, because two or more machines are running at the same time there is no delay in failover as would happen with non-clustered failover, and data is synced between the machines if they don't share storage). However a lot of the time they're used interchangeably in marketing materials. --Blowdart 05:51, 10 September 2007 (UTC)

Bots

Hi, I know about four programming languages, and I know how to put a bot up for approval etc, but what I was wondering was, what do most people find as the most user friendly interface for building a bot, like PASCAL or Python. Thanks! Yamakiri 22:45, 9 September 2007 (UTC)

First, you have to define "bot". There are many definitions of that term in Computer Science alone. -- kainaw™ 00:55, 10 September 2007 (UTC)

It sounds like the question is in reference to bots on Wikipedia. It doesn't really matter what you develop the bot in; so long as it is compliant with the standards (i.e. it can be deactivated by an admin if it malfunctions, etc). You might consider a technology that allows for easy standard data interchange, such as XML. What are you trying to do? That will help narrow down the "preferred" technology choices. See Wikipedia:Creating a bot for details and tools! Nimur 01:34, 10 September 2007 (UTC)

I think the reason most people use Python, anyway, is because there are already classes written in Python to help you interact with the Wiki. That is, you can skip pretty much to the "what should the bot do?" phase rather than worrying about the "how does the bot connect to the internet? how does it log in? how does it differentiate the content? how does it search?" etc. sorts of things. I could be wrong on this, though. --24.147.86.187 01:49, 10 September 2007 (UTC)

Since MediaWiki is written in PHP, I'd be rather surprised if there aren't already premade libraries for PHP as well. -- kainaw™ 01:53, 10 September 2007 (UTC)

It wouldn't help things that MediaWiki is written in PHP, since you wouldn't be interacting with its code directly—just its HTTP outputs/inputs. While I find PHP a pleasant scripting language, it is not generally used for things like bots because it does not lend itself to being run endlessly (most PHP scripts have very quick execute times are normally set up to automatically exit if they take more than a few seconds to execute). While you can make PHP iterate over a set of instructions again and again (or run it from command line interface), this is not really what it is good at and not really what it is designed for, and there is no real advantage to using it for such a thing in any case. --24.147.86.187 07:38, 10 September 2007 (UTC)

Oh, that's good then thanks! Didn't think about the PHP part though. Yamakiri 10:54, 10 September 2007 (UTC)

• Most people use Python, so I would probably use that. The library will be better, the number of people who can help you will be better, the chances for someone joining in on your project will be better, etc. --Sean 12:49, 10 September 2007 (UTC)

September 10

Latex equation captions

Is it possible to add a caption to an equation in LaTeX? Thanks. 139.80.7.123 00:05, 10 September 2007 (UTC)

What you're trying to do doesn't make sense. Either you want to put an equation into a figure (with a caption) or you want to talk about the equation in the surrounding text rather than caption it. Donald Hosek 17:08, 10 September 2007 (UTC)

Laptop AC Adapter Problems

A few hours ago, as my Dell Inspiron e1505 laptop was running off of the AC adapter, the adapter suddenly stopped working - the battery icon indicated that there was no adapter power and the adapter's green status light had turned off. I unplugged the adapter and replugged it into several different sockets, and after some tries, the light turned on again.

Just now, I had the same problem, and "fixed" it by the same method. However, as soon as I plugged the adapter into the computer, the green status light ceased. It is now broken for good as far as I can tell.

I was just going to buy a new adapter, but when I asked my friend about this, he said that he had the same problem himself twice (i.e., the status light turned off as he plugged it into his Dell laptop), and both times his computer stopped working and had to be sent for repairs. Both times customer service fixed it and told him that his motherboard had been fried.

Thus, my question is: Is this a problem of my adapter (in which case I should just get a new one), or is this a problem of my computer's motherboard or whatever (in which case I should be more worried)?

Thanks, -MagneticFlux 03:03, 10 September 2007 (UTC)

Unfortuately, this is a dell manufacturing error. My sister's laptop's adapter of the same model suddenly stopped working and a replacement was needed. (Another reason not to choose dell in my view, Go Acer!) ::Manors:: 16:33, 10 September 2007 (UTC)

Pascal

Where is Turbo Pascal help available?Beta alpha 07:14, 10 September 2007 (UTC)

http://shhs.1earth.net/kla/compstud/PascalTutorial_de_nz/fh-jena.de/~gmueller/Kurs/default.html is a helpsite for pascal. It's been about 10 years since I studied turbo pascal but I suspect that a large amount of it is the same as plain old pascal. ny156uk 18:56, 10 September 2007 (UTC)

multithreaded UNIX kernel

I am first year student of M.C.A. having diffculty in finding information about MULTI-THREADED UNIX KERNEL.So, give me brief introduction of MULTI-THREADED UNIX KERNEL.203.193.189.22 09:07, 10 September 2007 (UTC)pimpale_manjeet

Have you read our fine articles on Unix and POSIX Threads? Splintercellguy 09:17, 10 September 2007 (UTC)

Note that POSIX threads generally don't have anything to do with kernel threads, although I guess it's possible that some O/S out there uses them in kernel space. I'm not aware of one, though. --Sean 12:53, 10 September 2007 (UTC)

A little politeness would be nice too. ::Manors:: 16:34, 10 September 2007 (UTC)

I'm not sure how you interpreted my clarification as impolite. It certainly wasn't meant that way. Or do you mean SCG's response, which helpfully pointed the asker to the relevant articles? --Sean 17:42, 10 September 2007 (UTC)

Perhaps he means the OP, who used caps in part of his response. Splintercellguy 16:58, 11 September 2007 (UTC)

In which case a little WP:AGF would be nice too. --Kjoonlee 15:39, 13 September 2007 (UTC)

How do I set the hostname on Fedora 7?

How do I set the hostname on Fedora 7, so that it will apply even after I reboot? hostname only applies until I reboot the computer. JIP | Talk 10:03, 10 September 2007 (UTC)

There are multiple ways (all done as root)

• run hostname your.host.name
• Edit /etc/hostname and put your host name in the file
• Edit /etc/dhclient-eth0.conf (where "eth0" is your network device) and add send host-name "your.host.name"

I'm sure there are at least 27 more ways. -- kainaw™ 12:03, 10 September 2007 (UTC)

I believe that the Fedora way is to edit /etc/sysconfig/network. -- JSBillings 13:36, 10 September 2007 (UTC)

Actually, there is a program you can run (as root) in Fedora called system-config-network. You may need to yum install system-config-network first. -- kainaw™ 13:42, 10 September 2007 (UTC)

Go to System -> Administration -> Network, DNS tab, and enter the hostname. --Spoon! 15:04, 10 September 2007 (UTC)

That's 3 more ways. Only 24 more to go... -- kainaw™ 15:13, 10 September 2007 (UTC)

Email

Why we have asked to enter the verification code, while creating E-mail? —Preceding unsigned comment added by 61.247.255.10 (talk) 12:39, 10 September 2007 (UTC)

Can you be a bit more specific? Creating e-mail where? You may be talking about a CAPTCHA; they're used by some webmail providers to make sure it's a human creating the account. Computers can't read the text in the CAPTCHA image so they can't create an account. If computers were able to create accounts without the help of humans they could create large numbers of accounts automatically and use those accounts to send spam. — Matt Eason ^{(Talk • Contribs)} 13:13, 10 September 2007 (UTC)

