Category Archives: mono

Microsoft takes its .NET runtime open source and cross-platform, announces new C++ compilers for iOS and Android: unpacking today’s news

Microsoft announced today that the .NET runtime will be open source and cross-platform for Linux and Mac. There are a several announcements and it is potentially confusing, so here is a quick summary.

The .NET runtime, also known as the CLR (Common Language Runtime) is the virtual machine that runs Microsoft’s C#, F# and Visual Basic .NET languages, performing just –in-time compilation to native code and providing interop between the application code and the operating system APIs. It is distinct from the .NET Framework, which is the library of mostly C# code that underlies application platforms like ASP.NET, Windows Presentation Foundation (WPF), Windows Forms, Windows Communication Foundation and more.

There is is already a cross-platform version of .NET, an open source project called Mono founded by Miguel de Icaza in 2001, not long after the first preview release of C# in 2000. Mono runs on Linux, Mac and Windows. In addition, de Icaza is co-founder of Xamarin, which uses Mono together with its own technology to compile C# for iOS, Android and Mac OS X.

Further, some of .NET is already open source. At Microsoft’s Build conference earlier this year, Anders Hejlsberg made the Roslyn project, the compiler for the next generation of the .NET Runtime, open source under the Apache 2.0 license. I spoke to Hejlsberg about the announcement and wrote it up on the Register here. Note the key point:

Since Roslyn is the compiler for the forthcoming C# 6.0, does that mean C# itself is now an open source language? “Yes, absolutely,” says Hejlsberg.

What then is today’s news? Blow by blow, here are what seems to me the main pieces:

  • The CLR itself will be open source. This is the C++ code from which the CLR is compiled.
  • Microsoft will provide a full open source server stack for Mac and Linux including the CLR. This will not include the frameworks for client applications; no Windows Forms or WPF. Rather, it is the “.NET Core Runtime” and “.NET Core Framework”. However Microsoft is working with the Mono team which does support client applications so there could be some interesting permutations (bear in mind that Mono also has its own runtime). However Microsoft is focused on the server stack.
  • Microsoft will release C++ frameworks and compilers for iOS and Android, using the open source Clang (C and C++ compiler front-end) and LVVM (code generation back end), but with Visual Studio as the IDE. If you are targeting iOS you will need a Mac with a build agent, or you can use a cloud build service (see below). The Android compiler is available now in preview, the iOS compiler is coming soon. “You can edit and debug a single set of C++ source code, and build it for iOS, Android and Windows,” says Microsoft’s Soma Somasegar, corporate VP of the developer division.
  • Microsoft has a new Android emulator for Windows based on Hyper-V. This will assist with Android development using Cordova (the HTML and JavaScript approach also used by PhoneGap) as well as the new C++ option.


  • The next Visual Studio will be called Visual Studio 2015 and is now available in preview; download it here.
  • There will be a thing called Connected Services to make it easier to code against Office 365, Salesforce and Azure
  • A new edition of Visual Studio 2013, called the Community Edition, is now available for free, download it here. The big difference between this and the current Express editions is first that the Community Edition supports multiple target types, whereas you needed a different Express edition for Web applications, Windows Store and Phone apps, and Windows desktop apps.  Second, the Community Edition is extensible so that third parties can create plug-ins; today Xamarin was among the first to announce support. There may be some license restrictions; I am clarifying and will update later.
  • New Cloud Deployment Projects for Azure enable the cloud infrastructure associated with a project to be captured as code.
  • Release Management is being added to Visual Studio Online, Microsoft’s cloud-hosted Team Foundation Server.
  • Enhancements to the Visual Studio Online build service will support builds for iOS and OS X
  • Visual Studio 2013 Update 4 is complete. This is not a big update but adds fixes for TFS and Visual C++ as well as some new features in TFS and in GPU performance diagnostics.

The process by which these new .NET projects will interact with the open source community will be handled by the .NET Foundation.

What is Microsoft up to?

Today’s announcements are extensive, but with two overall themes.

The first is about open sourcing .NET,  a process that was already under way, and the second is about cross-platform.

It is the cross-platform announcements that are more notable, though they go hand in hand with the open source process, partly because of Microsoft’s increasingly close relationship with Mono and Xamarin. Note that Microsoft is doing its own C++ compilers for iOS and Android, but leaving the mobile C# and .NET space open for Xamarin.

