[mono.git] / faq

<a href="#basics">Basics</a><br>
<a href="#ximian">The Ximian Role in the Mono project</a><br>
<a href="#gnome">Mono and GNOME</a><br>
<a href="#gui">Building GUI applications with Mono</a><br>
<a href="#msft">Mono and Microsoft</a><br>
<a href="#pnpproject">Mono and the Portable.NET Project</a><br>
<a href="#webservices">Web Services</a><br>
<a href="#asp">Mono and ASP.NET</a><br>
<a href="#ado">Mono and ADO.NET</a><br>
<a href="#monodoc">MonoDoc</a><br>
<a href="#devel">Development Tools and Issues</a><br>
<a href="#java">Mono and Java</a><br>
<a href="#extending">Extending Mono</a><br>
<a href="#portability">Portability</a><br>
<a href="#reuse">Reusing Existing Code</a><br>
<a href="#gcc">Mono and GCC</a><br>
<a href="#performance">Performance</a><br>
<a href="#licensing">Licensing</a><br>
<a href="#patents">Patents</a><br>
<a href="#etc">Miscellaneous Questions</a><br>
<a href="#problems">Mono Common Problems</a><br>

A <a
href="http://www.es.gnome.org/documentacion/articulos/mono-puf/mono-puf/">Spanish
translation</a> is also available

<a name="basics"></a>
** Basics

Q: What is Mono exactly?

A: The Mono Project is an open development initiative sponsored by
   Ximian that is working to develop an open source, Unix
   version of the Microsoft .NET development platform.  Its objective
   is to enable Unix developers to build and
   deploy cross-platform .NET Applications.  The project will
   implement various technologies developed by Microsoft that have now
   been submitted to the ECMA for standardization.

Q: What is the difference between Mono and the .NET Initiative?

A: The ".NET Initiative" is a somewhat nebulous company-wide effort by
   Microsoft, one part of which is a cross-platform development
   framework.  Mono is an implementation of the development framework,
   but not an implementation of anything else related to the .NET
   Initiative, such as Passport, software-as-a-service, or
   corporate re-branding.

Q: What technologies are included in Mono?

A: Mono contains a number of components useful for building new
   software:

        <ul>
                * A Common Language Infrastructure (CLI) virtual
                  machine that contains a class loader, Just-in-time
                  compiler, and a garbage collecting runtime.

                * A class library that can work with any language
                  which works on the CLR.

                * A compiler for the C# language.  In the future we
                  might work on other compilers that target the Common
                  Language Runtime.
        </ul>


   Windows has compilers that target the virtual machine from <a
   href="http://msdn.microsoft.com/net/thirdparty/default.asp#lang">a
   number of languages:</a> Managed C++, Java Script, Eiffel,
   Component Pascal, APL, Cobol, Perl, Python, Scheme,
   Smalltalk, Standard ML, Haskell, Mercury and Oberon.

   The CLR and the Common Type System (CTS) enables applications and
   libraries to be written in a collection of different languages that
   target the byte code

   This means for example that if you define a class to do algebraic
   manipulation in C#, that class can be reused from any other
   language that supports the CLI.  You could create a class in C#,
   subclass it in C++ and instantiate it in an Eiffel program. 

   A single object system, threading system, class libraries, and
   garbage collection system can be shared across all these languages.
   
Q: Where can I find the specification for these technologies?

A: You can find the information here:
 

   C# <a href="http://www.ecma.ch/ecma1/STAND/ecma-334.htm">http://www.ecma.ch/ecma1/STAND/ecma-334.htm</a>

   CLI <a href="http://www.ecma.ch/ecma1/STAND/ecma-335.htm">http://www.ecma.ch/ecma1/STAND/ecma-335.htm</a>

Q: Will you implement the .NET Framework SDK class libraries?

A: Yes, we will be implementing the APIs of the .NET Framework SDK
   class libraries. 

Q: Will you offer an ECMA-compliant set of class libraries?

A: Eventually we will.  Our current focus is on inter-operating
   with the Microsoft SDK, but we will also offer an ECMA compliant
   set of libraries. 

Q: What does the name "Mono" mean?

A: Mono is the word for `monkey' in Spanish. We like monkeys.

Q: Is Mono usable?

A: The JIT engine is usable on Intel x86 machines.  An interpreter
   can be used on other non-Intel x86 machines.  

   The class libraries are mature enough to run some real applications
   (the compiler for instance, and every day more and more applications
   are natively developed with Mono).

Q: When will you ship it?

A: Different parts of Mono will achieve usability at different stages,
   once we are comfortable with the compiler, we will release "Mono Core",
   which contains everything needed to develop applications with the base
   class libraries, this will happen soon and in the meantime you can 
   download daily snapshots of our work. Also the full ASP.NET support is 
   close to completion. 

   Other higher level class libraries (ASP.NET, ADO.NET, WinForms) will
   be released when they become stable. 

Q: What major components will you include in Mono?

A: Hopefully everything that Microsoft ships on their Framework
   (ADO.NET, ASP.NET, WinForms), and we encourage third party developers to 
   create reusable components that work on both Mono and Windows.

