Wikipedia:Reference desk/Archives/Computing/2008 October 30

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October 30

Completely copying hdd

Would it be plausible/easy to copy all of the contents of a hard drive (including the OS) to another one? Mine is gettin' full, and I want to switch to a bigger, new one, but I want to keep all my files and stuff. Hypothetically, I could just plug the old hard drive into the master, and the new one into the slave, and just copy it all over using Windows (no fancy-schmancy cmd-line crap), right? flaminglawyer^c 00:43, 30 October 2008 (UTC)

As far as I understand it, you could copy all the data (pictures, text, movies, mp3s) but not the installed programs - you'd need to reinstall them on the new drive as they need to modify the registry etc to work. Exxolon (talk) 01:02, 30 October 2008 (UTC)

You can't just copy it over in the Windows interface—it won't copy certain system files correctly (like the registry) and the master boot record won't copy.

What you ought to do is set it up master/slave, and then use a program to "clone" one drive to the other. I recommend GParted (downloads as a CD that you use to boot up the computer with—it's Linux but it has a super easy, friendly interface), personally.

After that you'll probably have to boot into the Recovery Console and run "fixmbr" to fix the master boot record.

So a little command line stuff but not too tough. --98.217.8.46 (talk) 01:08, 30 October 2008 (UTC)

And that clones the OS and the data - good so far. But... could you elaborate on this whole "master boot record" thing? I've never heard of it before, and it seems to me that I need to know what I'm messing with before I mess with it. And thanks for directing me to the super-easy thing; I've tried a real Linux version before, and it was scary. flaminglawyer^c 04:32, 30 October 2008 (UTC)

And explain this "Recovery console," never heard of it either. flaminglawyer^c 04:33, 30 October 2008 (UTC)

Basically, there is a little hidden file that is not on your hard drive itself yet tells your computer how to boot up correctly. What it means in practice is that if you just clone the contents of one drive to another, and then try to boot up off of that other drive, you might end up with just a black screen—the computer won't be able to figure out where it is supposed to boot. If that happens, then you can start up the Recovery Console by putting in your Windows CD and starting up from the CD—I think you hold down F8 while booting and it will give you a menu. The Recovery Console is basically like DOS—you'll see a command line prompt. Just type in "fixmbr" and it should fix the problem, if you are getting the "blank screen" problem. Then reboot and you should be good. --98.217.8.46 (talk) 21:02, 30 October 2008 (UTC)

Try Clonezilla. It works well. manya (talk) 10:49, 30 October 2008 (UTC)

Is it possible to run the Recovery Console thing without a Windows disc? My comp came with XP, and I'm not about to spend 300 bucks on a CD that I'll only use once. flaminglawyer^c 21:47, 30 October 2008 (UTC)

This page has a few links that ought to let you create a Recovery Console disk either on a floppy or on a CD. --98.217.8.46 (talk) 16:02, 31 October 2008 (UTC)

Score. Done. Thanks to all. flaminglawyer^c 02:06, 1 November 2008 (UTC)

Singularity functions in Ti-89/84+

Does anyone know how to plot singularity functions/use macaulay brackets in a Ti-89 or a Ti-84+? I need to be able to plot functions such as y = x^2 - <x-5>^3. So I need the <x-5>^3 term to only appear when x>5 (it's equal to zero when x<5)

Thanks! --Fir0002 06:28, 30 October 2008 (UTC)

Not sure I fully understand your question, but from what I take of it, can't you just graph the example equation and then a partial (just y = x^2) and see where they intersect? I don't think that's exactly the right way to do it, but something like that. Also, try the math reference desk. DaRkAgE7_[Talk] 07:34, 30 October 2008 (UTC)

There's probably an easier way than this, but I can't find my calculator to try it out. Anyway, you should be able to create the partial equations as separate functions, thereby making your graph piecewise. Just multiply the function by a logic test: #F outputs as 0 and #T outputs as 1. You'll need to write different functions including/excluding terms as necessary and include the applicable logic in the function. You could do the example above as such: Y1=(x<5)(x^2) Y2=(X>=5)(X^2-(x-5)^3). Does that suit your needs? --Shaggorama (talk) 09:03, 30 October 2008 (UTC)