Note that while computers have difficulty reading CAPTCHAs (I wouldn't put it past a bot able to use an OCR program or algorithm to read the letters, although it is difficult - note the noise and patterns), the hash associated with the CAPTCHA can be cracked. So, in other words, it doesn't solve everything but it certainly stops the most basic scripts - ones that can be written with a few minutes of thought and AutoIT, for example. x42bn6 Talk Mess 16:55, 11 September 2007 (UTC)

online money

how to make real money online from a country like saudi arabia ??? —Preceding unsigned comment added by 212.107.116.238 (talk) 17:05, 10 September 2007 (UTC)

Sell something people want. Market your business so people who want what you sell know you are selling it. -- kainaw™ 17:11, 10 September 2007 (UTC)

can you give me a place where i can sell pc games and things like this ? —Preceding unsigned comment added by 212.107.116.238 (talk) 17:25, 10 September 2007 (UTC)

Ebay, Craig's List, Postaroo... there are hundreds of places. -- kainaw™ 23:12, 10 September 2007 (UTC)

Or you can get your own online store at Ecrater Djmckee1 - Talk-Sign 13:51, 15 September 2007 (UTC)

Vista and Ram

Hello, can anyone please tell me the maximum amount of DDR2 RAM windows vista will allow you to use without upgrading to 64bit? thanks. —Preceding unsigned comment added by 84.68.12.32 (talk) 18:41, 10 September 2007 (UTC)

This site says 4GB. This one agrees. The operating system shouldn't care about DDR2, that would be a consideration for the motherboard. --LarryMac | Talk 18:51, 10 September 2007 (UTC)

Or try...http://www.vistaclues.com/reader-question-maximum-memory-in-32-bit-windows-vista/ Not sure from a quick read over it what the answer is - but seems to suggest that with 4gb installed you'll not be able to utilise it all effectively. All very confusing unfortunately. ny156uk 18:52, 10 September 2007 (UTC)

Well, the short version is that a 32-bit processor has a limited number of addresses, and everything must have an address. That is, those addresses are used for both memory AND for communicating with devices. So, even if you fill the entire address space with memory, some of it will still be occluded by other things in the system. This is still a problem with 64-bit addressing, but the system area is unrealisticly far away. --Mdwyer 20:40, 10 September 2007 (UTC)

I believe the exact number is 3.5GB. -Wooty [Woot?] [Spam! Spam! Wonderful spam!] 05:57, 13 September 2007 (UTC)

I believe anything over 3 GB will be a waste of money (at least for now). Just have some expansion bays open for future upgrade and I am sure you will be fine. —Preceding unsigned comment added by Multipleidentitynumberthree (talk • contribs) 20:14, 13 September 2007 (UTC) --Do not click me! 20:15, 13 September 2007 (UTC)

Two firefoxes, one profile

I have Firefox portable on my flash drive, as well as the Mac Firefox. I would like to set it up so that the profile for each is the same. Is there some way I can redirect the windows Firefox to use the mac's profile, or vice versa?

Thanks in advance, --Omnipotence407 21:21, 10 September 2007 (UTC)

If you have IRC, irc://irc.mozilla.org/firefox might help. --h2g2bob (talk) 00:18, 11 September 2007 (UTC)

Nope, I don't have IRC, if you could summarize or something, that would be great. --74.37.228.44 00:21, 11 September 2007 (UTC)

The profile is stored as a load of files in a folder. I don't think you can change which folder it uses - it will always place them on the hard drive (although you can make the folder a symlink in OSX).

However, you can copy the contents of the folder by hand. I don't know of any way to make this automatic.

Some files can have information on locations of files on the disk (for example, if you set .ram files to always open with realplayer). This will change between OSs and may cause problems.

You should be able to copy your bookmarks (bookmarks.html) between profiles without any problems (until Firefox 3 is released). There's some firefox extensions which put bookmarks online for sharing between different computers - [2][3] - which would do this for you.

Hope this helps somewhat - take a look through http://kb.mozillazine.org/ for more info, and you should backup before doing anything risky. --h2g2bob (talk) 00:49, 11 September 2007 (UTC)

I think it's possible between Windows and Mac. I did it between Ubuntu and Windows once, and it worked fairly well. Some very complex plugins/add-ons might not work, but ones like AdBlock do. Basically, run firefox.exe (and/or thunderbird.exe) using the "-profilemanager" option. That allows you to change where the profile points to on the drive. So just set them both up to point to the same directory. But backing up your data first would definitely be a first step. --Bennybp 02:20, 11 September 2007 (UTC)

Hmm. Assuming you know where Firefox stores the profiles, could you replace that folder with a symlink to the other Firefox's profile? Confusing Manifestation 03:26, 13 September 2007 (UTC)

September 11

Computer Rebooting

I have a computer with Fedora on it that keeps rebooting randomly. It is not rebooting when a specific device is used, a specific program is run, or after a specific amount of time. I strongly suspect the memory is bad, but I was wondering if there are any Linux utilities that can keep a very close eye on the entire system and give me a good analysis of what happens just before each reboot. -- kainaw™ 00:44, 11 September 2007 (UTC)

One linux utility is strace. You use -p with pid number to indicate what you want to trace. It records all the system calls. using the -f option will also record all the child processes. It would be best to put the output to a file with -o option, and then try to read the file after a failure. The next step up is to use a debugger, though I expect there will already be too much output. It may be better if you can get hold of a memory tester. I havent seen one of these for at least 12 years, but they should still exist! Graeme Bartlett 04:38, 11 September 2007 (UTC)

strace only traces syscalls of a particular process, and won't help much here. I suggest checking the syslogs to see if anything is logged before it reboots. You might want to set up syslog to log to a remote host, in case the disk drivers crash before it reboots. In the end, you're going to want to test the hardware -- if you suspect bad memory, I suggest using the memtest86 memory testing tool. -- JSBillings 10:50, 11 September 2007 (UTC)

Log files reported nothing. Memtest86 ran all night - no help. No reboot though, so it isn't something inherently bad in the power supply (or power source from the wall). Ran with ide=nodma, still rebooted. I'm going to open it up and look for a loose cable. -- kainaw™ 12:20, 11 September 2007 (UTC)

I've had similar problems after i reseated the heatsink on the cpu, it could be overheating. If you have acpi setup you might be able to look at the cpu temp somewhere in /proc/acpi/. I solved my issue by cleaning the heatsink and using new heat-conductive paste. -- Diletante 14:54, 11 September 2007 (UTC)

I've seen this happen with systems that had a lot of "noise" in their power, or irregular power dips. Most electronic appliances work just fine with these problems, but computers are overly sensitive to irregularities in power. Also, if you suspect it is your CPU, try monitoring the temperature of your CPU. -- JSBillings 20:44, 11 September 2007 (UTC)

After memtest86 claimed the memory was OK, I checked further. Nothing in logs. Swapped out a lot of components. Finally, I believe I tracked it down. The CPU fan appears to be flaking out - just stopping every now and then. The BIOS doesn't provide monitoring of the fan to the OS, so it wasn't logged. I found out by having the case open and examining the inside while it was running. The fan just stopped. I tapped it and it started back up again. A few minutes later, it stopped again. Hopefully that's the source of this and I won't have to poke around this case anymore. -- kainaw™ 22:16, 11 September 2007 (UTC)

Turned out that the fan was stopping because the power supply was acting up. Just thought someone might want to know the status of this odd problem. -- kainaw™ 01:00, 12 September 2007 (UTC)

Yeah when my power supply was getting overloaded my computer kept on rebooting sporadically is well. It also gave the harddrives a lot of "clicks of deaths" (probably just head reset due to insufficient power), which lead to frantically getting more harddrives, which lead to more clicks... --antilived^{T | C | G} 10:41, 12 September 2007 (UTC)

Add a string of text to the end of every line of a text file.

