1 <a href="#basics">Basics</a><br>
2 <a href="#ximian">The Ximian Role in the Mono project</a><br>
3 <a href="#gnome">Mono and GNOME</a><br>
4 <a href="#gui">Building GUI applications with Mono</a><br>
5 <a href="#msft">Mono and Microsoft</a><br>
6 <a href="#pnpproject">Mono and the Portable.NET Project</a><br>
7 <a href="#webservices">Web Services</a><br>
8 <a href="#asp">Mono and ASP.NET</a><br>
9 <a href="#ado">Mono and ADO.NET</a><br>
10 <a href="#devel">Development Tools and Issues</a><br>
11 <a href="#java">Mono and Java</a><br>
12 <a href="#extending">Extending Mono</a><br>
13 <a href="#portability">Portability</a><br>
14 <a href="#reuse">Reusing Existing Code</a><br>
15 <a href="#gcc">Mono and GCC</a><br>
16 <a href="#performance">Performance</a><br>
17 <a href="#licensing">Licensing</a><br>
18 <a href="#patents">Patents</a><br>
19 <a href="#etc">Miscellaneous Questions</a><br>
20 <a href="#problems">Mono Common Problems</a><br>
23 href="http://www.es.gnome.org/documentacion/articulos/mono-puf/mono-puf/">Spanish
24 translation</a> is also available
29 Q: What is Mono exactly?
31 A: The Mono Project is an open development initiative sponsored by
32 Ximian that is working to develop an open source, Unix
33 version of the Microsoft .NET development platform. Its objective
34 is to enable Unix developers to build and
35 deploy cross-platform .NET Applications. The project will
36 implement various technologies developed by Microsoft that have now
37 been submitted to the ECMA for standardization.
39 Q: What is the difference between Mono and the .NET Initiative?
41 A: The ".NET Initiative" is a somewhat nebulous company-wide effort by
42 Microsoft, one part of which is a cross-platform development
43 framework. Mono is an implementation of the development framework,
44 but not an implementation of anything else related to the .NET
45 Initiative, such as Passport, software-as-a-service, or
46 corporate re-branding.
48 Q: What technologies are included in Mono?
50 A: Mono contains a number of components useful for building new
54 * A Common Language Infrastructure (CLI) virtual
55 machine that contains a class loader, Just-in-time
56 compiler, and a garbage collecting runtime.
58 * A class library that can work with any language
59 which works on the CLR.
61 * A compiler for the C# language. In the future we
62 might work on other compilers that target the Common
67 Windows has compilers that target the virtual machine from <a
68 href="http://msdn.microsoft.com/net/thirdparty/default.asp#lang">a
69 number of languages:</a> Managed C++, Java Script, Eiffel,
70 Component Pascal, APL, Cobol, Perl, Python, Scheme,
71 Smalltalk, Standard ML, Haskell, Mercury and Oberon.
73 The CLR and the Common Type System (CTS) enables applications and
74 libraries to be written in a collection of different languages that
77 This means for example that if you define a class to do algebraic
78 manipulation in C#, that class can be reused from any other
79 language that supports the CLI. You could create a class in C#,
80 subclass it in C++ and instantiate it in an Eiffel program.
82 A single object system, threading system, class libraries, and
83 garbage collection system can be shared across all these languages.
85 Q: Where can I find the specification for these technologies?
87 A: You can find the information here:
90 C# <a href="http://www.ecma.ch/ecma1/STAND/ecma-334.htm">http://www.ecma.ch/ecma1/STAND/ecma-334.htm</a>
92 CLI <a href="http://www.ecma.ch/ecma1/STAND/ecma-335.htm">http://www.ecma.ch/ecma1/STAND/ecma-335.htm</a>
94 Q: Will you implement the .NET Framework SDK class libraries?
96 A: Yes, we will be implementing the APIs of the .NET Framework SDK
99 Q: Will you offer an ECMA-compliant set of class libraries?
101 A: Eventually we will. Our current focus is on inter-operating
102 with the Microsoft SDK, but we will also offer an ECMA compliant
105 Q: What does the name "Mono" mean?
107 A: Mono is the word for `monkey' in Spanish. We like monkeys.
111 A: The JIT engine is usable on Intel x86 machines. An interpreter
112 can be used on other non-Intel x86 machines.
114 The class libraries are mature enough to run some real applications
115 (the compiler for instance, and every day more and more applications
116 are natively developed with Mono).
118 Q: When will you ship it?
120 A: Different parts of Mono will achieve usability at different stages,
121 once we are comfortable with the compiler, we will release "Mono Core",
122 which contains everything needed to develop applications with the base
123 class libraries. This should be available at some point during 2002.
125 Other higher level class libraries (ASP.NET, ADO.NET) will
126 be released when they become stable.
128 Q: What major components will you include in Mono?
130 A: Hopefully everything that Microsoft ships on their Framework
131 (ADO.NET, ASP.NET), and
132 we encourage third party developers to create reusable components that
133 work on both Mono and Windows.