That's what I'm currently doing, but the equations I'm doing have three or four such terms with varying "turn on" points and it's a bit of pain to have to type out several versions of the equation. I was hoping there was an inbuilt function which could handle this kind of thing. --Fir0002 09:54, 30 October 2008 (UTC)

If what Shaggorama suggests works, can't you just do Y1=x^2-(x>5)(x-5)^3? See also Iverson bracket: the Macaulay bracket $\{x\}\equiv x[x>0]$. --Tardis (talk) 15:50, 30 October 2008 (UTC)

It doesn't let you do a (x>5) term for graphing "argument must be an expression". So unfortunately that won't work --Fir0002 23:14, 30 October 2008 (UTC)

Does the calculator have a 'sign' function (ie a function that returns -1 if the input is negative, zero if the input is zero and +1 if the input is positive)? If so then you can 'fake' (x>5) using (sign(x-5)+1)/2 (well, more or less - it doesn't quite work when x is EXACTLY equal to 5...you can get it exactly right if you also have the 'abs' function but it starts to get complicated!). SteveBaker (talk) 01:17, 31 October 2008 (UTC)

Yeah that is an option, and I might use if I really want everything in a single graph but at 15 characters it's a little unwieldy for my purposes. Thanks anyway, but I guess these calculators can't do singularity functions with <> or equivalent. --Fir0002 04:57, 31 October 2008 (UTC)

I found an alternate method that puts the whole thing on a single line, but it ain't pretty. You could probably build a pretty lightweight program that could automatically spit out the singularity function for you (or at least the nastier part of the equation). --Shaggorama (talk) 05:41, 31 October 2008 (UTC)

The TI-84 will let you include (x>5) in an expression to be graphed: it will be equal to 0 if false and 1 if true. The TI-89 doesn't let you do that, but it does let you define your own functions, so you can just write your own function to act as an Iverson bracket or something and use that. —Bkell (talk) 20:38, 2 November 2008 (UTC)

Perfect - thanks a lot Bkell --Fir0002 05:37, 3 November 2008 (UTC)

Multi touch in XP

For those of you that haven't seen it, this techie Johnny Chung Lee figured out a really simple trick that allows you to use a wiimote and an IR pen to create interactive surfaces, such as an interactive whiteboard or touch screen. The software he developed also has multi-touch capabilities, but windows XP doesn't. Not natively anyway. Dell recently developed a new firmware update giving multitouch gesture support for their latitude line of tablet PCs (a feature windows was apprently planning on holding onto for win7). I have an XP desktop (dell even) and wanted to know if there was anyway I could make my XP multitouch compatible with Lee's wiimote hack. --Shaggorama (talk) 09:22, 30 October 2008 (UTC)

As you said, Dell's new firmware is only for displays on tablet PCs. AFAIK, it is not possible to get multi-touch on contemporary desktop without additional hardware. Have you tried Lee's wiimote hack yet? Kushal (talk) 22:38, 1 November 2008 (UTC)

Computer Won't Even Turn On!

You may recognize me as the guy who has the totally-screwed-up computer and is always asking stuff. Well, here's another puzzler. When i went to start my computer, it wouldn't start. At all. no fan action, no hard drive action, no nothing. The power cables are all connected, the hard drive is completely connected, and all the fans are working properly (i tested them on an older power supply). All my expansion cards are seated properly, as are my memory modules. Windows had run its automatic update thingie while i was sleeping and i awoke to find my computer no longer functional. Why did this happen? 31306D696E6E69636B6D (talk) 13:22, 30 October 2008 (UTC)

If the fans aren't turning at all, it is most likely a broken power supply. They are made from electronic components and break just as much as anything else that we pump a lot of electrons through. Nothing special or weird about it. -- kainaw™ 13:25, 30 October 2008 (UTC)

I agree with Kainaw, the PS probably failed. You said you tested the fans with another power supply; did you have that old power supply plugged into the same outlet as your possibly malfunctioning one? It's a long shot, but you may want to make sure it's not the power outlet with the issue. Laenir (talk) 14:46, 30 October 2008 (UTC)