Is there any options on a Windows application, that will find the end of every line (newline) and append a string of text to it. I know on with the Linux application VI (VIM) you can add text to the end of every line with the character "\n" representing a newline. I can't remember if this used a find and replace command, I just looked up the command and copied it. I was wondering if anyone knew a windows app that will do this. Preferably I use edit.exe a.k.a edit.com but if notepad, wordpad, or Microsoft Word had an option like this? – 69.150.209.13 01:57, 11 September 2007 (UTC)

I don't know if those other apps can do it, but you can get vim for Windows. --Allen 02:01, 11 September 2007 (UTC)

You could write a script, or find a text editor that uses Regular Expressions. Nimur 02:26, 11 September 2007 (UTC)

:1,$s/$/ia string of text

in vi, or sed could do the job too. Do you want to use wordpad or word for windows to do the job? Graeme Bartlett 03:34, 11 September 2007 (UTC)

On Windows, I'd recommend Notepad++ for an advanced text editor. You can use the replace function with regexps by pressing CTRL+R. — Kieff | Talk 04:11, 11 September 2007 (UTC)

In word for windows you can do edit replace, click more, click special and select paragraph mark, this can the be replaced with your trailing text and a new paragraph mark with a replace all button. Graeme Bartlett 04:29, 11 September 2007 (UTC)

Nod32

Hi, I am going to purchase Nod32 antivirus and would like to know what firewall is compatible with it. Thanks —Preceding unsigned comment added by Erendis (talk • contribs) 07:19, 11 September 2007 (UTC)

Anything, I suppose, since I'm not sure how a firewall could conflict with an AV. Splintercellguy 16:57, 11 September 2007 (UTC)

Yep they're nothing alike. Though you'll need to allow access to the AV for "autoupdates"- a bad idea btw, I always download virus definitions with my browser and manually install them. --froth^t 22:41, 11 September 2007 (UTC)

In response to

Though you'll need to allow access to the AV for "autoupdates"- a bad idea btw, I always download virus definitions with my browser and manually install them.

If you cannot trust your anti-virus program for auto update or think it has a security flaw that you fear others may exploit, please do not buy the antivirus program. Build one for yourself from scratch ... or customize ClamWin for your needs. --Do not click me! 20:08, 13 September 2007 (UTC)

Using ADBLOCK to remove a specific wikipedia link.

Hello, as I try to revert as much vandalism as possible in the shortest amount of time, I often mistakenly click the stupid 'Edit summary' link when one goes to edit the page, instead of clicking "Save Page" button. Now is there a way using adblock (or any other program) running in firefox or even in the background to block that link, ie make it not clickable? Phgao 09:32, 11 September 2007 (UTC)

I don't think you can do that with adblock, but I've made Greasemonkey scripts for similar purposes. -- JSBillings 10:47, 11 September 2007 (UTC)

You can also edit your monobook.css to hide that link by doing the following:

• go to User:Phgao/monobook.css
• add the line #minoredit_helplink {display: none;}

Rawling4851 22:01, 11 September 2007 (UTC)

EDIT: Sorry, if you don't use the monobook skin, you'll have to edit your CSS for whatever skin it is you use. Rawling4851 22:03, 11 September 2007 (UTC)

You may want to familiarize yourself with the access keys on Wikipedia. I have found that they greatly increase the speed of editing and navigation. For instance, saving a page is just access key 's'. I find the default key combination in Firefox slightly annoying, so I changed (in about:config) ui.key.contentAccess to 4 so that Alt+key was the combination instead of the default 5 (Shift+Alt+key). --Pekaje 11:24, 12 September 2007 (UTC)

Thanks for the sweet tips! I'll look into them. Phgao 08:08, 13 September 2007 (UTC)

Removing Windows Media Center

I play a lot of DVDs on my computer, for which I use Windows Media Player. Whenever I put in a DVD, Windows (in its infinite wisdom) automatically starts Windows Media Center, which I despise and have absolutely no use for. WMC doesn't seem to exist as a normal, removable program, but I'm desperate to remove it. Is there any way to uninstall it or, failing that, disable it? Thanks! Bhumiya (said/done) 09:39, 11 September 2007 (UTC)

This is based from your autoplay settings for the DVD drive, and can be changed. It's easy to do in Windows XP, while Vista has a slightly different configuration. --Sigma 7 10:49, 11 September 2007 (UTC)

You can remove it (xp) - start,set program access and defaults, "remove/uninstall", scroll down the list, press 'delete', or start help and search for uninstall...83.100.251.220 12:31, 11 September 2007 (UTC)

Thanks! I didn't know how to get rid of autoplay altogether. Bhumiya (said/done) 13:38, 11 September 2007 (UTC)

Regex in Java: finding expression 1, but not if it's part of expression 2

Hi all,

I'm having trouble writing a regular expression in Java. I want to find all instances of the string cde, but NOT if it's part of the string abcdefg.

So if I gave my parser the text abcdefgcdex, it should only find this "cde": abcdefgcdex.

Is that possible? I'm really not sure how to go about creating such an expression.

Any help much appreciated!

Thanks, Mary. 16:45, 11 September 2007 (UTC)

You can be verbose to make it very understandable. For example, simplify it to "cde" as long as it doesn't follow "ab" (you should easily how this can be expanded to check for following "fg"): (cde.*)|(.cde.*)|(.*[^a][^b]cde.*). In other words, if "cde" has nothing in front of it, that is fine. If it only has one character in front of it, that is fine. If it has two or more characters in front of it, they better not be "a" followed by "b". -- kainaw™ 17:38, 11 September 2007 (UTC)

How about something like this:

(?<!ab)cde|cde(?!fg)

"cde" as long as it's not preceded by "ab" or not followed by "fg". --Spoon! 17:54, 11 September 2007 (UTC)

Hi Spoon,

That works great, thanks! However, I'd like to be able to put a regex within the "(?<!ab)" section -- let's say an a followed by any number of b's. I would think that I should be able to say "(?<!ab*)" or "(?<!a(b)*)" or something, but I get an exception. Do you know what I could do?

Thanks!

Sam

Sorry. As far as I know lookahead assertions can take any regex; but lookbehind assertions can only take a fixed-width regex (because otherwise it is difficult to figure out where to start). --Spoon! 22:37, 11 September 2007 (UTC)

Rate of return

In determining the yield of a stock, I understand the most recent annual dividend is divided by the price. How do I find the "most recent annual dividend" of a particular stock? Thank you. Magemote —Preceding unsigned comment added by Magemote (talk • contribs) 17:14, 11 September 2007 (UTC)

Go to the firms website and look at their investor relations section. You should be able to find it there, alternatively try sites like bloomberg or FT.com as they may well have the details available. I use www.iii.co.uk myself. ny156uk 20:10, 11 September 2007 (UTC)

Random Microsoft Word Question

On my new Lenovo Thinkpad T60p with Windows XP and Microsoft Office 2007, the scroll wheel (button or pad, actually), which works on websites and other things, does not work in Microsoft word. As in every time I want to scroll down the page, I either have to drag the scroll bar on the right or press the down key. This is not the case with Excel. I don't get it. Is there any way to fix this? It's really annoying. —Preceding unsigned comment added by 140.247.42.228 (talk) 20:49, 11 September 2007 (UTC)