135 Q: How can I contribute?
137 A: Check the <a href="contributing.html">contributing</a> section.
139 Q: Aren't you just copying someone else's work?
141 A: We are interested in providing the best tools for programmers to
142 develop applications for Free Operating Systems. We also want to help
143 provide the interoperability that will allow those systems to fit in
144 with other standards.
146 For more background, read the <a href="http://www.go-mono.com/rationale.html">Mono
147 Project white paper</a>.
150 Q: Miguel said once that Mono was being implemented in COBOL. Is that true?.
152 A: No. It was a joke.
155 <a name="ximian"></a>
157 ** The Ximian Role in the Mono Project
159 Q: Why is Ximian working on .NET?
161 A: Ximian is interested in providing the best tools for programmers to
162 develop applications for Free Operating Systems.
164 For more information, read the project <a
165 href="rationale.html">rationale</a> page.
167 Q: Will Ximian be able to take on a project of this size?
169 A: Of course not. Ximian a supporter of the Mono project, but the only way
170 to implement something of this size is for the entire free software
171 community to get involved. Visit the <a href="contributing.html">contributing</a>
172 page if you'd like to help out.
174 Q: What pieces will Ximian be working on?
176 A: We will devote most of our resources to work on the pieces which are
177 on the critical path to release a development and execution
178 environment. Once the project is at a stage where it is useful in
179 the real world, it will achieve a critical mass of developers to
182 Q: Will Ximian offer Mono commercially?
184 A: When Mono is ready to be shipped Ximian will offer a commercial
185 support and services for Mono.
187 Q: Does Ximian provide consulting services around Mono?
189 A: Yes, Ximian does provide consulting services around Mono to
190 make it suitable to your needs. Porting the runtime engine,
191 customizing it, working on specific classes or tuning the code
192 for your particular needs.
194 Q: Will you wait until Mono is finished?
196 A: Mono will ship on various stages as they mature. Some people
197 require only a subset of the technologies, those will ship first.
199 More advanced features will take more time to develop. A support
200 time line will be available in June 2002.
205 Q: How is Mono related to GNOME?
207 A: In a number of ways. This project was born out of the need of
208 providing improved tools for the GNOME community, and will use
209 existing components that have been developed for GNOME when they
210 are available. For example, we plan to use Gtk+ and Libart to
211 implement Winforms and the Drawing2D API and are considering
214 Q: Has the GNOME Foundation or the GNOME team adopted Mono?
216 A: Mono is too new to be adopted by those groups. We hope that the
217 tools that we will provide will be adopted by free software
218 programmers including the GNOME Foundation members and the GNOME
221 Q: Should GNOME programmers switch over to Mono now?
223 A: It is still far to early for discussions of "switching over." No
224 pieces of Mono will be ready within the next six months, and a
225 complete implementation is roughly one year away.
227 We encourage GNOME developers to continue using the existing tools,
228 libraries and components. Improvements made to GNOME will have an
229 impact on Mono, as they would be the "back-end" for various classes.
231 Q: Will Mono include compatibility with Bonobo components? What is the
232 relationship between Mono and Bonobo?
234 A: Yes, we will provide a set of classes for implementing and using
235 Bonobo components from within Mono. Mono should allow you to write
236 Bonobo components more easily, just like .NET on Windows allows you
237 to export .NET components to COM.
239 Q: Does Mono depend on GNOME?
241 A: No, Mono does not depend on GNOME. We use a few packages produced by
242 the GNOME team like the `glib' library.
244 Q: But will I be able to build GNOME applications?
246 A: Yes, we will enable people to write GNOME applications using Mono.
248 Q: Do you have C# bindings for GNOME?.
250 A: Yes, we currently bind libgnome, libgnomecanvas, and libgnomeui --
251 although I dare say I have no idea how functional the bindings are
252 outside of what I tested in the sample app. I imagine other libraries
253 under the GNOME framework will be added on an as-needed (and as-requested)
254 basis...although a truly good bonobo binding will have to wait on the CORBA
255 remoting support which has been started recently.
260 Q: Will Mono enable GUI applications to be authored?
262 A: Yes, you will be able to build GUI applications. Indeed, that is our
263 main focus. We will provide both the Windows.Forms API and the Gtk# API.
265 Q: What is the difference between Gtk# and System.Windows.Forms?
267 A: Gtk# is a set of bindings for the Gtk+ toolkit for C# (and other
268 CIL-enabled languages). System.Windows.Forms is an API defined
269 by Microsoft to build GUI applications.
271 Q: Will I be able to run my smart clients on systems powered by Mono?
273 A: As long as your applications are 100% .NET and do not make use
274 of P/Invoke to call Win32 functions, your smart client applications
275 will run on Mono platforms.