Q: How can I contribute?

A: Check the <a href="contributing.html">contributing</a> section. 

Q: Aren't you just copying someone else's work?

A: We are interested in providing the best tools for programmers to
   develop applications for Free Operating Systems.  We also want to help
   provide the interoperability that will allow those systems to fit in
   with other standards.

   For more background, read the <a href="http://www.go-mono.com/rationale.html">Mono
   Project white paper</a>.
   the project.

Q: Miguel said once that Mono was being implemented in COBOL. Is that true?.

A: No. It was a joke.


<a name="ximian"></a> 

** The Ximian Role in the Mono Project

Q: Why is Ximian working on .NET?

A: Ximian is interested in providing the best tools for programmers to
   develop applications for Free Operating Systems.  

   For more information, read the project <a
   href="rationale.html">rationale</a> page.

Q: Will Ximian be able to take on a project of this size?  

A: Of course not. Ximian a supporter of the Mono project, but the only way
   to implement something of this size is for the entire free software
   community to get involved. Visit the <a href="contributing.html">contributing</a> 
   page if you'd like to help out.

Q: What pieces will Ximian be working on?

A: We will devote most of our resources to work on the pieces which are
   on the critical path to release a development and execution
   environment. Once the project is at a stage where it is useful in
   the real world, it will achieve a critical mass of developers to
   improve it further.

Q: Will Ximian offer Mono commercially?

A: When Mono is ready to be shipped Ximian will offer a commercial
   support and services for Mono. 

Q: Does Ximian provide consulting services around Mono?

A: Yes, Ximian does provide consulting services around Mono to
   make it suitable to your needs.  Porting the runtime engine,
   customizing it, working on specific classes or tuning the code
   for your particular needs. 

Q: Will you wait until Mono is finished?

A: Mono will ship on various stages as they mature.  Some people
   require only a subset of the technologies, those will ship first.

   More advanced features will take more time to develop.  A support
   time line will be available in June 2002.

<a name="gnome"></a> 
** Mono and GNOME

Q: How is Mono related to GNOME?

A: In a number of ways.  This project was born out of the need of
   providing improved tools for the GNOME community, and will use
   existing components that have been developed for GNOME when they
   are available.  For example, we plan to use Gtk+ and Libart to
   implement Winforms and the Drawing2D API and are considering
   GObject support.

Q: Has the GNOME Foundation or the GNOME team adopted Mono?

A: Mono is too new to be adopted by those groups. We hope that the
   tools that we will provide will be adopted by free software
   programmers including the GNOME Foundation members and the GNOME
   project generally.

Q: Should GNOME programmers switch over to Mono now?

A: It is still far to early for discussions of "switching over."  No
   pieces of Mono will be ready within the next six months, and a
   complete implementation is roughly one year away.

   We encourage GNOME developers to continue using the existing tools,
   libraries and components.  Improvements made to GNOME will have an
   impact on Mono, as they would be the "back-end" for various classes.

Q: Will Mono include compatibility with Bonobo components? What is the
   relationship between Mono and Bonobo?

A: Yes, we will provide a set of classes for implementing and using
   Bonobo components from within Mono.  Mono should allow you to write
   Bonobo components more easily, just like .NET on Windows allows you
   to export .NET components to COM.

Q: Does Mono depend on GNOME?

A: No, Mono does not depend on GNOME.  We use a few packages produced by
   the GNOME team like the `glib' library.  

Q: But will I be able to build GNOME applications?

A: Yes, we will enable people to write GNOME applications using Mono.

Q: Do you have C# bindings for GNOME?.

A: Yes, we currently bind libgnome, libgnomecanvas, and libgnomeui --
   although I dare say I have no idea how functional the bindings are
   outside of what I tested in the sample app. I imagine other libraries 
   under the GNOME framework will be added on an as-needed (and as-requested) 
   basis...although a truly good bonobo binding will have to wait on the CORBA 
   remoting support which has been started recently.

<a name="gui"></a>
** GUI applications

Q: Will Mono enable GUI applications to be authored?

A: Yes, you will be able to build GUI applications.  Indeed, that is our
   main focus.  We will provide both the Windows.Forms API and the Gtk# API.

Q: What is the difference between Gtk# and System.Windows.Forms?

A: Gtk# is a set of bindings for the Gtk+ toolkit for C# (and other
   CIL-enabled languages).  System.Windows.Forms is an API defined
   by Microsoft to build GUI applications.

Q: Will I be able to run my smart clients on systems powered by Mono?

A: As long as your applications are 100% .NET and do not make use
   of P/Invoke to call Win32 functions, your smart client applications
   will run on Mono platforms.

Q: Where can I learn more about Gtk#?

A: The following <a href="http://gtk-sharp.sourceforge.net>link</a> sends you to the page of the project.

Q: What can I do with Gtk#?. 

A: Gtk# is becoming very usable and you can create applications and
   applets like those you see in a GNOME desktop environment. It's 
   easy to install so it's worth a try. 