Hm, works for me. Try using microsoft drivers instead of IBM's? devmgmt.msc > Mice > whatever > driver > uninstall --froth^t 22:36, 11 September 2007 (UTC)

This website (http://www.techtalkz.com/microsoft-office/49769-re-how-can-i-enable-mouse-scroll-wheel-function-word-2007-a.html) seems to suggest it might hold the answer. For some reason my browser won't load it, but it's the top result of a google search for word + scroll + wheel + enable ny156uk 22:56, 11 September 2007 (UTC)

I sucessfully opened it [the webpage] in my computer (Win XP with IE). --Do not click me! 20:02, 13 September 2007 (UTC)

Zone Alarm

I have an old copy of Zone Alarm. If I uninstall it then I can not view Google Maps or Google Earth although I can view Mapquest maps and satellite images. If I reinstall Zone Alarms then I can view Google Maps. What is going on? Is there a way to view Google Maps without reinstalling Zone Alarm? Clem 22:59, 11 September 2007 (UTC)

Its just amazing. Could you explain it a bit more? --Do not click me! 20:01, 13 September 2007 (UTC)

September 12

Hard drive light/motion

I have a Lenovo laptop, a few months old. For certain periods of time, I will notice every second or two the harddrive light flashing and the harddrive turning (soft "clicking" sound). It will sometimes last continously for a quite a while, and even when no functions are being performed on the computer, no applications are running, and I'm not typing or inputting anything. Does anyone think this is a cause for concern? Thank you for your help. --24.211.242.80 01:29, 12 September 2007 (UTC)

The S.M.A.R.T. capability on my hardrive indicated it might fail. It finally did today. The sounds coming from it are a scraping and clicking sound like an oldtime '78 record player but with metal on metal scraping. Clem 02:06, 12 September 2007 (UTC)

The drive is very likely heading towards failure. The read head thinks it is out of alignment (it may or may not be). It is trying to get back in alignment. Since it is not a viable option to repair whatever is causing the head to think it is out of alignment, your best option is to back up your data and get a new drive - fast. -- kainaw™ 02:14, 12 September 2007 (UTC)

I'm the person with the first question...mine is making a light clicking sound, not a heavy scraping sound. Do you think my harddrive is still in danger? Thank you. --24.211.242.80 02:18, 12 September 2007 (UTC)

It could be failing, or there could be some sort of hard drive processes going on that you don't know about (logging by background processes which do not appear as applications in your taskbar; or potentially attempts by your computer to access virtual memory stored on the drive). I would first try getting something that would let you monitor hard drive I/O writes and see if it is actually writing or reading anything when it does that. In any case you should get some sort of external backup drive (a good practice anyway). As for possibility of failure, it can vary. I've seen drives with what I would call "minor" noises eventually fail, and I've seen others that kept on sounding like that for years without problems. At this point it sounds like a rather indefinite symptom, and so it is hard to diagnose not only what is causing it, but any sort of long-term prognosis. --72.83.173.248 04:23, 12 September 2007 (UTC)

Get a backup, now. Even if your drive isn't failing, you'll appreciate having a backup sometime later. Look into SMART tools to see if your drive is giving off failure messages. Look for Microsoft/Sysinternal's Filemon to see if there's actually a program doing some work on the disk. (My wireless card driver, for some reason, hits the drive a LOT.) Finally, it could be normal. Some drives will move the heads around from time to time to prevent wearing a hole in the drive. See Hitachi Deskstar for an example. --Mdwyer 19:30, 12 September 2007 (UTC)

Thanks for all your help. I've already got a few backup options, actually. Do you think harddrives on new laptops are sometimes prone to bad behavior (especially cheaper lines of laptops)? --24.211.242.80 02:14, 13 September 2007 (UTC)

This is just a vague personal recollection — so if anyone can supply actual data on the subject, please do — but I do seem to recall reading claims that hard drive failure rates are indeed double-peaked: they tend to fail either when they're new or when they're old, with a period of higher reliability in between. This at least makes intuitive sense: the drives that happen to be a bit off spec to begin with (but not badly enough to be caught by the manufacturer's testing) would be most likely to fail in fairly short order, whereas those that survive the first few months should have a good chance of surviving for several years until gradual wear starts taking its toll. The good news in this case is that if your drive does fail soon, it's likely to be covered by warranty. The bad news is that the warranty will cover a replacement drive, but not data recovery. So make those backups. —Ilmari Karonen (talk) 15:45, 13 September 2007 (UTC)

Bathtub curve. To the original poster: don't get nervous about every sound your HDD makes, just keep good backups and you'll be fine. -- Diletante 15:56, 13 September 2007 (UTC)

Zipped (compressed) folders

I need information on what happens when files contain large amounts of information are zipped (compressed) for a research project if you could help that would be great..

Thanks Teresa —Preceding unsigned comment added by Tkilpatrick (talk • contribs) 04:50, 12 September 2007 (UTC)

I'm not entirely clear on what you are asking, but you could try Data compression and ZIP (file format) for starters. --jjron 08:30, 12 September 2007 (UTC)

Lossless data compression is also one article I would look. --Do not click me! 19:54, 13 September 2007 (UTC)

change directory to user's home

In linux/bash there is a command to change directory to the user's home "cd ~" I was wondering if there is a command in windows/cmd.exe which will do the same? – 69.150.209.13 07:16, 12 September 2007 (UTC)

I don't have much experience with Windows or its limited shell, but you might be able to use some of the predefined variables listed here. Also, in bash it is not necessary to type "cd ~", as "cd" on its own brings you to your home directory by default (Windows might do something similar, try it). Another shortcut worth mentioning is "cd -", which brings you back to the previous directory you were in. --Pekaje 11:14, 12 September 2007 (UTC)

cd \ will bring you back to the drive (i.e. C:\). x42bn6 Talk Mess 15:25, 12 September 2007 (UTC)

A bare 'cd' command under DOS/Windows will just display your current directory. I don't know of a shortcut, but the user's home is stored in a number of environment variables. Run the command "set" to see them. In particular, you might have luck with "cd %USERPROFILE%" or "cd %HOMEPATH%" --Mdwyer 19:23, 12 September 2007 (UTC)

You can also use the set command to, well, set variables. F'rinstance "Set home = %HOMEPATH%" will set the value of new variable HOME to whatever the value of the system variable HOMEPATH is. Then, you can simply "cd home" and it will change to that. Caveats: every version of Windows does this a little differently; in XP if you do this with a command window, then close said window, this also will go away; you'd have to do it again, or set it up as a global startup command. Also, this won't work right if your focus is on another drive letter. -66.55.10.178 18:31, 13 September 2007 (UTC)

Need Information About RTMX .O.S.

