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• PC monitors shut off and system hangs while playing 3D games, but sound continues - Diagnosis?

  - by Jon Schneider

  Two days ago, I started running into a problem with my Windows PC: The PC's two connected monitors simultaneously lose signal and go black (as though the PC had been powered off). The keyboard's Numlock, Capslock, and Scroll Lights will become "stuck" in their current positions, as though the PC is hung. (For example, the Numlock light on the keyboard remains lit regardless of me pressing the Numlock key repeatedly.) No keyboard input does anything. (Ctrl+Alt+Del, Ctrl+Shift+Esc, Ctrl+C, etc.) However -- Whatever sound/music the PC was playing continues to play, and the PC's fans continue running, so the PC hasn't powered itself off or rebooted itself. Opening up the case, the graphics card is pretty hot to the touch. I had this happen 3 times in one evening. In all cases, I was playing a game with 3D graphics when the problem occurred (Torchlight, Minecraft, Magic: The Gathering 2012, Avadon: The Black Fortress demo). I have yet to have the problem happen when I'm not playing a game. This system has been running stable for about 2.5 years prior to this. I didn't make any changes to the system prior to the problem starting to occur. System specs: OS: Windows 7 64-bit Processor: Intel Core 2 Duo E7200 Wolfdale 2.53GHz Video Card: XFX GeForce 9800 GT 512 MB Motherboard: Foxconn P45A-S LGA 775 Intel ATX RAM: Corsair 4 GB (2x 2GB) DDR2-800 (PC2 6400) Full specs: New PC 2008 Troubleshooting tried so far (the problem occurred again after taking each of these steps, one at a time): Updated the video drivers with the latest drivers from NVidia's site. Opened up the case and cleaned out the video card and processor fans (both were pretty dirty). Installed and ran temperature monitor software. The processor idles at about 50 degrees C, and goes up to about 63 degrees C while playing a game (seems on the warm side, but not excessively so?). The software wasn't able to report the temperature of the GPU -- not sure this particular GPU supports software temperature readout? My initial diagnosis is that maybe the GPU is on its last legs (given that it seems to be running pretty hot, and the problem only occurs while playing 3D games). Does this seem likely? Or is it likely that this problem is caused by the processor, RAM, or motherboard? Or could this be a software issue of some kind? Thanks for any advice!

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• Can USB Hubs affect peripheral performance?

  - by Daniel Rasmussen

  Like many laptops, mine has 2 USB 2.0 ports. I'm looking to purchase a USB hub for my peripheral devices. I'm also planning on purchasing a laptop cooler with two USB powered fans, which connects to a USB port but can extend the plug, so it doesn't use one up. (Sorry for the poor description; see the link for a picture.) My questions are these: Can one plug 'too many' peripherals into a USB port? Can I plug my fans into a port, then the hub into the fans, then my keyboard and mouse, mic, and webcam into the extender..? Is it possible to draw too much power from a port? Secondly, will a USB hub affect the performance of any of my devices? I'm mostly worried about my mouse and keyboard. I like wired mice because I've noticed some lag in my Bluetooth mouse.

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• Is this an idiomatic way to pass mocks into objects?

