I have tried downloading Ubuntu desktop four times and it is downloading as a zip file instead of an iso file. When I open it it opens in my archive program. Hence I cannot mount it to disk and install it onto my computer. What can I do?
I've downloaded ubuntu-12.04.1-desktop-amd64.iso via Chrome. Once that was done, I wanted to burn it onto a CD but I can't find the .iso file.   When I opened the Downloads folder, the .iso extension is not there anymore, and it opens with WinRAR for unzipping. I tried unzipping and searching for any ISO files but no luck.   I'm trying to add Ubuntu onto VirtualBox on Windows 7 host OS. Please help.
I want to implement designed PID controller. But I am facing the problem of how to limit the saturation limit in both positive and negative direction? I tried using zener diode, but I would like to know if are there any design procedures to get anti-wind up scheme in the  implementation of PID controller using zener/diode combination?  EDIT:  this is the designed pid controller and i am using TL084 op-amps which has +15 volts and -15 volts as their supply. when the error is generated, due to integrator the control signal(Vc) output is going to saturation point of nearly 15 volts. I want Vc to be in the range of (0.85-3.8 volts), so that i can give this to SG3524 PWM IC to generate constant duty ratio PWM pulses. I tried by putting zener diode of 3.3 volt rating, but now Vc is coming upto 3.5 volts(basically saturation limit has come down to 3.5 volts) . The problem is how to limt the Vc to the specified range. Can any one please suggest modifications for proper design of anti-windup  working scheme of this.  Here VFb=-3 volts and VRef= 3 volts Is installing wine in Ubuntu safe? Performance of Non Clustered Indexes on Heaps vs Clustered Indexes Equality in an integral estimate Let $u,v\in W^{1,p}(\Omega)$ with $1&lt;p&lt;\infty$ and $\Omega$ be a bounded smooth domain in $\mathbb{R}^N$. Suppose, we have $$\int_{\Omega}|\nabla u|^{p-2}\nabla u\nabla v\,dx=\left(\int_{\Omega}|\nabla u|^p\,dx\right)^\frac{p-1}{p}\left(\int_{\Omega}|\nabla v|^p\,dx\right)^\frac{1}{p} $$ Suppose the equality $$ \int_{\Omega}|\nabla u|^p\,dx=\int_{\Omega}|\nabla v|^p\,dx $$ holds. Then can we say that $u=v$ in $\Omega$? I tried in the following way: Since the first given equality, which is the equality in Holder's inequality holds, and by the second given equality holds, we have $|\nabla u|=|\nabla v|$ in $\Omega$. Then I am unable to proceed. Can someone please help to give an argument? There are two Java Web Start tags:  : x 239 : x 320   Both tags refer to the same technology  refers to  both wiki point to  all questions tagged with  clearly relate to Java Web Start   I suggest they be merged into  (which appears in the auto-complete list if one types "webstart" in the Tags box when asking a new question). reference overlay numbers with names I've finished the game, got all the items except one. This is the one to the right of the green shark fin. What and where is it? How can I make a bootable, unattended USB restore disk? I have a load of 14.04 kiosk systems, halfway across the country. These are horrible little integrated devices. I need to upgrade them all to 16.04 to support a new software stack. do-release-upgrade works half the time. The other half it destroys the install. In addition, the CPUs are really slow and  network connections at some sites are also pretty shoddy. So even when it works, upgrading takes a long time.  So new plan. I can make a fully-installed system image for each kiosk in Virtualbox, or LXC, or whatever. I need a way to get these images unpacked onto the systems.  The main problem here is there are very few technical people available at the other end. And I don't want to fly 200 miles to do this myself. I need something that is almost completely automated and doesn't require a keyboard.  I'm imagining a scenario where:   I make a system image for each kiosk I make a bootable USB drive for each kiosk and copy on the kiosk image. I label each and post them. At the other end, a staff member with physical access to the USB ports just plugs in the right drive and reboots. The bootable element of this then writes and expands the disk image.   It's that "bootable element" that I'm looking for. I was expecting that something like this might already exist (for bulk reimaging installations) but it's possible I'm in new territory. Anything that gets my images installed without manual interference (past plugging it in) gets points.  As far as I know, options like Clonezilla require somebody with a keyboard to tell it what to do. I need something that doesn't require a keyboard, just gets on and does it. What is Skynet's ultimate goal after defeating the resistance? Most MTP () devices show up in Windows File Explorer under their device name or a GUID, but they don't have a drive letter assigned.  