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  • SQL Design Question regarding schema and if Name value pair is the best solution

    - by Aur
    I am having a small problem trying to decide on database schema for a current project. I am by no means a DBA. The application parses through a file based on user input and enters that data in the database. The number of fields that can be parsed is between 1 and 42 at the current moment. The current design of the database is entirely flat with there being 42 columns; some have repeated columns such as address1, address2, address3, etc... This says that I should normalize the data. However, data integrity is not needed at this moment and the way the data is shaped I'm looking at several joins. Not a bad thing but the data is still in a 1 to 1 relationship and I still see a lot of empty fields per row. So my concerns are that this does not allow the database or the application to be very extendable. If they want to add more fields to be parsed (which they do) than I'd need to create another table and add another foreign key to the linking table. The third option is I have a table where the fields are defined and a table for each record. So what I was thinking is to make a table that stores the value and then links to those two tables. The problem is I can picture the size of that table growing large depending on the input size. If someone gives me a file with 300,000 records than 300,000 x 40 = 12 million so I have some reservations. However I think if I get to that point than I should be happy it is being used. This option also allows for more custom displaying of information albeit a bit more work but little rework even if you add more fields. So the problem boils down to: 1. Current design is a flat file which makes extending it hard and it is not normalized. 2. Normalize the tables although no real benefits for the moment but requirements change. 3. Normalize it down into the name value pair and hope size doesn't hurt. There are a large number of inserts, updates, and selects against that table. So performance is a worry but I believe the saying is design now, performance testing later? I'm probably just missing something practical so any comments would be appreciated even if it’s a quick sanity check. Thank you for your time.

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  • How to close all, or only some, tabs in Safari using AppleScript?

    - by Form
    I have made a very simple AppleScript to close all tabs in Safari. The problem is, it works, but not completely. The problem is that only a couple of tabs are closed. Here's the code: tell application "Safari" repeat with aWindow in windows repeat with aTab in tabs of aWindow if [some condition is encountered] then aTab close end if end repeat end repeat end tell I've also tried this script: tell application "Safari" repeat with i from 0 to the number of items in windows set aWindow to item i of windows repeat with j from 0 to the number of tabs in aWindow set aTab to item j of tabs of aWindow if [some condition is encountered] then aTab close end if end repeat end repeat end tell ... but it does not work either (same behavior). I tried that on my system (MacBook Pro jan 2008), as well as on a Mac Pro G5 under Tiger and the script fails on both, albeit with a much less descriptive error on Tiger. Running the script a few times closes a few tab each time until none is left, but always fails with the same error after closing a few tabs. Under Leopard I get an out of bounds error. Since I am using fast enumeration (not using "repeat from 0 to number of items in windows") I don't see how I can get an out of bounds error with this... My goal is to use the Cocoa Scripting Bridge to close tabs in Safari from my Objective-C Cocoa application but the Scripting Bridge fails in the same manner. The non-deletable tabs show as NULL in the Xcode debugger, while the other tabs are valid objects from which I can get values back (such as their title). In fact I tried with the Scripting Bridge first then told myself why not try this directly in AppleScript and I was surprised to see the same results. I must have a glaring omission or something in there... (seems like a bug in Safari AppleScript support to me... :S) I've used repeat loops and Obj-C 2.0 fast enumeration to iterate through collections before with zero problems, so I really don't see what's wrong here. Anyone can help? Thanks in advance!

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  • Property trigger in XAML for IsMouseOver fails to set Border.Background

    - by Mal Ross
    I'm currently trying to create a ControlTemplate for the Button class in WPF, replacing the usual visual tree with something that makes the button look similar to the little (X) close icon on Google Chrome's tabs. I decided to use a Path object in XAML to achieve the effect. Using a property trigger, the control responds to a change in the IsMouseOver property by setting the icon's red background. Here's the XAML from a test app: <Window x:Class="Widgets.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <Window.Resources> <Style x:Key="borderStyle" TargetType="Border"> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Background"> <Setter.Value> <SolidColorBrush Color="#CC0000"/> </Setter.Value> </Setter> </Trigger> </Style.Triggers> </Style> <ControlTemplate x:Key="closeButtonTemplate" TargetType="Button"> <Border Width="12" Height="12" CornerRadius="6" BorderBrush="#AAAAAA" Background="Transparent" Style="{StaticResource borderStyle}" ToolTip="Close"> <Viewbox Margin="2.75"> <Path Data="M 0,0 L 10,10 M 0,10 L 10,0" Stroke="{Binding BorderBrush, RelativeSource={RelativeSource FindAncestor, AncestorType=Border, AncestorLevel=1}}" StrokeThickness="1.8"/> </Viewbox> </Border> </ControlTemplate> </Window.Resources> <Grid Background="White"> <Button Template="{StaticResource closeButtonTemplate}"/> </Grid> </Window> Note that the circular background is always there - it's just transparent when the mouse isn't over it. The problem with this is that the trigger just isn't working. Nothing changes in the button's appearance. However, if I remove the Background="Transparent" value from the Border object in the ControlTemplate, the trigger does work (albeit only when over the 'X'). I really can't explain this. Setters for any other properties placed in the borderStyle resource work fine, but the Background setter fails as soon as the default background is specified in the ControlTemplate. Any ideas why it's happening and how I can fix it? I know I could easily replace this code with, for example, a .PNG-based image, but I want to understand why the current implementation isn't working. Thanks! :)

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  • Why are USB 2.0 devices crashing my system?

    - by BenAlabaster
    Background on the machine I'm having a problem with: The machine was inherited and appears to be circa 2003 (there's a date stamp on the power supply which leads me to this conclusion). I've got it set up as a Skype terminal for my 2 year old to keep in touch with her grandparents and other members of the family - which everyone loves. It has a generic baby-ATX motherboard with no identifying markings. CPU-Z identifies the motherboard model as VT8601 but doesn't provide me with any manufacturer name. There's one stamp on the motherboard that says "Rev.B". On board it has 10/100 LAN, 2 x USB 1.0, VGA, PS/2 for KB and mouse, parallel port, 2 x serial ports, 2 x IDE, 1 x floppy, 2 x SDRAM slots, 1 x CPU housing that is seating a 1.3GHz Intel Celeron CPU, 3 x PCI, 1 x AGP - although you can only use 2 of the PCI slots if you use the AGP slot due to the physical layout of the board. It's got 768Mb PC133 SDRAM - 1 x 512Mb & 1 x 256Mb installed as well as a D-LINK WDA-2320 54G Wi-Fi network card and a generic USB 2.0 expansion board containing 3 x external + 1 x internal USB connectors. All this is sitting in a slimline case. I don't know the wattage of the PSU, but can post this later if this proves to be helpful. The motherboard is running a version of Award BIOS for which I don't have the version number to hand but can again post this later if it would be helpful. It has an 80Gb Western Digital hard drive freshly formatted and built with Windows XP Professional with Service Pack 3 and all current patches. In addition to Windows XP, the only other software it's running is Skype 4.1 (4.2 crashes the machine as soon as it starts up). It's got a Daytek MV150 15" touch screen running through the VGA and COM1 with the most current drivers from the Daytek website and the most current version of ELO-Touchsystems drivers for the touch component. The webcam is a Logitech Webcam C200 with the latest drivers from the Logitech website. The problem If I hook any USB 2.0 devices to this machine, it hangs the whole machine and I have to hard boot it to get it back up. Workarounds found I can plug the same devices into the on board USB 1.0 connectors and everything works fine, albeit at reduced performance. I've tried 3 different kinds of USB thumb drives, 3 different makes/models of webcams and my iPhone all with the same effect. They're recognized and don't hang the machine when I hook them to the USB 1.0 but if I hook them to the USB 2.0 ports, the machine hangs within a couple of seconds of recognizing the devices were connected. Attempted solutions I've tried disabling all the on board devices that I'm not using - such as the on board LAN, the second COM port, the AGP connector etc. through the BIOS in an (perhaps misguided or futile) attempt to reduce the power consumption... I don't think it had any effect but it didn't do any harm. I was wondering if the PSU wattage just isn't enough to drive the USB 2.0 devices; I've seen this suggested but haven't found any confirmation that this could really be an issue - nor have I found a way to work around this issue - if indeed it is one. Any ideas? The only thing I haven't done which I only just thought of while writing this essay is trying the USB 2.0 card in a different PCI slot, or re-ordering the wi-fi and USB cards in the slots... although I'm not sure if this will make any difference. I've installed the USB card in another machine and it works without issue, so it's not a problem with the USB card itself. Other thoughts Perhaps this is an incompatibility between the USB 2.0 card and the BIOS, would re-flashing the BIOS with a newer version help? Do I need to be able to identify the manufacturer of the motherboard in order to be able to find a BIOS edition specific for this motherboard or will any version of Award BIOS function in its place? Question Does anyone have any ideas that could help me get my USB 2.0 devices hooked up to this machine?

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  • The dynamic Type in C# Simplifies COM Member Access from Visual FoxPro

    - by Rick Strahl
    I’ve written quite a bit about Visual FoxPro interoperating with .NET in the past both for ASP.NET interacting with Visual FoxPro COM objects as well as Visual FoxPro calling into .NET code via COM Interop. COM Interop with Visual FoxPro has a number of problems but one of them at least got a lot easier with the introduction of dynamic type support in .NET. One of the biggest problems with COM interop has been that it’s been really difficult to pass dynamic objects from FoxPro to .NET and get them properly typed. The only way that any strong typing can occur in .NET for FoxPro components is via COM type library exports of Visual FoxPro components. Due to limitations in Visual FoxPro’s type library support as well as the dynamic nature of the Visual FoxPro language where few things are or can be described in the form of a COM type library, a lot of useful interaction between FoxPro and .NET required the use of messy Reflection code in .NET. Reflection is .NET’s base interface to runtime type discovery and dynamic execution of code without requiring strong typing. In FoxPro terms it’s similar to EVALUATE() functionality albeit with a much more complex API and corresponiding syntax. The Reflection APIs are fairly powerful, but they are rather awkward to use and require a lot of code. Even with the creation of wrapper utility classes for common EVAL() style Reflection functionality dynamically access COM objects passed to .NET often is pretty tedious and ugly. Let’s look at a simple example. In the following code I use some FoxPro code to dynamically create an object in code and then pass this object to .NET. An alternative to this might also be to create a new object on the fly by using SCATTER NAME on a database record. How the object is created is inconsequential, other than the fact that it’s not defined as a COM object – it’s a pure FoxPro object that is passed to .NET. Here’s the code: *** Create .NET COM InstanceloNet = CREATEOBJECT('DotNetCom.DotNetComPublisher') *** Create a Customer Object Instance (factory method) loCustomer = GetCustomer() loCustomer.Name = "Rick Strahl" loCustomer.Company = "West Wind Technologies" loCustomer.creditLimit = 9999999999.99 loCustomer.Address.StreetAddress = "32 Kaiea Place" loCustomer.Address.Phone = "808 579-8342" loCustomer.Address.Email = "[email protected]" *** Pass Fox Object and echo back values ? loNet.PassRecordObject(loObject) RETURN FUNCTION GetCustomer LOCAL loCustomer, loAddress loCustomer = CREATEOBJECT("EMPTY") ADDPROPERTY(loCustomer,"Name","") ADDPROPERTY(loCustomer,"Company","") ADDPROPERTY(loCUstomer,"CreditLimit",0.00) ADDPROPERTY(loCustomer,"Entered",DATETIME()) loAddress = CREATEOBJECT("Empty") ADDPROPERTY(loAddress,"StreetAddress","") ADDPROPERTY(loAddress,"Phone","") ADDPROPERTY(loAddress,"Email","") ADDPROPERTY(loCustomer,"Address",loAddress) RETURN loCustomer ENDFUNC Now prior to .NET 4.0 you’d have to access this object passed to .NET via Reflection and the method code to do this would looks something like this in the .NET component: public string PassRecordObject(object FoxObject) { // *** using raw Reflection string Company = (string) FoxObject.GetType().InvokeMember( "Company", BindingFlags.GetProperty,null, FoxObject,null); // using the easier ComUtils wrappers string Name = (string) ComUtils.GetProperty(FoxObject,"Name"); // Getting Address object – then getting child properties object Address = ComUtils.GetProperty(FoxObject,"Address");    string Street = (string) ComUtils.GetProperty(FoxObject,"StreetAddress"); // using ComUtils 'Ex' functions you can use . Syntax     string StreetAddress = (string) ComUtils.GetPropertyEx(FoxObject,"AddressStreetAddress"); return Name + Environment.NewLine + Company + Environment.NewLine + StreetAddress + Environment.NewLine + " FOX"; } Note that the FoxObject is passed in as type object which has no specific type. Since the object doesn’t exist in .NET as a type signature the object is passed without any specific type information as plain non-descript object. To retrieve a property the Reflection APIs like Type.InvokeMember or Type.GetProperty().GetValue() etc. need to be used. I made this code a little simpler by using the Reflection Wrappers I mentioned earlier but even with those ComUtils calls the code is pretty ugly requiring passing the objects for each call and casting each element. Using .NET 4.0 Dynamic Typing makes this Code a lot cleaner Enter .NET 4.0 and the dynamic type. Replacing the input parameter to the .NET method from type object to dynamic makes the code to access the FoxPro component inside of .NET much more natural: public string PassRecordObjectDynamic(dynamic FoxObject) { // *** using raw Reflection string Company = FoxObject.Company; // *** using the easier ComUtils class string Name = FoxObject.Name; // *** using ComUtils 'ex' functions to use . Syntax string Address = FoxObject.Address.StreetAddress; return Name + Environment.NewLine + Company + Environment.NewLine + Address + Environment.NewLine + " FOX"; } As you can see the parameter is of type dynamic which as the name implies performs Reflection lookups and evaluation on the fly so all the Reflection code in the last example goes away. The code can use regular object ‘.’ syntax to reference each of the members of the object. You can access properties and call methods this way using natural object language. Also note that all the type casts that were required in the Reflection code go away – dynamic types like var can infer the type to cast to based on the target assignment. As long as the type can be inferred by the compiler at compile time (ie. the left side of the expression is strongly typed) no explicit casts are required. Note that although you get to use plain object syntax in the code above you don’t get Intellisense in Visual Studio because the type is dynamic and thus has no hard type definition in .NET . The above example calls a .NET Component from VFP, but it also works the other way around. Another frequent scenario is an .NET code calling into a FoxPro COM object that returns a dynamic result. Assume you have a FoxPro COM object returns a FoxPro Cursor Record as an object: DEFINE CLASS FoxData AS SESSION OlePublic cAppStartPath = "" FUNCTION INIT THIS.cAppStartPath = ADDBS( JustPath(Application.ServerName) ) SET PATH TO ( THIS.cAppStartpath ) ENDFUNC FUNCTION GetRecord(lnPk) LOCAL loCustomer SELECT * FROM tt_Cust WHERE pk = lnPk ; INTO CURSOR TCustomer IF _TALLY < 1 RETURN NULL ENDIF SCATTER NAME loCustomer MEMO RETURN loCustomer ENDFUNC ENDDEFINE If you call this from a .NET application you can now retrieve this data via COM Interop and cast the result as dynamic to simplify the data access of the dynamic FoxPro type that was created on the fly: int pk = 0; int.TryParse(Request.QueryString["id"],out pk); // Create Fox COM Object with Com Callable Wrapper FoxData foxData = new FoxData(); dynamic foxRecord = foxData.GetRecord(pk); string company = foxRecord.Company; DateTime entered = foxRecord.Entered; This code looks simple and natural as it should be – heck you could write code like this in days long gone by in scripting languages like ASP classic for example. Compared to the Reflection code that previously was necessary to run similar code this is much easier to write, understand and maintain. For COM interop and Visual FoxPro operation dynamic type support in .NET 4.0 is a huge improvement and certainly makes it much easier to deal with FoxPro code that calls into .NET. Regardless of whether you’re using COM for calling Visual FoxPro objects from .NET (ASP.NET calling a COM component and getting a dynamic result returned) or whether FoxPro code is calling into a .NET COM component from a FoxPro desktop application. At one point or another FoxPro likely ends up passing complex dynamic data to .NET and for this the dynamic typing makes coding much cleaner and more readable without having to create custom Reflection wrappers. As a bonus the dynamic runtime that underlies the dynamic type is fairly efficient in terms of making Reflection calls especially if members are repeatedly accessed. © Rick Strahl, West Wind Technologies, 2005-2010Posted in COM  FoxPro  .NET  CSharp  