Q: How can I compile my HelloWorld.cs which uses Gtk#?.

A: Try: mcs --unsafe -o HelloWorld.exe -r glib-sharp -r pango-sharp -r
        atk-sharp -r gdk-sharp -r gtk-sharp -r gdk-imaging-sharp
        HelloWorld.cs

Q: Is there any way how to connect DataAdapter to some GTK# controls?

A: There is a sample file called `DbClient' in gtk-sharp/samples that you
   might to look at.  It is a sample program in Gtk# that adds/updates/deletes 
   information on a Postgress database. When we have the new table/tree widgets, 
   I am sure someone would write an adapter for System.Data (in Gtk2 the 
   tree/list widgets are written using a view/model, so you only need to write 
   a model that maps to the database). You can have a look at 
   gtk-sharp/sample/DbClient, where there is a GTK# application that uses 
   System.Data. It does not use DataAdapter, but DataReader though.

Q: Do you have an estimate for when Windows.Forms will be released?

A: We do not know, volunteers are working on this, but there is no set
   date yet.  The current approach is using the Wine Library to implement
   it.

<a name="msft"></a>
** Mono and Microsoft

Q: Is Microsoft helping Ximian with this project?

A: No. Ximian CTO Miguel de Icaza had a friendly conversation with
   Microsoft software architect David Stutz, but that's about the
   extent of the contact. Microsoft is interested in other
   implementations of .NET and are willing to help make the ECMA spec
   more accurate for this purpose.

   Ximian representatives have also spoken with Sam Ruby at the ECMA
   TG3 committee to discuss the same issues.

Q: Is Microsoft or Corel paying Ximian to do this?

A: No.

Q: Do you fear that Microsoft will change the spec and render Mono
   useless?

A: No.  Microsoft proved with the CLI and the C# language that it was
   possible to create a powerful foundation for many languages to
   inter-operate.  We will always have that.  

   Even if changes happened in the platform which were undocumented,
   the existing platform would a value on its own.

Q: Are you writing Mono from the ECMA specs?

A: Yes, we are writing them from the ECMA specs and the published
   materials in print about .NET.

Q: If my applications use Mono, will I have to pay a service fee?

A: No.  Mono is not related to Microsoft's initiative of
   software-as-a-service.

Q: Is the Mono Project is related to the Microsoft Hailstorm effort?  Is
   Ximian endorsing Hailstorm?  

A: No.  The Mono Project is focused on providing a compatible set of
   tools for the Microsoft .NET development platform.  It does not
   address, require, or otherwise endorse the MS Passport-based
   Hailstorm single sign-on system that is part of Windows XP and
   other services.

Q: Will Mono or .NET applications depend on Microsoft Passport?

A: No. MS Passport is unrelated to running .NET compatible applications
   produced with the Mono tools.  The only thing you will need is a
   just-in-time compiler (JIT).

Q: What is a 100% .NET application?

A: A `100% .NET application' is one that only uses the APIs defined
   under the System namespace and does not use PInvoke.  These
   applications would in theory run unmodified on Windows, Linux,
   HP-UX, Solaris, MacOS X and others. 

Q: If Microsoft will release a port of their .NET platform under the
   `Shared Source' license, why should I bother with anything else?

A: The Shared Source implementation will be expensive and its uses
   will be tightly restricted, especially for commercial use. We are
   working towards an implementation that will grant a number of
   important rights to recipients: use for any purpose,
   redistribution, modification, and redistribution of modifications.

   This is what we call <a
   href="http://www.gnu.org/philosophy/free-sw.html">Free Software</a>

Q: Is Mono a free implementation of Passport?

A: No. Mono is just a runtime, a compiler and a set of class
   libraries.

Q: Will the System.Web.Security.PassportIdentity class mean
   that my software will depend on Passport?
   
A: No.  Applications may use that API to contact a Passport site, but
   are not required to do so.

   As long as your application does not use Passport, you will not
   need Passport.  

Q: Will Mono running on Linux make Passport available for Linux?

A: No.  However, the Passport toolkit for Linux-based web servers is
   available from Microsoft.

Q: Will Mono allow me to run Microsoft Office on Linux?

A: No, it will not.  Microsoft Office is a Windows application.  To
   learn more about running Windows applications on Intel Unix systems
   refer to <a href="http://www.winehq.com">the Wine Project</a>.

Q: Will I be able to compile a Microsoft VB.NET application and execute 
   the resultant MSIL file under MONO on Linux without converting to C# 
   and recompiling?

A: Once we have a complete VisualBasic runtime, yes.

Q: Can mono run the WebMatrix?

A: No. That requires System.Windows.Forms support which is not
   currently implemented.

Q: Does mono have something like Passport? 
   Will mono have a server side Passport/Similar framework for XSP as well as client classes?

A: Not yet, but the client side API for authentication is not the problem. 
   We will likely have a lot of other authentication APIs, like the Liberty
   Alliance APIs. The problem is people on the web provider end that might use 
   this for authentication.

<a name="pnpproject"></a>
** Mono and Portable.NET

Q: What are the differences between Mono and Portable.NET?