By adding native code iOS and Android mobile into Visual Studio, Microsoft is signalling real commitment to these platforms. You could interpret this as an admission that Windows Phone and Windows tablets will never reach parity with their rivals, but it is more a consequence of the company’s focus on cloud, and in particular Office 365 and Azure. The company is prioritising the promotion of its cloud services by providing strong tooling for all major client platforms.

The provision of new Microsoft server-side .NET runtimes for Mac and Linux is a surprise to me. The Mac is not much used as a server but very widely used for development. Linux is an increasingly important operating system within the Azure cloud platform.

A side effect of all this is that the .NET Framework may finally fulfil its cross-platform promise, something Microsoft suppressed for years by only supporting it on Windows. That is good news for those who like programming in C#.

The .NET Framework is changing substantially in its next version. This is partly because of the Roslyn compiler, which is itself written in C# and opens up new possibilities for rich refactoring and code transformation; and partly because of .NET Core and major changes in the forthcoming version of ASP.NET.

Is Microsoft concerned that by supporting Linux it might reduce the usage of Windows Server? “In Azure, Windows and Linux are a core part of our platform,” Somesegar told me. “Helping developers by providing a good set of tools and letting them decide what server they run on, we feel is all goodness. If you want a complete open source platform, we have the tools for them.”

How big are these announcements? “I would say huge,”  Somasegar told me, “What is shows is that we are not being constrained by any one platform. We are doing more open source, more cross-platform, delivering Visual Studio free to a broader set of people. It’s all about having a great developer offering irrespective of what platform they are targeting or what kind of app they are building.”

That’s Microsoft’s perspective then. In the end, whether you interpret these moves as a sign of strength or weakness for Microsoft, developers will gain from these enhancements to Visual Studio and the .NET platform.

Xamarin announces large round of funding, plans international expansion

It is a case of “right time, right place” for Xamarin, as it scoops up Windows developers who need either to transition to iOS and Android, or to add mobile support to existing applications. You can also port applications to the Mac with its cross-platform development framework based on C#; no bad thing as Mac sales continue to boom.


Xamarin also fits with Microsoft’s new strategy, as I understand it, which is to provide strong support for iOS and Android for applications such as Microsoft Office, and services such as those hosted on Microsoft Azure.

Now the company has announced an additional $54 million of funding, which CEO Nat Friedman tells me is “the largest round of financing achieved by any mobile platform company ever”.

The financing comes from “new and existing investors, including Lead Edge Capital, Insight Venture Partners, Charles River Ventures, Ignition Partners, and Floodgate.”

What will the money be spent on? “Two things,” says Friedman. “We’re planning to expand our sales and marketing into Europe. We’re opening a sales office in London in the Fall. We did a roadshow with Microsoft in Europe and it was extremely successful. Second, we’re going to invest in improving the quality of our platforms.”

Friedman notes that mobile should not be considered a development niche. “Our view is that in the future all software will be mobile software in some way or another, when you build an application it will have to have some kind of mobile surface area.”

A few other points to note. One is that Xamarin Forms, recently introduced, has been a big hit with developers. “The Xamarin Forms forum has been our most popular forum,” says Friedman. “We’ve been really surprised.”

The company used to promote the idea of avoiding cross-platform code for the user interface, but then introduced Xamarin Forms as a cross-platform GUI framework, arguing that because it uses only native controls, it avoids the main drawbacks of the idea.

Some of the funding then will go into improving Xamarin Forms and tools to work with the framework.

Another key area is Visual Studio integration. The acquisition of the Visual Studio integration team from Clarius Consulting, in May 2014, is also significant here, since Clarius had strong expertise in this area.

Might Microsoft try to acquire Xamarin? Interesting question, and one which Friedman is not in a position to discuss; I am not a financial expert but would guess that Xamarin’s independent expansion increases its ability to be independent, though investors may be hoping to reap the rewards of an acquisition, who knows?

Microsoft Build 2014: what happened

It’s curious. Microsoft’s new CEO Satya Nadella has been in place for only a month which means that almost everything announced at Build, Microsoft’s developer conference which took place last week in San Francisco, must have been set before he was appointed; yet there was a sense of “all things new” at the event, as if he had overseen a wave of changes.