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  • On Her Majesty's Secret Source Code: .NET Reflector 7 Early Access Builds Now Available

    - by Bart Read
    Dodgy Bond references aside, I'm extremely happy to be able to tell you that we've just released our first .NET Reflector 7 Early Access build. We're going to make these available over the coming weeks via the main .NET Reflector download page at: http://reflector.red-gate.com/Download.aspx Please have a play and tell us what you think in the forum we've set up. Also, please let us know if you run into any problems in the same place. The new version so far comes with numerous decompilation improvements including (after 5 years!) support for iterator blocks - i.e., the yield statement first seen in .NET 2.0. We've also done a lot of work to solidify the support for .NET 4.0. Clive's written about the work he's done to support iterator blocks in much more detail here, along with the odd problem he's encountered when dealing with compiler generated code: http://www.simple-talk.com/community/blogs/clivet/96199.aspx. On the UI front we've started what will ultimately be a rewrite of the entire front-end, albeit broken into stages over two or three major releases. The most obvious addition at the moment is tabbed browsing, which you can see in Figure 1. Figure 1. .NET Reflector's new tabbed decompilation feature. Use CTRL+Click on any item in the assembly browser tree, or any link in the source code view, to open it in a new tab. This isn't by any means finished. I'll be tying up loose ends for the next few weeks, with a major focus on performance and resource usage. .NET Reflector has historically been a largely single-threaded application which has been fine up until now but, as you might expect, the addition of browser-style tabbing has pushed this approach somewhat beyond its limit. You can see this if you refresh the assemblies list by hitting F5. This shows up another problem: we really need to make Reflector remember everything you had open before you refreshed the list, rather than just the last item you viewed - I discovered that it's always done the latter, but it used to hide all panes apart from the treeview after a Refresh, including the decompiler/disassembler window. Ultimately I've got plans to add the whole VS/Chrome/Firefox style ability to drag a tab into the middle of nowhere to spawn a new window, but I need to be mindful of the add-ins, amongst other things, so it's possible that might slip to a 7.5 or 8.0 release. You'll also notice that .NET Reflector 7 now needs .NET 3.5 or later to run. We made this jump because we wanted to offer ourselves a much better chance of adding some really cool functionality to support newer technologies, such as Silverlight and Windows Phone 7. We've also taken the opportunity to start using WPF for UI development, which has frankly been a godsend. The learning curve is practically vertical but, I kid you not, it's just a far better world. Really. Stop using WinForms. Now. Why are you still using it? I had to go back and work on an old WinForms dialog for an hour or two yesterday and it really made me wince. The point is we'll be able to move the UI in some exciting new directions that will make Reflector easier to use whilst continuing to develop its functionality without (and this is key) cluttering the interface. The 3.5 language enhancements should also enable us to be much more productive over the longer term. I know most of you have .NET Fx 3.5 or 4.0 already but, if you do need to install a new version, I'd recommend you jump straight to 4.0 because, for one thing, it's faster, and if you're starting afresh there's really no reason not to. Despite the Fx version jump the Visual Studio add-in should still work fine in Visual Studio 2005, and obviously will continue to work in Visual Studio 2008 and 2010. If you do run into problems, again, please let us know here. As before, we continue to support every edition of Visual Studio exception the Express Editions. Speaking of Visual Studio, we've also been improving the add-in. You can now open and explore decompiled code for any referenced assembly in any project in your solution. Just right-click on the reference, then click Decompile and Explore on the context menu. Reflector will pop up a progress box whilst it decompiles your assembly (Figure 2) - you can move this out of the way whilst you carry on working. Figure 2. Decompilation progress. This isn't modal so you can just move it out of the way and carry on working. Once it's done you can explore your assembly in the Reflector treeview (Figure 3), also accessible via the .NET Reflector Explore Decompiled Assemblies main menu item. Double-click on any item to open decompiled source in the Visual Studio source code view. Use right-click and Go To Definition on the source view context menu to navigate through the code. Figure 3. Using the .NET Reflector treeview within Visual Studio. Double-click on any item to open decompiled source in the source code view. There are loads of other changes and fixes that have gone in, often under the hood, which I don't have room to talk about here, and plenty more to come over the next few weeks. I'll try to keep you abreast of new functionality and changes as they go in. There are a couple of smaller things worth mentioning now though. Firstly, we've reorganised the menus and toolbar in Reflector itself to more closely mirror what you might be used to in other applications. Secondly, we've tried to make some of the functionality more discoverable. For example, you can now switch decompilation target framework version directly from the toolbar - and the default is now .NET 4.0. I think that about covers it for the moment. As I said, please use the new version, and send us your feedback. Here's that download URL again: http://reflector.red-gate.com/Download.aspx. Until next time! Technorati Tags: .net reflector,7,early access,new version,decompilation,tabbing,visual studio,software development,.net,c#,vb

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  • Of C# Iterators and Performance

    - by James Michael Hare
    Some of you reading this will be wondering, "what is an iterator" and think I'm locked in the world of C++.  Nope, I'm talking C# iterators.  No, not enumerators, iterators.   So, for those of you who do not know what iterators are in C#, I will explain it in summary, and for those of you who know what iterators are but are curious of the performance impacts, I will explore that as well.   Iterators have been around for a bit now, and there are still a bunch of people who don't know what they are or what they do.  I don't know how many times at work I've had a code review on my code and have someone ask me, "what's that yield word do?"   Basically, this post came to me as I was writing some extension methods to extend IEnumerable<T> -- I'll post some of the fun ones in a later post.  Since I was filtering the resulting list down, I was using the standard C# iterator concept; but that got me wondering: what are the performance implications of using an iterator versus returning a new enumeration?   So, to begin, let's look at a couple of methods.  This is a new (albeit contrived) method called Every(...).  The goal of this method is to access and enumeration and return every nth item in the enumeration (including the first).  So Every(2) would return items 0, 2, 4, 6, etc.   Now, if you wanted to write this in the traditional way, you may come up with something like this:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         List<T> newList = new List<T>();         int count = 0;           foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 newList.Add(i);             }         }           return newList;     }     So basically this method takes any IEnumerable<T> and returns a new IEnumerable<T> that contains every nth item.  Pretty straight forward.   The problem?  Well, Every<T>(...) will construct a list containing every nth item whether or not you care.  What happens if you were searching this result for a certain item and find that item after five tries?  You would have generated the rest of the list for nothing.   Enter iterators.  This C# construct uses the yield keyword to effectively defer evaluation of the next item until it is asked for.  This can be very handy if the evaluation itself is expensive or if there's a fair chance you'll never want to fully evaluate a list.   We see this all the time in Linq, where many expressions are chained together to do complex processing on a list.  This would be very expensive if each of these expressions evaluated their entire possible result set on call.    Let's look at the same example function, this time using an iterator:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         int count = 0;         foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 yield return i;             }         }     }   Notice it does not create a new return value explicitly, the only evidence of a return is the "yield return" statement.  What this means is that when an item is requested from the enumeration, it will enter this method and evaluate until it either hits a yield return (in which case that item is returned) or until it exits the method or hits a yield break (in which case the iteration ends.   Behind the scenes, this is all done with a class that the CLR creates behind the scenes that keeps track of the state of the iteration, so that every time the next item is asked for, it finds that item and then updates the current position so it knows where to start at next time.   It doesn't seem like a big deal, does it?  But keep in mind the key point here: it only returns items as they are requested. Thus if there's a good chance you will only process a portion of the return list and/or if the evaluation of each item is expensive, an iterator may be of benefit.   This is especially true if you intend your methods to be chainable similar to the way Linq methods can be chained.    For example, perhaps you have a List<int> and you want to take every tenth one until you find one greater than 10.  We could write that as:       List<int> someList = new List<int>();         // fill list here         someList.Every(10).TakeWhile(i => i <= 10);     Now is the difference more apparent?  If we use the first form of Every that makes a copy of the list.  It's going to copy the entire list whether we will need those items or not, that can be costly!    With the iterator version, however, it will only take items from the list until it finds one that is > 10, at which point no further items in the list are evaluated.   So, sounds neat eh?  But what's the cost is what you're probably wondering.  So I ran some tests using the two forms of Every above on lists varying from 5 to 500,000 integers and tried various things.    Now, iteration isn't free.  If you are more likely than not to iterate the entire collection every time, iterator has some very slight overhead:   Copy vs Iterator on 100% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 5 Copy 5 5 5 Iterator 5 50 50 Copy 28 50 50 Iterator 27 500 500 Copy 227 500 500 Iterator 247 5000 5000 Copy 2266 5000 5000 Iterator 2444 50,000 50,000 Copy 24,443 50,000 50,000 Iterator 24,719 500,000 500,000 Copy 250,024 500,000 500,000 Iterator 251,521   Notice that when iterating over the entire produced list, the times for the iterator are a little better for smaller lists, then getting just a slight bit worse for larger lists.  In reality, given the number of items and iterations, the result is near negligible, but just to show that iterators come at a price.  However, it should also be noted that the form of Every that returns a copy will have a left-over collection to garbage collect.   However, if we only partially evaluate less and less through the list, the savings start to show and make it well worth the overhead.  Let's look at what happens if you stop looking after 80% of the list:   Copy vs Iterator on 80% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 4 Copy 5 5 4 Iterator 5 50 40 Copy 27 50 40 Iterator 23 500 400 Copy 215 500 400 Iterator 200 5000 4000 Copy 2099 5000 4000 Iterator 1962 50,000 40,000 Copy 22,385 50,000 40,000 Iterator 19,599 500,000 400,000 Copy 236,427 500,000 400,000 Iterator 196,010       Notice that the iterator form is now operating quite a bit faster.  But the savings really add up if you stop on average at 50% (which most searches would typically do):     Copy vs Iterator on 50% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 2 Copy 5 5 2 Iterator 4 50 25 Copy 25 50 25 Iterator 16 500 250 Copy 188 500 250 Iterator 126 5000 2500 Copy 1854 5000 2500 Iterator 1226 50,000 25,000 Copy 19,839 50,000 25,000 Iterator 12,233 500,000 250,000 Copy 208,667 500,000 250,000 Iterator 122,336   Now we see that if we only expect to go on average 50% into the results, we tend to shave off around 40% of the time.  And this is only for one level deep.  If we are using this in a chain of query expressions it only adds to the savings.   So my recommendation?  If you have a resonable expectation that someone may only want to partially consume your enumerable result, I would always tend to favor an iterator.  The cost if they iterate the whole thing does not add much at all -- and if they consume only partially, you reap some really good performance gains.   Next time I'll discuss some of my favorite extensions I've created to make development life a little easier and maintainability a little better.

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  • C#: LINQ vs foreach - Round 1.

    - by James Michael Hare
    So I was reading Peter Kellner's blog entry on Resharper 5.0 and its LINQ refactoring and thought that was very cool.  But that raised a point I had always been curious about in my head -- which is a better choice: manual foreach loops or LINQ?    The answer is not really clear-cut.  There are two sides to any code cost arguments: performance and maintainability.  The first of these is obvious and quantifiable.  Given any two pieces of code that perform the same function, you can run them side-by-side and see which piece of code performs better.   Unfortunately, this is not always a good measure.  Well written assembly language outperforms well written C++ code, but you lose a lot in maintainability which creates a big techncial debt load that is hard to offset as the application ages.  In contrast, higher level constructs make the code more brief and easier to understand, hence reducing technical cost.   Now, obviously in this case we're not talking two separate languages, we're comparing doing something manually in the language versus using a higher-order set of IEnumerable extensions that are in the System.Linq library.   Well, before we discuss any further, let's look at some sample code and the numbers.  First, let's take a look at the for loop and the LINQ expression.  This is just a simple find comparison:       // find implemented via LINQ     public static bool FindViaLinq(IEnumerable<int> list, int target)     {         return list.Any(item => item == target);     }         // find implemented via standard iteration     public static bool FindViaIteration(IEnumerable<int> list, int target)     {         foreach (var i in list)         {             if (i == target)             {                 return true;             }         }           return false;     }   Okay, looking at this from a maintainability point of view, the Linq expression is definitely more concise (8 lines down to 1) and is very readable in intention.  You don't have to actually analyze the behavior of the loop to determine what it's doing.   So let's take a look at performance metrics from 100,000 iterations of these methods on a List<int> of varying sizes filled with random data.  For this test, we fill a target array with 100,000 random integers and then run the exact same pseudo-random targets through both searches.                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     Any         10       26          0.00046             30.00%     Iteration   10       20          0.00023             -     Any         100      116         0.00201             18.37%     Iteration   100      98          0.00118             -     Any         1000     1058        0.01853             16.78%     Iteration   1000     906         0.01155             -     Any         10,000   10,383      0.18189             17.41%     Iteration   10,000   8843        0.11362             -     Any         100,000  104,004     1.8297              18.27%     Iteration   100,000  87,941      1.13163             -   The LINQ expression is running about 17% slower for average size collections and worse for smaller collections.  Presumably, this is due to the overhead of the state machine used to track the iterators for the yield returns in the LINQ expressions, which seems about right in a tight loop such as this.   So what about other LINQ expressions?  After all, Any() is one of the more trivial ones.  I decided to try the TakeWhile() algorithm using a Count() to get the position stopped like the sample Pete was using in his blog that Resharper refactored for him into LINQ:       // Linq form     public static int GetTargetPosition1(IEnumerable<int> list, int target)     {         return list.TakeWhile(item => item != target).Count();     }       // traditionally iterative form     public static int GetTargetPosition2(IEnumerable<int> list, int target)     {         int count = 0;           foreach (var i in list)         {             if(i == target)             {                 break;             }               ++count;         }           return count;     }   Once again, the LINQ expression is much shorter, easier to read, and should be easier to maintain over time, reducing the cost of technical debt.  So I ran these through the same test data:                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile   10       41          0.00041             128%     Iteration   10       18          0.00018             -     TakeWhile   100      171         0.00171             88%     Iteration   100      91          0.00091             -     TakeWhile   1000     1604        0.01604             94%     Iteration   1000     825         0.00825             -     TakeWhile   10,000   15765       0.15765             92%     Iteration   10,000   8204        0.08204             -     TakeWhile   100,000  156950      1.5695              92%     Iteration   100,000  81635       0.81635             -     Wow!  I expected some overhead due to the state machines iterators produce, but 90% slower?  That seems a little heavy to me.  So then I thought, well, what if TakeWhile() is not the right tool for the job?  The problem is TakeWhile returns each item for processing using yield return, whereas our for-loop really doesn't care about the item beyond using it as a stop condition to evaluate. So what if that back and forth with the iterator state machine is the problem?  Well, we can quickly create an (albeit ugly) lambda that uses the Any() along with a count in a closure (if a LINQ guru knows a better way PLEASE let me know!), after all , this is more consistent with what we're trying to do, we're trying to find the first occurence of an item and halt once we find it, we just happen to be counting on the way.  This mostly matches Any().       // a new method that uses linq but evaluates the count in a closure.     public static int TakeWhileViaLinq2(IEnumerable<int> list, int target)     {         int count = 0;         list.Any(item =>             {                 if(item == target)                 {                     return true;                 }                   ++count;                 return false;             });         return count;     }     Now how does this one compare?                         List<T> On 100,000 Iterations     Method         Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile      10       41          0.00041             128%     Any w/Closure  10       23          0.00023             28%     Iteration      10       18          0.00018             -     TakeWhile      100      171         0.00171             88%     Any w/Closure  100      116         0.00116             27%     Iteration      100      91          0.00091             -     TakeWhile      1000     1604        0.01604             94%     Any w/Closure  1000     1101        0.01101             33%     Iteration      1000     825         0.00825             -     TakeWhile      10,000   15765       0.15765             92%     Any w/Closure  10,000   10802       0.10802             32%     Iteration      10,000   8204        0.08204             -     TakeWhile      100,000  156950      1.5695              92%     Any w/Closure  100,000  108378      1.08378             33%     Iteration      100,000  81635       0.81635             -     Much better!  It seems that the overhead of TakeAny() returning each item and updating the state in the state machine is drastically reduced by using Any() since Any() iterates forward until it finds the value we're looking for -- for the task we're attempting to do.   So the lesson there is, make sure when you use a LINQ expression you're choosing the best expression for the job, because if you're doing more work than you really need, you'll have a slower algorithm.  But this is true of any choice of algorithm or collection in general.     Even with the Any() with the count in the closure it is still about 30% slower, but let's consider that angle carefully.  For a list of 100,000 items, it was the difference between 1.01 ms and 0.82 ms roughly in a List<T>.  That's really not that bad at all in the grand scheme of things.  Even running at 90% slower with TakeWhile(), for the vast majority of my projects, an extra millisecond to save potential errors in the long term and improve maintainability is a small price to pay.  And if your typical list is 1000 items or less we're talking only microseconds worth of difference.   It's like they say: 90% of your performance bottlenecks are in 2% of your code, so over-optimizing almost never pays off.  So personally, I'll take the LINQ expression wherever I can because they will be easier to read and maintain (thus reducing technical debt) and I can rely on Microsoft's development to have coded and unit tested those algorithm fully for me instead of relying on a developer to code the loop logic correctly.   If something's 90% slower, yes, it's worth keeping in mind, but it's really not until you start get magnitudes-of-order slower (10x, 100x, 1000x) that alarm bells should really go off.  And if I ever do need that last millisecond of performance?  Well then I'll optimize JUST THAT problem spot.  To me it's worth it for the readability, speed-to-market, and maintainability.

