I have a compaq Presario R3000 running hardy heron 8.04 with gnome.  I want to update to the latest version, but i am having a bit of trouble.  I've tried using Update Manager but when I try to upgrade to 10.04.4 (which is the only option) it says that it is no longer supported, but i keep going, and it starts downloading stuff then prepares to upgrade, but then when i gets to "setting new software channels" it gives an error.  I don't know how to boot off a usb.
Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc
I have just updated (through Software Update) to Ubuntu 16.04 LTS from 15.10. There are random instances of screen flickering throughout usage. After noticing this issue, I installed Compiz Config Settings Manager, selecting Force fulls screen redraws (buffer swap) on repaint, which did nothing.   Is there any way this could be related to compiz settings or is this another issue?    EDIT: not fixed after clean install, upgrade to kernel 4.5.2, however screen flickering is reduced, it is every now and then (10 minutes apart). I will see if upgrading to kernel 4.6.0-994-generic will fix this.     EDIT: fixed as of kernel 4.6.2 generic,  currently running 4.7.2 without any issues. How to programmatically click a button in WPF? Calling Table with custom iterator One of is followed by plural noun/pronoun and singular helping verb Why do the big nuts always remain at top? The Brazil-nut Effect Let $E$ be measurable and define $f:E\rightarrow\mathbb{R}$ such that $\{x\in E : f(x)&gt;c\}$ is measurable for all $c\in\mathbb{Q}$, is $f$ measurable?  There are a number of equivalent definitions for the measurability of a function and the most obvious one would be to show that $\{x\in E : f(x)&gt;c\}$ is measurable for all $c\in\mathbb{R}$.  Thus my strategy has been to consider an arbitrary irrational $y$ and use the density of the rationals in the reals to show that there exists some open set $O$ such that $m^*(O-\{x\in E : f(x)&gt;y\})&lt; \varepsilon$.  I would do this by choosing some rational $q&lt;y$, close enough to $y$, such that the set of values in $E$ which get sent under $f$ to values strictly greater than $q$ and less than or equal to $y$ is small enough.  But that doesn't in general seem possible since I could keep sending intervals of some fixed positive length to smaller and smaller regions just beneath $y$.  However conversely, such a function would not be enough for a counter example, since finding such a function only rules out this strategy, but doesn't necessarily entail non-measurability.  Is there a better definition of the measurability of a set I should use? or does the statement actually not imply measurability?  Thanks. I was wondering if there are functions for which $$f'(x) &gt; f(x)$$ for all $x$. Only examples I could think of were $e^x - c$ and simply $- c$ in which $c &gt; 0$. Also, is there any significance in a function that is always less than its derivative?    Edit: Thank you very much for all the replies. It seems almost all functions that apply are exponential by nature...  Are there more examples like - 1/x?  Again are there any applications/physical manifestations of these functions? [for example an object with a velocity that is always greater than its position/acceleration  is always greater than its velocity] Asynchronous shell exec in PHP I've got a PHP script that needs to invoke a shell script but doesn't care at all about the output. The shell script makes a number of SOAP calls and is slow to complete, so I don't want to slow down the PHP request while it waits for a reply. In fact, the PHP request should be able to exit without terminating the shell process.  I've looked into the various exec(), shell_exec(), pcntl_fork(), etc. functions, but none of them seem to offer exactly what I want. (Or, if they do, it's not clear to me how.) Any suggestions? How to recenter an object's origin? So, I'm working creating a lamp... yes, newbie here.  After modeling for a bit, I noticed that my point of origin was no longer the center of my object:    How to I reset an object origin point to the center of it's geometry? What happens if you call erase() on a map element while iterating from begin to end? In the following code I loop through a map and test if an element needs to be erased.  Is it safe to erase the element and keep iterating or do I need to collect the keys in another container and do a second loop to call the erase()?  