The wave began the previous week, with the simultaneous announcement and delivery of Office for iPad. The significance of this is threefold:

  • It demonstrated Microsoft’s decision to give first-class support to mobile platforms other than Windows
  • It demonstrated that Office can be redesigned to work nicely on a tablet
  • The quality of the product exceeded expectations, showing that in the right circumstances Microsoft can do excellent non-Windows software


Next came Build itself. It was a tale of two keynotes. The first was all about Windows client – both Phone and PC. The core news is the arrival of the Windows Runtime  (WinRT, the engine behind Metro/Store Apps) on Windows Phone 8.1. This means that WinRT is now the runtime that developers should target for apps that run across phone and desktop – and even, we were shown, Xbox One, which will support WinRT apps written in HTML and WinJS (Microsoft’s JavaScript library for Windows apps).

In support of this, Microsoft announced a new Universal App project for Visual Studio, which lets you share both visual and non-visual code across multiple targets. How much is shared is a developer choice.

There is more. A Universal App is now (kind-of) a desktop app as well as a Store app, since in a future free update to Windows 8, it will run on the desktop within a window, as well as appearing in the Start menu on the desktop. We were even shown this; apparently it is a mock-up. This was the biggest surprise at Build.


What did Executive VP Terry Myerson say about this? Here is the exact quote:

We are going all in with this desktop experience, to make sure your applications can be accessed and loved by people that love the Windows desktop. We’re going to enable your Universal Windows applications to run in a window. We’re going to enable your users to find, discover and run your Windows applications with the new Start menu. We have Live Tiles coming together with the familiar experience customers are looking for to start and run their applications and we’ll be making this available to all Windows 8.1 users as an update. I think there will be a lot of happy people out there.

This is significant. When Myerson says, “we are going all in with this desktop experience”, he does not mean backtracking on Windows Store apps, to return to desktop windows apps (Win32 or WPF) as the future of Windows development. Rather, he means Windows Store apps integrated into the desktop.

There is a further twist to this. Windows Store apps are sandboxed and cannot communicate with each other or with the operating system other than via carefully designed and secured paths. This is in general a good thing, but restrictive for businesses designing line of business apps. It also means that legacy code cannot be carried over into a Store app, other than by full porting.

In the just-released Windows 8.1 Update this has changed. Side-loaded apps (in other words, not deployed from the Windows Store) can now escape the sandbox thanks to Brokered Windows Runtime Components. There are some limitations (32-bit only on the desktop side, for example) but this will make it possible to implement business applications as Store apps even if they need to interact with existing desktop applications or services.

There is still a huge blocker to Store apps from a business perspective, which is that you need Windows 8. Still, my guess is that once the update with the restored Start menu appears, most of the objections to Windows 8 will melt away.

We also saw Office for the Windows Runtime, which will run on both Phone and PC. It is written, I discovered later, in XAML, DirectX and C++ (“Blazingly fast”, we were told). Corporate VP Kirk Koenigsbauer introduced a preview of this, or at least PowerPoint.


No detail yet, and several references to “early code” suggest to me that this is a year or more away from full release (giving Office on iPad a big head start); but it will come. Koenigsbauer did not call it cut-down; in fact, it was instanced as proof that WinRT is suitable for large-scale apps, so I would expect something more complete than Office on iPad; yet it is hard to imagine things like the VBA macro language appearing here in its current form (VBA is based on the ancient Visual Basic 6.0 runtime), so there will be some major differences.

We also saw Windows Phone 8.1, including the Cortana virtual personal assistant who responds to voice input. For me other things in Windows Phone 8.1 are more significant, including new swipe-style keyboard for fast text input, VPN, S/MIME secure email, and a new notification centre. Unlike touch Office, Windows Phone 8.1 is coming soon; Nokia’s Stephen Elop (soon to be in charge of Windows Phone at Microsoft) said that the first 8.1 Lumia devices could be out from May, depending on territory, and that all Lumia Windows Phone 8 devices will get the update in the summer.

On to day two, which was Cloud day, though we also got significant .NET developer news.

Executive VP Scott Guthrie introduced a new portal for Microsoft Azure, the cloud platform. This is not just a new look, but integrates with Visual Studio online so you can easily view and edit the code and track team projects. There are also new monitoring and analytics features so you can check page views, page load time, browser usage and more. Guthrie also announced integration with Puppet and Chef for deployment automation.


