I have a hp laptop with an AMD graphics card and I have installed Ubuntu 14.04 alongside my window 8.1. Under Ubuntu the laptop is quiet silent and smooth (no overheating) but the battery is draining very fast. It only last for one hour max. In windows it lasts for ~2.5 hours.
This question is present as a matter of historical interest.  While you are encouraged to help maintain its answers, please understand that "big list" questions are not generally allowed on Ask Ubuntu and will be closed per the .   It is possible to greatly extend the usage time of a laptop or netbook running on battery by disabling various services and installing various packages.   What tricks or tips do people have for getting an extra hour or two out of their batteries?
How to handle a lost KeyStore password in Android? Distributing distinct apples and pears to three people so that each person receives at least one pear How many ways are there to distribute seven distinct apples and six distinct pears to three distinct people such that each person has at least one pear.   Note: The first part of the problem was the same but the word distinct was replaced with identical apples and pears. That answer is $360$ ways.   What has to be done differently when the word identical is replaced with distinct? Show that the $\max{ \{ x,y \} }= \frac{x+y+|x-y|}{2}$. Show that the $\max{ \{ x,y \} }= \dfrac{x+y+|x-y|}{2}$.   I do not understand how to go about completing this problem or even where to start. SSH: How to disable weak ciphers? I have just started learning Japanese Mahjong and I am a bit lost as to why this hand failed.  I did several pons and chis over the course of a hand, having a total of three open melds (one set and two sequences).  Apart from these I had an incomplete bamboo sequence of II and III as well as a pair of dragons, therefore I was on a single wait for I or IV bamboo stick tile. When the IV tile appeared in one of the discards of other players, I was given a choice to do another chi and declare another open meld, but I couldn't win with a ron. Why was that?  Am I wrong that winning by ron guarantees a single needed yaku to win a hand, just like Closed Tsumo does?  After declaring the chi I was offered with, my hand was left with a single pair of tiles, one of which I had to discard.  Eventually the round finished with a draw.  Why couldn't I win this hand with a ron on the IV bamboo tile, and why was I given only the choice of chi instead? Is there any intuition or meaning regarding Cauchy-Riemann equations? Holomorphic functions are one of the most beautiful objects in mathematics. However, Cauchy-Riemann equations are a little bit of a mystery for me. What does that mean intuitively when a function satisfyes those equations? Ignoring programming style and design, is it "safe" to call delete on a variable allocated on the stack?  For example:     int nAmount;    delete &amp;nAmount;   or  class sample { public:     sample();     ~sample() { delete &amp;nAmount;}     int nAmount; } How is Leibniz's rule for the derivative of a product related to the binomial formula? Possible Duplicate:          The  describes the expansion of the $n$th power of the sum $(a+b)$:  $$(a+b)^n = \sum_{k = 0}^n {n\choose k}a^kb^{n-k}$$  In calculus, there is a generalization of the product rule called , which describes the expansion of the $n$th derivative of the product of two functions $f$ and $g$:  $$(fg)^{(n)} = \sum_{k = 0}^n {n\choose k}f^{(k)}g^{(n-k)}$$  It's not difficult to prove using the product rule and induction, what I'm really trying understand here is why the formula is true. Is there a way to prove it using the binomial formula? How are these two formulas related? Is there a combinatorial proof for Leibniz's rule like there is for the ?   I understand this question is a bit vague, but I hope you'll agree that these two formulas look so similar it just feels like there should be some relation between the two. Of course this is not necessarily true, but I'm hoping it's not just a crazy coincidence. What is the most "pythonic" way to iterate over a list in chunks? Problem  For what natural numbers is $n^3 &lt; 2^n$?  Attempt @ Solution   For $n=1$, $1 &lt; 2$ Suppose $n^3 &lt; 2^n$ for some $n = k \ge 1$ It looks like the inequality is true for $n = 0$, $n = 1$ and $n\ge10$ But, how can I prove this through induction? How do I install Ubuntu to a USB key? (without using Startup Disk Creator) Best way to implement keyboard shortcuts in a Windows Forms application? I'm looking for a best way to implement common Windows keyboard shortcuts (for example Ctrl+F, Ctrl+N) in my  application in C#.  