  - by Billy ONeal

  I'm a bit confused about passing in this mock class into an implementation class. It feels wrong to have all this explicitly managed memory flying around. I'd just pass the class by value but that runs into the slicing problem. Am I missing something here? Implementation: namespace detail { struct FileApi { virtual HANDLE CreateFileW( __in LPCWSTR lpFileName, __in DWORD dwDesiredAccess, __in DWORD dwShareMode, __in_opt LPSECURITY_ATTRIBUTES lpSecurityAttributes, __in DWORD dwCreationDisposition, __in DWORD dwFlagsAndAttributes, __in_opt HANDLE hTemplateFile ) { return ::CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile); } virtual void CloseHandle(HANDLE handleToClose) { ::CloseHandle(handleToClose); } }; } class File : boost::noncopyable { HANDLE hWin32; boost::scoped_ptr<detail::FileApi> fileApi; public: File( __in LPCWSTR lpFileName, __in DWORD dwDesiredAccess, __in DWORD dwShareMode, __in_opt LPSECURITY_ATTRIBUTES lpSecurityAttributes, __in DWORD dwCreationDisposition, __in DWORD dwFlagsAndAttributes, __in_opt HANDLE hTemplateFile, __in detail::FileApi * method = new detail::FileApi() ) { fileApi.reset(method); hWin32 = fileApi->CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile); } }; namespace detail { struct FileApi { virtual HANDLE CreateFileW( __in LPCWSTR lpFileName, __in DWORD dwDesiredAccess, __in DWORD dwShareMode, __in_opt LPSECURITY_ATTRIBUTES lpSecurityAttributes, __in DWORD dwCreationDisposition, __in DWORD dwFlagsAndAttributes, __in_opt HANDLE hTemplateFile ) { return ::CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile); } virtual void CloseHandle(HANDLE handleToClose) { ::CloseHandle(handleToClose); } }; } class File : boost::noncopyable { HANDLE hWin32; boost::scoped_ptr<detail::FileApi> fileApi; public: File( __in LPCWSTR lpFileName, __in DWORD dwDesiredAccess, __in DWORD dwShareMode, __in_opt LPSECURITY_ATTRIBUTES lpSecurityAttributes, __in DWORD dwCreationDisposition, __in DWORD dwFlagsAndAttributes, __in_opt HANDLE hTemplateFile, __in detail::FileApi * method = new detail::FileApi() ) { fileApi.reset(method); hWin32 = fileApi->CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile); } ~File() { fileApi->CloseHandle(hWin32); } }; Tests: namespace detail { struct MockFileApi : public FileApi { MOCK_METHOD7(CreateFileW, HANDLE(LPCWSTR, DWORD, DWORD, LPSECURITY_ATTRIBUTES, DWORD, DWORD, HANDLE)); MOCK_METHOD1(CloseHandle, void(HANDLE)); }; } using namespace detail; using namespace testing; TEST(Test_File, OpenPassesArguments) { MockFileApi * api = new MockFileApi; EXPECT_CALL(*api, CreateFileW(Eq(L"BozoFile"), Eq(56), Eq(72), Eq(reinterpret_cast<LPSECURITY_ATTRIBUTES>(67)), Eq(98), Eq(102), Eq(reinterpret_cast<HANDLE>(98)))) .Times(1).WillOnce(Return(reinterpret_cast<HANDLE>(42))); File test(L"BozoFile", 56, 72, reinterpret_cast<LPSECURITY_ATTRIBUTES>(67), 98, 102, reinterpret_cast<HANDLE>(98), api); }

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• How does reflection tell me when a property is hiding an inherited member with the 'new' keyword?

  - by TheDeeno

  So if I have: public class ChildClass : BaseClass { public new virtual string TempProperty { get; set; } } public class BaseClass { public virtual string TempProperty { get; set; } } How can I use reflection to see that ChildClass is hiding the Base implementation of TempProperty? I'd like the answer to be agnostic between c# and vb.net

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• Installing Team Foundation Server

  - by vzczc

  What are the best practices in setting up a new instance of TFS 2008 Workgroup edition? Specifically, the constraints are as follows: Must install on an existing Windows Server 2008 64 bit TFS application layer is 32 bit only Should I install SQL Server 2008, Sharepoint and the app layer in a virtual instance of Windows Server 2008 or 2003(I am already running Hyper-V) or split the layers with a database on the host OS and the app layer in a virtual machine? Edit: Apparently, splitting the layers is not recommended

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• COM Dual Interfaces

  - by Tony

  A dual interface in COM is one that is able to be accessed via a DispInterface or via VTable methods. Now can someone tell me what is exactly what the difference is between the two methods? I thought that a VTable is a virtual table which holds the pointers to the different functions when implementing a class hierarchy which has virtual functions that can be overridden in child classes. However I do not see how this is related to a dual interface in COM?

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• Entity Framework 4 CTP 5 POCO - Many-to-many configuration, insertion, and update?