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  • More Fun With Math

    - by PointsToShare
    More Fun with Math   The runaway student – three different ways of solving one problem Here is a problem I read in a Russian site: A student is running away. He is moving at 1 mph. Pursuing him are a lion, a tiger and his math teacher. The lion is 40 miles behind and moving at 6 mph. The tiger is 28 miles behind and moving at 4 mph. His math teacher is 30 miles behind and moving at 5 mph. Who will catch him first? Analysis Obviously we have a set of three problems. They are all basically the same, but the details are different. The problems are of the same class. Here is a little excursion into computer science. One of the things we strive to do is to create solutions for classes of problems rather than individual problems. In your daily routine, you call it re-usability. Not all classes of problems have such solutions. If a class has a general (re-usable) solution, it is called computable. Otherwise it is unsolvable. Within unsolvable classes, we may still solve individual (some but not all) problems, albeit with different approaches to each. Luckily the vast majority of our daily problems are computable, and the 3 problems of our runaway student belong to a computable class. So, let’s solve for the catch-up time by the math teacher, after all she is the most frightening. She might even make the poor runaway solve this very problem – perish the thought! Method 1 – numerical analysis. At 30 miles and 5 mph, it’ll take her 6 hours to come to where the student was to begin with. But by then the student has advanced by 6 miles. 6 miles require 6/5 hours, but by then the student advanced by another 6/5 of a mile as well. And so on and so forth. So what are we to do? One way is to write code and iterate it until we have solved it. But this is an infinite process so we’ll end up with an infinite loop. So what to do? We’ll use the principles of numerical analysis. Any calculator – your computer included – has a limited number of digits. A double floating point number is good for about 14 digits. Nothing can be computed at a greater accuracy than that. This means that we will not iterate ad infinidum, but rather to the point where 2 consecutive iterations yield the same result. When we do financial computations, we don’t even have to go that far. We stop at the 10th of a penny.  It behooves us here to stop at a 10th of a second (100 milliseconds) and this will how we will avoid an infinite loop. Interestingly this alludes to the Zeno paradoxes of motion – in particular “Achilles and the Tortoise”. Zeno says exactly the same. To catch the tortoise, Achilles must always first come to where the tortoise was, but the tortoise keeps moving – hence Achilles will never catch the tortoise and our math teacher (or lion, or tiger) will never catch the student, or the policeman the thief. Here is my resolution to the paradox. The distance and time in each step are smaller and smaller, so the student will be caught. The only thing that is infinite is the iterative solution. The race is a convergent geometric process so the steps are diminishing, but each step in the solution takes the same amount of effort and time so with an infinite number of steps, we’ll spend an eternity solving it.  This BTW is an original thought that I have never seen before. But I digress. Let’s simply write the code to solve the problem. To make sure that it runs everywhere, I’ll do it in JavaScript. function LongCatchUpTime(D, PV, FV) // D is Distance; PV is Pursuers Velocity; FV is Fugitive’ Velocity {     var t = 0;     var T = 0;     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     t = d / pv;     while (t > 0.000001) //a 10th of a second is 1/36,000 of an hour, I used 1/100,000     {         T = T + t;         d = t * fv;         t = d / pv;     }     return T;     } By and large, the higher the Pursuer’s velocity relative to the fugitive, the faster the calculation. Solving this with the 10th of a second limit yields: 7.499999232000001 Method 2 – Geometric Series. Each step in the iteration above is smaller than the next. As you saw, we stopped iterating when the last step was small enough, small enough not to really matter.  When we have a sequence of numbers in which the ratio of each number to its predecessor is fixed we call the sequence geometric. When we are looking at the sum of sequence, we call the sequence of sums series.  Now let’s look at our student and teacher. The teacher runs 5 times faster than the student, so with each iteration the distance between them shrinks to a fifth of what it was before. This is a fixed ratio so we deal with a geometric series.  We normally designate this ratio as q and when q is less than 1 (0 < q < 1) the sum of  + … +  is  – 1) / (q – 1). When q is less than 1, it is easier to use ) / (1 - q). Now, the steps are 6 hours then 6/5 hours then 6/5*5 and so on, so q = 1/5. And the whole series is multiplied by 6. Also because q is less than 1 , 1/  diminishes to 0. So the sum is just  / (1 - q). or 1/ (1 – 1/5) = 1 / (4/5) = 5/4. This times 6 yields 7.5 hours. We can now continue with some algebra and take it back to a simpler formula. This is arduous and I am not going to do it here. Instead let’s do some simpler algebra. Method 3 – Simple Algebra. If the time to capture the fugitive is T and the fugitive travels at 1 mph, then by the time the pursuer catches him he travelled additional T miles. Time is distance divided by speed, so…. (D + T)/V = T  thus D + T = VT  and D = VT – T = (V – 1)T  and T = D/(V – 1) This “strangely” coincides with the solution we just got from the geometric sequence. This is simpler ad faster. Here is the corresponding code. function ShortCatchUpTime(D, PV, FV) {     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     return d / (pv - fv); } The code above, for both the iterative solution and the algebraic solution are actually for a larger class of problems.  In our original problem the student’s velocity (speed) is 1 mph. In the code it may be anything as long as it is less than the pursuer’s velocity. As long as PV > FV, the pursuer will catch up. Here is the really general formula: T = D / (PV – FV) Finally, let’s run the program for each of the pursuers.  It could not be worse. I know he’d rather be eaten alive than suffering through yet another math lesson. See the code run? Select  “Catch Up Time” in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. That’s All Folks

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  • DevConnections Spring 2010 Speaker Evals and Tips

    As a conference speaker, I always look forward to hearing from attendees whether they felt my sessions were valuable and worth their time.  Its always gratifying  get a high score, but of course its the (preferably constructive) criticism thats key to continued improvement.  Im by no means the best technical presenter around, and Im always looking for ways to improve. Ive recently spoken at a few events, including TechEd and an Ohio event called Stir Trek.  DevConnections was actually back in April, but theyre just getting their final evals out to speakers.  TechEd, of course, does online evals so immediately after your talks you can see what people think.  Ill try and post my TechEd evals in the next week or so. I gave 3 talks at DevConnections Spring 2010 / VS2010 Launch which I discussed in this previous blog post.  In this follow-up, Im just going to share some eval info and my thoughts on it, albeit a couple of months later. Pragmatic ASP.NET Tips, Tricks, and Tools Evals Turned In: 27 Overall Eval: 3.74 Average Score: 3.47 89% found the technical level Just Right.  7.4% thought it was too basic (3.6% did not respond).  Since nobody thought the content was Too complex, I could perhaps have added some more complex material, but having about 90% say its Just Right is pretty good. 92% said at least 50% of the material was new to them.  36% said 75% or more was new.  Thats also pretty good, I think. 77.8% can use the information immediately; 15% can use it within 2-6 months (7.2 % no response). Overall 78% rated the session Excellent, 18% Good, 4% Fair. All comments (9): Steve did a great job Excellent session! It was good. Im now super excited to attend Steves other sessions later today.  Very useful. One of the best speakers here.  Bring him back to future conferences please. Continue to have this session with new and old stuff.  I always find something I did not know about. Excellent!  This was the best session Ive seen all week. Did not increase font on all pages could not see. For Steve to have had more sessions. Note to self make the fonts bigger across the board.  Otherwise, this is all good for my ego. :)  This is always a very popular session and one I really enjoy giving.  Tips and Tricks talks are pretty easy because you dont have to go in depth with any particular thing, and theyre almost always with existing technology so youre not dealing with betas, lack of documentation, and other issues.  Its an easy session to do well, in my experience, and one which I think attendees definitely appreciate.   Whats New in ASP.NET MVC 2 Evals Turned In: 23 Overall Eval: 3.77 Average Score: 3.47 (wow, I cant believe I scored better on this talk than the tips and tricks talk, which Ive given many times and was more excited about) 96% found the technical level Just Right.  90% found 50% or more of the material to be new.  43% can use the info immediately, and another 43% can use it within 2-6 months I guess that speaks to adoption rates of MVC 2 among my attendees Overall 74% said the session was Excellent, 22% Good.  4% No Response. All Comments (6): Great job, thank you. Great speaker! Really good, a little lost in the code at some points, but great information. Speaker needs to repeat questions from audience for everyone to hear. Exceeded my expectations. Great speaker, very informative. I really do try to religiously repeat questions from the audience for everyone to hear, but obviously I didnt do it 100% of the time.  Note to self remember to repeat questions.  That and making fonts big are really basic speaker best practices, which just goes to prove that fundamentals are always something that can be perfected.   SOLIDify Your ASP.NET MVC 2 Application Evals Turned In: 8 (!) Overall Eval: 3.63 Average Score: 3.47 As I recall this was one of the last talks of the day / show, which might account for the low number of evals turned in.  I dont recall speaking to an empty room for this talk, although it certainly wasnt as crowded as the tips and tricks talk. 100% found the technical level Just Right.  100% found at least half the material new.  62.5% can use it at once and 37.5% within 2-6 months.  62.5% rated the session Excellent overall; 37.5% Good.  Im thinking there were 5 evals with all 4s checked and 3 with all 3s checked (4 = Excellent, 3 = Good) All Comments (3): This covered many topics Ive read about recently, and it helped reinforce them. It was a nice overview of the solid principle, but I thought there might be specifics for MVC2.  I am glad there is not. Move a little slower. Ok, so another fundamental dont go too fast.  Looks like I got one fundamental tip from the comments of each talk. My Take-Aways Remember the fundamentals.  Its worth going through a checklist prior to presenting to make sure these things are fresh in your mind.  Increase all font sizes.  Repeat all questions from audience members without microphones (this is also a great way to stall for time, btw).  Resist the urge to move too quickly especially if youre nervous or short of time.  Writing this up in a blog post also further reinforces these fundamentals for me, which is one of the main reasons why I do it I retain things better when I write them, and even moreso when I write them for public consumption since I have to really think about what Im saying.  And maybe a few of you find this interesting or helpful, which is a bonus. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Why are my USB 2.0 devices hanging Windows XP?

    - by BenAlabaster
    Background on the machine I'm having a problem with: The machine was inherited and appears to be circa 2003 (there's a date stamp on the power supply which leads me to this conclusion). I've got it set up as a Skype terminal for my 2 year old to keep in touch with her grandparents and other members of the family - which everyone loves. It has a DFI CM33-TL/G ATX (identified using SiSoft Sandra) motherboard hosting an Intel Celeron 1.3GHz CPU, 768Mb PC133 SDRAM, a D-LINK WDA-2320 54G Wi-Fi network card and a generic USB 2.0 expansion board based on the NEC uPD720102 chipset containing 3 external and 1 internal USB sockets. It's also hosting a 1.44Mb floppy drive on FDD0, a new 80Gb Western Digital hard drive running as master on IDE0 and a Panasonic DVD+/-RW running as master on IDE1. All this is sitting in a slimline case running off a Macron Power MPT-135 135W Flex power supply. The motherboard is running a version of Award BIOS 05/24/2002-601T-686B-6A6LID4AC-00. Could this be updated? If so, from where? I've raked through the manufacturer's website but can't find any hint of downloads for either drivers or BIOS updates. The hard disk is freshly formatted and built with Windows XP Professional/Service Pack 3 and is up to date with all current patches. In addition to Windows XP, the only other software it's running is Skype 4.1 (4.2 hangs the whole machine as soon as it starts up, requiring a hard boot to recover). It's got a Daytek MV150 15" touch screen hooked up to the on board VGA and COM1 sockets with the most current drivers from the Daytek website and the most current version of ELO-Touchsystems drivers for the touch component. The webcam is a Logitech Webcam C200 with the latest drivers from the Logitech website. The problem: If I hook any devices to the USB 2.0 sockets, it hangs the whole machine and I have to hard boot it to get it back up. If I have any devices attached to the USB 2.0 sockets when I boot up, it hangs before Windows gets to the login prompt and I have to hard boot it to recover. Workarounds found: I can plug the same devices into the on board USB 1.0 sockets and everything works fine, albeit at reduced performance. I've tried 3 different kinds of USB thumb drives, 3 different makes/models of webcams and my iPhone all with the same effect. They're recognized and don't hang the machine when I hook them to the USB 1.0 but if I hook them to the USB 2.0 ports, the machine hangs within a couple of seconds of recognizing the devices were connected. Attempted solutions: I've seen suggestions that this could be a power problem - that the PSU just doesn't have the wattage to drive these ports. While I'm doubtful this is the problem [after all the motherboard has the same standard connector regardless of the PSU wattage], I tried disabling all the on board devices that I'm not using - on board LAN, the second COM port, the AGP connector etc. through the BIOS in what I'm sure is a futile attempt to reduce the power consumption... I also modified the ACPI and power management settings. It didn't have any noticeable affect, although it didn't do any harm either. Could the wattage of the PSU really cause this problem? If it can, is there anything I need to be aware of when replacing it or do I just need to make sure it's got a higher wattage than the current one? My interpretation was that the wattage only affected the number of drives you could hook up to the power connectors, is that right? I've installed the USB card in another machine and it works without issue, so it's not a problem with the USB card itself, and Windows says the card is installed and working correctly... right up until I connect a device to it. The only thing I haven't done which I only just thought of while writing this essay is trying the USB 2.0 card in a different PCI slot, or re-ordering the wi-fi and USB cards in the slots... although I'm not sure if this will make any difference - does anyone have any experience that would suggest this might work? Other thoughts/questions: Perhaps this is an incompatibility between the USB 2.0 card and the BIOS, would re-flashing the BIOS with a newer version help? Do I need to be able to identify the manufacturer of the motherboard in order to be able to find a BIOS edition specific for this motherboard or will any version of Award BIOS function in its place? Question: Does anyone have any ideas that could help me get my USB 2.0 devices hooked up to this machine?