A: Most of Mono is being written using C#, with only
   a few parts written in C (The JIT engine, the runtime, the
   interfaces to the garbage collection system).  

   It is easier to describe what is unique about Mono:
   <ul>
     <li> A self-hosting C# compiler written in C#, which is clean, easy
          to maintain.

     <li> A multi-platform runtime engine: both a JIT engine and an
          interpreter exist.  The JIT engine runs currently on x86
          systems, while the interpreter works on SPARC, StrongARM and
          PowerPC systems.  

     <li> Supports Linux, Windows and Solaris at this point.

     <li> The JIT engine is written using a portable instruction
          selector which not only generates good code (we are told
          that we are faster than Rotor, but it is hard to tell) but
          is also the foundation to re-target the JIT engine to other
          systems.  

          The system employed is described in various compiler
          books and it is very similar to what is described in the 
          book that covers LCC, the ANSI C retargetable C compiler.

     <li> The JIT engine supports in-lining, constant folding and propagation,

     <li> Full support for remoting in the runtime, but the class 
          libraries are still behind.

     <li> The C# compiler, the JIT engine and the class libraries are
          mature enough that the whole system is self-hosting.  This means that
          we develop Mono completely with itself at this point.

     <li> We are not yet done, and there is a lot of work left to be
          done

     <li> We have a great community of developers, without which Mono
          would not be possible.

     <li> We will provide an ahead of time compilation mode in the 
          future.
   </ul>

<a name="webservices"></a>
** Web Services

Q: How is Mono related to Web Services?

A: Mono is only related to Web Services in that it will implement the
   same set of classes that have been authored in the .NET Framework
   to simplify and streamline the process of building Web Services.

   But most importantly, Mono is an Open Source implementation of the
   .NET Framework.

Q: Can I author Web Services with Mono?

A: You will be able to write Web Services on .NET that run on Mono and
   vice-versa. 

Q: If Mono implements the SDK classes, will I be able to write and
   execute .NET Web Services with it?
   
A: Yes.  When the project is finished, you will be able to use the
   same technologies that are available through the .NET Framework SDK
   on Windows to write Web Services.

Q: What about Soup?  Can I use Soup without Mono?

A: Soup is a library for GNOME applications to create SOAP servers and
   SOAP clients, and can be used without Mono.  You can browse the
   source code for soup using <a
   href="http://cvs.gnome.org/bonsai">GNOME's Bonsai</a>.

Q: Can I use CORBA?

A: Yes. The CLI contains enough information about a class that
   exposing it to other RPC systems (like CORBA) is really simple, and
   does not even require support from an object.  

   We will be implementing CORBA inter-operation as an extension to the
   Mono classes so that we can integrate with Bonobo, just like
   Microsoft provides COM inter-operation classes and support
   mechanisms. 

Q: Can I serialize my objects to other things other than XML?

A: Yes, although the serializing tools have not yet been planned, and
   you would probably have to implement them yourself.

Q: Will Mono use ORBit?

A: No. Mono will be using a new implementation of CORBA that isn't still started. 

<a name="monodoc"></a>
** MonoDoc

Q: What is MonoDoc?

A: MonoDoc is a graphical documentation editor and viewer. Currently, MonoDoc 
   consists of a Gtk# application and is in heavy development. There is also a 
   Qt# version of it.


<a name="devel"></a>
** Development Tools and Issues

Q: Will it be possible to use the CLI features without using byte codes
   or the JIT?

A: Yes. The CLI engine will be made available as a shared library.
   The garbage collection engine, the threading abstraction, the
   object system, the dynamic type code system and the JIT will be
   available for C developers to integrate with their applications if
   they wish to do so. 

Q: Will you have new development tools?

A: With any luck, Free Software enthusiasts will contribute tools to
   improve the developer environment.  These tools could be developed
   initially using the Microsoft implementation of the CLI and then
   executed later with Mono.

Q: What kind of rules make the Common Intermediate Language useful for
   JITers?

A: The main rule is that the stack in the CLI is not a general purpose
   stack.   You are not allowed to use it for other purposes than
   computing values and passing arguments to functions or return
   values.  

   At any given call or return instruction, the types on the stack
   have to be the same independently of the flow of execution of your
   code. 

Q: Is it true that the CIL is ideal for JITing and not efficient for
   interpreters?

A: The CIL is better suited to be JITed than JVM byte codes, but you
   can interpret them as trivially as you can interpret JVM byte
   codes. 

Q: Isn't it a little bit confusing to have the name of "XSP" (the same 
   as in the Apache Project) for the ASP.NET support in Mono?.

A: In Mono, xsp is just the name of the C# code generator for ASP.NET 
   pages. In the Apache Project, it is a term for the "eXtensible Server 
   Pages" technology so as they are very different things, they don't 
   conflict.

Q: What about using something like Jabber instead of the System.Messaging 
   namespace?.

A: In short, MSMQ is not something like Jabber, but asynchronous messaging 
   through queues. Useful queues do more than serialize messages, they are 
   also platform bridges.