  - by Saxman

  I really need someone to help me to fully understand how to do many-to-many relationship with Entity Framework 4 CTP 5, POCO. I need to understand 3 concepts: How to config my model to indicates some tables are many-to-many. How to properly do insert. How to properly do update. Here are my current models: public class MusicSheet { [Key] public int ID { get; set; } public string Title { get; set; } public string Key { get; set; } public virtual ICollection<Author> Authors { get; set; } public virtual ICollection<Tag> Tags { get; set; } } public class Author { [Key] public int ID { get; set; } public string Name { get; set; } public string Bio { get; set; } public virtual ICollection<MusicSheet> MusicSheets { get; set; } } public class Tag { [Key] public int ID { get; set; } public string TagName { get; set; } public virtual ICollection<MusicSheet> MusicSheets { get; set; } } As you can see, the MusicSheet can have many Authors or Tags, and an Author or Tag can have multiple MusicSheets. Again, my questions are: What to do on the EntityTypeConfiguration to set the relationship between them as well as mapping to an table/object that associates with the many-to-many relationship. How to insert a new music sheets (where it might have multiple authors or multiple tags). How to update a music sheet. For example, I might set TagA, TagB to MusicSheet1, but later I need to change the tags to TagA and TagC. It seems like I need to first check to see if the tags already exists, if not, insert the new tag and then associate it with the music sheet (so that I doesn't re-insert TagA?). Or this is something already handled by the framework? Thank you very much. I really hope to fully understand it rather than just doing it without fully understand what's going on. Especially on #3.

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• Hosting a VST/DX instrument in C#/C++?

  - by James D

  I'm trying to get a read on the effort level involved in building a barebones virtual instrument host in C++ or C# but I haven't been able to get any hard information. Does anybody know any good starter apps, tutorials, helper libraries for this sort of thing? If it matters, the goal would be to a) accept incoming MIDI events and b) dispatch them to the virtual instrument. In C++ or C#, if possible. Thanks!

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• How to stop scheduled chkdisk on windows 7?

  - by AndrejaKo

  Hi! I have a problem with windows 7 64-bit. I was trying out chkdsk command line options and scheduled a chddsk /r on next start. After that I disassembled the laptop on which I set the chkdsk. After I reassembled it, windows gets normally to the point where it should start the check and then hangs when the countdown reaches 1 second. During the countdown, it doesn't detect any input from keyboard. At first I thought that I didn't correctly install the keyboard, but under GNU/Linux, everything is working fine and I can normally mount the windows partition . So is there any way to stop the scheduled chkdsk? I really don't feel like reinstalling windows again because I just finished setting up my tool-chain the way I like it and compiled about 6GiB worth of dependencies I need for some project I'm working on.

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• Should we denormalize database to improve performance?

  - by Groo

  We have a requirement to store 500 measurements per second, coming from several devices. Each measurement consists of a timestamp, a quantity type, and several vector values. Right now there is 8 vector values per measurement, and we may consider this number to be constant for needs of our prototype project. We are using HNibernate. Tests are done in SQLite (disk file db, not in-memory), but production will probably be MsSQL. Our Measurement entity class is the one that holds a single measurement, and looks like this: public class Measurement { public virtual Guid Id { get; private set; } public virtual Device Device { get; private set; } public virtual Timestamp Timestamp { get; private set; } public virtual IList<VectorValue> Vectors { get; private set; } } Vector values are stored in a separate table, so that each of them references its parent measurement through a foreign key. We have done a couple of things to ensure that generated SQL is (reasonably) efficient: we are using Guid.Comb for generating IDs, we are flushing around 500 items in a single transaction, ADO.Net batch size is set to 100 (I think SQLIte does not support batch updates? But it might be useful later). The problem Right now we can insert 150-200 measurements per second (which is not fast enough, although this is SQLite we are talking about). Looking at the generated SQL, we can see that in a single transaction we insert (as expected): 1 timestamp 1 measurement 8 vector values which means that we are actually doing 10x more single table inserts: 1500-2000 per second. If we placed everything (all 8 vector values and the timestamp) into the measurement table (adding 9 dedicated columns), it seems that we could increase our insert speed up to 10 times. Switching to SQL server will improve performance, but we would like to know if there might be a way to avoid unnecessary performance costs related to the way database is organized right now. [Edit] With in-memory SQLite I get around 350 items/sec (3500 single table inserts), which I believe is about as good as it gets with NHibernate (taking this post for reference: http://ayende.com/Blog/archive/2009/08/22/nhibernate-perf-tricks.aspx). But I might as well switch to SQL server and stop assuming things, right? I will update my post as soon as I test it.