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  • Why are my USB 2.0 devices hanging Windows XP?

    - by BenAlabaster
    Background on the machine I'm having a problem with: The machine was inherited and appears to be circa 2003 (there's a date stamp on the power supply which leads me to this conclusion). I've got it set up as a Skype terminal for my 2 year old to keep in touch with her grandparents and other members of the family - which everyone loves. It has a generic ATX motherboard with no identifying markings other than one stamp that says "Rev.B". CPU-Z identifies the motherboard model as VT8601 but doesn't provide me with any manufacturer name. On board it has 1 x 10/100 LAN, 2 x USB 1.0, VGA, PS/2 for KB and mouse, parallel port, 2 x serial ports, 2 x IDE, 1 x floppy, 2 x SDRAM slots, 1 x CPU housing that is seating a 1.3GHz Intel Celeron CPU, 3 x PCI, 1 x AGP - although you can only use 2 of the PCI slots if you use the AGP slot due to the physical layout of the board. It's got 768Mb PC133 SDRAM - 1 x 512Mb & 1 x 256Mb installed as well as a D-LINK WDA-2320 54G Wi-Fi network card and a generic USB 2.0 expansion board containing 3 x external + 1 x internal USB connectors - it has a NEC uPD720102 chipset. It has a DVD+/-RW running as master on IDE1 and a 1.44Mb 3.5" floppy drive connected to the floppy connector. It has an 80Gb Western Digital hard drive running as master on IDE0. All this is sitting in a slimline case. I don't know the wattage of the PSU, but can post this later if this proves to be helpful. The motherboard is running a version of Award BIOS for which I don't have the version number to hand but can again post this later if it would be helpful. The hard disk is freshly formatted and built with Windows XP Professional/Service Pack 3 and is up to date with all current patches. In addition to Windows XP, the only other software it's running is Skype 4.1 (4.2 hangs the whole machine as soon as it starts up, requiring a hard boot to recover). It's got a Daytek MV150 15" touch screen hooked up to the on board VGA and COM1 sockets with the most current drivers from the Daytek website and the most current version of ELO-Touchsystems drivers for the touch component. The webcam is a Logitech Webcam C200 with the latest drivers from the Logitech website. The problem: If I hook any devices to the USB 2.0 sockets, it hangs the whole machine and I have to hard boot it to get it back up. If I have any devices attached to the USB 2.0 sockets when I boot up, it hangs before Windows gets to the login prompt and I have to hard boot it to recover. Workarounds found: I can plug the same devices into the on board USB 1.0 sockets and everything works fine, albeit at reduced performance. I've tried 3 different kinds of USB thumb drives, 3 different makes/models of webcams and my iPhone all with the same effect. They're recognized and don't hang the machine when I hook them to the USB 1.0 but if I hook them to the USB 2.0 ports, the machine hangs within a couple of seconds of recognizing the devices were connected. Attempted solutions: I've seen suggestions that this could be a power problem - that the PSU just doesn't have the wattage to drive these ports. While I'm doubtful this is the problem [after all the motherboard has the same standard connector regardless of the PSU wattage], I tried disabling all the on board devices that I'm not using - on board LAN, the second COM port, the AGP connector etc. through the BIOS in what I'm sure is a futile attempt to reduce the power consumption... I also modified the ACPI and power management settings. It didn't have any noticeable affect, although it didn't do any harm either. Could the wattage of the PSU really cause this problem? If it can, is there anything I need to be aware of when replacing it or do I just need to make sure it's got a higher wattage than the current one? My interpretation was that the wattage only affected the number of drives you could hook up to the power connectors, is that right? I've installed the USB card in another machine and it works without issue, so it's not a problem with the USB card itself, and Windows says the card is installed and working correctly... right up until I connect a device to it. The only thing I haven't done which I only just thought of while writing this essay is trying the USB 2.0 card in a different PCI slot, or re-ordering the wi-fi and USB cards in the slots... although I'm not sure if this will make any difference - does anyone have any experience that would suggest this might work? Other thoughts/questions: Perhaps this is an incompatibility between the USB 2.0 card and the BIOS, would re-flashing the BIOS with a newer version help? Do I need to be able to identify the manufacturer of the motherboard in order to be able to find a BIOS edition specific for this motherboard or will any version of Award BIOS function in its place? Question: Does anyone have any ideas that could help me get my USB 2.0 devices hooked up to this machine? Edit: Updated the USB 2.0 info with reference to actual card - http://www.xpcgear.com/lpnec4u.html

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  • Why are my USB 2.0 devices crashing Windows XP?

    - by BenAlabaster
    Background on the machine I'm having a problem with: The machine was inherited and appears to be circa 2003 (there's a date stamp on the power supply which leads me to this conclusion). I've got it set up as a Skype terminal for my 2 year old to keep in touch with her grandparents and other members of the family - which everyone loves. It has a generic ATX motherboard with no identifying markings other than one stamp that says "Rev.B". CPU-Z identifies the motherboard model as VT8601 but doesn't provide me with any manufacturer name. On board it has 1 x 10/100 LAN, 2 x USB 1.0, VGA, PS/2 for KB and mouse, parallel port, 2 x serial ports, 2 x IDE, 1 x floppy, 2 x SDRAM slots, 1 x CPU housing that is seating a 1.3GHz Intel Celeron CPU, 3 x PCI, 1 x AGP - although you can only use 2 of the PCI slots if you use the AGP slot due to the physical layout of the board. It's got 768Mb PC133 SDRAM - 1 x 512Mb & 1 x 256Mb installed as well as a D-LINK WDA-2320 54G Wi-Fi network card and a generic USB 2.0 expansion board containing 3 x external + 1 x internal USB connectors. It has a DVD+/-RW running as master on IDE1 and a 1.44Mb 3.5" floppy drive connected to the floppy connector. It has an 80Gb Western Digital hard drive running as master on IDE0. All this is sitting in a slimline case. I don't know the wattage of the PSU, but can post this later if this proves to be helpful. The motherboard is running a version of Award BIOS for which I don't have the version number to hand but can again post this later if it would be helpful. The hard disk is freshly formatted and built with Windows XP Professional/Service Pack 3 and is up to date with all current patches. In addition to Windows XP, the only other software it's running is Skype 4.1 (4.2 hangs the whole machine as soon as it starts up, requiring a hard boot to recover). It's got a Daytek MV150 15" touch screen hooked up to the on board VGA and COM1 sockets with the most current drivers from the Daytek website and the most current version of ELO-Touchsystems drivers for the touch component. The webcam is a Logitech Webcam C200 with the latest drivers from the Logitech website. The problem: If I hook any devices to the USB 2.0 sockets, it hangs the whole machine and I have to hard boot it to get it back up. If I have any devices attached to the USB 2.0 sockets when I boot up, it hangs before Windows gets to the login prompt and I have to hard boot it to recover. Workarounds found: I can plug the same devices into the on board USB 1.0 sockets and everything works fine, albeit at reduced performance. I've tried 3 different kinds of USB thumb drives, 3 different makes/models of webcams and my iPhone all with the same effect. They're recognized and don't hang the machine when I hook them to the USB 1.0 but if I hook them to the USB 2.0 ports, the machine hangs within a couple of seconds of recognizing the devices were connected. Attempted solutions: I've seen suggestions that this could be a power problem - that the PSU just doesn't have the wattage to drive these ports. While I'm doubtful this is the problem [after all the motherboard has the same standard connector regardless of the PSU wattage], I tried disabling all the on board devices that I'm not using - on board LAN, the second COM port, the AGP connector etc. through the BIOS in what I'm sure is a futile attempt to reduce the power consumption... I also modified the ACPI and power management settings. It didn't have any noticeable affect, although it didn't do any harm either. Could the wattage of the PSU really cause this problem? If it can, is there anything I need to be aware of when replacing it or do I just need to make sure it's got a higher wattage than the current one? My interpretation was that the wattage only affected the number of drives you could hook up to the power connectors, is that right? I've installed the USB card in another machine and it works without issue, so it's not a problem with the USB card itself, and Windows says the card is installed and working correctly... right up until I connect a device to it. The only thing I haven't done which I only just thought of while writing this essay is trying the USB 2.0 card in a different PCI slot, or re-ordering the wi-fi and USB cards in the slots... although I'm not sure if this will make any difference - does anyone have any experience that would suggest this might work? Other thoughts/questions: Perhaps this is an incompatibility between the USB 2.0 card and the BIOS, would re-flashing the BIOS with a newer version help? Do I need to be able to identify the manufacturer of the motherboard in order to be able to find a BIOS edition specific for this motherboard or will any version of Award BIOS function in its place? Question: Does anyone have any ideas that could help me get my USB 2.0 devices hooked up to this machine?

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  • Isn't it better to use a single try catch instead of tons of TryParsing and other error handling sometimes?

    - by Ryan Peschel
    I know people say it's bad to use exceptions for flow control and to only use exceptions for exceptional situations, but sometimes isn't it just cleaner and more elegant to wrap the entire block in a try-catch? For example, let's say I have a dialog window with a TextBox where the user can type input in to be parsed in a key-value sort of manner. This situation is not as contrived as you might think because I've inherited code that has to handle this exact situation (albeit not with farm animals). Consider this wall of code: class Animals { public int catA, catB; public float dogA, dogB; public int mouseA, mouseB, mouseC; public double cow; } class Program { static void Main(string[] args) { string input = "Sets all the farm animals CAT 3 5 DOG 21.3 5.23 MOUSE 1 0 1 COW 12.25"; string[] splitInput = input.Split(' '); string[] animals = { "CAT", "DOG", "MOUSE", "COW", "CHICKEN", "GOOSE", "HEN", "BUNNY" }; Animals animal = new Animals(); for (int i = 0; i < splitInput.Length; i++) { string token = splitInput[i]; if (animals.Contains(token)) { switch (token) { case "CAT": animal.catA = int.Parse(splitInput[i + 1]); animal.catB = int.Parse(splitInput[i + 2]); break; case "DOG": animal.dogA = float.Parse(splitInput[i + 1]); animal.dogB = float.Parse(splitInput[i + 2]); break; case "MOUSE": animal.mouseA = int.Parse(splitInput[i + 1]); animal.mouseB = int.Parse(splitInput[i + 2]); animal.mouseC = int.Parse(splitInput[i + 3]); break; case "COW": animal.cow = double.Parse(splitInput[i + 1]); break; } } } } } In actuality there are a lot more farm animals and more handling than that. A lot of things can go wrong though. The user could enter in the wrong number of parameters. The user can enter the input in an incorrect format. The user could specify numbers too large or too small for the data type to handle. All these different errors could be handled without exceptions through the use of TryParse, checking how many parameters the user tried to use for a specific animal, checking if the parameter is too large or too small for the data type (because TryParse just returns 0), but every one should result in the same thing: A MessageBox appearing telling the user that the inputted data is invalid and to fix it. My boss doesn't want different message boxes for different errors. So instead of doing all that, why not just wrap the block in a try-catch and in the catch statement just display that error message box and let the user try again? Maybe this isn't the best example but think of any other scenario where there would otherwise be tons of error handling that could be substituted for a single try-catch. Is that not the better solution?

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  • Where are the function address literals in c++?

    - by academicRobot
    First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). <UPDATE> After some reading with help from answer by Chris Dodd, what I'm looking for is literal function addresses as template parameters. Chris' answer indicates how to do this for standard functions, but how can the addresses of member functions be used as template parameters? Since the standard prohibits non-static member function addresses as template parameters (c++03 14.3.2.3), I suspect the work around is quite complicated. Any ideas for a workaround? Below the original form of the question is left as is for context. </UPDATE> The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one. Edit The intent of this question is not to implement delegates, rather to identify a pattern that will embed a conventional function call, (in immediate mode) directly into third party code, possibly a template.

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  • Retreiving multiple rows from a loop-created form... Stuck.