The application has a main form which hosts many child forms (one at a time). When a user hits Ctrl+F, I'd like to show a custom search form. The search form would depend on the current open child form in the application.  I was thinking of using something like this in the ChildForm_KeyDown event:     if (e.KeyCode == Keys.F &amp;&amp; Control.ModifierKeys == Keys.Control)         // Show search form   But this doesn't work. The event doesn't even fire when you press a key. What is the solution? Were these other people Chronicoms? We know that Enoch is a Chronicom, which is to say a sort of alien temporal observer.   When Enoch and his agents came and kidnapped       Coulson’s team,   for the purpose of sending them where they wanted; were these other agents also Chronicoms? I’m inclined to think they must have been (would Enoch have shared their advanced technology and goals, etc. with mere mortals), but on the other hand only one pod was mentioned. Headphone jack not working? Python element-wise tuple operations like sum Is there anyway to get tuple operations in Python to work like this:  &gt;&gt;&gt; a = (1,2,3) &gt;&gt;&gt; b = (3,2,1) &gt;&gt;&gt; a + b (4,4,4)   instead of:  &gt;&gt;&gt; a = (1,2,3) &gt;&gt;&gt; b = (3,2,1) &gt;&gt;&gt; a + b (1,2,3,3,2,1)   I know it works like that because the __add__ and __mul__ methods are defined to work like that. So the only way would be to redefine them? Plot an elliptic curve in Latex It always takes a  and money to find the next . Why is it so important to do this work and what is the application those numbers? Why does ltablex skip a number in captions? The below example presents two tables with an tabularx environment (taken from package ltablex) and a caption. After each tabularx-table, the table counter skips one, as if both the caption and the tabularx environment increase it, while the latter shouldn't.  \documentclass{report} \usepackage{ltablex} \begin{document}  \begin{table} \caption{Caption 1.} % "Table 1" \begin{tabularx}{\linewidth}{|c|} empty table \end{tabularx} \end{table}  \begin{table} \caption{Caption 2.} % "Table 3" \begin{tabularx}{\linewidth}{|c|} empty table \end{tabularx} \end{table}  \end{document}   My reputation doesn't allow me to upload a picture, but the captions are Table 1 and Table 3 respectively. Package Cache File corrupted From advice on  , I've opened a new question about the same issue, as it turned out my problem was not the one described in the question, information I did not know at the time. I'm running Ubuntu 16.04.  $ sudo apt-get update  Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease Get:2 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB] Get:3 http://archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB] Get:4 http://archive.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Get:5 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 DEP-11 Metadata [307 kB] Get:6 http://archive.ubuntu.com/ubuntu xenial-updates/main DEP-11 64x64 Icons [226 kB] Get:7 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 DEP-11 Metadata [185 kB] Get:8 http://archive.ubuntu.com/ubuntu xenial-updates/universe DEP-11 64x64 Icons [268 kB] Get:9 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 DEP-11 Metadata [5,888 B] Get:10 http://archive.ubuntu.com/ubuntu xenial-backports/main amd64 DEP-11 Metadata [3,324 B] Get:11 http://archive.ubuntu.com/ubuntu xenial-backports/universe amd64 DEP-11 Metadata [4,712 B] Get:12 http://archive.ubuntu.com/ubuntu xenial-security/main amd64 DEP-11 Metadata [62.7 kB] Get:13 http://archive.ubuntu.com/ubuntu xenial-security/main DEP-11 64x64 Icons [71.2 kB] Get:14 http://archive.ubuntu.com/ubuntu xenial-security/universe amd64 DEP-11 Metadata [51.3 kB] Get:15 http://archive.ubuntu.com/ubuntu xenial-security/universe DEP-11 64x64 Icons [85.1 kB] Fetched 1,578 kB in 1s (1,529 kB/s)                                     Reading package lists... Error! E: Read error - read (5: Input/output error) W: You may want to run apt-get update to correct these problems E: The package cache file is corrupted   If there's any more information you need, don't hesitate to ask in the comments.  Edit 1:  $ sudo df -h Filesystem      Size  Used Avail Use% Mounted on udev            5.9G     0  5.9G   0% /dev tmpfs           1.2G  9.4M  1.2G   1% /run /dev/sda1       135G  7.2G  121G   6% / tmpfs           5.9G   14M  5.9G   1% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           5.9G     0  5.9G   0% /sys/fs/cgroup tmpfs           1.2G   88K  1.2G   1% /run/user/1000 /dev/sdb1       932G  300G  633G  33% /media/adoria298/MDrive1   Edit 2 SMART Test results: Oracle SQL Syntax: Quoted identifier