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• Microsoft Ergonomic Keyboards With Card Readers?

  - by Steve

  When I started working at my current job I developed tendinitis in my wrists. Luckily that cleared up when I started using a Microsoft ergonomic keyboard. The problem is that where I work is moving to more security. We will need to stick a card into a slot to log into our PCs. They bought a bunch of new keyboards with these slots built in. All regular keyboards. Is there something like the Microsoft Ergonomic keyboard that comes with such a card slot? Thanks.

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• UIView, UIScrollView and UITextFields problem calling Method

  - by Jeff Groby

  I have a view with several embedded UITextFields, this UIView is subordinated to a UIScrollView in IB. Each text field is supposed to invoke a method called updateText defined in the viewcontroller implementation file when the user is done editing the field. For some reason, the method updateText never gets invoked. Anyone have any ideas how to go about fixing this? The method fired off just fine when the UIScrollView was not present in the project but the keyboard would cover the text fields during input, which was annoying. Now my textfields move up above the keyboard when it appears, but won't fire off the method when done editing. Here is my implementation file: #import "MileMarkerViewController.h" @implementation MileMarkerViewController @synthesize scrollView,milemarkerLogDate,milemarkerDesc,milemarkerOdobeg,milemarkerOdoend,milemarkerBusiness,milemarkerPersonal,milemarker; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Initialization code } return self; } - (BOOL) textFieldShouldReturn: (UITextField*) theTextField { return [theTextField resignFirstResponder]; } - (void)viewDidLoad { [super viewDidLoad]; [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(keyboardWasShown:) name: UIKeyboardDidShowNotification object: nil]; [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(keyboardWasHidden:) name: UIKeyboardDidHideNotification object: nil]; keyboardShown = NO; // 1 [scrollView setContentSize: CGSizeMake( 320, 480)]; // 2 } - (void)keyboardWasShown:(NSNotification*)aNotification { if (keyboardShown) return; NSDictionary* info = [aNotification userInfo]; // Get the size of the keyboard. NSValue* aValue = [info objectForKey:UIKeyboardBoundsUserInfoKey]; CGSize keyboardSize = [aValue CGRectValue].size; // Resize the scroll view (which is the root view of the window) CGRect viewFrame = [scrollView frame]; viewFrame.size.height -= keyboardSize.height; scrollView.frame = viewFrame; // Scroll the active text field into view. CGRect textFieldRect = [activeField frame]; [scrollView scrollRectToVisible:textFieldRect animated:YES]; keyboardShown = YES; } - (void)keyboardWasHidden:(NSNotification*)aNotification { NSDictionary* info = [aNotification userInfo]; // Get the size of the keyboard. NSValue* aValue = [info objectForKey:UIKeyboardBoundsUserInfoKey]; CGSize keyboardSize = [aValue CGRectValue].size; // Reset the height of the scroll view to its original value CGRect viewFrame = [scrollView frame]; viewFrame.size.height += keyboardSize.height; [scrollView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES]; scrollView.frame = viewFrame; keyboardShown = NO; } - (void)textFieldDidBeginEditing:(UITextField *)textField { activeField = textField; } - (void)textFieldDidEndEditing:(UITextField *)textField { activeField = nil; } - (IBAction)updateText:(id) sender { NSLog(@"You just entered: %@",self.milemarkerLogDate.text); self.milemarker.logdate = self.milemarkerLogDate.text; self.milemarker.desc = self.milemarkerDesc.text; self.milemarker.odobeg = self.milemarkerOdobeg.text; self.milemarker.odoend = self.milemarkerOdoend.text; self.milemarker.business = self.milemarkerBusiness.text; self.milemarker.personal = self.milemarkerPersonal.text; NSLog(@"Original textfield is set to: %@",self.milemarker.logdate); [self.milemarker updateText]; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)dealloc { [super dealloc]; } @end