    - by hangston
    Hi All, Let me start by saying that I'm new to PHP, but I'm here to learn and would really appreciate your help. I use the following code to pull in data and create a form. This creates up to 40 lines for a user to fill out. Each line consists of the same information: Description, Amount, and Frequency. The remainder of the information needed is generated by the database. (See hidden fields) <?php $row = 0; do { $optid = $row_options['option_id']; echo "<tr>\n\t<td>" . htmlentities($row_options['option']) . "</td>\n"; echo "\t<td>" . "<input name='description' type='text' size='40' maxlength='120'/>" . "</td>\n"; echo "\t<td>" . "<input name='option_id' type='hidden' value='$optid' />$<input name='amount' type='text' size='10' maxlength='7'/>" . "</td>\n"; echo "\t<td>" . "<select name='assisted_frequency'> <option value='Monthly'>Monthly</option> <option value='Weekly'>Weekly</option> <option value='Daily'>Daily</option> <option value='Hourly'>Hourly</option> <option value='One-Time'>One-Time</option> </select>" . "</td>\n</tr>\n"; $array[$row] = array( $arraydesc[$row] = $_POST['description'], $arrayamto[$row] = $_POST['amount'], $arrayoptid[$row] = $optid, $arrayfreq[$row] = $_POST['frequency'], ); $row ++; } while ($row_options = mysql_fetch_assoc($options)); $counter = $row - 1; ?> I'm having troubles retrieving the information that the user inputs. My intent is to loop through each row after the user has input their information, then upload the mix of my database information and the user's information into another database. For example, the user would see, albeit prettier: form1 Option 1: description [input box] amount [input box] frequency [option box] Option 2: description [input box] amount [input box] frequency [option box] Option 3: description [input box] amount [input box] frequency [option box] Option 4: description [input box] amount [input box] frequency [option box] submit Upon submitting the form above, I'm using a query similar to the following to input the data into the database: for($row=0; $row<=$counter; $row++){ $insertSQL2 = sprintf("INSERT INTO table (option_id, amount, description, frequency) VALUES (%s, %s, %s, %s)", GetSQLValueString($arrayoptid[$row], "int"), GetSQLValueString($arrayamto[$row], "int"), GetSQLValueString($arraydesc[$row], "text"), GetSQLValueString($arrayfreq[$row], "text")); // code to submit query } I've tried for, foreach, arrays (what feels like the everything I know) to post each row (row by row) into the database. I either get just the last row of data, or no data at all. I also worry that the [$row] technique is adding characters to my data. What is the best way to retrieve each row of the user's inputs, then upload this data (row by row) into the database? Also, I would really appreciate your suggestions for improving my coding technique and the approach I'm taking. Thank you, Hangston

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  • Calculate the number of ways to roll a certain number

    - by helloworld
    I'm a high school Computer Science student, and today I was given a problem to: Program Description: There is a belief among dice players that in throwing three dice a ten is easier to get than a nine. Can you write a program that proves or disproves this belief? Have the computer compute all the possible ways three dice can be thrown: 1 + 1 + 1, 1 + 1 + 2, 1 + 1 + 3, etc. Add up each of these possibilities and see how many give nine as the result and how many give ten. If more give ten, then the belief is proven. I quickly worked out a brute force solution, as such int sum,tens,nines; tens=nines=0; for(int i=1;i<=6;i++){ for(int j=1;j<=6;j++){ for(int k=1;k<=6;k++){ sum=i+j+k; //Ternary operators are fun! tens+=((sum==10)?1:0); nines+=((sum==9)?1:0); } } } System.out.println("There are "+tens+" ways to roll a 10"); System.out.println("There are "+nines+" ways to roll a 9"); Which works just fine, and a brute force solution is what the teacher wanted us to do. However, it doesn't scale, and I am trying to find a way to make an algorithm that can calculate the number of ways to roll n dice to get a specific number. Therefore, I started generating the number of ways to get each sum with n dice. With 1 die, there is obviously 1 solution for each. I then calculated, through brute force, the combinations with 2 and 3 dice. These are for two: There are 1 ways to roll a 2 There are 2 ways to roll a 3 There are 3 ways to roll a 4 There are 4 ways to roll a 5 There are 5 ways to roll a 6 There are 6 ways to roll a 7 There are 5 ways to roll a 8 There are 4 ways to roll a 9 There are 3 ways to roll a 10 There are 2 ways to roll a 11 There are 1 ways to roll a 12 Which looks straightforward enough; it can be calculated with a simple linear absolute value function. But then things start getting trickier. With 3: There are 1 ways to roll a 3 There are 3 ways to roll a 4 There are 6 ways to roll a 5 There are 10 ways to roll a 6 There are 15 ways to roll a 7 There are 21 ways to roll a 8 There are 25 ways to roll a 9 There are 27 ways to roll a 10 There are 27 ways to roll a 11 There are 25 ways to roll a 12 There are 21 ways to roll a 13 There are 15 ways to roll a 14 There are 10 ways to roll a 15 There are 6 ways to roll a 16 There are 3 ways to roll a 17 There are 1 ways to roll a 18 So I look at that, and I think: Cool, Triangular numbers! However, then I notice those pesky 25s and 27s. So it's obviously not triangular numbers, but still some polynomial expansion, since it's symmetric. So I take to Google, and I come across this page that goes into some detail about how to do this with math. It is fairly easy(albeit long) to find this using repeated derivatives or expansion, but it would be much harder to program that for me. I didn't quite understand the second and third answers, since I have never encountered that notation or those concepts in my math studies before. Could someone please explain how I could write a program to do this, or explain the solutions given on that page, for my own understanding of combinatorics? EDIT: I'm looking for a mathematical way to solve this, that gives an exact theoretical number, not by simulating dice

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  • Retrieving multiple rows from a loop-created form... Stuck.

    - by hangston
    Let me start by saying that I'm new to PHP, but I'm here to learn and would really appreciate your help. I use the following code to pull in data and create a form. This creates up to 40 lines for a user to fill out. Each line consists of the same information: Description, Amount, and Frequency. The remainder of the information needed is generated by the database. (See hidden fields) <?php $row = 0; do { $optid = $row_options['option_id']; echo "<tr>\n\t<td>" . htmlentities($row_options['option']) . "</td>\n"; echo "\t<td>" . "<input name='description' type='text' size='40' maxlength='120'/>" . "</td>\n"; echo "\t<td>" . "<input name='option_id' type='hidden' value='$optid' />$<input name='amount' type='text' size='10' maxlength='7'/>" . "</td>\n"; echo "\t<td>" . "<select name='assisted_frequency'> <option value='Monthly'>Monthly</option> <option value='Weekly'>Weekly</option> <option value='Daily'>Daily</option> <option value='Hourly'>Hourly</option> <option value='One-Time'>One-Time</option> </select>" . "</td>\n</tr>\n"; $array[$row] = array( $arraydesc[$row] = $_POST['description'], $arrayamto[$row] = $_POST['amount'], $arrayoptid[$row] = $optid, $arrayfreq[$row] = $_POST['frequency'], ); $row ++; } while ($row_options = mysql_fetch_assoc($options)); $counter = $row - 1; ?> I'm having troubles retrieving the information that the user inputs. My intent is to loop through each row after the user has input their information, then upload the mix of my database information and the user's information into another database. For example, the user would see, albeit prettier: form1 Option 1: description [input box] amount [input box] frequency [option box] Option 2: description [input box] amount [input box] frequency [option box] Option 3: description [input box] amount [input box] frequency [option box] Option 4: description [input box] amount [input box] frequency [option box] submit Upon submitting the form above, I'm using a query similar to the following to input the data into the database: for($row=0; $row<=$counter; $row++){ $insertSQL2 = sprintf("INSERT INTO table (option_id, amount, description, frequency) VALUES (%s, %s, %s, %s)", GetSQLValueString($arrayoptid[$row], "int"), GetSQLValueString($arrayamto[$row], "int"), GetSQLValueString($arraydesc[$row], "text"), GetSQLValueString($arrayfreq[$row], "text")); // code to submit query } I've tried for, foreach, arrays (what feels like the everything I know) to post each row (row by row) into the database. I either get just the last row of data, or no data at all. I also worry that the [$row] technique is adding characters to my data. What is the best way to retrieve each row of the user's inputs, then upload this data (row by row) into the database? Also, I would really appreciate your suggestions for improving my coding technique and the approach I'm taking.

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  • Letter to Ballmer: Making Better Consumer Devices

    - by andrewbrust
    Last year, I wrote Steve Ballmer an email, and he was kind enough to write me back.  The email contained a scan of a column I wrote praising Microsoft’s BI strategy.  His reply contained three simple words: “Super nice  thanks.” Well, now I’d like to write to Steve again, in an open letter format, and this time the love may be a bit tougher.  But I’m still super earnest. The past two days have been eventful ones for Microsoft: The company announced the departure of company veterans Robbie Bach and J Allard and the market announced Apple is now besting Microsoft in market capitalization. Plus, announcements were made that make it plain that Ballmer will, in effect, be running Microsoft’s Entertainment & Devices division himself. With that in mind, I’d like to offer my list of a dozen things I think Microsoft’s CEO should do to improve that division’s offerings and, hopefully, its bottom line. So here goes:   1. On Windows Phone 7, Stay the Course The press is teeming with headlines and reader comments proclaiming the death-before-arrival of Windows Phone 7.  That’s plain silly.  You’ve got the makings of a great and unique SmartPhone platform, and you’re the only company (even considering RIM) that can offer full fidelity Exchange integration, not to mention implementing Office on the device.  Let the existing team finish this puppy and ship it. And then have them pump out a few updates, over-the-air, quickly.  Show them that Google Android’s not the only product that can do good, rapid dot releases. And another thing: make sure your OEMs’ devices have flawless touch screens.  If they don’t, then you shouldn’t certify them for delivery to customers.  Period. Oh, and kill the Kin, quietly.  It was DOA, and you know it.   2. Move Media Center to the Xbox Platform Media Center is, at its core, a good product.  But delivering a media distribution and DVR platform on a sophisticated PC operating system like Windows 7 just creates too many moving parts.  Xbox already functions as the best Media Center extender device – it should actually be the hub as well. Media Center is mostly based on .NET code – and XNA is a .NET environment for Xbox – find a way to bridge that small gap and make Media Center a joy to work with instead of a frustration.  Beating Apple TV out of this sub-market is the lowest hanging fruit on the tree (goofy pun, but it’s true).   3. Integrate Media Center with Mediaroom, or Kill the Latter You have two media products with almost identical names.  One is for standalone DVRs and the other is for IPTV cable set tops with DVR capabilities.  Can we merge these please?  My previous request of putting Media Center on Xbox would seem to tie into this nicely, since you’ve announced plans to do that with Mediaroom already.   4. Fix the Red Ring of Death People love the Xbox, but they really don’t love sending their consoles back every 18-24 months, when they get a bunch of red lights flashing on power up.  You’ve handled this defect about as gracefully as possible, but it’s been around for a long time now and it doesn’t seem to be fixed yet.  You can do better.  In fact, you must do better, or you insult your customers.   5. Add Blu Ray to Xbox I know, streaming movies are the future; physical media is legacy technology.  So if that’s true, why did you back HD DVD so hard?  You know why: for now, the film studios won’t allow a large selection of new release, HD, surround sound content be distributed on any medium other than Blu Ray or cable pay per view/on-demand.  Don’t you want home theater buffs to see the Xbox as a fantastic device for their rigs?  Don’t you want to put PlayStation 3 out of its misery?  And if you follow my suggestions above (move Media Center to the Xbox and fix the Red Ring problem), you’d have it all sewn up.  Do I think Blu Ray functionality will move a lot of units?  No.  Do I think that it would move more units with desperately needed influential home theater consumers?  You bet.  And you might sell more ZunePass subscriptions in the process. But while you’re at it, make the fan quieter, please.   6. Make More of Windows Home Server Home Server is a fantastic product.  And for reasons unknown to me, it seems like you’re letting it languish.  Development of the add-in ecosystem seems underfunded.  WHS’ unparalleled ease of use and reliability for home PC backup (and emergency restores) goes unsung.  Product cycles are slow.  Support for your OEMs, who are doing great work, especially in the green space with Atom CPUs, seems lacking.  You’ve married a trophy girl and you keep her cloistered at home!  That’s cruel, unusual and, um, incredibly ill-advised.  Make use of this ace card, and while you’re at it, give it real integration with Media Center.  The integration thus far proof-of-concept quality.  You should go way past that – both products will benefit immeasurably.   7. Set Up a Partner Platform for Custom Installers There’s a whole sub-industry of companies that install, integrate and configure home theater, security and connected home products.  They have an industry group. They are influential in the high-end of the consumer electronics industry, and so are their customers.  They love Media Center and they love Windows Home Server.  But I have talked to several of them at the Consumer Electronics Show and they tell me you don’t love them.  They find it very difficult to do business with Microsoft, even though they want nothing more than to sell and evangelize your platform.  This is a travesty.  Please fix it.  Get Allison Watson and the Microsoft Partner Network on board and have her hire someone who knows how to run a channel program for consumer electronics companies.  Problem solved.  Markets expanded.   8. Make Your Own Hardware In other areas, I know you love your partners.  I help run one, so I appreciate that.  But when it came to Xbox and Zune you built them it yourself (albeit on a contract basis, which is fine).  Windows Phone 7 has a chance to work as an OEM play, but it would work better if you produced the devices.  At least consider building a reference device that sells alongside your OEMs’ offerings.  That’s what Google did with the Nexxus One.  And while that phone was not itself a big seller, it catalyzed two wonderful things : (1) a quality bar was set and (2) partners exceeded it.  Before the Nexxus One, the best Android handset out there was the Motorola Droid. The Nexxus One was better, and the HTC Droid Incredible and Evo 4G are now even better than Google’s phone, which is why Verizon and Sprint decided not to carry it.  Imagine if all Windows Phone 6.x devices were on par with the HTC HD2.  I tend to believe you’d have a lot bigger market share than you do now.   9. Continue with Your Retail Initiative From what I hear, it sounds like it’s going well.  And this goes right along with making your own hardware.  When you build it, they will come.  And then it makes the likes of Best Buy and Staples do better.   10. Make an Acquisition (or Two) TiVo and/or Moxi look ripe for the picking.  With their ability to build stuff people love and your ability to run a business, you might just have something.  But do a better job than you did when you bought Danger.  Buy the ideas, not just the customers, eh?   11. Make Beautiful Stuff You’ve heard this one before, I know.  But I have some head-shrinking advice on this one.  You know that Apple obsesses over its industrial design.  You know that appeals to consumers.  But it seems you think doing so is Apple’s game exclusively and so you shouldn’t even try.  Bull dinky.  Come to New York and visit the Museum of Modern Art’s Architecture and Design gallery.  You’ll see that lots of companies and product categories have had very high design value well before Apple existed.  You can do this, and the Zune HD was a great start.  Now run with that.  Find those negative voices in your head that are telling you that you can’t and shut them up.  For good.   12. Burst the Bubble Some of the products you’ve built seem like they were conceived in a bizarro world.  That would appear to be the result of groupthink.  You must do better.  And there’s lots of people willing to advise you.  This includes just about everyone in the Regional Director program, and probably a bunch of MVPs.  Heck, I bet the guys at Engadget could help out too.  Imagine if you let them see the Kin before it shipped.  Talk to high-end gear consumers.  Talk to Best Buy and CostCo customers too.   Signing Off I hope this was of value to you.  As I wrote this I kept telling myself how obvious, even trite, some of these pieces of advice were and then, because of that, doubting they’d really help.  But I decided that they must not be obvious to Microsoft.  Sometimes when you get wrapped up in stuff, it’s hard to clear your head.  I think my head’s pretty clear here though (I’m wrapped up in other stuff), so maybe my perspective can help.  If not, well, then, I guess they all can’t be super nice.

