Wikipedia:Reference desk/Archives/Computing/2012 December 10

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December 10

Laptop mouse

On my Asus laptop computer. My mouse pointer is very sensitive to everything. My "page up and down" option keeps interupting my pointer when I move about the page and I have to keep left clicking to go back to my pointer. This is very annoying. How do I stop he mouse from being so sensitive. — Preceding unsigned comment added by Bill2345bill (talk • contribs) 02:25, 10 December 2012 (UTC)

Do you mean the touchpad or an external mouse? Hcobb (talk) 03:37, 10 December 2012 (UTC)

And are the "page up and down options" the page up and page down buttons on the keyboard ? StuRat (talk) 04:25, 10 December 2012 (UTC)

I sometimes have the same problem. I think it is because my touchpad has a strip on the edge which acts like page up / page down. If you keep your fingers more towards the middle, maybe thet will reduce the problem. Astronaut (talk) 12:57, 10 December 2012 (UTC)

Or you could cover that strip with tape, perhaps. StuRat (talk) 19:16, 10 December 2012 (UTC)

You can disable the scroll function completely. From here: Click Start > Settings > Control Panel > Mouse. On Mouse Properties tab: Device Settings Tab > Settings > Virtual Scroll. Then remove the dot from the Enable fields.

You can also adjust the sensitivity of the touchpad in the same dialog box, although this mainly affects the 'speed', i.e. how far you have to push the mouse to move the cursor a given distance. It's possible that your touchpad driver has other options, so if the above doesn't give the solution you require, post back here with the details of your driver (can be found usingthese instructions). - Cucumber Mike (talk) 19:41, 10 December 2012 (UTC)

Wifi is only accpeting my laptop but not the others

I just received a new modem.. So I configured it, but seems it only accepting my laptop for wifi and no one else can Join the network either. Also, it doesn't have a "non-passworded" option. I want to make it so, the other laptops/devices can connect..

Here is a screenie of the interface. http://i.imgur.com/xHUdj.png Thanks for your help 181.50.171.193 (talk) 04:36, 10 December 2012 (UTC)

Try the "Access Control" section on the left. The other devices may be blocked by MAC address (or rather, not specifically permitted, and need their MAC addresses added here). -- Chuq (talk) 05:44, 10 December 2012 (UTC)

It doesn't seem that it is blocking any adress, it says "allow/block" filtering is "unactivated" meaning they should be able to connect to the network. 181.50.171.193 (talk) 06:13, 10 December 2012 (UTC)

INSTALLING ANDROID TO A PC

What are the advantages of installing Android Software to a Personal Computer? Any disadvantages? Thank you.175.157.50.100 (talk) 06:17, 10 December 2012 (UTC)

Do you mean installing a virtual android? The only advantage I can think of, is that if the operating system fails, you won't lose anything of value.. 181.50.171.193 (talk) 06:19, 10 December 2012 (UTC)

The biggest hurdle you can expect to run into is driver support. Although the system will likely boot and run, you probably won't have accelerated graphics out of the box. You'll also want to see if there is support for your touchscreen, if you have one. It's been over a year since I last experimented with Android on x86, so things may have improved greatly since then. You won't be able to run normal PC software any more, but you will have access to the app store. 209.131.76.183 (talk) 12:32, 10 December 2012 (UTC)

If all you want to do is run Android apps on your PC, there are solutions for that. BlueStacks lets you easily do so on Windows and OS X. With that, I'm not altogether sure what advantages installing a full-blown Android OS (e.g. Android-x86) on your computer would bring... -- Consumed Crustacean (talk) 18:47, 10 December 2012 (UTC)

Modifying the hardware of the Nokia 101?

How do I modify the hardware of my Nokia 101, adding a camera and web browsing? Write English in Cyrillic (talk) 12:00, 10 December 2012 (UTC)

Your only option is to get a camera, and a small device that can browse the Internet, and to use Duct tape to join it all together.

My personal advice is to get a new phone.

doubt on synchronized block 3

Do not think that it already asked question
the general form of synchronized block is

class table  
   
   {     

   .......   
 
    void printTable(int n) 
    
   {     

   synchronized(obj)  
   
   {  
  
    ...... 
   
    } 
    
   }  
  
    } 
   

Here obj means object of table class or object of any class.
1)If we write this in place of obj we get lock on the object of table class.
That means we can’t access the synchronized block simultaneously by same object of table class.
2) But if write other object’s name other than table class in place of obj,what it means?
Then which object can’t access the synchronized block simultaneously?
— Preceding unsigned comment added by Phanihup (talk • contribs) 12:16, 10 December 2012 (UTC)

Don't ask the same question over and over again. I already answered your question you asked a couple of days ago, read that answer instead. JIP | Talk 19:53, 10 December 2012 (UTC)

How to let Firefox extension FireGestures do "Open URL in new tab and active it / Search for Selection"?