Q: Are you supporting XMLDocument and relatives?.

A: Currently, we aren't implementing them yet. It would require updates to 
   most of the XmlNode derivatives so it's not a trivial task. We are 
   currently focusing on getting XPath support working. 

Q: Is there any plan to develop an aspx server for Mono?.

A: The web server turned out to be very simple compared to the rest of the 
   work. Gonzalo has got the page generator mostly done (a module called 
   xsp, who has nothing to do with the XSP term used in the Apache Project).
   Patrik has done a lot of the work to get the ProcessRequest to work.
   You can try to help in the final touches to the System.Web classes and
   writing regression tests for the widgets we have.

Q: Is there any way I can develop the class libraries using Linux yet?

A: Yes. Some class libraries can be developed on Linux. Search for
   Paolo's post (he lists which classes can be compiled fine now).

Q: Is there any way I can install a known working copy of mono in /usr, 
   and an experimental copy somewhere else, and have both copies use 
   their own libraries? (I'm still not very good at library paths in 
   Linux)

A: Yes. Just use two installation prefixes.

Q: How should I write tests or a tests suite?

A: If you do a test suite for C#, you might want to keep it 
   independent of the Mono C# compiler, so that other compiler 
   implementations can later use it.  

Q: Would it be too terrible to have another corlib signed as mscorlib? 

A: We rename corlib to mscorlib also when saving the PE files, in fact, 
   the runtime can execute program created by mono just fine.  

Q: Is there a relatively straightforward way to repeat the steps taken 
   by Paolo to get Mono completely self-hosted on Linux?

A: To build the compiler and class libraries in Linux, run:
   <ul><li>make -f makefile.gnu. To install them, run: </li>
       <li>make -f makefile.gnu install prefix=/opt/mono</li>
   </ul>

   If you want to produce and distribute a monocharge tarball, run:
   make -f makefile.gnu dist
   Of course you have to run these in the top level mcs directory.

Q: Is it possible to build a C# file to some sort of intermediate format which 
   can linked into a final module, like the traditional .c -> .o -> .so path? 
   
A: You could do: mcs /target:module file1.cs, mcs /target:module file2.cs, 
   mcs /target:exe file1.dll file2.dll /out:mybin.exe

Q: Is there any plans for implementing remoting in the near future?, When will 
   work in System.Runtime.Remoting.dll start?

A: The remoting infrastructure is in place. Some of the channels and 
   formatters are not.

Q: I'm wondering if there are any plans to start using nant to build the
   class lib + test lib. i think that every project need/should use an
   automated build process and nant + a couple of tools enables this. is
   the problem that the compiler can't run nant yet?

A: Maybe well be doing some sort of automated build process + testing when
   the summer finish.

<a name="asp">
** Mono and ASP.NET

Q: Is Mono supporting ASP.NET?

A: Yes. The development of the support for ASP.NET comes in various stages, 
   here is what Gonzalo has been working on: 1. The Parser. 2. Getting the 
   parser to generate output compatible with ASP.NET. 3. Running the sample 
   output with the real Microsoft runtime but using our generated page. 4. 
   Running the sample with our classes with the .NET runtime. 5. Running 
   our sample code with our classes with our runtime. This is the process 
   we are following. Currently Gonzalo has reached point 5.

Q: Do I need install cygwin to work on ASP.NET in mono or Linux is enough since 
   it is self host right now.

A: Linux is enough.

Q: Any plan to make ASP.NET in mono works with Apache in Linux?.

A: Yes, we have plans to do so, but we need to wait for Patrik's patches to
   HttpRuntime. Once that is there, writing a mod_mono should be trivial 
   (look at mono/samples/embed for a sample embedded application).

<a name="ado">
** Mono and ADO.NET

Q: What is the status of ADO.NET support?. Could I start migrating 
   applications from MS.NET to Mono?.

A: You could start right now using the ADO.NET support in mono, of course,
   if you want to help filling the missing gaps while you develop your app
   :-) Well, what I mean is that we're not that far to having full ADO.NET
   support in Mono, and we've got a lot of working things, so if we could
   get more help, we'd finish it really soon :-)

Q: In developing the data architecture for the application are there and
   objects I should stay away from in order to insure the smoothest possible
   transition (minimum code rewrite) to Mono's ADO.NET implementation?  (For
   example, strongly typed datasets versus untyped datasets, etc...)

A: We are implementing all the classes in Microsoft .NET's System.Data, so
   you can be sure that things will work the same in Mono as with the Microsoft
   implementation. 

<a name="java">
** Mono and Java
   
Q: Why don't you use Java?  After all, there are many languages that
   target the Java VM.

A: You can get very good tools for doing Java development on free
   systems right now.  <a href="http://www.redhat.com">Red Hat</a> has
   contributed a <a href="http://gcc.gnu.org">GCC</a> <a
   href="http://gcc.gnu.org/java">front-end for Java</a> that can take
   Java sources or Java byte codes and generate native executables; <a
   href="http://www.transvirtual.com">Transvirtual</a> has implemented
   <a href="http://www.kaffe.org">Kaffe</a> a JIT engine for Java;
   Intel also has a Java VM called <a
   href="http://www.intel.com/research/mrl/orp">ORP</a>.