Language designer Anders Hejsberg also came on stage. He announced the release version of TypeScript, a “typed superset of JavaScript” which is suitable for large applications. He also announced a new preview release of the compiler project code-named Roslyn, and on stage pushed the button that published it as open source. What is Roslyn? It is the next generation compiler for C# and VB, and is itself written in C#. This enables compiler and workspace APIs, which in turn enable rich editor features:

The transition to compilers as platforms dramatically lowers the barrier to entry for creating code focused tools and applications. It creates many opportunities for innovation in areas such as meta-programming, code generation and transformation, interactive use of the C# and VB languages, and embedding of C# and VB in domain specific languages.

Roslyn will be fully released in the next version of Visual Studio, for which we do not yet have a date. Roslyn will be delivered alongside C# 6.0.

There is also a new .NET Foundation which will oversee open source projects for .NET, with backing from folk including Xamarin’s Miguel de Icaza and Umbraco’s Niels Hartvig. It is all a bit vague at the moment:

In the upcoming months, the .NET Foundation will be inviting many companies and community leaders to join the foundation, including its Board of Directors and will then finalize its operational details, including governance models for its open source initiatives, membership structure and industry and community engagement.

Another significant event in the .NET story is the arrival of true native code compilation for .NET, although currently only for 64-bit Store apps. More on this soon.

A couple of events during Build caught my eye. One was de Icaza’s session on using C# to build for iOS and Android, not so much for the content itself (though there was nothing wrong with it), but rather for the huge attendance it drew.


The session was moved to the Build keynote room, and while there were spare seats, the room felt well filled. This speaks loudly about the importance of those platforms even to Microsoft platform developers, as well as of Microsoft’s support of Xamarin’s work.

Another was the appearance of John Gruber, author of the Daring Fireball blog and an Apple enthusiast. He appeared in a video during the keynote, explaining how a project in which he is involved uses Azure for back-end services, and then in person at another session, interviewing journalist Ed Bott about what is changing at Microsoft.


Gruber seems to me representative of a group of smart observers who have not in general been impressed with Microsoft’s endeavours over the past few years; but he for one is now more positive on the subject. Windows Phone is much better than its market share suggests, he said. This alongside Azure and a new openness to supporting third-party clients has made him look more favourably on the company.

My summary is this. On the Windows client side, Microsoft is taking its unpopular Windows release and its minority Phone platform and making them better and more compatible with each other, making sense of the client platform in a way that should result in growth of the app ecosystem both on Phone and PC/Tablet. On the cloud side, the company is building Azure and Office 365 (two platforms united by Azure Active Directory) into a one-stop platform that is increasingly compelling. The result was a conference and a direction that was largely welcomed by those in attendance, as far as I could tell.

That does not mean that the PC will stop declining, or that iOS and Android will become less dominant in mobile. There is progress though, and more clarity about the direction of Microsoft’s platform than we have seen for some years.

For the official news from Build, see the Build Newsroom.

What does Xamarin’s success say about open source versus proprietary? Miguel de Icaza says he has never been happier


Yesterday Xamarin, which offers tools for targeting iOS, Android and Mac with C#, announced a partnership with Microsoft, an announcement which I wrote up on The Register. It drew a few comments, several complaining about the cost:

So it cost more then Visual Studio Pro.

And that is for 1 target platform?


Not so useful for little indie developers at those prices.


From open source to $999 per developer per year. Monetising Mono seems to have worked, so perhaps PCL being open sourced won’t be such a bargain either.

If you check Xamarin’s pricing you will see that the tools are not cheap for casual users; of course, if you are selling thousands of apps or developing corporate apps at normal rates the tools soon pay for themselves.

Xamarin is doing well as far as I am aware; CEO Nat Friedman told me of rapid growth in the number of customers and I have seen for myself the high interest in the tools at events like Microsoft BUILD earlier this year in San Francisco.

This gives me pause for reflection. What does the success of Xamarin, and the relative lack of success of Mono (the open source C# compiler and .NET Framework on which Xamarin is based) say about how well the open source business model works in the real world?

I was reminded of a conversation I had with Miguel de Icaza, creator of Mono and co-founder of Xamarin, Friedman back in February of this year, when Xamarin 2.0 was launched. I asked de Icaza if the new company publishes the source code for all its products?

“No. Our company does proprietary tools for iOS and Android apps. The entire iOS and Android support is proprietary as well as our commercial Mac support. All those three pieces are proprietary while the IDE and the Mono runtime are open source. Whether the code is open source or not depends on whether it is part of core Mono or core MonoDevelop. Otherwise it tends to end up as proprietary.”

Friedman added: “Mono has a thriving open source community around it, and Xamarin has a thriving community of developers who are building commercial mobile apps. We have 12,000 customers, many of them have never heard of Mono. They came to us because they had a problem to solve, they were C# developers and they wanted to get an iOS or Android app built. We solved that problem and that was worth money to them. The reason we have a business is that Microsoft developers do pay for tools, unlike Web developers for example. It’s been a great market for us. It allows us to invest.”

I asked de Icaza if he gets any grief from the open source community for having proprietary code in his company.

“Actually no. We started doing the proprietary bit at Novell. In fact we’ve been doing proprietary for a long time, even before we were acquired by Novell, at Ximian. We didn’t get a lot of grief from people. I can tell you though that when I was working in the Linux world, they were very stressful days for me, because people constantly complain about a “secret conspiracy” and that thing just went out of control. There are some advocates in the Linux world that don’t like anything that has the label Microsoft on.

“Ever since we did Xamarin which meant we focused on Mac and Windows, all that stress is gone, I don’t think I have ever been happier. In the past I was enduring this constant barrage of senseless attacks, and now I never hear about this.

“One thing that happened in the Linux world is that I was very proud of the four or five big apps that were built with Mono. F-spot that we built, Banshee, and a couple of others. Now with Xamarin I can’t keep track of them any more because they are measured in the thousands. There are thousands of very large apps, over a millions lines of code, that people send us. It’s a very different world, it’s just so much larger than all the work we did in Linux days back then.”

Build Mac and iOS apps in Visual Studio: Oxygene for Cocoa

Remobjects has released Oxygene for Cocoa, which lets you build apps for Mac and iOS using Visual Studio and the Oxygene language.

Oxygene is a Delphi-like language, making this an easy transition for Delphi developers. Until the most recent release, a version of Oxygene, called Prism, was bundled with Delphi, though this targeted .NET rather than Cocoa. Oxygene can also build apps for the Java runtime, making it a three platform solution.

The cross-platform approach is different from that taken by Embarcadero with FireMonkey, a cross-platform framework for Delphi itself. FireMonkey abstracts the GUI as well as the non-visual code, and in many cases controls are drawn by FireMonkey rather than using the native controls on platforms such as iOS. By contrast, Oxygene works directly with the Cocoa frameworks, so you will build the GUI in code or using the Xcode tools on the Mac.

More like Xamarin then? “We do work together with Mono and with Xamarin,” says Remobjects chief Marc Hoffman. “Oxygene for .NET works with the regular Mono framework for desktop or server apps. But when you get to the devices, the benefit with Oxygene is that you get much closer to the framework, you don’t have the weight of providing an abstraction for the classes you want to use.  If you write a UITableViewController to define a view, then you really write a UITableViewController, the same as you would in Objective-C, just the language is different, whereas in Xamarin you write a different class that sits on top and Mono does the mapping.”

Why not just use Xcode? This is in part a language choice. Remobjects says that Oxygene is “better than Objective-C” thanks to features like automatic boxing of integers, floats and strings, and generic arrays. There is more about the language here. Perhaps more important, if you know Pascal or Delphi it will look more familiar. You also get the ability to share code between Windows, Android, Mac and iOS, though this will be the non-visual code. Developers can also work mainly in Visual Studio rather than in Xcode.

The disadvantage is that you need two machines, or a VM running Windows on a Mac, and a remote connection to a Mac in order to debug.

I plan to try out Oxygene for Cocoa soon and of course will report on the experience.

Xamarin 2.0 and Xamarin Studio announced, build for OSX, iOS and Android with C#

Xamarin has announced significant updates to its developer platform. Xamarin is the company formed around 18 months ago, when Novell discontinued its investment in Mono, a cross-platform implementation of C# and the .NET Framework. Its focus is on mobile platforms, in particular iOS and Android, though there is also support for the Mac. On Windows and Windows Phone, the presumption is that developers will continue to use Microsoft’s .NET Framework.

“If you look at what you can develop with C#, there’s about 1.2 billion Windows machines out there, but there’s now about a billion Android and iOS devices. Together we can make C# a universal language for application development and reach 2.2 billion devices,” Xamarin co-founder and CEO Nat Friedman told me.