Hi ALL, I Am in big trouble! I really don't know what is " RTMX.O.S." so please if you have any information reagarding this then put it here! I will be very very thankful to you!!!--203.193.189.22 09:39, 12 September 2007 (UTC)

RTMX is a Real-time operating system based on OpenBSD. -- JSBillings 13:28, 12 September 2007 (UTC)

Loading device drivers

How can a user load a device driver without administrator privileges in Windows, without a system administrator doing it for the user or giving them administrator rights? Think outside the box 09:59, 12 September 2007 (UTC)

?? Thousands of virus-writers want the answer to this question. Thousands of security programmers are trying to prevent this from happening. Why do you want to add things to the OS, without the person responsible for the box knowing about it? -66.55.10.178 18:35, 13 September 2007 (UTC)

Which version of Microsoft Windows? I believe your answer would have at least something to do with that too. --Do not click me! 19:53, 13 September 2007 (UTC)

Online based revision control software

I am starting a small project (~1000 lines) with a teammate this semester and I would like to use some sort of revision control for the code we will write. SVN has many nice features but I do not have access to a public server where I could install SVN and create a repository. Are there any web based RCS available? Ideally, I would need to be able to upload, download, merge and compare revisions all from a common web interface. --Jcmaco 12:03, 12 September 2007 (UTC)

I win. Websvn or.. the motherlode --froth^t 01:54, 13 September 2007 (UTC)

transitor/logic gate switching energy

(I've been looking at a model of a processor that would need ~10¹⁸ logic gate transistions per second.)

My question is: what is the lowest transistor/logic gate switching energy currently available or likely to be available?, and what about the switching energy at smaller than current feature sizes. Thanks.87.102.16.32 12:11, 12 September 2007 (UTC) (I'd like to know how big the power supply would need to be...)87.102.16.32 13:06, 12 September 2007 (UTC)

I approached this question like a Fermi problem. See Transistor count for some ballpark transistor numbers in modern processors. Let's say you have a Pentium 4, with some ~50 million gates, clocked at ~2 GHz. That will automatically give you 10^17 transistor switches per second. (But this is using the completely unrealistic notion that every gate switches every clock cycle!) In any case, it gives you a first-pass estimate figure for the power consumption. Your hypothetical processor will need on the order of ten times more power than a Pentium 4 (if you used similarly fabricated transistors). Of course, depending on the complexity of your model, you can start doing more detailed analysis. Nimur 15:57, 12 September 2007 (UTC)

You hit the nail on the head with the backwards engineered pentium problem - I considered that - but noticed the same thing - well at least I've got a (very low) lower bound. I'd be suprised if more than 10% are active on average and probably a lot less..87.102.16.32 16:13, 12 September 2007 (UTC)

I'd work from a different CPU: the Pentium 4 bears little resemblance to any other. Switching energy depends greatly on things like transistor size, switching speed, operating voltage, and the like. Further, a large part of a modern CPU's transistor count is cache memory rather than functional units, and has a totally different energy profile. Find a CPU that's similar to what you're considering and estimate from there. --Carnildo 23:42, 12 September 2007 (UTC)

Maybe a celeron without any L2 cache? --Wirbelwindヴィルヴェルヴィント (talk) 16:20, 13 September 2007 (UTC)

Application for ordering lists.

Is there an application that will re-arrange a list, putting it in alphabetical order, based on the first letter of a line? —Preceding unsigned comment added by 202.10.86.63 (talk) 12:27, 12 September 2007 (UTC)

Whenever I need that, I use sort. Without knowing more context, that's all the help I can provide. Some examples of what your requirements are, and information on your computing environment, would be very helpful. --Pekaje 12:32, 12 September 2007 (UTC)

Alas, I run Windows XP. My list consists of movie titles, formatted as:

Donnie Brasco
Godzilla vs. The Sea Monster
Being John Malkovich
etc. 202.10.86.63 12:40, 12 September 2007 (UTC)

XP also comes with a command-line sort (windows\system32\sort.exe). Also, all of the standard Unix command-line utilities have XP ports -- see GnuWin32 and Cygwin. -- BenRG 12:46, 12 September 2007 TC)

Perfect, I had no idea that was there. Thanks a lot, BenRG. 202.10.86.63 13:00, 12 September 2007 (UTC)

The documentation on sort.exe is here — Matt Eason ^{(Talk &#149; Contribs)} 13:14, 12 September 2007 (UTC)

You could paste the data into MS Excel and do a sort. If it is CSV (Comma seperated values) you can have excel 'convert' it and sort it appropriately. ny156uk 17:01, 12 September 2007 (UTC)

How much does it cost to develop and make a device

I want to know how much does it cost to develop a new device from scratch. I read of a company called asiatotal.net which came with a device called iT which can be found in their website asiatotal.net. Apart from them, there are many companies like OLPC and mobilis (ncoretech.com). More can be found in http://www.infodev.org/en/Publication.107.html 1) I just want to know how much does it cost to develop such devices. 2) What are the costs involved in it 3) More info on that —Preceding unsigned comment added by 59.96.26.179 (talk) 12:56, 12 September 2007 (UTC)

The OLPC machines are about US$150, and they aren't trying to make a profit on them, so that's about what they cost to make. They were trying to make it $100, but couldn't manage it. I don't think the development cost is known, as it was a heavily volunteer-supported effort. Intel's Classmate PC is made for a similar market, but priced higher (around $200, apparently). --Sean 15:14, 12 September 2007 (UTC)

questions

my computer has a hard disk error.it cant boot my machine.when i try to boot my pc a message saying "insert proper boot device then resart" appears.i used a friends hard disk and my machine boots okay.when i place my bad hard disk as a slave it slows my computer.it makes my 3.2 operate like a

2.0.what could be wrong with it.the place i bought it have no idea whats wrong with itcause everything looks fine on it,it just wont boot my machine.help.. 2.i recently forgot my password.am administrator and i had to run xp a fresh.i have read sumthin about sam files.is there a way i can deactivate my password if i dont remember it.and what do the sam files do? 3.i recently got some videos and they were so crystal clear.they had hdd written on them.my friend told me the music videos are clear coz they r hdd.whats this hdd in relation to videos. 4.how can i explain to my small bro what voip is.in simple language.hope am not asking to many questions —Preceding unsigned comment added by 196.202.195.74 (talk) 14:14, 12 September 2007 (UTC)

1. Your hard disk failing? While I think the boot sector is screwy, your best bet is to use Linux System Rescue CD to get any data off the drive. 2. There are many LiveCDs dedicated to either resetting a Windows password or recovering it. Our article on Security Account Manager discusses what SAM files do. 3. As for the videos, you might be thinking of the term HD, specifically in relation to HD video. 4. Our article on VoIP has everything you need. Splintercellguy 17:18, 12 September 2007 (UTC)

Could you rephrase this part for me? --Do not click me! 19:51, 13 September 2007 (UTC) "it makes my 3.2 operate like a 2.0."

SSE

I'm trying to use DRAWPLUS on my computer,but when I go to brushes it tells me that the computer doesn't read SSE. Is it because I have an Athlon or is there some other reason? Can anyone help me with this problem? -- ALAN SAUNDERS —Preceding unsigned comment added by 81.145.241.34 (talk) 18:08, 12 September 2007 (UTC)

The original Athlon (before Athlon XP) processors do not support SSE --Spoon! 18:35, 12 September 2007 (UTC)

.mid files out of tune

I noticed that when playing .mid files in my Windows Mediaplayer (11) under XP, the pitch isn't right. Normaly the A3 should be 440hz, but when playing the midi files it's tuned way below that (aprox. 410hz), which sounds ugly and makes it hard to play along on my piano. Is there a way I can change this? 82.169.159.161 19:51, 12 September 2007 (UTC)

I don't know much about this stuff (not as much as you seem to do, anyway) but this isn't something that can be fixed with the built in equalizer? Sorry if I'm way of base, but isn't that what it's for? --Oskar 20:02, 12 September 2007 (UTC)

The equalizer only allows you to change the 'frequency envelope' of the sound. What I mean is tuning the pitch of the built-in wavetable-synthesizer that is used when the WMP plays the midi files. I understand that is not an everyday question, but maybe someone knows the answer. 82.169.159.161 20:10, 12 September 2007 (UTC)

The same thing happens to me. Either every note of my computer's midi or every key of my piano is exactly one half step different from the other, and I can't quite figure out which it is. --Russoc4 20:32, 12 September 2007 (UTC)

Many early music groups use A = 415 Hz. Maybe your Windows time zone is set to Colossal Baroque. -- BenRG 01:40, 13 September 2007 (UTC)

... That's a joke, right? --Russoc4 01:41, 13 September 2007 (UTC)

It could be possible that the pitch control in the audio manager is on something other than zero (if you even have one). The audio manager is an icon in the taskbar that looks like a speaker (different to volume control) or a blue square with a yellow thing in it. Even if that's not what's causing the problem you may be able to adjust the pitch there

Mix Lord 03:23, 13 September 2007 (UTC)

What is Bluetooth?