   The JVM is not designed to be a general purpose virtual machine.
   The Common Intermediate Language (CIL), on the other hand, is
   designed to be a target for a
   wide variety of programming languages, and has a set of rules
   designed to be optimal for JITers.

Q: Could Java target the CLI?

A: Yes, Java could target the CLI.  We have details on a <a
   href="ideas.html#guavac">project</a> that someone could take on to
   make this happen.  

   Microsoft has an implementation of the Java language called J# that
   can target the CIL execution engine. 

Q: Is it possible to write a JVM byte code to CIL converter?

A: Yes, it is possible.  Here are a few starting point:

        <ul>
                * A byte code representation is really a flattened forest of
                  trees.  Look at the Mono JIT engine to see how we compute
                  the basic blocks (this is used to figure out the "trees").

                  The forest is just an array of trees.

                  Indeed, run the JIT engine with -d (mono -d prog.exe) and
                  you will see how these trees look like.

                  You will have to do something similar for Java.

                * Each "forest of trees" has a meaning.  This meaning can now
                  be translated into the equivalent "meaning" in CLR-land.
        </ul>

Q: Could mono become a hybrid CIL/java platform?

A: No. It is quite far from the philosophy of the project. The idea of Mono 
   is, to have only _one_ VM, on which all can run. And if there existing a 
   binary-converter from Java-.class to IL and if there existing something 
   like J-Sharp on Mono, you can write programs in Java, which than can run 
   on Mono. You do not need two bindings (like your example: GTK-Sharp _and_ 
   Java-Gnome). You need only _one_ of it (GTK-Sharp). Thats the idea of Mono.
   An other point is, that there are no people, who use Open Source-JVMs. They 
   all prefer Suns original. But for Unix there don't exist a .NET-Framework. 
   So it is possible, that in the future Mono is the standard .NET for Unixes.

Q: Do you plan to implement a Javascript compiler?

A: Yes. Eto Demerzal has started a Rhino port to C#.
   After this is completed, we will begin developing
   the JavaScript compiler.

<a name="extending"></a>
** Extending Mono

Q: Would you allow other classes other than those in the
   specification?

A: Yes.  The Microsoft class collection is very big, but it is by no
   means complete.  It would be nice to have a port of `Camel' (the
   Mail API used by Evolution inspired by Java Mail) for Mono
   applications.  

   You might also want to look into implementing CORBA for Mono.  Not
   only because it would be useful, but because it sounds like a fun
   thing to do, given the fact that the CLI is such a type rich
   system. 

   For more information on extending Mono, see our <a
   href="ideas.html">ideas</a> page.

Q: Do you plan to Embrace and Extend .NET?

A: Embracing a good technology is good.  Extending technologies in
   incompatible ways is bad for the users, so we do not plan on 
   extending the technologies.

   If you have innovative ideas, and want to create new classes, we 
   encourage you to make those classes operate correctly well in both
   Mono and .NET.

Q: Is there any way I can develop the class libraries using Linux yet?

A: Yes. Some class libraries can be developed on Linux. Search for
   Paolo's post (he lists which classes can be compiled fine now).

Q: Is there any way I can install a known working copy of mono in /usr, 
   and an experimental copy somewhere else, and have both copies use 
   their own libraries? (I'm still not very good at library paths in 
   Linux)

A: Yes. Just use two installation prefixes.


<a name="portability"></a>
** Portability

Q: Will Mono only work on Linux?

A: Currently, we are doing our work on Linux-based systems and
   Windows.  We do not expect many Linux-isms in the code, so it
   should be easy to port Mono to other UNIX variants.   

Q: What about Mono on non Linux-based systems?

A: Our main intention at Ximian is to be able to develop GNOME
   applications with Mono, but if you are interested in providing a
   port of the Winforms classes to other platforms (frame buffer or
   MacOS X for example), we would gladly integrate them, as long
   they are under an open source license.  

Q: What operating systems/CPUs do you support

A: Mono currently runs on Linux, Windows, Solaris and FreeBSD.
   There is a JIT engine available for x86 processors that can
   generate code and optimizations tailored for a particular CPU.

   Interpreters exist for the SPARC, PowerPC and StrongARM CPUs.

Q: Does Mono run on Windows?

A: Yes.   You can get pre-compiled
   binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>

Q: Does Mono run on Linux?

A: Yes.  You can get pre-compiled
   binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>

Q: Will I require Cygwin to run mono?

A: No.  Cygwin is only required to build Mono.

Q: Will Mono depend on GNOME?

A: It will depend only if you are using a particular assembly (for
   example, for doing GUI applications).  If you are just interested
   in Mono for implementing a `Hello World Enterprise P2P Web
   Service', you will not need any GNOME components.

Q: Is anyone working on porting Mono to IA-64?

A: Nobody is working on such port.