“There’s a wonderful built-in audience of C# developers, millions of them, who need a bridge to mobile. We can help them take their existing skills and tools, and even code they’ve already written, and bring them to mainstream mobile platforms like iOS and Android.”

The key announcements:

  • Xamarin Studio is  an updated version of MonoDevelop, the Mono IDE. It runs on Mac and Windows.#
  • You can now develop iOS apps in Visual Studio for the first time
  • MonoTouch, the framework for iOS, has been renamed Xamarin.iOS
  • Mono for Android is now called Xamarin.Android
  • A new component store has pre-built components for download, some free, some commercial.
  • Xamarin now offers a free Starter edition, and pricing plans for independent developers, smaller businesses, and enterprises. Indie is $299 per platform per year, Business is $999 per platform/year, and Enterprise $1800 platform/year.

The Starter edition is not much use. It has a limited app size, and even the sample project I downloaded, an Employee Directory, exceeded that size and I had to register for a trial.

Xamarin’s philosophy is to share non-visual code, but to create a user interface that is native for each platform. This is a compromise in terms of the effort involved in supporting multiple platforms, but ensures a native experience on each device. “That’s fundamental to our platform,” says Friedman. “We tell our developers to separate the UI layer from the rest of the app. That allows them to share all the non-UI code across platforms, but to deliver a fully native UI, even though the whole app is written in C#. That’s what users demand now, people want native experiences.”

“We’ve been building tools that essentially project the underlying iOS APIs or Java [Android] APIs into C#”, explains co-founder Miguel de Icaza. “What it means is that people need to build a new UI for each platform.” He adds that Microsoft platform developers should be used to this, as Microsoft itself has several similar but incompatible .NET platforms. “There’s the one on Silverlight, the one on WPF, the one on Windows RT, and the one on the phone, it’s four,” he says. “Developers have had to resort to putting their logic into shared libraries, and build a per-platform UI. We’re reusing that knowledge.”

The ability to develop for iOS in Visual Studio is new. “It’s our most-requested feature of all time.” said Friedman.

I downloaded Xamarin Studio, which in my case was around 1.3GB including an updated Android SDK.


The IDE itself is clean and fast, and very much code-centric. It lacks the bloat of Visual Studio, though you will miss many of the features of Microsoft’s IDE.


I build the sample Employee Directory app and deployed it to an Android emulator which I use for Nexus 7 development. Deploying the runtime components took a long time, but after waiting patiently the app launched successfully.


If you want to do iOS development you will need a Mac of course. Although you can code on Windows, if you then the code is pushed over the the Mac side for compilation and debugging. In order to use Visual Studio, one option is to run Windows in a virtual machine on a Mac, as I have done with reasonable success using Embarcadero’s cross-platform tools.

Xamarin says it is growing fast. There have been 230,000 downloads of its tools, increasing by around 700 per day, and over 12,000 paying customers.

Despite Xamarin’s roots in the open source world (and Mono is still open source), a quick look at the pricing table shows that this is a fully commercial offering and priced accordingly. Presuming customers keep on subscribing, that is a good thing, ensuring the future of the platform; but it is not so good for the smallest developers who might otherwise give it a try.

Xamarin brings C# to development of apps for the Mac App Store

Xamarin has released Xamarin Mac which adds Mac support to the existing iOS and Android compilers from the company:

  • MonoTouch: apps for iPhone and iPad using the MonoDevelop IDE on the Mac
  • Mono for Android: apps for Android using either Visual Studio or MonoDevelop
  • Xamarin.Mac: apps for Mac OS X using MonoDevelop on the Mac

The major platforms missing from the above are Windows and Linux (unless you count Android), even though Mono began as a Linux implementation of Microsoft’s .NET platform.

Xamarin says that a Windows version is not necessary since you can use Microsoft’s tools to code in C# for Windows desktop and Windows phone.

You can also get Mono for Windows, Mac and Linux from the old Mono project site.

Why would you bother with paid-for Xamarin.Mac when you can get Mono for Mac as a free download? There is even a Mac packager which lets you create a standalone package for your Mono app. A good question, but I guess the answer is the benefit of Xamarin-specific libraries and support from the company. Xamarin has also done the work to ensure that you can distribute your app via the Mac App Store.

Xamarin.Mac costs $399 for personal use, or $999 for an enterprise license which allows internal as well as app store distribution. A one year, one seat license with priority support costs $2,499.