How can I access the files on such devices from the command line? Using either cmd.exe or PowerShell. Creating label in QGIS? I am using QGIS 2.18.16 on Windows 10.    What I want is a label to appear within the boundaries of a polygon.    I select a layer, then select command Layer>Labelling, and I get:    From here, I can change "No Labels" to "Show labels for this layer".  But I can't actually create label text.  I find a clue in a prior question:    “Labelling polygon using QGIS?”    The answer was:  The layer you are trying to label must have at least one attribute field populated with data. You can then turn on labelling in Layer Properties and select which attribute field to use for your labels.  I can enter command Layer>Open Attribute Table, and what I get is:    If I need something in the attribute table in order to apply a label, how do I accomplish that? How to calculate bounce angle? I played around with it for a while, but I simply can't figure it out.  I made a tank that fires missiles, and when the missiles hit the walls, I want them to bounce off, but I want them to bounce off to the right angle.  Right now I haven't got any obstacles, the missiles just bounce off when they get outside the viewportRectangle I made.  Is the solution I'm looking for quite advanced?  Is there a relativly simple way to do it? Story about a deadly alien creature on another planet that has some chemical in its body that makes it faster I can not remember if it was a short story or a novel, but I am leaning towards it being a novel. There is a colony of humans and I can't remember if they crash-landed or not.   There is a creature that they come to discover after it has killed a few people. The creature has some kind of chemical in its body that is like a super-adrenaline. One part is I remember is one of these creatures getting very hot from using up its reserve of this chemical and it dived into a river or pond and it started to steam. Something like that.  It has to be at least 10 years since I read the story. How to change the snapping increment in different units? I would like to know how to change the increments used for snapping transforms.  This would be useful in a number of situations but my problem now is that when I change the units it does not scale the snapping increments to match.  So when holding down ctrl the cube snaps from here:    To here:    I would like it to snap to the 1 foot grid, or possibly any other amount I find useful.  It would also be nice to be able to change the rotation snap as well. Why is carbon dating limit only 40,000 years? When I watch the news I've noticed that the Gallup polls for things like presidential elections have [I assume random] sample sizes of well over 1,000.  From what I remember from college statistics was that a sample size of 30 was a "significantly large" sample.  It was made to seem that a sample size over 30 is pointless due to diminishing returns. Does a non-abelian semigroup without identity exist? How to make `man` work for shell builtin commands and keywords? How to make a water vortex I'm very new to Blender and I'm trying to make a water vortex like this.(may be not the easyest first project for a newbie)     I watched several tutorial on liquids particle etc but I'm not sure what is the best aproach. What I tried  until now:   I made a particle system with a vortex force field. It looks good, but I'm not able to add the right material.      I played around with the fluid physics, the water looks good but if I add a vortex force field it does nothing.   I would be very grateful if somebody could point me in the right direction because I'm definitely stocked. How to secure my laptop so that hacking by physical access is not possible? I messed up my system earlier, I was greeted with a black screen, when booting in to Ubuntu. When I started up my laptop, I selected the recovery option from the grub menu, and chose fallback at root terminal. I saw that I was able to use the add user command, with it, I probably could use to create a privileged user on my machine.   Isn't that a security issue?  One could have stolen my laptop and at startup chose recovery and add another user, I'm fudged then. Including my data.  Come to think of it, even if you somehow remove that entry, one could boot from a live-CD, get a chroot up and running and then add another user, with the right privileges that allows it to see all my data.   If I set the BIOS to boot at my HD only, no USB, CD/DVD, Network startup, and set a BIOS password, it still wouldn't matter, because you'd still have that grub recovery startup entry.  I am fairly certain that someone from China, Russia can't hack my Ubuntu Trusty Tahr, from the network, because it's secure like that. But, if one has physical access to my - your - machine, then, well, that's why I'm asking this question. How can I secure my machine so that hacking through physical access is not possible?    Bug Report: