I am trying to copy all the files off a failing/unreliable hard drive(has read errors) using robocopy using this command : robocopy /E /XO /R:1 /W:1 /V /MT:128 E:\ L:\ /Z /xd E:\System Volume Information E:$RECYCLE.BIN E:\OLD$RECYCLE.BIN  But after a few minutes, it gets stuck, and resource monitor shows robocopy is still reading lots of bytes per second (up to 18 million ) yet writing 2000 bytes or less per second, I have left my computer running for hours and the cmd display still shows robocopy being stuck on the same file despite all this supposed data reading robocopy is performing. What should I do to fix this? EDIT: I fixed this by changing /MT:128 to the default setting of /MT:8 and it somehow worked
What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:
Prove by Double Counting Method $\sum\limits_{k = 0}^m \binom{m}{k}\binom{n}{r + k} = \binom{m + n}{m + r}$ Show by combinatorial arguments that:   $$\sum_{k = 0}^m \binom{m}{k}\binom{n}{r + k} = \binom{m + n}{m + r}$$  Hello ,  I want to prove this argument by double counting method, i kinda have an idea of proving by comb args. but not by double counting... Can someone give any clues or ideas? thanks :) Deleting Objects in JavaScript Hide Command Window of .BAT file that Executes Another .EXE File How to convert numbers between hexadecimal and decimal How do you convert between hexadecimal numbers and decimal numbers in C#? Affiliate Ads Are Coming To The Network Some time ago, we announced that . This has gone well and we're extremely thankful to everyone for their support and feedback. Because it has been successful so far, we're going to be extending the program to the majority of our graduated sites. Well, we've pretty much already done that, but there are quite a few sites that have ads enabled, yet still display nothing. The thing is, we don't really have an abundance of clients offering products that a  would find relevant, but Amazon has stand mixers, a selection of super fine chinois, deliciously sharp cutlery and enough cast iron to fill the Gulf Of Mexico with . Beginning as early as this week (week of 5 February 2018), our ad team is going to be hand selecting affiliate ads to be displayed on select sites. The use of inventory will of course depend on the availability of relevant ads to display which means:  Some sites might see very few, if any ads. Some topics simply don't come remotely close to orbiting anything worth advertising. Furthermore, while graduated, some sites simply don't have enough activity for ads to make sense.  Since these are hand-selected, it could take a while for ads to appear initially.  These would of course yield to inventory from clients if clients had products that were relevant to any given topic.   Nothing changes when it comes to the . If you're used to occasionally seeing a community promotion ad, you'll just notice that you'll also occasionally see an ad for something that is likely to be of interest to someone interested in the topic that your site covers. In fact, to be clear, this is simply a continuation of the announcement we made in November of 2016. We just wanted folks to know that we're going to be continuing the program where there's good potential to show relevant advertisements, even if we don't have clients lined up with a demand for it. Where can I give feedback about a certain ad on [site]? Open a meta post on your per-site meta and let us know. Please remember, the bulk of advertisements are an effort to get something small back from folks that hit the sites through search engines and are extremely unlikely to ever become contributors. Their soufflé stopped falling, and we'll probably never see them again. Maybe we can get a few bucks once they realized that copper ions help egg whites stiffen properly and buy a bowl or a proper bloom whisk. However, you're the experts on these topics and we're very likely going to listen to you. What sites, specifically? Are any sites exempt? If you're a former Stack Exchange 1.0 site and / or subsequently joined the network under a special charter, nothing changes - don't panic :) For the rest, we're just extending what we're currently doing with ads on graduated sites to also include those where there's an opportunity to make sensible use of affiliate ads. If a site has less than 15k (average) daily visits, or fewer than roughly 50k combined total posts - it might not yet be time to invest in selecting ads to be shown there. But, part of this exercise is also seeing what works best. I don't really have feedback, just some suggestions Ads aren't just an opportunity to sell stuff, they're an opportunity to really show people that we understand a given topic. That, of course, makes suggestions from people that do that stuff every day quite valuable. Post on your per-site meta and our community / ad critters will take a look. Questions? Comments? Kvetches? Let us know in an answer or comment below. If anything about the plan changes, we'll update this post to let folks know. Convergence of $\int_0^\infty $sin$ (x^p) dx$ How does a wheelie work? So I've been trying to create a mathematical model for an electric motorcycle and began to wonder about the maximum possible torque that could be supplied to the rear driven wheel without having the bike begin to lift up on one wheel.  I found ways to calculate this value online; however, the basic concept as to how the bike actually lifts escapes me.    My problem started when I began to think about what axis the bike will rotate about when it is doing the wheelie.  My first intuition was that the frame and front wheel, together, rotate about the rear axle.  But when I drew a free body diagram of the frame/front wheel system just at liftoff (see below) I made note that the only forces acting about the rear axle, point O, is the force of weight.  This means that an increase in applied torque and subsequently, the applied force Fa, should not effect the rotation about the rear axle.  I know that the applied force on the back wheel is indeed correlated with the propensity for a bike to wheelie, so I considered that the axis of rotation I was choosing was wrong.  If we take the free body diagram above and sum the moments about the center of mass, we would find that an increased applied force would in fact cause the solid body to rotate.  The problem with this understanding is that during rotation, the center of mass of the drawn system should actually rises relative to the surface the bike is moving across.  If the bike were to be truly rotating about its center of mass, then the back wheel would begin to dip below the surface of the road like you might see in a glitchy video game.    