Xamarin knows how to charge then, and in the end that may be a key reason why the project is working, whereas Mono struggled as an open source project that never had the resources it deserved.

The Mono Project site now says that it is “sponsored by Xamarin” so open source developers are getting some benefit from the commercial offshoot.

Xamarin is important for the C# language, since it represents a viable implementation which is independent of Microsoft.

GPU Programming for .NET: Tidepowerd’s GPU.NET gets some improvements, more needed

When I attended the 2010 GPU programming conference hosted by NVIDIA I encounted Tidepowerd, which has a .NET library called GPU.NET for GPU programming.

GPU programming enables amazing performance improvements for certain types of code. Most GPU programming is done in C/C++, but Typepowerd lets you run code in .NET, simply marking any methods you want to run on the GPU with a [kernel] attribute:


private static void AddGpu(float[] a, float[] b, float[] c)


// Get the thread id and total number of threads

int ThreadId = BlockDimension.X * BlockIndex.X + ThreadIndex.X;

int TotalThreads = BlockDimension.X * GridDimension.X;

for (int ElementIndex = ThreadId; ElementIndex < a.Length; ElementIndex += TotalThreads)


c[ElementIndex] = a[ElementIndex] + b[ElementIndex];



GPU.NET is now at version 2.0 and includes Visual Studio Error List and IntelliSense support. This is useful, since some C# code will not run on the GPU. Strings, for example, are not supported. Take a look at this article which lists .NET OpCodes that do not work in GPU.NET.

GPU.NET requires an NVIDIA GPU with CUDA support and a CUDA 3.0 driver. It can run on Mac and Linux using Mono, the open source implementation of .NET. In principle, GPU.NET could also work with AMD GPUs or others via a vendor-specific runtime:


but the latest FAQ says:

Support for AMD devices is currently under development, and support for other hardware architectures will follow shortly.

Another limitation is support for multiple GPUs. If you want to do serious supercomputing relatively cheaply, stuffing a PC with a bunch of Tesla GPUs is a great way to do it, but currently GPU.NET only used one GPU per active thread as far as I can tell from this note:

The GPU.NET runtime includes a work-scheduling system which can distribute device method (“kernel”) calls to multiple GPUs in the system; at this time, this only works for applications which call device-based methods from multiple host threads using multiple CPU cores. In a future release, GPU.NET will be able to use multiple GPUs to execute a single method call.

I doubt that GPU.NET or other .NET libraries will ever compete with C/C++ for performance, but ease of use and productivity count for a lot too. Potentially GPU.NET could bring GPU programming to the broad range of .NET developers.

It is also worth checking out hoopoe’s CUDA.NET and OpenCL.NET which are free libraries. I have not done a detailed comparison but would be interested to hear from others who have.

The strategy behind Mono has shifted: ten years of open source .NET

Yesterday, SUSE and Xamarin announced, in effect, the transfer of all things Mono to Xamarin.

The agreement grants Xamarin a broad, perpetual license to all intellectual property covering Mono, MonoTouch, Mono for Android and Mono Tools for Visual Studio. Xamarin will also provide technical support to SUSE customers using Mono-based products, and assume stewardship of the Mono open source community project.

Xamarin is a startup formed by Mono founder Miguel de Icaza following the acquisition of Novell and SUSE by Attachmate, which ceased Mono development.

Attachmate acquired Novell in November 2010. Mono has been plucked from the abyss with impressive speed.

That said, the strategy behind Mono has shifted. Mono exists because de Icaza liked what Microsoft announced back in 2000 when it introduced C# and the .NET Framework. Microsoft made a show of standardizing the .NET CLI (Common Language Infrastructure), which made PR sense at the time since there was controversy over Sun’s ownership of Java, though nobody really believed that Microsoft knew how to steward an open source development platform or indeed believed that it was really serious about it. History largely justifies that scepticism; but de Icaza called Microsoft’s bluff and forged ahead with Mono, implementing not only the CLI and C# but most of the .NET Framework as well.

The goal of Mono, as I recall, was to bring the benefits of C# and .NET to Linux developers, and to enable developers to move applications freely between Windows and Linux. Apple OS X was also on the radar, though it took longer to become much use. Recalling Mono’s early days, de Icaza said:

Mono to me is a means to an end: a technology to help Linux succeed on the desktop.