Could someone please explain this to me in plain English. Basically, I want to know what it does and how it works. Isn't it some sort of local area networking?--70.129.203.0 22:56, 12 September 2007 (UTC)

It's like wifi but instead of connecting a computer to a network, it's made to connect a wireless device to your computer. It's designed so that your computer doesn't use half its processing thinking it's a router to an entire network, when it's really just connecting to like 2 devices. So different protocol. --froth^t 23:52, 12 September 2007 (UTC)

Saying it's for connecting a wireless device to your computer is a bit misleading. Bluetooth is like WiFi in that it's a wireless communication protocol, and used for two devices (such as phone and bluetooth headset). It generally has a low power consumption, short range, and relatively easy to set up. So in a way, it's like the more familiar USB connection; it makes set up easier, but it has limitations, such as causing USB drives to be slower than internal drives, etc. And bluetooth devices still use radio waves, just like USB still uses electricity. --Wirbelwindヴィルヴェルヴィント (talk) 16:07, 13 September 2007 (UTC)

External USB hard drives

What are the disadvantages? Are they as fast as internal parallel bus drives? —Preceding unsigned comment added by 212.139.105.199 (talk) 23:31, 12 September 2007 (UTC)

Far, far slower transfer rate. My very high-end model (at $150 for 70GB it'd better be high end) transfers 10GB in approx 20 minutes. No effective difference in read/write.. the usb is the bottleneck. But what do you mean "parallel bus drives"? Serial is not any slower. --froth^t 23:50, 12 September 2007 (UTC)

Another disadvantage is that they cost more, especially if you buy the ready to use ones (as opposed to buying a standard internal drive plus a case then building it yourself, which still costs more as you have to buy the case). --jjron 09:26, 13 September 2007 (UTC)

It shouldn't be that slow. I just benchmarked my external USB drive at 24.7 MiB/sec sustained, which is 10 GiB in less than 7 minutes. This isn't a high-end drive, just an ordinary consumer IDE drive in a cheap made-in-china case. -- BenRG 23:05, 13 September 2007 (UTC)

SSH

1) If the server doesn't have your public key (or you never created a keypair), will SSH still be secure? Does the client generate the key pair on the fly and send the public key as part of the handshake?

2) How do you set up the SSH server so that it only accepts connections from people whose public keys are on the server? --froth^t 23:47, 12 September 2007 (UTC)

For 1, I think you're confusing the Pubkey authentication with the session encryption used by SSH. They're two different things. For 2, you set up the sshd on the remote server to only accept PubKey Authentication, and nothing else. -- JSBillings 01:22, 13 September 2007 (UTC)

I know that your key pair can be used for authentication, but isn't it always used to encrypt your session too? It wouldn't make any sense to use an RSA key pair just for authentication. So does SSH have session encryption separate from that that kicks in if you aren't using pre-generated keys? Or does it just make one up automatically? I used to have sshd set up and when I connected to it with putty, putty asked me if I wanted to accept the server's public key.. so presumably the server and putty both generated a key pair on their own without being asked.. right? --froth^t 01:38, 13 September 2007 (UTC)

As far as I can remember, the client's public key is only used for authentication. Client authentication doesn't happen until after the client and server have agreed on the session keys, so the security is unaffected by which authentication mechanism you use. SSH supports shared-secret authentication for the client but not for the server, so the server needs a public key but the client doesn't. -- BenRG 01:58, 13 September 2007 (UTC)

The prompt that you get when connecting to an ssh server for the first time (when the client doesn't recognize the key and wants you to decide whether to believe that the server is who he says he is) - that is about the server's host key, which is generated once when the server is installed, and stored on disk so that it persists for the lifetime of the server. In ssh version 2, this can be an RSA key or a DSA key (ssh1 didn't use DSA). Your client will remember this key, and later if you connect to the same server and it's using a different key you'll get a big warning saying the host key has changed. This is a sign that you're not talking a different server using the same name - possibly an impersonator. All of this happens before the user authentication is even considered. --tcsetattr (talk / contribs) 05:59, 13 September 2007 (UTC)

• Your key pair is never used for encrypting the session, since public key encryption is many times more computationally expensive than symmetric encryption. The public key crypto is only used for authentication and for exchanging single-use symmetric session keys. --Sean 14:02, 13 September 2007 (UTC)

September 13

Registering a second-level domain

How could I register a domain name making amusing use of country code TLDs, such as (whatever).bit.ch or (whatever).fu.ck? Someoneinmyheadbutit'snotme 00:50, 13 September 2007 (UTC)

You'd have to contact whoever owns bit.ch or fu.ck. -- JSBillings 01:16, 13 September 2007 (UTC)

Use whois and you'll find bit.ch is owned by Inware AG in Zurich. However, fu.ck is not owned. There are two reasons - the registrar doesn't offer it because it is offensive. Also, the registrar doesn't give out two-letter names. -- kainaw™ 01:40, 13 September 2007 (UTC)

Looks like it doesn't allow any registrations at the second level either (from .ck). Businesses can register a .co.ck though. — Matt Eason ^{(Talk &#149; Contribs)} 18:21, 13 September 2007 (UTC)

How about pri.ck? Someoneinmyheadbutit'snotme 19:32, 13 September 2007 (UTC)

This reference desk is not a whois database. Look these up elsewhere. I think you will find that most of the obvious possible words are taken. -- Diletante 19:40, 13 September 2007 (UTC)

Sending Novell messages

Our school computers are running Windows XP with the Novell Server software. I have received messages from other students (non-Admin accounts) through the Novell messaging pop-ups. I am curious, how does one do this (send messages to all users) with a non-Admin account? Thanks. Acceptable 01:15, 13 September 2007 (UTC)

I think it's a little application.. at my old school it was in the Novell NetWare program group in the start menu called Messenger or something --froth^t 01:42, 13 September 2007 (UTC)

I can't remember what network software was in use (I think it may have been Novell), but at my old school you opened up the command prompt / Run dialog and typed "net send *username* *message*" (without asterisks). Confusing Manifestation 03:15, 13 September 2007 (UTC)

Right-click on the Novell icon on the task bar. (It's a big N) Some options should pop up, one of which should be send message to user or something. You may have to know their login id, however. YeoungBraxx 10:39, 13 September 2007 (UTC)

In C should I use exit() or return() to exit main{}

Which should I use to exit the main function of a C program? exit() or return()? A friend tells me that exit() is the better option because it cleans up memory allocations etc, but lint (the error checking program) complains if I don't use return(). —Preceding unsigned comment added by 124.176.36.88 (talk) 03:20, 13 September 2007 (UTC)

I don't really think memory clean-up matters at all during application exit. Any modern OS will clean it up for you. If I remember the C standard correctly, a return from main is defined as being equivalent to a call to exit, with the same parameter.