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  • The Low Down Dirty Azure Blues

    - by SGWellens
    Remember the SETI screen savers that used to be on everyone's computer? As far I as know, it was the first bona-fide use of "Cloud" computing…albeit an ad hoc cloud. I still think it was a brilliant leveraging of computing power. My interest in clouds was re-piqued when I went to a technical seminar at the local .Net User Group. The speaker was Mike Benkovitch and he expounded magnificently on the virtues of the Azure platform. Mike always does a good job. One killer reason he gave for cloud computing is instant scalability. Not applicable for most applications, but it is there if needed. I have a bunch of files stored on Microsoft's SkyDrive platform which is cloud storage. It is painfully slow. Accessing a file means going through layers and layers of software, redirections and security. Am I complaining? Hell no! It's free! So my opinions of Cloud Computing are both skeptical and appreciative. What intrigued me at the seminar, in addition to its other features, is that Azure can serve as a web hosting platform. I have a client with an Asp.Net web site I developed who is not happy with the performance of their current hosting service. I checked the cost of Azure and since the site has low bandwidth/space requirements the cost would be competitive with the existing host provider: Azure Pricing Calculator. And, Azure has a three month free trial. Perfect! I could try moving the website and see how it works for free. I went through the signup process. Everything was proceeding fine until I went to the MS SQL database management screen. A popup window informed me that I needed to install Silverlight on my machine. Silverlight? No thanks. Buh-Bye. I half-heartedly found the Azure support button and logged a ticket telling them I didn't want Silverlight on my machine. Within 4 to 6 hours (and a myriad (5) of automated support emails) they sent me a link to a database management page that did not require Silverlight. Thanks! I was able to create a database immediately. One really nice feature was that after creating the database, I was given a list of connection strings. I went to the current host provider, made a backup of the database and saved it to my machine. I attached to the remote database using SQL Server Studio 2012 and looked for the Restore menu item. It was missing. So I tried using the SQL command: RESTORE DATABASE MyDatabase FROM DISK ='C:\temp\MyBackup.bak' Msg 40510, Level 16, State 1, Line 1 Statement 'RESTORE DATABASE' is not supported in this version of SQL Server. Are you kidding me? Why on earth…? This can't be happening! I opened both the source database and destination database in SQL Management Studio. I right clicked the source database, selected "Tasks" and noticed a menu selection called "Deploy Database to SQL Azure" Are you kidding me? Could it be? Oh yes, it be! There was a small problem because the database already existed on the Azure machine, I deployed to a new name, deleted the existing database and renamed the deployed database to what I needed. It was ridiculously easy. Being able to attach SQL Management Studio to remote databases is an awesome but scary feature. You can limit the IP addresses that can access the database which enhances security but when you give people, any people, me included, that much power, one errant mouse click could bring a live system down. My Advice: Tread softly and carry a large backup thumb-drive. Then I created a web site, the URL it returned look something like this: http://MyWebSite.azurewebsites.net/ Azure supports FTP, but I couldn't figure out the settings until I downloaded the publishing profile. It was an XML file that contained the needed information. I still couldn't connect with my FTP client (FileZilla). After about an hour of messing around, I deleted the port number from the FileZilla setup page….and voila, I was in like Flynn.   There are other options of deploying directly from Visual Studio, TFS, etc. but I do not like integrated tools that do things without my asking: It's usually hard to figure out what they did and how to undo it. I uploaded the aspx , cs , webconfig, etc. files. Bu it didn't run. The site I ported was in .NET 3.5. The Azure website configuration page gave me a choice between .NET 2.0 and 4.0. So, I switched to Visual Studio 2010, chose .NET 4.0 and upgraded the site. Of course I have the original version completely backed up and stored in a granite cave beneath the Nevada desert. And I have a backup CD under my pillow. The site uses ReportViewer to generate PDF documents. Of course it was the wrong version. I removed the old references to version 9 and added new references to version 10 (*see note below). Since the DLLs were not on the Azure Server, I uploaded them to the bin directory, crossed my fingers, burned some incense and gave it a try. After some fiddling around it ran. I don't know if I did anything particular to make it work or it just needed time to sort things out. However, one critical feature didn't work: ReportViewer could not programmatically generate PDF documents. I was getting this exception: "An error occurred during local report processing. Parameter is not valid." Rats. I did some searching and found other people were having the same problem, so I added a post saying I was having the same problem: http://social.msdn.microsoft.com/Forums/en-US/windowsazurewebsitespreview/thread/b4a6eb43-0013-435f-9d11-00ee26a8d017 Currently they are looking into this problem and I am waiting for the results. Hence I had the time to write this BLOG entry. How lucky you are. This was the last message I got from the Microsoft person: Hi Steve, Windows Azure Web Sites is a multi-tenant environment. For security issue, we limited some API calls. Unfortunately, some GDI APIS required by the PDF converting function are in this list. We have noticed this issue, and still investigation the best way to go. At this moment, there is no news to share. Sorry about this. Will keep you posted. If I had to guess, I would say they are concerned with people uploading images and doing intensive graphics programming which would hog CPU time.  But that is just a guess. Another problem. While trying to resolve the ReportViewer problem, I tried to write a file to the PDF directory to see if there was a permissions problem with some test code: String MyPath = MapPath(@"~\PDFs\Test.txt"); File.WriteAllText(MyPath, "Hello Azure");     I got this message: Access to the path <my path> is denied. After some research, I understood that since Azure is a cloud based platform, it can't allow web applications to save files to local directories. The application could be moved or replicated as scaling occurs and trying to manage local files would be problematic to say the least. There are other options: Use the Azure APIs to get a path. That way the location of the storage is separated from the application. However, the web site is then tied Azure and can't be moved to another hosting platform. Use the ApplicationData folder (not recommended). Write to BLOB storage. Or, I could try and stream the PDF output directly to the email and not save a file. I'm not going to work on a final solution until the ReportViewer is fixed. I am just sharing some of the things you need to be aware of if you decide to use Azure. I got this information from here. (Note the author of the BLOG added a comment saying he has updated his entry). Is my memory faulty? While getting this BLOG ready, I tried to write the test file again. And it worked. My memory is incorrect, or much more likely, something changed on the server…perhaps while they are trying to get ReportViewer to work. (Anyway, that's my story and I'm sticking to it). *Note: Since Visual Studio 2010 Express doesn't include a Report Editor, I downloaded and installed SQL Server Report Builder 2.0. It is a standalone Report Editor to replace the one not in Visual Studio 2010 Express. I hope someone finds this useful. Steve Wellens CodeProject

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  • HPET for x86 BSP (how to build it for WCE8)

    - by Werner Willemsens
    Originally posted on: http://geekswithblogs.net/WernerWillemsens/archive/2014/08/02/157895.aspx"I needed a timer". That is how we started a few blogs ago our series about APIC and ACPI. Well, here it is. HPET (High Precision Event Timer) was introduced by Intel in early 2000 to: Replace old style Intel 8253 (1981!) and 8254 timers Support more accurate timers that could be used for multimedia purposes. Hence Microsoft and Intel sometimes refers to HPET as Multimedia timers. An HPET chip consists of a 64-bit up-counter (main counter) counting at a frequency of at least 10 MHz, and a set of (at least three, up to 256) comparators. These comparators are 32- or 64-bit wide. The HPET is discoverable via ACPI. The HPET circuit in recent Intel platforms is integrated into the SouthBridge chip (e.g. 82801) All HPET timers should support one-shot interrupt programming, while optionally they can support periodic interrupts. In most Intel SouthBridges I worked with, there are three HPET timers. TIMER0 supports both one-shot and periodic mode, while TIMER1 and TIMER2 are one-shot only. Each HPET timer can generate interrupts, both in old-style PIC mode and in APIC mode. However in PIC mode, interrupts cannot freely be chosen. Typically IRQ11 is available and cannot be shared with any other interrupt! Which makes the HPET in PIC mode virtually unusable. In APIC mode however more IRQs are available and can be shared with other interrupt generating devices. (Check the datasheet of your SouthBridge) Because of this higher level of freedom, I created the APIC BSP (see previous posts). The HPET driver code that I present you here uses this APIC mode. Hpet.reg [HKEY_LOCAL_MACHINE\Drivers\BuiltIn\Hpet] "Dll"="Hpet.dll" "Prefix"="HPT" "Order"=dword:10 "IsrDll"="giisr.dll" "IsrHandler"="ISRHandler" "Priority256"=dword:50 Because HPET does not reside on the PCI bus, but can be found through ACPI as a memory mapped device, you don't need to specify the "Class", "SubClass", "ProgIF" and other PCI related registry keys that you typically find for PCI devices. If a driver needs to run its internal thread(s) at a certain priority level, by convention in Windows CE you add the "Priority256" registry key. Through this key you can easily play with the driver's thread priority for better response and timer accuracy. See later. Hpet.cpp (Hpet.dll) This cpp file contains the complete HPET driver code. The file is part of a folder that you typically integrate in your BSP (\src\drivers\Hpet). It is written as sample (example) code, you most likely want to change this code to your specific needs. There are two sets of #define's that I use to control how the driver works. _TRIGGER_EVENT or _TRIGGER_SEMAPHORE: _TRIGGER_EVENT will let your driver trigger a Windows CE Event when the timer expires, _TRIGGER_SEMAPHORE will trigger a Windows CE counting Semaphore. The latter guarantees that no events get lost in case your application cannot always process the triggers fast enough. _TIMER0 or _TIMER2: both timers will trigger an event or semaphore periodically. _TIMER0 will use a periodic HPET timer interrupt, while _TIMER2 will reprogram a one-shot HPET timer after each interrupt. The one-shot approach is interesting if the frequency you wish to generate is not an even multiple of the HPET main counter frequency. The sample code uses an algorithm to generate a more correct frequency over a longer period (by reducing rounding errors). _TIMER1 is not used in the sample source code. HPT_Init() will locate the HPET I/O memory space, setup the HPET counter (_TIMER0 or _TIMER2) and install the Interrupt Service Thread (IST). Upon timer expiration, the IST will run and on its turn will generate a Windows CE Event or Semaphore. In case of _TIMER2 a new one-shot comparator value is calculated and set for the timer. The IRQ of the HPET timers are programmed to IRQ22, but you can choose typically from 20-23. The TIMERn_INT_ROUT_CAP bits in the TIMn_CONF register will tell you what IRQs you can choose from. HPT_IOControl() can be used to set a new HPET counter frequency (actually you configure the counter timeout value in microseconds), start and stop the timer, and request the current HPET counter value. The latter is interesting because the Windows CE QueryPerformanceCounter() and QueryPerformanceFrequency() APIs implement the same functionality, albeit based on other counter implementations. HpetDrvIst() contains the IST code. DWORD WINAPI HpetDrvIst(LPVOID lpArg) { psHpetDeviceContext pHwContext = (psHpetDeviceContext)lpArg; DWORD mainCount = READDWORD(pHwContext->g_hpet_va, GenCapIDReg + 4); // Main Counter Tick period (fempto sec 10E-15) DWORD i = 0; while (1) { WaitForSingleObject(pHwContext->g_isrEvent, INFINITE); #if defined(_TRIGGER_SEMAPHORE) LONG p = 0; BOOL b = ReleaseSemaphore(pHwContext->g_triggerEvent, 1, &p); #elif defined(_TRIGGER_EVENT) BOOL b = SetEvent(pHwContext->g_triggerEvent); #else #pragma error("Unknown TRIGGER") #endif #if defined(_TIMER0) DWORD currentCount = READDWORD(pHwContext->g_hpet_va, MainCounterReg); DWORD comparator = READDWORD(pHwContext->g_hpet_va, Tim0_ComparatorReg + 0); SETBIT(pHwContext->g_hpet_va, GenIntStaReg, 0); // clear interrupt on HPET level InterruptDone(pHwContext->g_sysIntr); // clear interrupt on OS level _LOGMSG(ZONE_INTERRUPT, (L"%s: HpetDrvIst 0 %06d %08X %08X", pHwContext->g_id, i++, currentCount, comparator)); #elif defined(_TIMER2) DWORD currentCount = READDWORD(pHwContext->g_hpet_va, MainCounterReg); DWORD previousComparator = READDWORD(pHwContext->g_hpet_va, Tim2_ComparatorReg + 0); pHwContext->g_counter2.QuadPart += pHwContext->g_comparator.QuadPart; // increment virtual counter (higher accuracy) DWORD comparator = (DWORD)(pHwContext->g_counter2.QuadPart >> 8); // "round" to real value WRITEDWORD(pHwContext->g_hpet_va, Tim2_ComparatorReg + 0, comparator); SETBIT(pHwContext->g_hpet_va, GenIntStaReg, 2); // clear interrupt on HPET level InterruptDone(pHwContext->g_sysIntr); // clear interrupt on OS level _LOGMSG(ZONE_INTERRUPT, (L"%s: HpetDrvIst 2 %06d %08X %08X (%08X)", pHwContext->g_id, i++, currentCount, comparator, comparator - previousComparator)); #else #pragma error("Unknown TIMER") #endif } return 1; } The following figure shows how the HPET hardware interrupt via ISR -> IST is translated in a Windows CE Event or Semaphore by the HPET driver. The Event or Semaphore can be used to trigger a Windows CE application. HpetTest.cpp (HpetTest.exe)This cpp file contains sample source how to use the HPET driver from an application. The file is part of a separate (smart device) VS2013 solution. It contains code to measure the generated Event/Semaphore times by means of GetSystemTime() and QueryPerformanceCounter() and QueryPerformanceFrequency() APIs. HPET evaluation If you scan the internet about HPET, you'll find many remarks about buggy HPET implementations and bad performance. Unfortunately that is true. I tested the HPET driver on an Intel ICH7M SBC (release date 2008). When a HPET timer expires on the ICH7M, an interrupt indeed is generated, but right after you clear the interrupt, a few more unwanted interrupts (too soon!) occur as well. I tested and debugged it for a loooong time, but I couldn't get it to work. I concluded ICH7M's HPET is buggy Intel hardware. I tested the HPET driver successfully on a more recent NM10 SBC (release date 2013). With the NM10 chipset however, I am not fully convinced about the timer's frequency accuracy. In the long run - on average - all is fine, but occasionally I experienced upto 20 microseconds delays (which were immediately compensated on the next interrupt). Of course, this was all measured by software, but I still experienced the occasional delay when both the HPET driver IST thread as the application thread ran at CeSetThreadPriority(1). If it is not the hardware, only the kernel can cause this delay. But Windows CE is an RTOS and I have never experienced such long delays with previous versions of Windows CE. I tested and developed this on WCE8, I am not heavily experienced with it yet. Internet forum threads however mention inaccurate HPET timer implementations as well. At this moment I haven't figured out what is going on here. Useful references: http://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/software-developers-hpet-spec-1-0a.pdf http://en.wikipedia.org/wiki/High_Precision_Event_Timer http://wiki.osdev.org/HPET Windows CE BSP source file package for HPET in MyBsp Note that this source code is "As Is". It is still under development and I cannot (and never will) guarantee the correctness of the code. Use it as a guide for your own HPET integration.

