In Windows 7, lets say I have a "works" directory which containts my work, personal etc information. I want to use a program which always checks the disk and make mirror(s) of this directory. Something like a RAID technology. How can I do that? Thats important, I have now bad sectors....
I want to synchronise two folders in real time under Windows 7.  Basically, I want to monitor a folder and synchronise each change (new files, changed files, deleted files) to another drive. It has to be in real time, so it gets synchronised instantly when a change happens. A one-direction synchronisation is enough.  I tried Microsoft's , but it does only syncing by hand or scheduled (thus not satisfying the "real-time" requirement).  Can this be achieved with Windows 7 itself? If not, are there other methods of doing this?
Captured variable in a loop in C# I met an interesting issue about C#. I have code like below.  List&lt;Func&lt;int&gt;&gt; actions = new List&lt;Func&lt;int&gt;&gt;();  int variable = 0; while (variable &lt; 5) {     actions.Add(() =&gt; variable * 2);     ++ variable; }  foreach (var act in actions) {     Console.WriteLine(act.Invoke()); }   I expect it to output 0, 2, 4, 6, 8. However, it actually outputs five 10s.  It seems that it is due to all actions referring to one captured variable. As a result, when they get invoked, they all have same output.  Is there a way to work round this limit to have each action instance have its own captured variable? PCA on correlation or covariance? What are the main differences between performing principal component analysis (PCA) on the correlation matrix and on the covariance matrix? Do they give the same results? Which databases use real multidimensional indices? Is oracle ever using several indices to get data from tables, or will it always take the one that seems to have the highest selectivity? How about other dbms? Test Class for a Custom Controller I would like to replace the usual \hat in maths with a larger one, but I do not want it to stretch. The size I want is "the smallest \widehat" (as in $\widehat{.}$). Is there a way to put that one above a wide character like M ($\widehat{M}$ would stretch and give be an even wider hat).  I guess I have a lack of understanding for the mechanism behind accents that extend, so feel free to explain. What is the best choice for .NET inter-process communication? A composition of a periodic function that is somehow not periodic. I think the questions says it all! :)  By TeX, I mean any derivative of TeX as long as the code is clearly a derivative of TeX, i.e. that it could belong on TeX.SX (and not pure Lua for example).  I'll give two answers myself so you see what I mean. lim sup inequality $\limsup ( a_n b_n ) \leq \limsup a_n \limsup b_n $ I´m not sure how to start with this proof, how can I do it? $$ \limsup ( a_n b_n ) \leqslant \limsup a_n \limsup b_n  $$ I also have to prove, if $ \lim a_n $ exists then: $$ \limsup ( a_n b_n  ) = \limsup a_n \limsup b_n  $$ Help please, it´s not a homework I want to learn. How did they post process before Photoshop? Why is it called John Dies at the End? The 2012 adaptation of David Wong's "John Dies at the End" ends without John dying at the end at all. While the core of the film espouses the belief that time is not linear, the word "end" suggests there is a beginning and an end to things.  Why is the movie called John Dies at the End? Is there a filesystem that is "friendly" to both windows and Linux? Is hyperref really the best way to add metadata to a TeX file? So I know one of hyperref's features is that it can add metadata to you PDFs. This is a nice feature and if you're putting stuff online, it's good to include metadata.  But is the hyperref package really the best way to do it? I mean, if you're using hyperref anyway, that's fine. But if you don't want hyperrefs in your document, it seems weird to include the package, and then turn off pretty much all its functionality. And given that hyperref is a shorthand for "package conflict nightmare", is seems insane that you should have to deal with it just for the sake of some metadata.  So I have two questions.   Is there a good reason that hyperref includes this functionality which is apparently unrelated to its primary purpose? Is there a better (smaller, less conflicty, easier...) option to include metadata in my PDFs? What is terminal velocity? I've heard the term especially when the Discovery Channel is covering something about sky diving. Also, it is commonly known that HALO (Hi-Altitude, Lo-Opening) infantry reaches terminal velocity before their chutes open.    Can the terminal velocity be different for one individual weighing 180 pounds versus an individual weighing 250 pounds? If $a^2$ divides $b^2$, then $a$ divides $b$ What is the default /etc/inittab file on a fresh install of Debian Jessie? I'm looking for the full contents of the default /etc/inittab file on a fresh install of Debian 8.7 before any system-specific modifications are made.    I searched for this on the Debian website and other forums, but could not find it. Infinite Geometric Series Formula Derivation When is $\phi(n)$ a prime number? I was thinking about this problem today. If $p$ divides $n$, then $p-1$ must divide $\phi(n)$. But $p-1$ is even for all primes greater than $2$, so must $\phi(n) = 2$ - the only even prime? I feel like this argument is shaky and not very rigorous! How do threads work in Python, and what are common Python-threading specific pitfalls? I've been trying to wrap my head around how threads work in Python, and it's hard to find good information on how they operate. I may just be missing a link or something, but it seems like the official documentation isn't very thorough on the subject, and I haven't been able to find a good write-up.  From what I can tell, only one thread can be running at once, and the active thread switches every 10 instructions or so?  Where is there a good explanation, or can you provide one? It would also be very nice to be aware of common problems that you run into while using threads with Python. Where can I find information about past versions of iOS and code-signing windows? I have an iPad 2 that is currently running iOS 5.0.1. I'm generally happy with it but some applications require a more recent iOS version. So I started to look into upgrading it, but the only upgrade that it offers is to iOS 7.  From the look of it I don't like the new design of iOS 7 too much and also upgrading to a version this fresh doesn't appeal to me. So my question is: is there a way to upgrade to some version of iOS 5.x or iOS 6.x instead of upgrading to iOS 7?