mono/web/rationale

* The Mono Project

** Background.

	The GNOME project goal was to bring missing technologies to
	Unix and make it competitive in the current market place for
	desktop applications.  We also realized early on that language
	independence was important, and that is why GNOME APIs were
	coded using a standard that allowed the APIs to be easily
	wrapped for other languages.  Our APIs are available to most
	programming languages on Unix (Perl, Python, Scheme, C++,
	Objective-C, Ada). 

	Later on we decided to use better methods for encapsulating
	our APIs, and we started to use CORBA to define interfaces to
	components. We complemented it with policy and a set of
	standard GNOME interfaces for easily creating reusable,
	language independent components, controls and compound
	documents.  This technology is known as <a
	href="http://www.ximian.com/tech/bonobo.php3">Bonobo</a>.
	Interfaces to Bonobo exist for C, Perl, Python, and
	Java.

	CORBA is good when you define coarse interfaces, and most
	Bonobo interfaces are coarse.  The only problem is that
	Bonobo/CORBA interfaces are not good for small interfaces.
	For example, an XML parsing Bonobo/CORBA component would be
	inefficient compared to a C API.

** Another explanation

	I recently explained our motivations to Dave Winer, and he posted
	it <a
	href="http://scriptingnews.userland.com/stories/storyReader$1275">here</a>

** Microsoft's .NET

	The Microsoft .NET initiative is confusing because it is a
	company wide effort that ranges from development tools to end
	user applications.  .NET is a branding formative that
	has been applied to:

	<ul>
		* The .NET development platform, a new platform for
		  writing software.

		* Web services.

		* Microsoft Server Applications.

		* New tools that use the new development platform.

		* Hailstorm, the Passport centralized single-signon
		  system that is being integrated into Windows XP.

	</ul>

	Mono is an implementation of the .NET development platform.

** The Common Language Infrastructure platform. 

	Microsoft has created a new development platform.  The
	highlights of this new development platform are:

	<ul>
		* A runtime environment that provides garbage
		  collection, threading and a virtual machine
		  specification (The Virtual Execution System, VES)

		* A comprehensive class library.  

		* A new language, C#.  Very similar to Java,  C#
		  allows programmers to use all the features available
		  on the .NET runtime.

		* A language specification that compilers can
		  follow if they want to generate classes and code
		  that can interoperate with other programming
		  languages (The Common Language Specification: CLS)
	</ul>

	The Common Language Infrastructure platform is similar to the
  	goals we had in GNOME of giving language independence to
  	programmers.  It is more mature, documented, larger in scope,
  	and has a consistent design.

	Any API that is written using a CLS provider language can be
  	used by any language that is a CLS consumer.  Compilers
  	generate code in a format called Common Intermediate Language
  	(CIL) which is an intermediate representation of a compiled
  	program and is easy to compile to native code or compiled
  	using Just-in-Time (JIT) engines.  The restrictions placed by
  	the runtime on the CIL byte codes ensures that it is possible
  	to do a good job at optimizing the code in a JIT compiler.

	There is not really a lot of innovation in this platform: we
	have seen all of these concepts before, and we are all
	familiar with how these things work.

	What makes the Common Language Infrastructure development
  	platform interesting is that it is a good mix of technologies
  	that have been nicely integrated.

	The .NET development platform is essentially a new foundation
	for program development that gives Microsoft a room to grow
  	for the coming years. 

** ECMA standards.

	Microsoft has submitted the
  	specifications of C#, the runtime, the metadata and the
  	other various bits of the .NET development platform to the
  	<a href="http://www.ecma.ch">ECMA</a> for standarization.

	You can get a copy of the specifications submitted to ECMA
	from: <a href="http://www.dotnetexperts.com/ecma">http://www.dotnetexperts.com/ecma</a>

** Mono: an Open Source Common Language Infrastructure implementation. 

	Ximian has begun work on Mono, a project that aims to bring
  	the Common Language Infrastructure platform to free systems.  

	When the GNU project was launched, they picked the best
  	operating system that was available out there, and they
  	began to clone it: Unix.

	The .NET development platform is a very rich, powerful, and
  	well designed platform that would help improve the free
  	software development platform.  Just like the GNU project
  	began to clone Unix sixteen years ago, we will be cloning the
  	.NET development platform because it is a great platform to
  	build on.

** What makes up Mono?

	There are various pieces that will make up Mono:

	<ul>
		* A C# compiler.

		* The Virtual Execution System: that will have the
  		  Just-in-Time compiler, garbage collector, loader,
  		  threading engine.

		  A byte code interpreter will be provided for quickly
  		  porting Mono to new systems and debugging the JIT
		  purposes, but it is not intended to be the ideal
		  execution environment.

		* An implemenation of the .NET class library.

		* Visual development tools. 

		* A CIL GCC frontend.
	</ul>

** Why use GNOME components?

	GNOME is an umbrella project that consists of infrastructural
	components (GUI toolkit, XML libraries, CORBA implementation,
	printing architecture, imaging system), a desktop environment,
	and productivity applications.

	The GNOME infrastructural components can be used to quickly
	implement various pieces of the class libraries without reinventing
	the wheel, and since all those components are licensed under
	the terms of the GNU LGPL it is a perfect fit.  

	Libart will be used to implement the Drawing.2D API; Gtk+ and
	the GNOME libraries will be used to implement the WinForms
	API and of course Glib and libxml will be used in various
	places.