Gah, not a return from main, but the final return from main. There may be obscure reasons to call main recursively. BTW, see this FAQ for references. --Pekaje 08:40, 13 September 2007 (UTC)

Thanks! 203.22.236.14 08:44, 13 September 2007 (UTC) (same person 124.176.36.88, but on a different machine)

Note also that return is a keyword, not a function, so it's misleading to refer to it as "return()". As for the question, I personally think it's better stylistically to always return from a non-void function, but if your compiler knows that exit() never returns then it doesn't really matter. --Sean 13:58, 13 September 2007 (UTC)

IIRC, most standard C libraries automatically call exit() when main reaches the end of the function. Whether you use exit() or return won't ultimately make any difference, as such resources will be cleaned up one way or another. However, you should use return - should you decide to move the code from main() to another function, you won't have to worry about changing as much code. --Sigma 7 18:45, 13 September 2007 (UTC)

what are the key features of Xerox Alto?

What are the different versions of Microsoft, mention fro the earliest to the leates? Why " LIsa doomed to failure"? What are the best features of FUI that you can observe in Windows XP?Jahanzeb87 04:25, 13 September 2007 (UTC)

This sounds like a curious mix between homework and questions that don't make much sense. Perhaps start with Xerox_Parc#Accomplishments, Apple Lisa, Microsoft Windows, and History of Microsoft Windows. And what is FUI? Do you mean GUI? --jjron 09:32, 13 September 2007 (UTC)

What is FUI anyway> --Do not click me! —Preceding unsigned comment added by Multipleidentitynumberthree (talk • contribs) 19:44, 13 September 2007 (UTC) Did you mean GUI? --Do not click me! 19:45, 13 September 2007 (UTC)

How to resize Flash in the Wikipedia editor

Hi

I'm trying to insert a flash banner into my Wikipedia site but I'm having problems with the sizing, for some reason it makes it really small.

All I've done is to paste the URL into the code window and tried to play around adding in width=750 height=120 but with no success, I've been searching round for the actual Wikipedia syntax for height and width but i can't find it anywhere, someone please help it's driving me mad.

Many Thanks

Dave —Preceding unsigned comment added by 193.123.249.157 (talk) 14:57, 13 September 2007 (UTC)

Why would you need Flash? I'm assuming you mean on your user page? --LarryMac | Talk 15:10, 13 September 2007 (UTC)

Yeah just on my user page —Preceding unsigned comment added by 193.123.249.157 (talk) 15:51, 13 September 2007 (UTC)

You can't use flash. Thank God. --froth^t 18:46, 13 September 2007 (UTC)

You could always have it as a gif file or something I guess. --Do not click me! 19:43, 13 September 2007 (UTC)

Black Bars on a Plasma Screen TV

Hi, not sure this is the right place for this question but... I just bought a new LG 42" plasma screen tv. I've turned on low contrast and the pixel orbiter, but I've been told not to watch movies with black bars on the side. Unfortunately, quite a few of my movie are 16:9, which can only be decently viewed with bars on the side. And if I watch a movie, I'll have black bars for a least 1.5 hours, maybe 3.5 if I watch Lord of the Rings. Can I make it full screen without screwing up the picture? Do I really need to worry about the black bars or is that still even a problem? Thanks! 24.178.112.241 15:25, 13 September 2007 (UTC)JMC

To explain the issue VERY briefly... When you buy a new plasma, the phospors are brand new and glowing brightly. They will degrade as they are used. If you have black bars on the sides for an extensive amount of time, those sides won't degrade at the same rate. The result is that the middle will be dimmer than the sides when viewing wide-screen video. The fix is to use gray bars instead of black bars to make the sides degrade at the same rate as the middle. -- kainaw™ 15:44, 13 September 2007 (UTC)

Are you sure you have black bars on the *side* while watching 16:9 movies? You should have small black bars on the top and bottom (letterboxing). Bars on the left and right is known as pillarboxing and should only appear when watching 4:3 movies or TV shows. As you say your TV is new and has pixel shifting, I would not worry about burn in. From what I read, the problem is virutally non-existent in modern plasmas. Unless you are displaying the same info for days at a time (like an airport flight display), I wouldn't worry about it. All modern DVD players and game systems have built-in dimmers and screensavers. Congrats on your new purchase! --24.249.108.133 16:01, 13 September 2007 (UTC)

(edit conflict)Most movies aren't exactly 16:9, but nevertheless, widescreen movies would be the ones that don't display with bars on the sides. There might be some at the top and bottom. Standard definition TV, 4:3, is usually where you get bars on the sides. All of this is complicated by the settings on your DVD player and your TV, which most likely has settings to stretch the picture out in various ways. Off the top of my head, I think the settings on my Sony are "normal", "wide", and "wide zoom". --LarryMac | Talk 16:02, 13 September 2007 (UTC)

Thanks for the quick replies! I have done some research... and yes it is letterboxing, not on the side as in 4:3 tv. It's actually pretty good at displaying SDTV fullscreen and with the pixel orbiter and frequent commericial breaks, I'm not worried about tv logos. I'm just worried about hurting my investment by watching movies, when that's what I got it for. Pixel orbiter won't help if it's an extended fixed image right (like a black bar)? There doesn't seem to be an option to turn 16:9 letterboxing to gray (though that is on 4:3 aspect ratio I never use. Although... the letterboxing doesn't seem to be as black as the black in my favorite space movies... so perhaps it's on automatically? Is there a way to find out? Am I freaking out for no reason? Should I just watch what I want... but maybe not LOTR for a while... and not worry about it? It's my first big tv and my first big purchase after my car. I guess I'm looking for some reassurance. Thanks! 24.178.112.241 16:12, 13 September 2007 (UTC)JMC

Honestly, I wouldn't worry about it, unless you're planning on watching LOTR exclusively, over and over again, for days at a time. If you watch a variety of sources -- 4:3 TV, 16:9 TV, widescreen movies, Wii Sports . . . you should be fine. --LarryMac | Talk 18:34, 13 September 2007 (UTC)

And if you only watched video in this format, you would not notice that the pixels in the black section were brighter! Graeme Bartlett 21:41, 13 September 2007 (UTC)

I think it's a good idea to run the display full screen for the first 150 to 200 hours. Checkout AVS forums. —Wayward ^Talk 01:53, 14 September 2007 (UTC)

Closing the lid

I just got an awesome new monitor so that I can have more screen space. I'm a big fan of locking my session (Flag + L) when I'm out of the room. It doesn't make any sense not to, and it doesn't make any sense to "sleep" your computer for security. So I use lock.. anyway, when I close my laptop lid, my monitor becomes the primary display. Very cool behavior, perfect for watching movies. But when I lock my session and close my lid, my monitor changes to my laptop resolution (same vertical resolution, just less pixels on the sides) and switches its mode to a "mirrored" display of the primary display! This doesn't go away when I open my laptop lid, so I have to go into display settings every time and check "Extend my desktop onto this monitor." Any ideas on how I can fix this? --froth^t 18:43, 13 September 2007 (UTC)