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• Pinax installation problem

  - by 47

  I'm trying to setup a Pinax demo to work on and I've tried it under both Windows and FreeBSD with no luck...in both OS's, the virtual environment is created without a hitch, but then the following happens: For Windows, I can start the virtal environment and clone one of the sample projects as my starting point....however, running: manage.py syncdb Gives this error:Error: Can't import Pinax. Make sure you're in a virtual environment that has Pinax installed... For FreeBSD, when I try to start the environment: Badly placed ()'s What could be the problem?

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• Retrieving/Updating Entity Framework POCO objects that already exist in the ObjectContext

  - by jslatts

  I have a project using Entity Framework 4.0 with POCOs (data is stored in SQL DB, lazyloading is enabled) as follows: public class ParentObject { public int ID {get; set;} public virtual List<ChildObject> children {get; set;} } public class ChildObject { public int ID {get; set;} public int ChildRoleID {get; set;} public int ParentID {get; set;} public virtual ParentObject Parent {get; set;} public virtual ChildRoleObject ChildRole {get; set;} } public class ChildRoleObject { public int ID {get; set;} public string Name {get; set;} public virtual List<ChildObject> children {get; set;} } I want to create a new ChildObject, assign it a role, then add it to an existing ParentObject. Afterwards, I want to send the new ChildObject to the caller. The code below works fine until it tries to get the object back from the database. The newChildObjectInstance only has the ChildRoleID set and does not contain a reference to the actual ChildRole object. I try and pull the new instance back out of the database in order to populate the ChildRole property. Unfortunately, in this case, instead of creating a new instance of ChildObject and assigning it to retreivedChildObject, EF finds the existing ChildObject in the context and returns the in-memory instance, with a null ChildRole property. public ChildObject CreateNewChild(int id, int roleID) { SomeObjectContext myRepository = new SomeObjectContext(); ParentObject parentObjectInstance = myRepository.GetParentObject(id); ChildObject newChildObjectInstance = new ChildObject() { ParentObject = parentObjectInstance, ParentID = parentObjectInstance.ID, ChildRoleID = roleID }; parentObjectInstance.children.Add(newChildObjectInstance); myRepository.Save(); ChildObject retreivedChildObject = myRepository.GetChildObject(newChildObjectInstance.ID); string assignedRoleName = retreivedChildObject.ChildRole.Name; //Throws exception, ChildRole is null return retreivedChildObject; } I have tried setting MergeOptions to Overwrite, calling ObjectContext.Refresh() and ObjectContext.DetectChanges() to no avail... I suspect this is related to the proxy objects that EF injects when working with POCOs. Has anyone run into this issue before? If so, what was the solution?

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• CentOS Live CD Creation issues

  - by Dheeraj

  I am creating my customized CentOS 6.3 Live CD. I am following information given at https://projects.centos.org/trac/livecd/wiki/GetToolset My "livecd-creator" command completes successfully and an ISO image is created. But when I try to boot up my system with this ISO, it goes up to the CentOS blue screen and then the CAPS lock and Scroll Lock LEDs on the keyboard starts flashing. Then from here after, the system takes no input from keyboard and I have to power cycle it and it does the same thing. Could you get me any suggestion why this is causing and possible workaround. Thanks.

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• What am I not getting about this abstract class implementation?

  - by Schnapple

  PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

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• How to identify cause of system lock on debian squeeze?