map&lt;string, SerialdMsg::SerialFunction_t&gt;::iterator pm_it; for (pm_it = port_map.begin(); pm_it != port_map.end(); pm_it++) {     if (pm_it-&gt;second == delete_this_id) {         port_map.erase(pm_it-&gt;first);     } }   UPDATE: Of course, I then  which I didn't think would be related but answers my question. Login as other user setting for other profile except System Adminsitrator If a user is setup as System Administrator profile, the user can login as other user. However, is there any option that I can enable this function for other profile except System Administrator because I don't want to give them other System Administrator permission access?  In the past as I remember in summer 12, there's an option called "managing user permission" which allow me to disable or enable the profile to login as other user. But I don't see this anymore. Since reading the answers to my question about  I've been good about giving my meat time to defrost in the refrigerator. However, my plans for tonight have changed and I'd like to defrost some ground beef that is completely frozen for dinner this evening. What are my options to do so quickly and safely? After the DEM creation, I wanted to create slope layer.   However, the result has not satisfied me. I don't think the slope map is correct. Have you ever encountered false calculated terrain map?  This is the DEM:    And this is the slope layer. Can I recover app data after the phone has been Factory Reset? Without remembering application data, I reset my Galaxy S3 to factory state. Now, I lost data for one expense manager app. Is there any way to recover the data? Cannot boot because: Kernel panic - not syncing: Attempted to kill init! This is what I've got. I cannot boot and I see the two of three little lights on the keyboard blinking all the time and the cooling is working on full power, almost.  I saw in other askubuntu topic suggestion for memory test. I did it. I didn't have any errors.  I am 99,9% sure it is not a hardware problem, because I have Windows 7 and I can boot it and it works just fine.  This problem came without any warning or something. I just turned off the laptop one day and at the other day I couldn't boot.   From recovery mode I get this: I don't really know how to anticipate the changes in an option's price.  If I have an call set to expire the following Friday at $10 above the current share price, I know in the absence of other changes it loses value with each day that passes getting closer to its expiration. (Talking about American options.) But it gains value as the share price gets closer to the strike price.  So, if two days pass but the stock goes up $3, would the option have gained value or lost value? Is there any way to calculate this? Proof that the Euler characteristic is additive I'm reading through a set of notes which assumes that the Euler characteristic is additive, but doesn't give a proof, so I would like to understand why this is.  Let $A_n$ be a finitely generated Abelian group, non-zero for $0&lt;n&lt;k$. Consider the long exact sequence  $ \cdots \rightarrow A_n \rightarrow B_n \rightarrow C_n \rightarrow A_{n-1} \rightarrow B_{n-1} \rightarrow C_{n-1} \rightarrow \cdots $  where $B_n$, $C_n$ defined similarly to $A_n$.   I know that the Euler characteristic of $A$ is given by $\chi(A) = \sum_0^k (-1)^n \text{rank}(A_n)$, with similar definitions for $B$ and $C$. I want to prove that $\chi(B) = \chi(A) + \chi(C)$.  The notes say that for an exact sequence  $0 \rightarrow X \rightarrow Y \rightarrow Z \rightarrow 0$  of finitely generated Abelian groups $X,Y,Z$, we have the result rank($Y$) $=$ rank($X$) +  rank($Z$), and that the additivity of the Euler characteristic follows from this fact, but I can't see how. StringTokenizer? Convert the String to a char[] and iterate over that? Something else? I want to get records from custom object sort by a field as number. The field I want to sort is string type. Is there any way to do that? I am storing result in list, is there a way to sort list based on the string field but sort it as number? How do you determine what technology a website is built on? Quite often I come across a nice looking or functional website, and wonder what technology was used to create it. What techniques are available to figure out what a particular website was built with?  Few frameworks seem to include any kind of generator meta tag like web editors do. Are there any tell-tale signs of particular languages and/or frameworks?    Summary of answers  Site URLs may betray the framework and/or programming language but cannot be relied upon (e.g. file extensions such as .asp). HTTP response headers, cookies, stylesheets and source comments may also give clues.  Some nice tools for querying site details (no doubt there are many more):          Firefox addons:    - CMS, frameworks/libraries, e-commerce, message boards etc.  - IP, country and webserver details  - Javascript libraries in use   Chrome Extensions:        Bookmarklets:    - shows Javascript framework in use