So I suspect that the bike is in fact rotating about the back axle, but I don't understand why, please help!  edit: I added the external torque from the back wheel to the frame, which would allow the bike to rotate about the back axle  edit 2:  I suppose that the torque acting on the frame via the engine should not effect the rotation as the movement of a motorcycle can be perfectly replicated by applying a force at the back axle.  A third possible axis of rotation might be the lowest point of the back wheel. How would you categorize email subjects to find similar emails? I have a list of email subjects like:  &lt;XYZ&gt; commented on &lt;ABC&gt; Weekly review for &lt;Company&gt; Your account is ready    And I want to find patterns in them so I can group them.  Is there a well known algorithm I can use?    Preferably with wide language implementations or easy re-implementation. The algorithm should be unsupervised. The number of different emails is not known.   Update:  I think I can break this down into two problems:   Group subjects by the similar words they use, resulting in the following. Each group should be very distinct from the rest (they should be almost perfectly exclusive) and the algorithm should give relatively small number of groups with good length of the common words.  [commented, on] [weekly, review] [your, account, is, ready]  Once grouped, it should be easy to find a state automaton that accepts only the group's subject and thus eliminates variable Then I can go back and check if there are any intersections and tweak the variables.   Having said that, is it better to use a completley different approach like neural nets maybe? I have zero experience with those, but if it makes more sense, I am open to learning. My dev team is getting ready to start a new project. The shop has been a "VB shop" since the days of VB3, but the prevailing opinion now is that we're a ".NET shop" and since C# was created specifically for .NET, whereas VB.NET was a retrofit, we've decided to move forward writing C# only. The controversy revolves around the question of whether the Microsoft.VisualBasic namespace has a legitimate place in new development or if it is only for backward compatibility for VB6 (and older) code. A further, and more interesting question is whether the code "under" the Microsoft.VisualBasic namespace is even .NET code of if it is really the old VB runtime carefully packaged in a .NET wrapper, making it in fact a COM interop control (similar to how WinForms wraps the non-.NET Win32 windowing API but exposes only .NET APIs for consumption).  To make this even more confusing, our dev team has a Microsoft Consulting Services consultant telling us Microsoft no longer supports Visual Basic, including the VB runtime underlying the Microsoft.VisualBasic namespace.  What I'm looking for are links -- preferably to unimpeachable Microsoft sources -- to documentation that definitively answers this question one way or the other. I've already tried several search permutations on Google and not gotten any closer to getting to the bottom of this question.  EDIT: Apparently I didn't make my question clear. I'm not asking if VB.NET is true .NET code. I'm trying to determine if whatever is "under" the Microsoft.VisualBasic namespace is .NET code or if it's the old VB6 runtime carefully packaged and exposed as .NET code. Someone already said that 9/10 of the namespace simply wraps code from elsewhere in .NET; what about that other 1/10? I'm calling a function in Python which I know may stall and force me to restart the script.   How do I call the function or what do I wrap it in so that if it takes longer than 5 seconds the script cancels it and does something else? How do lexical closures work? I have downloaded tar.gz files. But I don't know how to install it. How do I install this kind of file? Is there any difference between the usage of 'later' and 'later on'?         I'll see you later.   I'll finish it later on. Singular or plural verb after a series connected by "or" The following sentence refers to an apocalyptic story where money no longer has any value:     A can of sardines, radio batteries, or a bicycle is/are more precious than money.   Should I use is or are after the series? Port forwarding with UFW I realize UFW is mainly just for enabling/disabling access on particular ports, but I'm trying to forward one port to another. I want any connection to port 1724 to be forwarded to 1723.   The file /etc/default/ufw already has DEFAULT_FORWARD_POLICY="ACCEPT". And I believe I need to uncomment net/ipv4/ip_forward=1 in /etc/ufw/sysctl.conf. Finally I need to edit /etc/ufw/before.rules to add an iptables rule.   And here is where I get lost because I can't find any documentation for this file. Where do I add the rule? And how exactly?  In particular:   On exactly which line do I add the rule? Do I put anything before or after it? I want to display from cache for a long time and I want a slightly different behavior on page render vs loading the page from cache.  Is there an easy way I can determine this with JavaScript? I have a string that contains both double-quotes and backslashes that I want to set to a variable in Python. However, whenever I try to set it, the quotes or slashes are either removed or escaped. Here's an example:  &gt;&gt;&gt; foo = 'baz "\"' &gt;&gt;&gt; foo 'baz ""'   So instead of baz "\" like I want I'm getting baz "". If I then try to escape the backslash, it doesn't help either:  &gt;&gt;&gt; foo = 'baz "\\"' &gt;&gt;&gt; foo 'baz "\\"'   Which now matches what I put in but wasn't what I originally wanted. How do you get around this problem? On several occasions, I was reading a question thinking "I know a guy that knows the answer to this" and that guy (or gal) also happens to be a registered user. How can I bring this to the attention of this user? Ice skater increase of energy This may be a very basic question but I am not seeing how it works. Consider the standard example of an ice skate rotating about his/her center of mass and pulling in his/her arms. The torque is zero so we have conservation of angular momentum. This implies that $\omega$ increases to keep $I\omega$ constant, but then $K_{rot}=\frac{1}{2}I\omega^2$ doesn't stay constant, it increases. This implies that there is work done, but what force is doing this work? How exactly does a  work?  This is an extremely broad question. What code keeps things bouncing against each other, what code makes the player walk into a wall instead of walk through the wall? How does the code constantly refresh the players position and objects position to keep gravity and collision working as it should?  If you don't know what a collision engine is, basically it's generally used in  to make the player acutally hit walls and the like. There's the 2D type and the 3D type, but they all accomplish the same thing: collision.  So, what keeps a collision engine ticking?