Can't install Ubuntu 15.10 from USB - Windows Dualboot
My computer boots to a black screen, what options do I have to fix it?
Good textbooks on homological algebra Breitbart today:   What is the source for the term nothing-burger? What is a good word to describe 'exceptional positive' research work? Book where girl can grow nails and might be a thief I'll apologize for this being a vague description up front. I read a book about 8 years ago about a girl who could grow her nails into essentially razorblades or long enough that they could be used as razors. She travels to a city and either becomes an assassin or a thief (pretty sure it was a thief). I vaguely remember the book opening with her being chased by a mob. At some point during her thief training she realizes that the layout of the city is the key to some important plot device. I think she was given some scroll or cryptic image and then during her training she realizes that the layout of the city correlates to it.  Although I did read this 8 years ago I'm pretty sure the book was at least 5-10 years older than that, maybe even more because it was my mom who gave it to me and she said had read it when she was younger. The dust cover was missing when I read it so I have no description for the cover. I do remember that the author was male. It was a fantasy setting and there may have been vampires involved at some point but that part of my recollection of the book is even fuzzier than what I've already described. I've tried googling for this book but obviously my description is fairly vague. I will gladly answer any follow up questions that I can to try and help figure this out because it has been bothering me for years. Cannot find my keyboard layout I'm in Belgium (french part) and I cannot find the proper keyboard layout in Settings > Region and Languages > Input Sources.  the closest I found is the french (AZERTY) one but for the symbols such as ! and _ it's not the same keys...  what can I do to solve it ?  Thank you. What is the command line way of sending files to the recycle bin? Is there a command line program that can send files to the recycle bin? This is on XP and Vista. Simple prime number generator in Python Could someone please tell me what I'm doing wrong with this code? It is just printing 'count' anyway.  I just want a very simple prime generator (nothing fancy).   import math  def main():     count = 3     one = 1     while one == 1:         for x in range(2, int(math.sqrt(count) + 1)):             if count % x == 0:                  continue             if count % x != 0:                 print count          count += 1 how to get output of a script/program into a file? Show that if the Riesz map is surjective on $H$, then $H$ is a Hilbert space Let $H$ be a vector space equipped with an inner product $(\cdot, \cdot)$ and $f:H\to H',\ f(x)=(\cdot,x)$ surjective. Now, why $H$  is a Hilbert space? The other direction is clear by Riesz' representation theorem but what about this? The rules on  state:     Massive damage can kill you instantly. When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum [...]   Does this only apply if you aren't already at 0 HP? Or rather, what happens if you are currently at 0 HP and take massive damage? Find the asymptotic tight bound in  $$ T(n) = 4T\left(\frac{n}{2}\right) + n^{2}\log n. $$  where $ \log n= \log _{2}n $ and $T(1) = 1$.  I should solve this using all three common methods: iteration, master theorem and substitution.  It is highly likely that this kind of recurrence equation will be in my test in two days. Thank you very much in advance! I posted a question recently regarding my Windows 10 upgrade which ended up with a black screen and cursor.   I reverted back to Windows 8.1 using the "Revert to previous build" option in recovery, and all seems fine, except that Virtualisation is disabled.  I tried to open BIOS settings but it just boots into Windows. I've tried the usual F2 key and Shift F2, all the other F keys, tried pressing B and Shift+B but no luck.  I tried pressing the Lenovo key on the laptop when it is powered down, which shows a menu to either boot into BIOS, recovery, or show boot menu. I choose BIOS and it just boots into Windows.  I tried going into advanced startup options from Windows (Shift+Restart) and choosing "UEFI FIRMWARE SETTINGS" but it just reboots back into Windows.  Before the Windows 10 upgrade it was working perfectly.  Lenovo G580 laptop - Core i3 with Intel 4000 graphics. 8GB of RAM and a Crucial MX100 512GB SSD (replaced the original hard drive with this SSD). New breaker and panel: What's the brown goo where they connect? Sync +- 70 000 records from CSV into drupal I have a CSV file with approx. 70.000 records that I want to import into Drupal 7. Once this is done the client will provide a new CSV file on a daily base that has to sync the updated rows to Drupal.   I wrote a import with  and the  module, but in both cases it takes like forever to import the 70.000 rows. Is there any other solution to import the data faster in Drupal 7? How do I set a user environment variable? (permanently, not session) This is irritating me. I seen several suggestions (all using different files and syntax) and none of them worked.  How do I set an environment variable for a specific user? I am on debian squeeze. What is the exact syntax I should put in the file to make ABC = "123"? How long are the life phases of a dragon? What do the nomodeset, quiet and splash kernel parameters mean? What do Kernel command line parameters (also also known as boot options) mean?  When you go to Ubuntu (or better, GRUB) options, you have things like nomodeset, quiet and splash. What do these options mean?  I am also interested in other parameters and would be interested to see descriptions of any kernel parameter (like acpi), but these are not essential. How do I tunnel and browse the server webpage on my laptop? I run a web app in one of my lab servers, and I have already setup X11 Forwarding on those machines. Other lab members can tunnel through SSH, and browse that web app on their local browser at home.  I can't. Last time I checked with them, there is almost nothing I need to do.  When I type 192.168.1.113/webapp I get nothing.   Any tips?  THanks.    I ended up using the second method :)  ssh -L 8080:&lt;server-ip-address&gt;:80 &lt;username&gt;@&lt;remote-addr&gt; -N It is a common practice to apply PCA (principal component analysis) before a clustering algorithm (such as k-means). It is believed that it improves the clustering results in practice (noise reduction).   However I am interested in a comparative and in-depth study of the relationship between PCA and k-means. For example, Chris Ding and Xiaofeng He, 2004,  showed that "principal components are the continuous solutions to the discrete cluster membership indicators for K-means clustering". However, I have hard time understanding this paper, and Wikipedia actually .  Also, the results of the two methods are somewhat different in the sense that PCA helps to reduce the number of "features" while preserving the variance, whereas clustering reduces the number of "data-points" by summarizing several points by their expectations/means (in the case of k-means). So if the dataset consists in $N$ points with $T$ features each, PCA aims at compressing the $T$ features whereas clustering aims at compressing the $N$ data-points.  I am looking for a layman explanation of the relations between these two techniques + some more technical papers relating the two techniques. I have written a C++ program and complied it to produce a.out file. However, whenever I try to run it, I get Permission Denied. I read that we can use sudo, but I can't quite get it to work. I use something like, sudo "./a.out" but that too doesn't work.  Edit:  Here is the message I get when I try "./a.out".  bash: ./a.out: Permission denied