  - by David Sanders

  I have a desktop system at work with debian squeeze installed. Every couple days or so, when I come in in the morning, the system appears to be asleep and won't wake up. I suspect it goes into power save mode and then doesn't receive the wake up signal when I click the mouse or touch the keyboard. Does anyone know where I should look in order to start tracking this down? Like log files, etc? I doubt it, but maybe the fact that I'm using a mac aluminum usb keyboard and a wireless usb mouse (that has an off switch) has something to do with it? Maybe, when I turn my mouse off at the end of the day, the system loses track of the device somehow? I dunno :P. Thanks in advance.

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• System.Runtime.InteropServices.COMException : This command is unavailable because the license to use

  - by sam

  I am running 3 virtual machines that are running tests using cc.net server. Currently tests are running simultanously on 3 machines. All the tests require to access Excel file. When tests run individually they all work fine but running them on virtual server is causing this error. Any idea how to resolve this issue.

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• Stubbing out methods that explicitly implement an interface using Rhino Mocks

  - by Ben Aston

  How can I stub out methods that explicitly implement an interface using Rhino Mocks? As I understand it, Rhino Mocks requires stubbed out methods to be virtual, and explicitly implemented interface members are not virtual.

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• How to obtain a pointer out of a C++ vtable?

  - by Josh Haberman

  Say you have a C++ class like: class Foo { public: virtual ~Foo() {} virtual DoSomething() = 0; }; The C++ compiler translates a call into a vtable lookup: Foo* foo; // Translated by C++ to: // foo->vtable->DoSomething(foo); foo->DoSomething(); Suppose I was writing a JIT compiler and I wanted to obtain the address of the DoSomething() function for a particular instance of class Foo, so I can generate code that jumps to it directly instead of doing a table lookup and an indirect branch. My questions are: Is there any standard C++ way to do this (I'm almost sure the answer is no, but wanted to ask for the sake of completeness). Is there any remotely compiler-independent way of doing this, like a library someone has implemented that provides an API for accessing a vtable? I'm open to completely hacks, if they will work. For example, if I created my own derived class and could determine the address of its DoSomething method, I could assume that the vtable is the first (hidden) member of Foo and search through its vtable until I find my pointer value. However, I don't know a way of getting this address: if I write &DerivedFoo::DoSomething I get a pointer-to-member, which is something totally different. Maybe I could turn the pointer-to-member into the vtable offset. When I compile the following: class Foo { public: virtual ~Foo() {} virtual void DoSomething() = 0; }; void foo(Foo *f, void (Foo::*member)()) { (f->*member)(); } On GCC/x86-64, I get this assembly output: Disassembly of section .text: 0000000000000000 <_Z3fooP3FooMS_FvvE>: 0: 40 f6 c6 01 test sil,0x1 4: 48 89 74 24 e8 mov QWORD PTR [rsp-0x18],rsi 9: 48 89 54 24 f0 mov QWORD PTR [rsp-0x10],rdx e: 74 10 je 20 <_Z3fooP3FooMS_FvvE+0x20> 10: 48 01 d7 add rdi,rdx 13: 48 8b 07 mov rax,QWORD PTR [rdi] 16: 48 8b 74 30 ff mov rsi,QWORD PTR [rax+rsi*1-0x1] 1b: ff e6 jmp rsi 1d: 0f 1f 00 nop DWORD PTR [rax] 20: 48 01 d7 add rdi,rdx 23: ff e6 jmp rsi I don't fully understand what's going on here, but if I could reverse-engineer this or use an ABI spec I could generate a fragment like the above for each separate platform, as a way of obtaining a pointer out of a vtable.

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• MacPro will freeze after first startup and first time screen saver activates

  - by Rob Segal

  I've run into a bizarre situation every time my MacPro first starts up in the morning when I get to work and the screen saver activates for the first time. When I try to deactivate the screen saver hitting the keyboard or mouse nothing will happen. At best I will get one of the following... Able to move the mouse but clicking does nothing Login prompt will show up but typing on the keyboard does nothing At worst the screen will be fully locked. In all cases I will have to reboot my machine to get it to work again. After this initial restart the machine is fine for the rest of the day. Anyone encountered something like this before?

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• Design Technique: How to design a complex system for processing orders, products and units.

