I got this error during installation.     The installer encountered an error   copying files to the hard disk: [Errno   5] Input/output error This is often   due to a faulty CD/DVD disk or drive,   or a faulty hard disk. It may help to   clean the CD/DVD, to burn the CD/DVD   at a lower speed, to clean the CD/DVD   drive lens (cleaning kits are often   available from electronics suppliers),   to check whether the hard disk is old   and in need of replacement, or to move   the system to a cooler environment.   How can I fix this and what does it mean specifically? I'm installing via USB so it can't be the CD. the laptop is recent so it cant be an old HD.
Today I downloaded Ubuntu for my laptop. It runs great from a bootable USB, but when I tried to install it, I got the following error message: The installer encountered an error copying files to the hard disk:  [Errno 5] Input/output error  This is often due to a faulty CD/DVD disk or drive, or a faulty hard    disk. It may help to clean the CD/DVD, to burn the CD/DVD at a lower   speed, to clean the CD/DVD drive lens (cleaning kits are often    available from electronics suppliers), to check whether the hard disk   is old and in need of replacement, or to move the system to a cooler   environment.     I tried everything to install it on my laptop including redownloading the Ubuntu ISO image, but nothing worked.
Grant group traversal rights on a folder Is past simple ever justified with 'by'? Can anyone shed some light on the following aspect?  By 5 PM I gave him the book.  By 5 PM I had given him the book.  In both the sentences the book was given before 5 PM and no later than 5 PM. But I can't understand then what the difference between them is. a Also is it right to use simple past with 'by' at all? If yes, then why and if not, then why is it incorrect to use simple past with 'by'? Still alive, still alive after kill -9 / SIGKILL An apache2 process got stuck on my server and caused problems with other services. (original problem: kerneloops after USB hardware disconnect)   root@server:~# ps aux | grep apache2 | grep -v grep www-data 12917  0.0  0.1 412148 16156 ?        D    Jun27   0:00 /usr/sbin/apache2 -k start   Naturally, I killd it. it's still alive. so I kill -9d it. It's still "alive".  Now this is where the question gets serverfault/unix&amp;linux-worthy: Is there a way to get port 443 back without doing the obvious thing: rebooting? Iptables is installed.  Update: I could not resolve the Problem withouth rebooting. The general approach (use lsof or /proc/$PID/fd to find out which and get rid of that drive) as described here and in the "duplicate" could well have worked if not for additional (probably) hardware defects. How to power a button's LED within a guitar? I'm working on a guitar, and the plan is to use three latching push buttons so that each pickup can be turned on and off individually. I'm fairly confident that the following diagram should work for that (Feel free to correct me)   The buttons I want to use are , which have a built-in LED when turns on when the button is pressed.   Which brings me to my question: Is there a way to power the LED? If I introduce a 9volt into the wiring, wouldn't that cause problems with the guitar's standard electronics? How to automatically fit many bars in barchart using pgfplots? I am trying to use PGFPlots to display a large amount of bars, and I run into the problem that it cuts off the last of them.  MWE:  \documentclass[crop,tikz]{standalone}  \usepackage{pgfplots} \usepackage{pgfplotstable} \pgfplotsset{compat=1.13}  \begin{document}  \pgfplotstableread{ row label runtime 0 1 5264 1 2 2971 2 4 1866 3 8 1384 4 16 1205 5 32 1144 6 64 1109 7 128 1095 8 256 1108 9 512 1178 10 1024 1335 11 2048 1667 12 4096 1588 13 8192 2843 14 16384 5541 15 32768 10985 16 65536 21873 17 131072 43687 18 262144 87064 19 524288 174119 }\mytable   \begin{tikzpicture}   \begin{axis}[         ylabel={runtime (${\mu}s$)},         xticklabels from table={\mytable}{label},         xtick=data,         ymin=0,         ymax=10000,         ybar,         xticklabel style={           anchor=north west,           align=left,           rotate=-45,           font=\tiny,           inner sep=1pt,         }, ] \addplot+ [] table [y=runtime, x expr=\coordindex] {\mytable}; \end{axis} \end{tikzpicture}  \end{document}   Result:    By adding the following to the axis options, I can make all the bars fit. But I need to manually adjust bar width (and xmax)  xmin=-1, xmax=20, bar width=7pt,     Is there a way to handle many bars in a barplot automatically? Object on curve wont stay flat! Is leaving airport at a stop before the final destination illegal? There are tricks such as  or  which involve booking a ticket composed of several connecting flights, then leaving the airport at a stop, possibly even "hopping off" a plane (intermediate landing). Rationale: Sometimes these tickets are cheaper than a ticket to one of the stops. So one adds an additional leg and discards it.  Some people say that when using such tricks, one enters a legal gray area. But I wonder:  Could leaving the airport at a stop really be illegal, i.e. violating an airline's or a travel agency's terms?  