It's not the outlet or the power supply (i tested the power supply and the outlet just to be sure). I just got the BIOS logo to come up for about half a second before it turned off again. Also, something made some weird noise like a food processor grinding bricks. 31306D696E6E69636B6D (talk) 16:02, 30 October 2008 (UTC)

The question I have to ask (and please forgive me for that) is do you hear any beeps and if yes, could you describe those beeps (number of beeps, duration of each beep) to us here along with manufacturer and make of your motherboard. 12.169.180.178 (talk) 16:07, 30 October 2008 (UTC)

Yeah - if you hear beeps, that's the CPU trying to tell you what's wrong when things are so broken that it can't get to the display or even to main memory! The number of beeps tells you what's wrong - but sadly every motherboard seems to have a different set of 'beep codes' - so you really need the motherboard manual to figure out what it's telling you.

When the power seems to fail, it could still be the motherboard. The push-button that does the work of power switch AND reset button on many modern PC's is hooked up to some circuitry on the motherboard. The power supply provides a tiny amount of current to keep it running even when the PC is theoretically turned off - and the circuit is responsible for telling the power supply to go to full voltage when you push the button again. So that circuit could be broken. I had a PC for a while that wouldn't turn on - but I could trick it into doing so by shorting a couple of wires together on the power supply connector. Once the PC was started up - it would reliably keep running until you shut if off again. However, I'd put my money on it being the power supply - on the general principle that when you don't know which thing is broken - you're better off replacing the cheaper part first! However, if swapping out the power supply doesn't work - then you might need a new motherboard.

The grinding noise you hear sounds like it could be a fan that's busted. The CPU would get hot fairly quickly and (if it's a reasonably modern one) may turn itself off to protect itself. Urgh...this is not nice!

SteveBaker (talk) 01:09, 31 October 2008 (UTC)

Fans can keep a computer from turning on. I was rather happy with myself a few eons ago when my two month old Amiga 4000 wouldn't turn on and, for some reason, I decided to replace the power supply fan. After replacing it with a $2 fan from a local electronics dealer, it came right back on and worked great. -- kainaw™ 01:14, 31 October 2008 (UTC)

No beeps at all...but i did manage to find something else...the power switch connector had snapped off the motherboard...i managed to short the connections to start the computer. The grinding noise was my case fan ripping the power switch connector off the motherboard. 31306D696E6E69636B6D (talk) 13:16, 31 October 2008 (UTC)

It might just legit be broken, just as all things eventually get. How old is it? Yakeyglee (talk) 03:39, 3 November 2008 (UTC)

WEBSPHERE DEVELOPER

Hi,

I would like to have a clarification, if WEBSPHERE PORTAL DEVELOPER and WEBSPHERE DEVELOPER are the same. If there is a difference how?!! please clarify me on this.

I'd guess the first is interested in developers with knowledge of IBM's Websphere. The second wants someone who's had experience with the Portals bit of Websphere (see Websphere#Portals). --h2g2bob (talk) 19:19, 30 October 2008 (UTC)

Very likely, the Portal developer will specialize in JSP programming while the Websphere internals programmer will specialize in the related Java EE programming and software-engineering technology. In any case, the specific tasks of these individual jobs are going to be highly dependent on particular projects. Nimur (talk) 17:46, 3 November 2008 (UTC)

Visual .net remotely asess user

I wanted to make a program for my school so teachers could net send messages to students, and one thing I wanted to do was make it so that I could have them find the username of the currently logged on user. I have no idea how to do this in visual net, but I know how to find current user on current system.

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal _
   e As System.EventArgs) Handles MyBase.Load
   lblUserName.Text = SystemInformation.UserName
   End Sub

Is there a way to get it so you can see current user on remote system? Forai (talk) 22:39, 30 October 2008 (UTC)

I'm not sure, but psloggedon will do the job: http://technet.microsoft.com/en-us/sysinternals/bb897545.aspx .--Account created to post on Reference Desk (talk) 22:58, 30 October 2008 (UTC)

I saw that and figured that would be my last resort, I wanted to use only visual basic coding but if nobody has any other ideas then I can go with that Forai (talk) 23:18, 30 October 2008 (UTC)

It looks like there is a global variable, Environment.UserName (in fact it looks like Environment will give you access to all Windows environment variables. Nimur (talk) 17:51, 3 November 2008 (UTC)