  - by Shyam

  Hi, Programming is fun: I learned that by trying out simple challenges, reading up some books and following some tutorials. I am able to grasp the concepts of writing with OO (I do so in Ruby), and write a bit of code myself. What bugs me though is that I feel re-inventing the wheel: I haven't followed an education or found a book (a free one that is) that explains me the why's instead of the how's, and I've learned from the A-team that it is the plan that makes it come together. So, armed with my nuby Ruby skills, I decided I wanted to program a virtual store. I figured out the following: My virtual Store will have: Products and Services Inventories Orders and Shipping Customers Now this isn't complex at all. With the help of some cool tools (CMapTools), I drew out some concepts, but quickly enough (thanks to my inferior experience in designing), my design started to bite me. My very first product-line were virtual "laptops". So, I created a class (Ruby): class Product attr_accessor :name, :price def initialize(name, price) @name = name @price = price end end which can be instantiated by doing (IRb) x = Product.new("Banana Pro", 250) Since I want my virtual customers to be able to purchase more than one product, or various types, I figured out I needed some kind of "Order" mechanism. class Order def initialize(order_no) @order_no = order_no @line_items = [] end def add_product(myproduct) @line_items << myproduct end def show_order() puts @order_no @line_items.each do |x| puts x.name.to_s + "\t" + x.price.to_s end end end that can be instantiated by doing (IRb) z = Order.new(1234) z.add_product(x) z.show_order Splendid, I have now a very simple ordering system that allows me to add products to an order. But, here comes my real question. What if I have three models of my product (economy, business, showoff)? Or have my products be composed out of separate units (bigger screen, nicer keyboard, different OS)? Surely I could make them three separate products, or add complexity to my product class, but I am looking for are best practices to design a flexible product object that can be used in the real world, to facilitate a complex system. My apologies if my grammar and my spelling are with error, as english is not my first language and I took the time to check as far I could understand and translate properly! Thank you for your answers, comments and feedback!

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• Notepad/Edit equivalent for Linux command line

  - by Jason Kester

  I'm looking for a simple text editor that I can use from the command line in Linux to edit files. I'm used to editing files in windows, so I'm looking for something with the same keyboard interface. That means: SHIFT+Arrow Keys/PGUP/PGDN to select text CTRL+C, CTRL+X, CTRL+V to copy/cut/paste And that's pretty much it. Surprisingly I'm having a tough time finding something like this. Vi/emacs are naturally out. Nano comes close, but has its own non-standard cut/paste/select keyboard shortcuts. Surely this thing exists somewhere. Thanks in advance for pointing me in the right direction.

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• MS-DOS 7.1, Active-Boot

  - by user3005255

  I created a MS-DOS 7.1 (Win 98) active-boot USB-flash stick and it functions properly. Nevertheless I still have some unsolved issues: I want to change my keyboard-layout to german but I don´t know where to start since I only have the "basic-DOS" with IO.sys, MSDOS.sys + command.com. I already created Autoexec.bat + config.sys but don´t know which files I need and which I have to change in order to get a german keyboard. Also I can´t really shutdown my DOS properly, what is the right way to do it in MS-DOS 7.1? Thanks very much in advance for your help!

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• Ubuntu 9.10: switch in KVM, mouse is detected but not usable immediately

  - by CarlF

  I use a KVM switch to jump between my tower and laptop, both placed on my desk. With Ubuntu 9.04 this worked perfectly. In 9.10, when I switch to the tower, then back to the laptop, the mouse is detected (as shown by /var/log/messages) but moving it has no effect. If I use Ctrl-Alt-F1 to switch to the TTY, then Alt-F7 back to Xorg, the mouse starts working. The tower is running Windows 7, but that shouldn't matter. Sometimes, but not other times, the USB keyboard on the KVM switch is also not usable and I have to use the laptop's built-in keyboard to switch to the TTY. The laptop has two monitors, the built-in and an external. It's (obviously) the external panel that is attached via the KVM switch. Any suggestions? Report to Canonical as a bug?

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