Hello. I found a script in official site — "[Hybrid] Open Link in New Tab / Search for Selection", but it opens link in a background tab. Or is it influenced with other plugin (like Tab Mix Plus)? --202.117.145.244 (talk) 14:29, 10 December 2012 (UTC)

You might want to go to about:config and check your prefs that match InBackground. ¦ Reisio (talk) 20:09, 10 December 2012 (UTC)

ISO images vs burnt image

I'm trying to verify the integrity of a burnt DVD/CD image from a verified ISO, after the fact. Bit for bit the images are nearly identical, except the burnt DVD had about 300k of extra data. However upon looking at it, the extra is simply 0s. I assume this is padding, but can someone confirm that for me? Shadowjams (talk) 20:57, 10 December 2012 (UTC)

Do you mean decimal 0's (that is, the actual number zero), or binary 0's (that is, no data) ? StuRat (talk) 21:50, 10 December 2012 (UTC)

Those are the same thing. I think you mean ascii "0"s, which no, it is not. I'm really asking if someone is familiar with either the UDF format or how authoring software handle non-uniform end-blocks. Shadowjams (talk) 22:01, 10 December 2012 (UTC)

It's probably just the remainder that hasn't been written to. Mount the image and do a recursive diff or cmp and you can be sure. ¦ Reisio (talk) 23:39, 10 December 2012 (UTC)

I did, it seems to be on a sector boundary and the 300k or so of null data appears to be padding. It of course makes summing the disc/iso difficult because they're different (although if you exclude the 0s they sum perfectly). Shadowjams (talk) 00:05, 11 December 2012 (UTC)

Perhaps more important than the file format: what API or tool are you using to read the data from the DVD? For example, dd is generally the lowest-level file data-access available without directly calling into the device-driver. Those extra zeros could have been added by the file-reading function, and might not actually be present on the disc. Nimur (talk) 23:48, 10 December 2012 (UTC)

That's kind of interesting... how would I read more low level than dd though? I suppose it's an interesting point about whether it's the authoring software or dd that's padding the end, and maybe moot, but I guess my instinct is the authoring software's more likely to do the padding than dd is (or I guess to your point, the cdrom device driver). Shadowjams (talk) 00:05, 11 December 2012 (UTC)

It's not dd; dd is as dumb as a bucket - it just calls read(2) and write(2) until it's done. If you're calling read(2) on a block device like /dev/sr0 then that's a straight pass through to the block device driver. On doing something like you're doing I see exactly 16Kbytes of 00s when I read the disk back. I tried to read Brasero's source, so I could give you a meaningful answer about what "integrity check" really means, but doing that just made me sad. -- Finlay McWalterჷTalk 00:56, 11 December 2012 (UTC)

From my experience with Windows software, most software and/or drives do not add that much padding. I'm not entirely sure whether the drive or software is required to add padding if the DVD size is not a multiple of recording frames (i.e. the number of 2048 byte data sectors is not a multiple of 16) or whether it's acceptable to leave it as is. Some software or drives do add padding to ensure its a multiple of recording frames. Obviously an entire recording frame will be written in any case but I think if the disc says it's only X sectors, most software will read it as X sectors even if its only giving part of a frame, at least IIRC I have had discs which weren't an integer of recording frames. But this is irrelevent in your case since the extra size is significantly more then the maximum possible extra needed to ensure an entire recording frame is used (~30k). I'm pretty sure there's no reason to add that much and I don't think I've ever burnt something where I ended up with that much padding and I used to burn a lot of images, although I don't really understand the mention of 'authorising software'. My impression from the original question is we're referring to an ISO, in which case it was already authored and no authoring software need be involved, simply something to write the ISO to the disc. (It's possible you may be using authoring software to write the image, but in that case it's still not functioning as authoring software.) Nil Einne (talk) 06:02, 11 December 2012 (UTC)

I did some experiments on Linux with Brasero and then with growisofs (the part of dvd+rw-tools which, despite its name, actually writes iso images to disk); I think utilities like Brasero actually use growisofs to do the burning. I see that Brasero will pad files with 00s to the next 32kbyte boundary, so even a 1 byte iso will read back as a 32kbyte file, with all but the first byte 00s. The reason appears to be that growisofs insists on files that are multiples of 32kbytes. That's not the same as the block device's native block size (as reported by the BLKGETSIZE ioctl) which is 2048 bytes, as you would expect. So I'd understand where you'd get up to 32kbytes of 00 padding, but not 300kbytes. -- Finlay McWalterჷTalk 13:13, 11 December 2012 (UTC)

In case there was some confusion with my answer above, a DVD has a sector size of 2048 data bytes which is the same as for CDs. But a recording frame or ECC block is 16 sectors [1], so I'm pretty sure the minimum you can record or read is 16 sectors (which is where the 32k comes from). However as each sector is invidually addressable and the DVD size is I believe simply recorded as the number of sectors in the lead-in, I don't think there's anything stopping you writing a number of sectors that isn't a multiple of 16, except possibly for software and drives which may reject such images or pad them, although I'm also not sure if it would be spec compliant if you don't. I expect most authoring software will generate DVD images with a multiple of 16 sectors so if you have a DVD image it's likely to be a multiple of 16, but perhaps not CD images. P.S. I used the term recording frame in my first reply and recording frame/ECC block here, these don't refer to the same thing but I believe from the POV of how many data sectors are involved, they are the same thing. The actual encoding is fairly complicated, see [2] for details. Nil Einne (talk) 12:22, 12 December 2012 (UTC)

If it were me, I would consider the extra padding safe, assuming the rest of the file was copied properly. If you want to be sure, you could look into the specifications of ISO 9660 and make sure that extra data at the end won't hurt anything. I suspect that the various tables and directory entries specify the sizes and locations of everything, so there is no reason a reader would ever look past the end of the data into the zeroes (or further). If the directory is malformed, I suppose it could point past the end, but in that case your original has problems too. 209.131.76.183 (talk) 13:41, 11 December 2012 (UTC)

Thank you all for the thoughtful replies. Yeah, I'm confounded by the size of the padding, although it's all 0's so I'm not concerned about its integrity. The burning software in question was nero an it was just burning a standard ISO for a linux distro. It is a curious finding though. Maybe I'll experiment with the same ISO on a different burning program later and see if it's the same result. Shadowjams (talk) 16:58, 11 December 2012 (UTC)