Microsoft open-sources .NET for embedded devices

The software giant has released most of its .NET Micro Framework product, used in devices ranging from sat-nav units to remote controls, under the Apache 2.0 licence

Microsoft has open-sourced most of the .NET Micro Framework, the company's development and execution environment for embedded systems.

The .NET Micro Framework is used in devices ranging from parking meters to sat-nav devices and smart remote controls. On Monday, Microsoft released version 4.0 of the framework at its Professional Developer Conference (PDC) in Los Angeles, while also releasing most of the source code under the Apache 2.0 licence and removing the licence fees associated with the framework.

However, the framework's TCP/IP communication stack and cryptography libraries are not being open-sourced. According to Peter Galli, open-source community manager for Microsoft's platform strategy group, these omissions result from the fact that Microsoft licenses the TCP/IP stack from a third party, EBSNet, and the cryptography libraries are "used outside the scope of the .NET Micro Framework".

"Customers who need to have access to the code in the cryptography functions will find that these libraries can be replaced," Galli said in a blog post, adding that those seeking the source code for the TCP/IP stack could "contact EBSNet directly".

"Including the source code for almost all of the product... ensures that developers now also get access to the Base Class Libraries that were implemented for .NET Micro Framework and the CLR code itself," Galli wrote.

Galli quoted Colin Miller, the programme's manager, as saying Microsoft intended to remain actively involved in the programme's development so as to avoid fragmentation.

"We are planning on establishing a core technology team that is made up of both Microsoft and non-Microsoft contributors that continues the goals of producing a high-quality product for very small devices," Miller is quoted as saying. "This group will act as the gateway to community contributions while, at the same time, Microsoft developers will continue add functionality and co-ordinate with the overall .NET team."

The lightweight .NET Micro Framework can be used with a variety of processors, including those built on ARM architecture rather than the standard x86 architecture that Microsoft most commonly addresses.

The embedded device market is becoming increasingly competitive, with ARM having opened up a resource centre on Tuesday for developers looking to work with Google's Android open-source mobile operating system on ARM architecture. Other flavours of Linux are also commonly used in such devices.