How to encrypt a shared NTFS partition that is used by Windows and Linux on a dual boot system? I use an NTFS partition for data that I want to access with applications both on Windows 10 and Ubuntu (Text files, Emails, Source code, ...).  Is there a way to encrypt this data partition such that it stays accessible for both OS that I have installed? Also it should be possible to make a backup, the backup however doesn't need to be encrypted (even preferably not encrypted).
How to share an encrypted storage on Windows, Mac OS X and Linux in a secure way I got a 2 TB drive that I have to use with both Windows 8.1 / Windows 10 and Yosemite to OS X / OS X El Capitan and maybe even on Linux.  I need to encrypt the volume. Or rather, I want to create two partitions: a 1.7 TB encrypted and unencrypted the remaining space.  Now I use Windows BitLocker to 512bit. On Mac and Linux nothing, obviously.  What do you recommend?  I saw TrueCrypt (and I read about all the confusion created after May 2014), of VeraCrypt, of GNUPG, Disklocker to read BitLocker on Unix.  But I feel lost and without a good idea.  And if I use TrueCrypt 7.1a waiting for new solutions such as precautions to prevent memory dumps and other potential crack?  And then how should I use TrueCrypt to format the drive? In GPT? MBR? Journaled? FAT?
I'm looking for the fastest way to determine if a long value is a perfect square (i.e. its square root is another integer):    I've done it the easy way, by using the built-in  function, but I'm wondering if there is a way to do it faster by restricting yourself to integer-only domain. Maintaining a lookup table is impractical (since there are about 231.5 integers whose square is less than 263).   Here is the very simple and straightforward way I'm doing it now:  public final static boolean isPerfectSquare(long n) {   if (n &lt; 0)     return false;    long tst = (long)(Math.sqrt(n) + 0.5);   return tst*tst == n; }   Note: I'm using this function in many  problems.  So no one else will ever have to maintain this code.  And this kind of micro-optimization could actually make a difference, since part of the challenge is to do every algorithm in less than a minute, and this function will need to be called millions of times in some problems.    I've tried the different solutions to the problem:   After exhaustive testing, I found that adding 0.5 to the result of Math.sqrt() is not necessary, at least not on my machine. The  was faster, but it gave incorrect results for n >= 410881.  However, as suggested by , we can use the FISR hack for n &lt; 410881. Newton's method was a good bit slower than Math.sqrt().  This is probably because Math.sqrt() uses something similar to Newton's Method, but implemented in the hardware so it's much faster than in Java.  Also, Newton's Method still required use of doubles. A modified Newton's method, which used a few tricks so that only integer math was involved, required some hacks to avoid overflow (I want this function to work with all positive 64-bit signed integers), and it was still slower than Math.sqrt(). Binary chop was even slower.  This makes sense because the binary chop will on average require 16 passes to find the square root of a 64-bit number. According to John's tests, using or statements is faster in C++ than using a switch, but in Java and C# there appears to be no difference between or and switch. I also tried making a lookup table (as a private static array of 64 boolean values).  Then instead of either switch or or statement, I would just say if(lookup[(int)(n&amp;0x3F)]) { test } else return false;.  To my surprise, this was (just slightly) slower. This is because . How to use sed to replace only the first occurrence in a file? Cycles Emit Light from area on Texture So I have a giant object that is completely uv unwrapped. I would like to make areas of the object with a specific area of texture emit light.   The problem is that this object (and it is only one object) only has one material. I would like the lava to emit light, but I cannot move it to a separate material without breaking something.  I'd like to find a method where I can select a part of the texture and tell blender that whatever has that part of the texture emits light.  Is this possible?  Thanks. How can I send an email by Java application using GMail, Yahoo, or Hotmail? Is it possible to send an email from my Java application using a GMail account?  I have configured my company mail server with Java app to send email, but that's not going to cut it when I distribute the application. Answers with any of using Hotmail, Yahoo or GMail are acceptable. How can we prove charge invariance under Lorentz Transformation? We have gravitational force between two massive particles and we have electromagnetic force between two charged particles. When special relativity suggests that mass is not an invariant quantity why we have electric charge as an invariant quantity ? How can I make something that looks like this?  --------   Text   ---------  where the horizontal rules extend to the margin on either side? Could we have the ability to mark a change as minor in questions or answers? It would be nice to allow users to mark a change in an answer (or question) as minor (e.g. for a simple spelling or grammar correction). A change marked as minor wouldn't push the question on top of the list of questions on the home page or in the feeds. It wouldn't trigger any notification. This could be implemented with a "Minor change" checkbox when editing an entry (a la Confluence). What do you think? Do not hide VLQ flag option from users who already flagged and may wish to retract System hides an option to flag Very Low Quality in few cases, namely when post is:        Because of that users who already flagged it when none of above conditions applied miss an option to .  Suggest1 to show this flag option to such users so that they could retract a flag.    1 Frankly I won't mind if this gets  because I doubt that it is important. This is posted mainly to document how system behaves and to provide reference for those who may wonder why they can't retract flag in some cases. General relativity (gravitation) in time and one spatial dimension I don't have any idea of general relativity but intend to learn. Is it a good idea to study general relativity in two dimensions (time and single spatial dimension) in the begining to get good idea on the subject? If it is, then please give some references for such a treatment. Value of $x=\sum\limits_{n=1}^\infty {\frac{1}{10^n-1}} $ and location of second digit $1$ of $x$ What is the value of the series   $\sum\limits_{n=1}^\infty {\frac{1}{10^n-1}}$   and can one find closed forms for the sums   $\sum\limits_{n=1}^N {\frac{1}{10^n-1}}$?   I found that $\sum_{n=1}^N {\frac{1}{10^n-1}} $  =  $\sum_{n=1}^N (\lim_{m\to\infty  }{\frac{10^{-n}-10^{-nm}}{1-10^{-n}}})$  =  $0.111\ldots+0.0101\ldots+\ldots$ but I can't go farther.     The original question is: "Where does the second '1' appear?" How to replace a character by a newline in Vim I'm trying to replace each , in the current file by a new line:  :%s/,/\n/g    But it inserts what looks like a ^@ instead of an actual newline. The file is not in DOS mode or anything.  What should I do?  If you are curious, like me, check the question  as well. Calculate daily sums using python pandas What's the problem with my Young slits experiment? My Young's slits experiment doesn’t work. I mean I tried to see wave effect of light but I didn’t see any thing expect particles! I’ve sent you a pic of my laser and a short video of the experiment. Is there any problem you think? How this java code produces deadlock? I have critical low storage level and can't understand what takes much of it and how that's possible that the installed applications can use 7 GB? I only use a few social media clients without any games or soft like Photoshop. Also on the second screenshot it indicates that the apps are using just 1.13 GB and so I can't understand the situation. Also what is the "Other"? What's the difference between a microcontroller and a microprocessor? I keep reading about  ('PPAs') and people answer questions with a link to a PPA. What's the best way to use these?     There are multiple valid answers for this question spanning over several versions of Ubuntu. For your convenience, an index of each is below. How do I do a case-insensitive string comparison? How can I do case insensitive string comparison in Python?  I would like to encapsulate comparison of a regular strings to a repository string using in a very simple and Pythonic way. I also would like to have ability to look up values in a dict hashed by strings using regular python strings. I'm working under 12.04 and suppose I have a Firefox windows active (or in foreground) with English as input language and I need to type a document in other language using some text editor.   With the text editor in foreground (or active) and the input language set to a non-English one, when I bring Firefox in foreground (or making it active) the input language remains set to the non-English and the language flag does not switch to English (as it would be expected, since I do not alter the language during the whole Firefox session).  Because of this, I have to make extra moves and change the input language manually every time I switch from the text editor to Firefox and back to text editor. This was not happening with 10.04, and each application windows had the corresponding input language set to its default or previous session every time I was bringing it to the foreground!   How will I make 12.04 to behave the same way? Split Excel table over multiple PowerPoint slides I have a table in Excel which is too long for one PowerPoint slide. So I would like to split it over 2 or 3 slides, but have the header on each of the slides. What is the easiest way to accomplish that? I am using Excel and PowerPoint 2007.