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  • array and array_view from amp.h

    - by Daniel Moth
    This is a very long post, but it also covers what are probably the classes (well, array_view at least) that you will use the most with C++ AMP, so I hope you enjoy it! Overview The concurrency::array and concurrency::array_view template classes represent multi-dimensional data of type T, of N dimensions, specified at compile time (and you can later access the number of dimensions via the rank property). If N is not specified, it is assumed that it is 1 (i.e. single-dimensional case). They are rectangular (not jagged). The difference between them is that array is a container of data, whereas array_view is a wrapper of a container of data. So in that respect, array behaves like an STL container, whereas the closest thing an array_view behaves like is an STL iterator (albeit with random access and allowing you to view more than one element at a time!). The data in the array (whether provided at creation time or added later) resides on an accelerator (which is specified at creation time either explicitly by the developer, or set to the default accelerator at creation time by the runtime) and is laid out contiguously in memory. The data provided to the array_view is not stored by/in the array_view, because the array_view is simply a view over the real source (which can reside on the CPU or other accelerator). The underlying data is copied on demand to wherever the array_view is accessed. Elements which differ by one in the least significant dimension of the array_view are adjacent in memory. array objects must be captured by reference into the lambda you pass to the parallel_for_each call, whereas array_view objects must be captured by value (into the lambda you pass to the parallel_for_each call). Creating array and array_view objects and relevant properties You can create array_view objects from other array_view objects of the same rank and element type (shallow copy, also possible via assignment operator) so they point to the same underlying data, and you can also create array_view objects over array objects of the same rank and element type e.g.   array_view<int,3> a(b); // b can be another array or array_view of ints with rank=3 Note: Unlike the constructors above which can be called anywhere, the ones in the rest of this section can only be called from CPU code. You can create array objects from other array objects of the same rank and element type (copy and move constructors) and from other array_view objects, e.g.   array<float,2> a(b); // b can be another array or array_view of floats with rank=2 To create an array from scratch, you need to at least specify an extent object, e.g. array<int,3> a(myExtent);. Note that instead of an explicit extent object, there are convenience overloads when N<=3 so you can specify 1-, 2-, 3- integers (dependent on the array's rank) and thus have the extent created for you under the covers. At any point, you can access the array's extent thought the extent property. The exact same thing applies to array_view (extent as constructor parameters, incl. convenience overloads, and property). While passing only an extent object to create an array is enough (it means that the array will be written to later), it is not enough for the array_view case which must always wrap over some other container (on which it relies for storage space and actual content). So in addition to the extent object (that describes the shape you'd like to be viewing/accessing that data through), to create an array_view from another container (e.g. std::vector) you must pass in the container itself (which must expose .data() and a .size() methods, e.g. like std::array does), e.g.   array_view<int,2> aaa(myExtent, myContainerOfInts); Similarly, you can create an array_view from a raw pointer of data plus an extent object. Back to the array case, to optionally initialize the array with data, you can pass an iterator pointing to the start (and optionally one pointing to the end of the source container) e.g.   array<double,1> a(5, myVector.begin(), myVector.end()); We saw that arrays are bound to an accelerator at creation time, so in case you don’t want the C++ AMP runtime to assign the array to the default accelerator, all array constructors have overloads that let you pass an accelerator_view object, which you can later access via the accelerator_view property. Note that at the point of initializing an array with data, a synchronous copy of the data takes place to the accelerator, and then to copy any data back we'll see that an explicit copy call is required. This does not happen with the array_view where copying is on demand... refresh and synchronize on array_view Note that in the previous section on constructors, unlike the array case, there was no overload that accepted an accelerator_view for array_view. That is because the array_view is simply a wrapper, so the allocation of the data has already taken place before you created the array_view. When you capture an array_view variable in your call to parallel_for_each, the copy of data between the non-CPU accelerator and the CPU takes place on demand (i.e. it is implicit, versus the explicit copy that has to happen with the array). There are some subtleties to the on-demand-copying that we cover next. The assumption when using an array_view is that you will continue to access the data through the array_view, and not through the original underlying source, e.g. the pointer to the data that you passed to the array_view's constructor. So if you modify the data through the array_view on the GPU, the original pointer on the CPU will not "know" that, unless one of two things happen: you access the data through the array_view on the CPU side, i.e. using indexing that we cover below you explicitly call the array_view's synchronize method on the CPU (this also gets called in the array_view's destructor for you) Conversely, if you make a change to the underlying data through the original source (e.g. the pointer), the array_view will not "know" about those changes, unless you call its refresh method. Finally, note that if you create an array_view of const T, then the data is copied to the accelerator on demand, but it does not get copied back, e.g.   array_view<const double, 5> myArrView(…); // myArrView will not get copied back from GPU There is also a similar mechanism to achieve the reverse, i.e. not to copy the data of an array_view to the GPU. copy_to, data, and global copy/copy_async functions Both array and array_view expose two copy_to overloads that allow copying them to another array, or to another array_view, and these operations can also be achieved with assignment (via the = operator overloads). Also both array and array_view expose a data method, to get a raw pointer to the underlying data of the array or array_view, e.g. float* f = myArr.data();. Note that for array_view, this only works when the rank is equal to 1, due to the data only being contiguous in one dimension as covered in the overview section. Finally, there are a bunch of global concurrency::copy functions returning void (and corresponding concurrency::copy_async functions returning a future) that allow copying between arrays and array_views and iterators etc. Just browse intellisense or amp.h directly for the full set. Note that for array, all copying described throughout this post is deep copying, as per other STL container expectations. You can never have two arrays point to the same data. indexing into array and array_view plus projection Reading or writing data elements of an array is only legal when the code executes on the same accelerator as where the array was bound to. In the array_view case, you can read/write on any accelerator, not just the one where the original data resides, and the data gets copied for you on demand. In both cases, the way you read and write individual elements is via indexing as described next. To access (or set the value of) an element, you can index into it by passing it an index object via the subscript operator. Furthermore, if the rank is 3 or less, you can use the function ( ) operator to pass integer values instead of having to use an index object. e.g. array<float,2> arr(someExtent, someIterator); //or array_view<float,2> arr(someExtent, someContainer); index<2> idx(5,4); float f1 = arr[idx]; float f2 = arr(5,4); //f2 ==f1 //and the reverse for assigning, e.g. arr(idx[0], 7) = 6.9; Note that for both array and array_view, regardless of rank, you can also pass a single integer to the subscript operator which results in a projection of the data, and (for both array and array_view) you get back an array_view of rank N-1 (or if the rank was 1, you get back just the element at that location). Not Covered In this already very long post, I am not going to cover three very cool methods (and related overloads) that both array and array_view expose: view_as, section, reinterpret_as. We'll revisit those at some point in the future, probably on the team blog. Comments about this post by Daniel Moth welcome at the original blog.

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  • eBooks on iPad vs. Kindle: More Debate than Smackdown

    - by andrewbrust
    When the iPad was presented at its San Francisco launch event on January 28th, Steve Jobs spent a significant amount of time explaining how well the device would serve as an eBook reader. He showed the iBooks reader application and iBookstore and laid down the gauntlet before Amazon and its beloved Kindle device. Almost immediately afterwards, criticism came rushing forth that the iPad could never beat the Kindle for book reading. The curious part of that criticism is that virtually no one offering it had actually used the iPad yet. A few weeks later, on April 3rd, the iPad was released for sale in the United States. I bought one on that day and in the few additional weeks that have elapsed, I’ve given quite a workout to most of its capabilities, including its eBook features. I’ve also spent some time with the Kindle, albeit a first-generation model, to see how it actually compares to the iPad. I had some expectations going in, but I came away with conclusions about each device that were more scenario-based than absolute. I present my findings to you here.   Vital Statistics Let’s start with an inventory of each device’s underlying technology. The iPad has a color, backlit LCD screen and an on-screen keyboard. It has a battery which, on a full charge, lasts anywhere from 6-10 hours. The Kindle offers a monochrome, reflective E Ink display, a physical keyboard and a battery that on my first gen loaner unit can go up to a week between charges (Amazon claims the battery on the Kindle 2 can last up to 2 weeks on a single charge). The Kindle connects to Amazon’s Kindle Store using a 3G modem (the technology and network vary depending on the model) that incurs no airtime service charges whatsoever. The iPad units that are on-sale today work over WiFi only. 3G-equipped models will be on sale shortly and will command a $130 premium over their WiFi-only counterparts. 3G service on the iPad, in the U.S. from AT&T, will be fee-based, with a 250MB plan at $14.99 per month and an unlimited plan at $29.99. No contract is required for 3G service. All these tech specs aside, I think a more useful observation is that the iPad is a multi-purpose Internet-connected entertainment device, while the Kindle is a dedicated reading device. The question is whether those differences in design and intended use create a clear-cut winner for reading electronic publications. Let’s take a look at each device, in isolation, now.   Kindle To me, what’s most innovative about the Kindle is its E Ink display. E Ink really looks like ink on a sheet of paper. It requires no backlight, it’s fully visible in direct sunlight and it causes almost none of the eyestrain that LCD-based computer display technology (like that used on the iPad) does. It’s really versatile in an all-around way. Forgive me if this sounds precious, but reading on it is really a joy. In fact, it’s a genuinely relaxing experience. Through the Kindle Store, Amazon allows users to download books (including audio books), magazines, newspapers and blog feeds. Books and magazines can be purchased either on a single-issue basis or as an annual subscription. Books, of course, are purchased singly. Oddly, blogs are not free, but instead carry a monthly subscription fee, typically $1.99. To me this is ludicrous, but I suppose the free 3G service is partially to blame. Books and magazine issues download quickly. Magazine and blog subscriptions cause new issues or posts to be pushed to your device on an automated basis. Available blogs include 9000-odd feeds that Amazon offers on the Kindle Store; unless I missed something, arbitrary RSS feeds are not supported (though there are third party workarounds to this limitation). The shopping experience is integrated well, has an huge selection, and offers certain graphical perks. For example, magazine and newspaper logos are displayed in menus, and book cover thumbnails appear as well. A simple search mechanism is provided and text entry through the physical keyboard is relatively painless. It’s very easy and straightforward to enter the store, find something you like and start reading it quickly. If you know what you’re looking for, it’s even faster. Given Kindle’s high portability, very reliable battery, instant-on capability and highly integrated content acquisition, it makes reading on whim, and in random spurts of downtime, very attractive. The Kindle’s home screen lists all of your publications, and easily lets you select one, then start reading it. Once opened, publications display in crisp, attractive text that is adjustable in size. “Turning” pages is achieved through buttons dedicated to the task. Notes can be recorded, bookmarks can be saved and pages can be saved as clippings. I am not an avid book reader, and yet I found the Kindle made it really fun, convenient and soothing to read. There’s something about the easy access to the material and the simplicity of the display that makes the Kindle seduce you into chilling out and reading page after page. On the other hand, the Kindle has an awkward navigation interface. While menus are displayed clearly on the screen, the method of selecting menu items is tricky: alongside the right-hand edge of the main display is a thin column that acts as a second display. It has a white background, and a scrollable silver cursor that is moved up or down through the use of the device’s scrollwheel. Picking a menu item on the main display involves scrolling the silver cursor to a position parallel to that menu item and pushing the scrollwheel in. This navigation technique creates a disconnect, literally. You don’t really click on a selection so much as you gesture toward it. I got used to this technique quickly, but I didn’t love it. It definitely created a kind of anxiety in me, making me feel the need to speed through menus and get to my destination document quickly. Once there, I could calm down and relax. Books are great on the Kindle. Magazines and newspapers much less so. I found the rendering of photographs, and even illustrations, to be unacceptably crude. For this reason, I expect that reading textbooks on the Kindle may leave students wanting. I found that the original flow and layout of any publication was sacrificed on the Kindle. In effect, browsing a magazine or newspaper was almost impossible. Reading the text of individual articles was enjoyable, but having to read this way made the whole experience much more “a la carte” than cohesive and thematic between articles. I imagine that for academic journals this is ideal, but for consumer publications it imposes a stripped-down, low-fidelity experience that evokes a sense of deprivation. In general, the Kindle is great for reading text. For just about anything else, especially activity that involves exploratory browsing, meandering and short-attention-span reading, it presents a real barrier to entry and adoption. Avid book readers will enjoy the Kindle (if they’re not already). It’s a great device for losing oneself in a book over long sittings. Multitaskers who are more interested in periodicals, be they online or off, will like it much less, as they will find compromise, and even sacrifice, to be palpable.   iPad The iPad is a very different device from the Kindle. While the Kindle is oriented to pages of text, the iPad orbits around applications and their interfaces. Be it the pinch and zoom experience in the browser, the rich media features that augment content on news and weather sites, or the ability to interact with social networking services like Twitter, the iPad is versatile. While it shares a slate-like form factor with the Kindle, it’s effectively an elegant personal computer. One of its many features is the iBook application and integration of the iBookstore. But it’s a multi-purpose device. That turns out to be good and bad, depending on what you’re reading. The iBookstore is great for browsing. It’s color, rich animation-laden user interface make it possible to shop for books, rather than merely search and acquire them. Unfortunately, its selection is rather sparse at the moment. If you’re looking for a New York Times bestseller, or other popular titles, you should be OK. If you want to read something more specialized, it’s much harder. Unlike the awkward navigation interface of the Kindle, the iPad offers a nearly flawless touch-screen interface that seduces the user into tinkering and kibitzing every bit as much as the Kindle lulls you into a deep, concentrated read. It’s a dynamic and interactive device, whereas the Kindle is static and passive. The iBook reader is slick and fun. Use the iPad in landscape mode and you can read the book in 2-up (left/right 2-page) display; use it in portrait mode and you can read one page at a time. Rather than clicking a hardware button to turn pages, you simply drag and wipe from right-to-left to flip the single or right-hand page. The page actually travels through an animated path as it would in a physical book. The intuitiveness of the interface is uncanny. The reader also accommodates saving of bookmarks, searching of the text, and the ability to highlight a word and look it up in a dictionary. Pages display brightly and clearly. They’re easy to read. But the backlight and the glare made me less comfortable than I was with the Kindle. The knowledge that completely different applications (including the Web and email and Twitter) were just a few taps away made me antsy and very tempted to task-switch. The knowledge that battery life is an issue created subtle discomfort. If the Kindle makes you feel like you’re in a library reading room, then the iPad makes you feel, at best, like you’re under fluorescent lights at a Barnes and Noble or Borders store. If you’re lucky, you’d be on a couch or at a reading table in the store, but you might also be standing up, in the aisles. Clearly, I didn’t find this conducive to focused and sustained reading. But that may have more to do with my own tendency to read periodicals far more than books, and my neurotic . And, truth be known, the book reading experience, when not explicitly compared to Kindle’s, was still pleasant. It is also important to point out that Kindle Store-sourced books can be read on the iPad through a Kindle reader application, from Amazon, specific to the device. This offered a less rich experience than the iBooks reader, but it was completely adequate. Despite the Kindle brand of the reader, however, it offered little in terms of simulating the reading experience on its namesake device. When it comes to periodicals, the iPad wins hands down. Magazines, even if merely scanned images of their print editions, read on the iPad in a way that felt similar to reading hard copy. The full color display, touch navigation and even the ability to render advertisements in their full glory makes the iPad a great way to read through any piece of work that is measured in pages, rather than chapters. There are many ways to get magazines and newspapers onto the iPad, including the Zinio reader, and publication-specific applications like the Wall Street Journal’s and Popular Science’s. The New York Times’ free Editors’ Choice application offers a Times Reader-like interface to a subset of the Gray Lady’s daily content. The completely Web-based but iPad-optimized Times Skimmer site (at www.nytimes.com/timesskimmer) works well too. Even conventional Web sites themselves can be read much like magazines, given the iPad’s ability to zoom in on the text and crop out advertisements on the margins. While the Kindle does have an experimental Web browser, it reminded me a lot of early mobile phone browsers, only in a larger size. For text-heavy sites with simple layout, it works fine. For just about anything else, it becomes more trouble than it’s worth. And given the way magazine articles make me think of things I want to look up online, I think that’s a real liability for the Kindle.   Summing Up What I came to realize is that the Kindle isn’t so much a computer or even an Internet device as it is a printer. While it doesn’t use physical paper, it still renders its content a page at a time, just like a laser printer does, and its output appears strikingly similar. You can read the rendered text, but you can’t interact with it in any way. That’s why the navigation requires a separate cursor display area. And because of the page-oriented rendering behavior, turning pages causes a flash on the display and requires a sometimes long pause before the next page is rendered. The good side of this is that once the page is generated, no battery power is required to display it. That makes for great battery life, optimal viewing under most lighting conditions (as long as there is some light) and low-eyestrain text-centric display of content. The Kindle is highly portable, has an excellent selection in its store and is refreshingly distraction-free. All of this is ideal for reading books. And iPad doesn’t offer any of it. What iPad does offer is versatility, variety, richness and luxury. It’s flush with accoutrements even if it’s low on focused, sustained text display. That makes it inferior to the Kindle for book reading. But that also makes it better than the Kindle for almost everything else. As such, and given that its book reading experience is still decent (even if not superior), I think the iPad will give Kindle a run for its money. True book lovers, and people on a budget, will want the Kindle. People with a robust amount of discretionary income may want both devices. Everyone else who is interested in a slate form factor e-reading device, especially if they also wish to have leisure-friendly Internet access, will likely choose the iPad exclusively. One thing is for sure: iPad has reduced Kindle’s market, and may have shifted its mass market potential to a mere niche play. If Amazon is smart, it will improve its iPad-based Kindle reader app significantly. It can then leverage the iPad channel as a significant market for the Kindle Store. After all, selling the eBooks themselves is what Amazon should care most about.