Mono worked remarkably well from quite early on, but never quite well enough to persuade mainstream developers it was a sensible choice for applications that would otherwise have run on Windows. It did emerge as a viable and productive toolset and platform for Linux and a number of Mono applications became popular, including Beagle search, Tomboy notes, and F-Spot photo management. Some ASP.NET applications run on Mono; I have one on this site. Another Mono success was its use as the scripting engine in Unity, a game development platform.

A big problem for Mono though was the lack of a business model. There was support and servicing of course, which must have generated some revenue for Novell, but most Mono use is free. Novell possibly had in mind that Mono could be significant as an application server, but it has never become a really trusted platform in the Enterprise. For example, as Alan Radding (Dancing Dinosaur) notes:

DancingDinosaur has not found any SUSE on z user that has successfully implemented .NET apps on the mainframe. A few have tried but reported that Mono on z wasn’t ready for prime time.

Even among the free software and open source community, Mono was hampered by suspicion of Microsoft. If Mono became successful enough to threaten Microsoft, would lawyers appear? Given the way Microsoft is currently behaving with Android, filing legal actions and signing up licensees, those fears might not be unwarranted.

So what is Mono today? The answer is that Mono is now primarily a mobile platform. The Xamarin home page makes this clear, as well as making it apparent that the Mono team has discovered the value of a business model:


Xamarin is tapping into two real business needs. One is the need for a cross-platform mobile development platform that works. The second is a way for Windows developers to use their existing C# skills for mobile development, given that they might not be happy with the tiny market share currently achieved by Windows Phone 7.

When I had a quick try with Monotouch I was impressed, and I would like to spend some more time with it and with Mono for Android.

Mono has touch competition though. In particular, PhoneGap, Appcelerator’s Titanium, and Adobe AIR. I was interested to see that Adobe is coming up with a packager for AIR on Android, which may significantly improve it as a cross-platform mobile toolkit.

Still, Xamarin is small and nimble and I expect it to succeed. It has also has Visual Studio integration, which is an advantage. One of the pieces Xamarin has now licensed from SUSE is Mono for Visual Studio.

The downside of these latest developments is that if you depend on Mono for the desktop or for ASP.NET, you may find these parts of the Mono project getting little attention from the new company. But Mobile is all that matters now, right?

I write this on July 19 2011. According to Wikipedia:

Recognizing that their small team could not expect to build and support a full product, they launched the Mono open source project, on July 19, 2001 at the O’Reilly conference.

Well, if there was a launch there it was low-key. It is not mentioned in this report. But de Icaza does recall:

We planned the announcement to come by July 19th 2001, so we could announce this at the O’Reilly conference, as Tim O’Reilly had been very supportive of this effort, and had offered his help since the early stages, when it was still a very young idea. When we announced the project launch we had our team in place, and we were shipping our metadata framework and our C# compiler as well as a few initial classes So officially the Mono project was launched on that date, but it had been brewing for a very long time.

Happy Anniversary!

C# vs C++ and .NET vs Mono vs Compact Framework performance tests

A detailed benchmark posted on codeproject investigates the performance of basic operations including string handling, hash tables, math generics, simple arithmetic, sorting, file scanning and (for C#) platform invoke of native code. These are the conclusions:

  • There is only a small performance penalty for C# on the desktop versus C++.
  • Mono is generally slower than Microsoft .NET but still acceptable, and all the benchmarks ran without modification.
  • The Compact Framework, an implementation of .NET for mobile devices, performs poorly.

My observations: this matches my own experiments. Why then do some .NET applications still perform badly? When Evernote switched its application from .NET to native code it got much better performance.

The main reason is a couple of issues that this kind of benchmark hides. One is the GUI layer, which involves a ton of platform invoke code under the covers. Another is the large size of .NET applications because of the runtime and library overhead; a lot more stuff gets loaded into memory.

One thing to like about Silverlight is that it is truly optimized for client programming and load time tends to be faster than for a desktop .NET application.

Note that for mobile these benchmarks suggest that C++ still has a big advantage. It would be interesting to see them applied to Silverlight apps on Windows Phone 7. As I understand it, the Silverlight .NET runtime in Windows Phone 7 shares code with the Compact Framework on Windows Mobile, so it is possible that the poor results for the Compact Framework would also apply to Silverlight on Windows Phone 7. Unfortunately developers do not have the option for C++ on Windows Phone 7.