Also there are suggestions that one should not request an upgrade, because then the trick may be discovered by the airline. Here I wonder:  How can they know that one will throw away the last leg? Commutator subgroup and cyclic normal subgroup Where do Orc babies come from? I've not seen/read any female Orcs mentioned in the movies or in the books. In one of the movies, an Uruk-hai is momentarily shown emerging from a giant, grown-Orc sized flesh packet. So are they created with spells, or do they follow the Standard Reproductive Model. Is there a (basic) way to understand why a limit cannot be brought inside of a sum, in certain situations? I have seen that the method of "dominated convergence" implies that sometimes a limit cannot be brought inside of a sum, but is there a more basic way to understand this, preferably without using integrals?   A conceptual or simple answer would be helpful. Thank you! I have some files/directories on an external hard drive connected using USB to my Windows XP laptop. I am trying to delete those files but every time I try, I get an error "Cannot delete ....: Access Denied. Make sure disk is not full or write protected and that the file is not currently in use".  I checked that the directory is not is use. However, the permissions are set to read-only. Even if I remove the "read-only" checkbox, in Properties->Attributes, it automatically comes back again. How do I fix this? Is it a virus that is automatically changing it back to read-only?  regards,  JP Should "Applied Cryptography" be capitalized? Is it a proper noun? I'm trying to write a cover letter for a fairly prestigious job, and I'm aiming for (arguably too much) perfection in my cover letter. I don't want to be turned away only because the hiring people though I was too careless with my punctuation and capitalization.  My sentence goes as follows:     I hope to one day go on to complete a Masters degree in Computer Science with a focus in Applied Cryptography.   I've never been great with the technical rules of the English language, despite being a native speaker. Computing sums of divisors in $O(\sqrt n)$ time? I have a sequence: $1,3,5,8,10,14,16,20,23,27,\dots$  I know that the recursive relation is:  $$p[i] := p[i-1] + \text{number of factors of $i$}, \quad \text{with $p[1]=1$.}$$  How do I solve this recursive relation in $O(n^{0.5})$ time? I have to write a program for it, and $n$ can be as large as $10^9$. So, some appropriate precomputation and prestorage is allowed, provided that they comply (memory and time wise) with the range of $n$. How can I permanently enable cheating? Is every open subset of $ \mathbb{R} $ uncountable? Is every open subset of $\mathbb{R}$ uncountable?  I was crafting a proof for the theorem that states every open subset of $\mathbb{R}$ can be written as the union of a countable number of disjoint intervals when this question came up.  I feel like the answer is yes, but I'm not sure how to go about proving it or whether there is a crazy construction (like the Cantor Set)  that creates a countable, open subset of $\mathbb{R}$. Any ideas? How many numbers of 6 digits, that can be formed with digits 2,3,9. And also divided by 3? How many numbers of 6 digits, that can be formed with digits 2,3,9. And also divided by 3?  $$$$ I was trying to to add 2^6 (when there is no 2)+ C(6,2)2^2 (when 2 can be in two places)+C(6,3)2^3 (when 2 can be in three places)... Why PlotStyle->Dashed make everything dashed? Find n such that $n^5 - n$ is divisible by $120$. (*Here $n$ belongs to the natural number set)  Seems a trivial problem, but the answer mentioned in the text book seemed incomplete to me so I'm here just to ensure whether approach to this problem is correct or not.  So my approach is as follows: We know that $n^5 - n$ can be written as $n^5-n = n(n-1)(n+1)(n^2 + 1)$  Now since it's product of three consecutive natural numbers so it's divisible by $3! = 6$. Now using Fermat's Little theorem we can prove that $n^5= n \mod5$ hence $n^5 - n$ is divisible by $5$ as well. So $n^5 - n$ is divisible by $30$. Now to ensure their is another factor of $4$ in the term we need to ensure that $n^5 - n$ is divisible by $8$. I found that all odd natural numbers and multiples of $8$ makes $n^5 - n$ divisible by $8$, hence $n^5 - n$ is divisible by $120$. But in the text book they have only mentioned odd natural numbers as answer, which seemed incomplete to me.  Thanking everyone in advance:P On page 19 of the textbook  (by James, Witten, Hastie and Tibshirani--it is freely downloadable on the web, and very good), the following is stated:  Consider a given estimate $$\hat{Y} = \hat{f}(x)$$ Assume for a moment that both $$\hat{f}, X$$ are fixed. Then, it is easy to show that: $$\mathrm{E}(Y - \hat{Y})^2 = \mathrm{E}[f(X) + \epsilon - \hat{f}(X)]^2$$ $$ = [f(X) - \hat{f}(X)]^2 + \mathrm{Var}(\epsilon)$$  It is further explained that the first term represents the reducible error, and the second term represents the irreducible error. I am not fully understanding how the authors arrive at this answer. I worked through the calculations as follows: $$\mathrm{E}(Y - \hat{Y})^2 = \mathrm{E}[f(X) + \epsilon - \hat{f}(X)]^2$$ This simplifies to $[f(X) - \hat{f}(X) + \mathrm{E}[\epsilon]]^2 = [f(X) - \hat{f}(X)]^2$ assuming that $\mathrm{E}[\epsilon] = 0$. Where is the $\mathrm{Var}(x)$ indicated in the text coming from? Any suggestions would be greatly appreciated. What was the purpose of banning use/development of cloaking technology in Treaty of Algeron? The  prohibited the development or use of cloaking technology by the Federation. This treaty was a peace treaty and use of cloaking technology in one's own space couldn't disturb peace. Plus, the Romulans already had cloaking technology, so banning it was unfair for the Federation. So, why was this ban introduced?  Another thing: There were many things to ban, but why cloaking technology?