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  • How to Run Low-Cost Minecraft on a Raspberry Pi for Block Building on the Cheap

    - by Jason Fitzpatrick
    We’ve shown you how to run your own blocktastic personal Minecraft server on a Windows/OSX box, but what if you crave something lighter weight, more energy efficient, and always ready for your friends? Read on as we turn a tiny Raspberry Pi machine into a low-cost Minecraft server you can leave on 24/7 for around a penny a day. Why Do I Want to Do This? There’s two aspects to this tutorial, running your own Minecraft server and specifically running that Minecraft server on a Raspberry Pi. Why would you want to run your own Minecraft server? It’s a really great way to extend and build upon the Minecraft play experience. You can leave the server running when you’re not playing so friends and family can join and continue building your world. You can mess around with game variables and introduce mods in a way that isn’t possible when you’re playing the stand-alone game. It also gives you the kind of control over your multiplayer experience that using public servers doesn’t, without incurring the cost of hosting a private server on a remote host. While running a Minecraft server on its own is appealing enough to a dedicated Minecraft fan, running it on the Raspberry Pi is even more appealing. The tiny little Pi uses so little resources that you can leave your Minecraft server running 24/7 for a couple bucks a year. Aside from the initial cost outlay of the Pi, an SD card, and a little bit of time setting it up, you’ll have an always-on Minecraft server at a monthly cost of around one gumball. What Do I Need? For this tutorial you’ll need a mix of hardware and software tools; aside from the actual Raspberry Pi and SD card, everything is free. 1 Raspberry Pi (preferably a 512MB model) 1 4GB+ SD card This tutorial assumes that you have already familiarized yourself with the Raspberry Pi and have installed a copy of the Debian-derivative Raspbian on the device. If you have not got your Pi up and running yet, don’t worry! Check out our guide, The HTG Guide to Getting Started with Raspberry Pi, to get up to speed. Optimizing Raspbian for the Minecraft Server Unlike other builds we’ve shared where you can layer multiple projects over one another (e.g. the Pi is more than powerful enough to serve as a weather/email indicator and a Google Cloud Print server at the same time) running a Minecraft server is a pretty intense operation for the little Pi and we’d strongly recommend dedicating the entire Pi to the process. Minecraft seems like a simple game, with all its blocky-ness and what not, but it’s actually a pretty complex game beneath the simple skin and required a lot of processing power. As such, we’re going to tweak the configuration file and other settings to optimize Rasbian for the job. The first thing you’ll need to do is dig into the Raspi-Config application to make a few minor changes. If you’re installing Raspbian fresh, wait for the last step (which is the Raspi-Config), if you already installed it, head to the terminal and type in “sudo raspi-config” to launch it again. One of the first and most important things we need to attend to is cranking up the overclock setting. We need all the power we can get to make our Minecraft experience enjoyable. In Raspi-Config, select option number 7 “Overclock”. Be prepared for some stern warnings about overclocking, but rest easy knowing that overclocking is directly supported by the Raspberry Pi foundation and has been included in the configuration options since late 2012. Once you’re in the actual selection screen, select “Turbo 1000MhHz”. Again, you’ll be warned that the degree of overclocking you’ve selected carries risks (specifically, potential corruption of the SD card, but no risk of actual hardware damage). Click OK and wait for the device to reset. Next, make sure you’re set to boot to the command prompt, not the desktop. Select number 3 “Enable Boot to Desktop/Scratch”  and make sure “Console Text console” is selected. Back at the Raspi-Config menu, select number 8 “Advanced Options’. There are two critical changes we need to make in here and one option change. First, the critical changes. Select A3 “Memory Split”: Change the amount of memory available to the GPU to 16MB (down from the default 64MB). Our Minecraft server is going to ruin in a GUI-less environment; there’s no reason to allocate any more than the bare minimum to the GPU. After selecting the GPU memory, you’ll be returned to the main menu. Select “Advanced Options” again and then select A4 “SSH”. Within the sub-menu, enable SSH. There is very little reason to keep this Pi connected to a monitor and keyboard, by enabling SSH we can remotely access the machine from anywhere on the network. Finally (and optionally) return again to the “Advanced Options” menu and select A2 “Hostname”. Here you can change your hostname from “raspberrypi” to a more fitting Minecraft name. We opted for the highly creative hostname “minecraft”, but feel free to spice it up a bit with whatever you feel like: creepertown, minecraft4life, or miner-box are all great minecraft server names. That’s it for the Raspbian configuration tab down to the bottom of the main screen and select “Finish” to reboot. After rebooting you can now SSH into your terminal, or continue working from the keyboard hooked up to your Pi (we strongly recommend switching over to SSH as it allows you to easily cut and paste the commands). If you’ve never used SSH before, check out how to use PuTTY with your Pi here. Installing Java on the Pi The Minecraft server runs on Java, so the first thing we need to do on our freshly configured Pi is install it. Log into your Pi via SSH and then, at the command prompt, enter the following command to make a directory for the installation: sudo mkdir /java/ Now we need to download the newest version of Java. At the time of this publication the newest release is the OCT 2013 update and the link/filename we use will reflect that. Please check for a more current version of the Linux ARMv6/7 Java release on the Java download page and update the link/filename accordingly when following our instructions. At the command prompt, enter the following command: sudo wget --no-check-certificate http://www.java.net/download/jdk8/archive/b111/binaries/jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz Once the download has finished successfully, enter the following command: sudo tar zxvf jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz -C /opt/ Fun fact: the /opt/ directory name scheme is a remnant of early Unix design wherein the /opt/ directory was for “optional” software installed after the main operating system; it was the /Program Files/ of the Unix world. After the file has finished extracting, enter: sudo /opt/jdk1.8.0/bin/java -version This command will return the version number of your new Java installation like so: java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b111) Java HotSpot(TM) Client VM (build 25.0-b53, mixed mode) If you don’t see the above printout (or a variation thereof if you’re using a newer version of Java), try to extract the archive again. If you do see the readout, enter the following command to tidy up after yourself: sudo rm jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz At this point Java is installed and we’re ready to move onto installing our Minecraft server! Installing and Configuring the Minecraft Server Now that we have a foundation for our Minecraft server, it’s time to install the part that matter. We’ll be using SpigotMC a lightweight and stable Minecraft server build that works wonderfully on the Pi. First, grab a copy of the the code with the following command: sudo wget http://ci.md-5.net/job/Spigot/lastSuccessfulBuild/artifact/Spigot-Server/target/spigot.jar This link should remain stable over time, as it points directly to the most current stable release of Spigot, but if you have any issues you can always reference the SpigotMC download page here. After the download finishes successfully, enter the following command: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Note: if you’re running the command on a 256MB Pi change the 256 and 496 in the above command to 128 and 256, respectively. Your server will launch and a flurry of on-screen activity will follow. Be prepared to wait around 3-6 minutes or so for the process of setting up the server and generating the map to finish. Future startups will take much less time, around 20-30 seconds. Note: If at any point during the configuration or play process things get really weird (e.g. your new Minecraft server freaks out and starts spawning you in the Nether and killing you instantly), use the “stop” command at the command prompt to gracefully shutdown the server and let you restart and troubleshoot it. After the process has finished, head over to the computer you normally play Minecraft on, fire it up, and click on Multiplayer. You should see your server: If your world doesn’t popup immediately during the network scan, hit the Add button and manually enter the address of your Pi. Once you connect to the server, you’ll see the status change in the server status window: According to the server, we’re in game. According to the actual Minecraft app, we’re also in game but it’s the middle of the night in survival mode: Boo! Spawning in the dead of night, weaponless and without shelter is no way to start things. No worries though, we need to do some more configuration; no time to sit around and get shot at by skeletons. Besides, if you try and play it without some configuration tweaks first, you’ll likely find it quite unstable. We’re just here to confirm the server is up, running, and accepting incoming connections. Once we’ve confirmed the server is running and connectable (albeit not very playable yet), it’s time to shut down the server. Via the server console, enter the command “stop” to shut everything down. When you’re returned to the command prompt, enter the following command: sudo nano server.properties When the configuration file opens up, make the following changes (or just cut and paste our config file minus the first two lines with the name and date stamp): #Minecraft server properties #Thu Oct 17 22:53:51 UTC 2013 generator-settings= #Default is true, toggle to false allow-nether=false level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=false spawn-animals=true texture-pack= snooper-enabled=true hardcore=false online-mode=true pvp=true difficulty=1 player-idle-timeout=0 gamemode=0 #Default 20; you only need to lower this if you're running #a public server and worried about loads. max-players=20 spawn-monsters=true #Default is 10, 3-5 ideal for Pi view-distance=5 generate-structures=true spawn-protection=16 motd=A Minecraft Server In the server status window, seen through your SSH connection to the pi, enter the following command to give yourself operator status on your Minecraft server (so that you can use more powerful commands in game, without always returning to the server status window). op [your minecraft nickname] At this point things are looking better but we still have a little tweaking to do before the server is really enjoyable. To that end, let’s install some plugins. The first plugin, and the one you should install above all others, is NoSpawnChunks. To install the plugin, first visit the NoSpawnChunks webpage and grab the download link for the most current version. As of this writing the current release is v0.3. Back at the command prompt (the command prompt of your Pi, not the server console–if your server is still active shut it down) enter the following commands: cd /home/pi/plugins sudo wget http://dev.bukkit.org/media/files/586/974/NoSpawnChunks.jar Next, visit the ClearLag plugin page, and grab the latest link (as of this tutorial, it’s v2.6.0). Enter the following at the command prompt: sudo wget http://dev.bukkit.org/media/files/743/213/Clearlag.jar Because the files aren’t compressed in a .ZIP or similar container, that’s all there is to it: the plugins are parked in the plugin directory. (Remember this for future plugin downloads, the file needs to be whateverplugin.jar, so if it’s compressed you need to uncompress it in the plugin directory.) Resart the server: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Be prepared for a slightly longer startup time (closer to the 3-6 minutes and much longer than the 30 seconds you just experienced) as the plugins affect the world map and need a minute to massage everything. After the spawn process finishes, type the following at the server console: plugins This lists all the plugins currently active on the server. You should see something like this: If the plugins aren’t loaded, you may need to stop and restart the server. After confirming your plugins are loaded, go ahead and join the game. You should notice significantly snappier play. In addition, you’ll get occasional messages from the plugins indicating they are active, as seen below: At this point Java is installed, the server is installed, and we’ve tweaked our settings for for the Pi.  It’s time to start building with friends!     

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  • Rails 3 / RVM - Acts_as_list compiled locally - Why Can't Ruby See This Gem?

    - by rabbit on rails
    I cannot figure out why rails/ruby cannot see this gem, despite each telling me that the gem is visible. I compiled this gem locally from a github branch since the main version seems to be broken in Rails 3. Or perhaps I am missing something else entirely. Ovid:lightserve dlipa$ gem list *** LOCAL GEMS *** .. acts_as_list (0.2.1) .. And Ovid:lightserve dlipa$ cat Gemfile ... gem "acts_as_list", "0.2.1" ... And Ovid:lightserve dlipa$ bundle install ... Using acts_as_list (0.2.1) Your bundle is updated! Use `bundle show [gemname]` to see where a bundled gem is installed But Ovid:lightserve dlipa$ r c RubyGems Environment: - RUBYGEMS VERSION: 1.6.1 - RUBY VERSION: 1.9.2 (2011-02-18 patchlevel 180) [x86_64-darwin10.6.0] - INSTALLATION DIRECTORY: /Users/dlipa/.rvm/gems/ruby-1.9.2-p180 - RUBY EXECUTABLE: /Users/dlipa/.rvm/rubies/ruby-1.9.2-p180/bin/ruby - EXECUTABLE DIRECTORY: /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/bin - RUBYGEMS PLATFORMS: - ruby - x86_64-darwin-10 - GEM PATHS: - /Users/dlipa/.rvm/gems/ruby-1.9.2-p180 - /Users/dlipa/.rvm/gems/ruby-1.9.2-p180@global - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :benchmark => false - :backtrace => false - :bulk_threshold => 1000 - :sources => ["http://rubygems.org/", "http://gems.github.com"] - REMOTE SOURCES: - http://rubygems.org/ - http://gems.github.com Loading development environment (Rails 3.0.5) ruby-1.9.2-p180 :001 > require 'acts_as_list' LoadError: no such file to load -- acts_as_list from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:239:in `require' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:239:in `block in require' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:225:in `block in load_dependency' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:596:in `new_constants_in' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:225:in `load_dependency' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/activesupport-3.0.5/lib/active_support/dependencies.rb:239:in `require' from (irb):1 from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.5/lib/rails/commands/console.rb:44:in `start' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.5/lib/rails/commands/console.rb:8:in `start' from /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/gems/railties-3.0.5/lib/rails/commands.rb:23:in `<top (required)>' from script/rails:6:in `require' from script/rails:6:in `<main>' ruby-1.9.2-p180 :002 > And Ovid:lightserve dlipa$ irb ruby-1.9.2-p180 :001 > require 'acts_as_list' LoadError: no such file to load -- acts_as_list from /Users/dlipa/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require' from /Users/dlipa/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in `require' from (irb):1 from /Users/dlipa/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>' ruby-1.9.2-p180 :002 > Can anyone explain why this might be happening? I'd really appreciate it! ** UPDATE -- Response to Andrew Marshall's suggestion** I changed Gemfile to read the gem directly from git, but it did not resolve the problem. Does this mean that there is a problem with this gem? The error message is not very helpful ;-) Removed: Ovid:lightserve dlipa$ bundle show acts_as_list Could not find gem 'acts_as_list' in the current bundle. Then added back via: gem "acts_as_list", :git => "git://github.com/vpereira/acts_as_list.git" Ovid:lightserve dlipa$ bundle install Updating git://github.com/vpereira/acts_as_list.git ... Same problem even though bundle show matches the commit on that page: Ovid:lightserve dlipa$ bundle show acts_as_list /Users/dlipa/.rvm/gems/ruby-1.9.2-p180/bundler/gems/acts_as_list-4cb76a8b198c Ovid:lightserve dlipa$ irb ruby-1.9.2-p180 :001 > require 'acts_as_list' LoadError: no such file to load -- acts_as_list from /Users/dlipa/.rvm/rubies/ruby-1.9.2-.. I just looked in the gem and it appears there is no file called 'acts_as_list' in the gem. So it appears to be idiosyncratic, albeit poorly reported by Rails/Ruby. The API appears to have changed to: ruby-1.9.2-p180 :003 > require 'active_record/acts/list' => nil ruby-1.9.2-p180 :004 > ActiveRecord::Acts::List => ActiveRecord::Acts::List

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