Q: If I were about to start a Mono port to IA-64,would the same lburg code 
   generator work for IA-64 also? or anything else need to be used for code 
   generation(as the processor architecture is totally different from IA32)

A: The lburg approach can be use for any processor architecture. But you might
   think in another better approach.

Q: Do you plan to port Rhino to C#?.

A: Eto Demerzal has started a Rhino port to C#.

Q: Has anyone succeeded in building a Mac version of the C# environment. 
   If so can you explain how?  

A: You could try to check with the Darwin people, or the Fink people.
   Mono/C# is self hosting on Linux/PPC which is the hard part, so it
   should be relatively simple to get it to work on MacOS

<a name="reuse"></a>
** Reusing Existing Code

Q: What projects will you reuse or build upon?

A: We want to get Mono in the hands of programmers soon.  We are
   interested in reusing existing open source software.

Q: What about Intel's research JIT framework, ORP?

A: At this time, we are investigating whether we can use elements of
   ORP for Mono.   ORP is a research JIT engine that has a clearly
   defined API that splits the JIT from the GC system and the actual
   byte code implementation.

   We are using some pieces of ORP (Their code generation interface)
   and we use it as a source of inspiration for optimizations.  Paolo
   and Dietmar consider ORP as being one of the best JIT engines out
   there (and their research work and papers are very useful if you are
   interested in JIT technology).

Q: What about using GNU Lightning?

A: We are not using GNU Lightning.  Our JIT is using an instruction
   selector based on tree-pattern matching, and a code generation
   interface that is very tied to the current architecture.

Q: Will I be able to use Microsoft SQL Server 2000 or will I need to switch
   to a specific Open Source Database. Will I need to recode?

A: There should not be any need to recode.

Q: What do I need to watch out for when programming in VB.NET so that I'm
   sure to be able to run those apps on Linux?

A: Not making any PInvoke or DLL calls should and not using anything in
   the Microsoft.* namespaces should suffice. Also do not use any 
   Methods/Classes marked as "This type/method supports the .NET Framework 
   infrastructure and is not intended to be used directly from your code." 
   even if you know what these classes/methods do.

Q: Will built-in reporting be supported for crystal reports? This is a
   heavily used part of our system.

A: Probably not. Crystal Reports are propriety. Someone may try to emulate
   the behavior, but no-one has yet volunteered.

Q: Who about writing to the registry? As I understand it, Linux does not have
   a counterpart to the registry. Should I avoid relying on that feature?

A: Try to avoid it. Although there would be a emulation for registry in
   Mono too. GNOME does have a registry like mechanism for configuration. But
   Even if gnome has a configuration system similar to the registry, the keys 
   will not be equal, so you will probably end up having to do some runtime 
   detection, and depending on this load an assembly that has your 
   platform-specific hacks.

Q: System.Data.SqlClient with FreeTDS, will you port parts of these to C# and 
   use them?

A: if their license is compatible with mono's, yes, we'd think about porting 
   them. If not, we'll continue with the plan of using FreeTDS.

<a name="gcc"></a>
** Mono and GCC

Q: Are you working on a GCC front-end to C#? A GCC back-end that will
   generate CIL images? What about making a front-end to GCC that
   takes CIL images and generates native code?

A: We are currently seeking volunteers for those projects.
   Visit the <a href="contributing.html">contributing</a> section if
   you are interested.

Q: But would this work around the GPL in the GCC compiler and allow
   people to work on non-free front-ends?

A: People can already do this by targeting the JVM byte codes (there
   are about 130 compilers for various languages that target the JVM).

Q: Why are you writing a JIT engine instead of a front-end to GCC?

A: We want the JIT engine and runtime engine because they will be able
   to execute CIL executables generated on Windows, and so no recompilation 
   will be necessary.

<a name="performance"></a>
** Performance

Q: How fast will Mono be?

A: We can not predict the future, but a conservative estimate is that
   it would be at least `as fast as other JIT engines'.

   We would like to ship various JIT engines with Mono, just like
   Microsoft has done with their .NET development platform. We could
   provide a faster, JIT for fast load times but lower performance,
   and an and an optimizing JIT that would be slower at generating
   code but produce more optimal output.

   The CIL has some advantages over the Java byte code:  it is really
   an intermediate representation and there are a number of
   restrictions on how you can emit CIL code that simplify creating
   better JIT engines.

   For example, on the CIL, the stack is not really an abstraction
   available for the code generator to use at will.  Rather, it is a
   way of creating a postfix representation of the parsed tree.  At
   any given call point or return point, the contents of the stack are
   expected to contain the same object types independently of how the
   instruction was reached.

<a name="licensing"></a>
** Licensing

Q: Will I be able to write proprietary applications that run with
   Mono?

A: Yes.  The licensing scheme is planned to allow proprietary
   developers to write applications with Mono.
   
Q: What license or licenses are you using for the Mono Project?