I don't know the answer but I am curious. Which OS are you on? (Was it obvious from the fact that you mentioned flag plus l?) --Do not click me! 22:44, 13 September 2007 (UTC)

yep. Vista. I figured it wouldn't be any difference vista/xp --froth^t 22:47, 13 September 2007 (UTC)

xp reinstall

I have windows and SUSE. What happens if I reinstall windows? is suse still there, and the grub bootloader? —Preceding unsigned comment added by Jorgenssen (talk • contribs) 20:01, 13 September 2007 (UTC)

If you do not delete the partition(s) with SuSE on it, the installation will remain there, however, it will likely rewrite the primary disk's boot sector, so you'll need to use a LiveCD or rescue disk to re-run the grub installer after windows has been (re)installed -- JSBillings 20:07, 13 September 2007 (UTC)

well, everything is on the same disc anyway, so I don't suppose "primary disc" is really a factor. I don't intend to delete the partition. I take it "boot sector" to mean my bootloader (the thing which selects either windows or suse) will disappear? SUSE doesn't have a live CD, but I think there is a system restore. —Preceding unsigned comment added by Jorgenssen (talk • contribs) 20:25, 13 September 2007 (UTC)

Just boot from the first suse install disk. When it asks what you want to do just say boot into the already installed suse partition (if that's not an option you might have to actually enter the installer, which gives you the option). Once suse is running, go to yast and the grub install utility. --froth^t 20:55, 13 September 2007 (UTC)

Ah. Thanks. I would come back if any problems cropped up, but that might be some time. --Jorgenssen, September 13th (UTC) —Preceding unsigned comment added by Jorgenssen (talk • contribs)

grin. Use ~~~~ to sign your posts, don't try to do it manually :3 --froth^t 23:12, 13 September 2007 (UTC)

net view equivalent for bash/linux

Is there a bash equivalent of the dos command "net view" which lets you view all of the computers on your LAN, Domain, and Network. – 69.150.209.13 20:22, 13 September 2007 (UTC)

Not /bin/bash, since enumerating SMB machines isn't really the domain of the shell, but smbtree? Splintercellguy 22:10, 13 September 2007 (UTC)

Neither is "net" in the domain of the shell. The OP just means "a command line program". --192.58.221.248 22:53, 13 September 2007 (UTC)

True, but the OP said bash, while you could run such apps on any shell, really. Splintercellguy 23:08, 13 September 2007 (UTC)

Laptop computer + external LCD monitor

I have a Compaq Presario laptop computer that supports outputs in resolutions in 1600 x 900 and 1400 x 950. What will happen if I connect it to a 1680 x 1050 or a 1400 x 900 LCD monitor? -- Toytoy 20:46, 13 September 2007 (UTC)

Once you connect the new monitor, you can go into Control Panel, then System, Hardware, Device Manager, right click on Monitors, then scan for hardware changes; and it should automatically update itself so that you can select the correct resolution for the new monitor. At least that's how it would work on a desktop, I'm not 100% sure if that will work on a laptop, but I'm sure someone will come along who does know for sure. --69.118.235.97 21:24, 13 September 2007 (UTC)

It just depends on whether your video card supports it. What card do you have? --froth^t 22:49, 13 September 2007 (UTC)

Spybot - Search & Destroy

I just ran spybot and for some reason it seems to be picking up Microsoft.WindowsSecurityCenter as a threat against this computer. Is this normal?--69.118.235.97 20:59, 13 September 2007 (UTC)

If you look more closely, it is picking up the fact that one of the Security Center settings is overridden or something. This is usually done by many antivirus and/or firewall programs. --192.58.221.248 21:27, 13 September 2007 (UTC)

Spanish Dictionary

Is there a program, like WordWeb, that is for Spanish? --74.37.228.44 21:33, 13 September 2007 (UTC)

Docx vs PDF

I am new to MS Office 2007. I used the Save as command in MS Office 2007 to save a two page document in PDF. I got 13 KB for DocX format whereas for PDF, I got a 155 KB file.

I wonder why the same document produced in MS Office Word 2007 and saved in two formats, Docx and PDF differ by so much. Is it purely because, with the default settings in MS Office 2007, DocX compresses the data and PDF does not? I don't think so. Does PDF hold more information than DocX? What is this extra information then?

I find this whole business weird.

Do you have any non-obvious answers?

Regards, Kushal --Do not click me! 22:41, 13 September 2007 (UTC) --Do not click me!

[Post written by a bored Wikipedian. Delete if necessary.]

For one, all fonts used in a pdf are packaged with the pdf, unlike a docx. --froth^t 22:59, 13 September 2007 (UTC)

I used only one font though, arial unicode MS. What other reasons might there be? --Do not click me! 01:34, 14 September 2007 (UTC)

Dell Inspiron 1520N

Does anyone here own one? I am thinking of getting a new computer by late October or early november so I wanted to know which laptop I should buy (or should I even buy a laptop? Should I even buy a computer?)

Is it too early to start researching? Which would be the best laptop to buy for a college student?

The question above is too generic and will likely attract spammers/trolls so I am limiting myself to comments about the Dell Inspiron 1520N AND the Apple MacBook.

Regards, --Do not click me! 22:48, 13 September 2007 (UTC)

Well my experience is that you don't really need a laptop. After a few years in college I've never once needed my laptop in class for notetaking. It's distracting in class and cumbersome to carry around. And all my computing and lab classes have workstations in the classroom for each student. Laptops are much more expensive, impossible to upgrade (I got a Yonah T2600 the week before Merom was released early, and now I'm stuck with it!), have cooling problems with gaming, and have underpowered graphics cards compared to their desktop cousins. Literally the only advantages to a laptop form factor is portability and utterly perfect quality of LCD displays (for high end laptops). Just save yourself a ton of money and get a really good desktop computer that you can upgrade on a rolling basis on the cheap instead of wasting your money on a laptop and being stuck with the same computer for years. --froth^t 23:06, 13 September 2007 (UTC)

Interesting and really helpful comment. Thank you very much Froth!

If I should get a desktop so that I can upgrade it on a rolling basis, does it not preclude the all in one wonder, savior of design, and [all the great adjectives in the world], Apple iMac? --Do not click me! 01:32, 14 September 2007 (UTC)

Firefox and IE

Hello, so i've been using IE and now changed to FF. I've found that with IE, when I click back, it automatically refreshes the previous page, or reloads it, which is good when I'm viewing recent changes. But FF does not do this, how can I get it to do it? Since Twinkle works on FF not IE, I need to find this out. Thanks! Phgao 22:56, 13 September 2007 (UTC)

According to RFC 2616, section 13.13, Firefox is implementing the back button correctly. I see no configuration item that appears to be related, so this is probably not configurable behavior at this time. If you need fast navigation back to the current recent changes list, look at my note on access keys above. The recent changes list is access key "R". --Pekaje 23:06, 13 September 2007 (UTC)

It's called cache and it's extremely useful. When I click back I want to see what I saw before, not what the page I was looking at before now looks like. My only complaint is that you can't control it from the server side. It's infuriating trying to write server scripts that are constantly foiled by firefox's cache.. it totally ignores the relevant HTTP headers --froth^t 23:10, 13 September 2007 (UTC)

If you want to reload a page in firefox, you hit ctrl-R, I believe. --24.147.86.187 01:14, 14 September 2007 (UTC)

September 14

SQL Function CAST question.

SQL> select order_date,(cast(order_date as timestamp) - cast(current_timestamp as timestamp)) from TABLE_X limit to 1 row;

%SQL-F-INTNOTQUAL, Interval expression not qualified

Why is it returning an error?

Going on similar lines, what do i do if i want to find the age of a person today, from a table which has birthdate of a person, using current_timestamp?