Regular readers of this blog will know of my interest in Mono, the open-source implementation of Microsoft’s .NET Framework.

A common objection to Mono is its fuzzy legal position. Although parts of .NET are ECMA standards open for anyone to implement, other parts (including ASP.NET) are not. Mono implements ASP.NET as well as other non-ECMA class libraries. The worry has been: if Mono gets successful enough to threaten Microsoft, will there be legal problems?

I say “has been”, because it appears that the just-announced agreement with Novell covers Mono. See Miguel de Icaza’s post where he says:

…today we have secured a peace of mind for Novell customers that might have been worried about possible patent infringements open source deployments. This matters in particular for Mono, because for a long time its been the favorite conversation starter for folks that find dates on Slashdot.

This is big news for anyone with an interest in cross-platform .NET. However, note that the agreement refers to Novell’s customers. I am not a lawyer; but it is not clear to me whether this deal provides comfort to Mono users not using Novell’s SUSE Linux. For example, what about those using Mono on the Mac, one of its more interesting applications? I hope to discover more next week at Tech-Ed, where there will be an out-of-hours presentation on Mono.

Update

See the comments below for more. It seems this falls short of a promise not to sue over patent breaches in Mono, if they exist, except in certain defined circumstances (Novell customers or non-commercial). I guess that is not surprising.