A: The C# Compiler is released under the terms of the <a 
   href="http://www.opensource.org/licenses/gpl-license.html">GNU GPL</a>.  The runtime
   libraries are under the <a
   href="http://www.opensource.org/licenses/lgpl-license.html">GNU
   Library GPL</a>.  And the class libraries are released
   under the terms of the <a
   href="http://www.opensource.org/licenses/mit-license.html">MIT X11</a>
   license.

   The Mono runtime and the Mono C# Compiler are also available under
   a proprietary license for those who can not use the LGPL and the
   GPL in their code.  

   For licensing details, contact <a
   href="mailto:mono-licensing@ximian.com">mono-licensing@ximian.com</a>


Q: I would like to contribute code to Mono under a particular
   license. What licenses will you accept?

A: We will have to evaluate the licenses for compatibility first,
   but as a general rule, we will accept the code under the same
   terms of the "container" module. 

Q: Is the Mono 


<a name="patents"></a>
** Patents

Q: Could patents be used to completely disable Mono (either submarine
   patents filed now, or changes made by Microsoft specifically to
   create patent problems)?

A: No.  First, its basic functional capabilities have pre-existed too
   long to be held up by patents.  The basic components of Mono are
   technologically equivalent to Sun's Java technology, which has been
   around for years.  

   Mono will also implement multi-language and
   multi-architecture support, but there are previous technologies
   such as UCSD p-code and ANDF that also support multiple languages
   using a common intermediate language.  The libraries are similar
   to other language's libraries, so again, they're too similar to
   be patentable in large measure.

   However, if Microsoft does patent some technology, then our plan is
   to either (1) work around it, (2) chop out patented pieces, (3) 
   find prior art that would render the patent useless.
 
   Not providing a patented capability would weaken the
   interoperability, but it would still provide the free software /
   open source software community with good development tools, which
   is the primary reason for developing Mono.  

<a name="etc"></a> 
** Miscellaneous Questions

Q: You say that the CLI allows multiple languages to execute on the
   same environment.  Isn't this the purpose of CORBA?

A: The key difference between CORBA (and COM) and the CLI is that the
   CLI allows "data-level interoperability" because every
   language/component uses the same data layout and memory management.

   This means you can operate directly upon the data types that someone
   else provides, without having to go via their interfaces.  It also
   means you don't have to "marshal" (convert) parameters (data
   layouts are the same, so you can just pass components directly) and
   you don't have to worry about memory management, because all
   languages/components share the same garbage collector and address
   space.  This means much less copying and no need for reference
   counting.

Q: Will you support COM?

A: The runtime will support XPCOM on Unix systems and COM on Windows.
   Most of the code for dynamic trampolines exists already.

Q: Will Ximian offer certifications on Mono or related technologies?. 

A: It's possible. But there is no plan about this. So the short answer is no.

Q: Are there any Boehm's GC binaries?

A: Yes. You can find RPMs <a href="http://java.thn.htu.se/~toor/">here</a>, though
   if your distribution provides the correct packages, you should use those.
   The suggested version of the Boehm GC is 6.1.

Q: How can I report a bug?

A: The best thing is to track down the bug and provide a simple test to
   reproduce the bug. You can then add the bug to the 
   <a href="http://bugzilla.ximian.com/enter_bug.cgi">bugtracking system</a>.

   Please provide information about what version of mono you're using
   and any relevant details to be able to reproduce the bug. Note that
   bugs reported on the mailing-list may be easily forgotten, so it's
   better to file them in the <a href="http://bugzilla.ximian.com/enter_bug.cgi">bug tracking system</a>.

Q: Does mcs support the same command line options as the MS C# 
   compiler?

A: The Mono C# compiler now supports the same command line
   arguments as the Microsoft C# compiler does.

Q: How about getting searchable archives on lists.ximian.com? 

A: You can perform a search on the mono-related mailing lists 
   <a href="http://www.go-mono.com/mailing-lists.html">here</a>.

Q: When using mono from cvs or from a snapshot, I get an error messaage
   saying that Mono and the runtime are out of sync. How do I fix that?

A: If you use mono from cvs, you need to be prepared for changes in the
   runtime internals. This means that you should keep a working setup 
   before blindling updating (a working setup may just be the last released
   tarball or a recent binary snapshot).
   Usually, compiling corlib with mcs before recompiling the C runtime does
   the right thing (but occasionally you may need to do it the other 
   way around).

Q: Why are you going for a GtkHtml implementation?

A: GtkHTML is just a lightweight HTML rendering engine that does not
   support CSS, so we need it to look decent for those of us that will 
   be using the documentation in our day-to-day work on Linux. The 
   Web-based interfaces lack the agility that you get from a native GUI
   tool to browse your documentation. Probably later on, we will write 
   scripts and generate a full documentation set that is web-browsable, 
   but we need a command-line and GUI tools that we can use natively on 
   Linux when disconnected from the Web (and that has better 
   interactions than a web page).

<a name="problems"></a>
** Mono Common Problems

   If you are having problems compiling or running Mono software
   or if you think that you found a bug, etc. Please visit the
   <a href="http://geneura.ugr.es/~jaime/deploy/mono-common-problems.html">Mono Common Problems</a> document and try there.