277 Q: Where can I learn more about Gtk#?
279 A: The following <a href="http://gtk-sharp.sourceforge.net>link</a> sends you to the page of the project.
281 Q: What can I do with Gtk#?.
283 A: Gtk# is becoming very usable and you can create applications and
284 applets like those you see in a GNOME desktop environment. It's
285 easy to install so it's worth a try.
287 Q: How can I compile my HelloWorld.cs which uses Gtk#?.
289 A: Try: mcs --unsafe -o HelloWorld.exe -r glib-sharp -r pango-sharp -r
290 atk-sharp -r gdk-sharp -r gtk-sharp -r gdk-imaging-sharp
293 Q: Is there any way how to connect DataAdapter to some GTK# controls?
295 A: There is a sample file called `DbClient' in gtk-sharp/samples that you
296 might to look at. It is a sample program in Gtk# that adds/updates/deletes
297 information on a Postgress database. When we have the new table/tree widgets,
298 I am sure someone would write an adapter for System.Data (in Gtk2 the
299 tree/list widgets are written using a view/model, so you only need to write
300 a model that maps to the database). You can have a look at
301 gtk-sharp/sample/DbClient, where there is a GTK# application that uses
302 System.Data. It does not use DataAdapter, but DataReader though.
304 Q: Do you have an estimate for when Windows.Forms will be released?
306 A: We do not know, volunteers are working on this, but there is no set
307 date yet. The current approach is using the Wine Library to implement
311 ** Mono and Microsoft
313 Q: Is Microsoft helping Ximian with this project?
315 A: No. Ximian CTO Miguel de Icaza had a friendly conversation with
316 Microsoft software architect David Stutz, but that's about the
317 extent of the contact. Microsoft is interested in other
318 implementations of .NET and are willing to help make the ECMA spec
319 more accurate for this purpose.
321 Ximian representatives have also spoken with Sam Ruby at the ECMA
322 TG3 committee to discuss the same issues.
324 Q: Is Microsoft or Corel paying Ximian to do this?
328 Q: Do you fear that Microsoft will change the spec and render Mono
331 A: No. Microsoft proved with the CLI and the C# language that it was
332 possible to create a powerful foundation for many languages to
333 inter-operate. We will always have that.
335 Even if changes happened in the platform which were undocumented,
336 the existing platform would a value on its own.
338 Q: Are you writing Mono from the ECMA specs?
340 A: Yes, we are writing them from the ECMA specs and the published
341 materials in print about .NET.
343 Q: If my applications use Mono, will I have to pay a service fee?
345 A: No. Mono is not related to Microsoft's initiative of
346 software-as-a-service.
348 Q: Is the Mono Project is related to the Microsoft Hailstorm effort? Is
349 Ximian endorsing Hailstorm?
351 A: No. The Mono Project is focused on providing a compatible set of
352 tools for the Microsoft .NET development platform. It does not
353 address, require, or otherwise endorse the MS Passport-based
354 Hailstorm single sign-on system that is part of Windows XP and
357 Q: Will Mono or .NET applications depend on Microsoft Passport?
359 A: No. MS Passport is unrelated to running .NET compatible applications
360 produced with the Mono tools. The only thing you will need is a
361 just-in-time compiler (JIT).
363 Q: What is a 100% .NET application?
365 A: A `100% .NET application' is one that only uses the APIs defined
366 under the System namespace and does not use PInvoke. These
367 applications would in theory run unmodified on Windows, Linux,
368 HP-UX, Solaris, MacOS X and others.
370 Q: If Microsoft will release a port of their .NET platform under the
371 `Shared Source' license, why should I bother with anything else?
373 A: The Shared Source implementation will be expensive and its uses
374 will be tightly restricted, especially for commercial use. We are
375 working towards an implementation that will grant a number of
376 important rights to recipients: use for any purpose,
377 redistribution, modification, and redistribution of modifications.
379 This is what we call <a
380 href="http://www.gnu.org/philosophy/free-sw.html">Free Software</a>
382 Q: Is Mono a free implementation of Passport?
384 A: No. Mono is just a runtime, a compiler and a set of class
387 Q: Will the System.Web.Security.PassportIdentity class mean
388 that my software will depend on Passport?
390 A: No. Applications may use that API to contact a Passport site, but
391 are not required to do so.
393 As long as your application does not use Passport, you will not
396 Q: Will Mono running on Linux make Passport available for Linux?
398 A: No. However, the Passport toolkit for Linux-based web servers is
399 available from Microsoft.
401 Q: Will Mono allow me to run Microsoft Office on Linux?
403 A: No, it will not. Microsoft Office is a Windows application. To
404 learn more about running Windows applications on Intel Unix systems
405 refer to <a href="http://www.winehq.com">the Wine Project</a>.
407 Q: Will I be able to compile a Microsoft VB.NET application and execute
408 the resultant MSIL file under MONO on Linux without converting to C#
411 A: Once we have a complete VisualBasic runtime, yes.
413 Q: Can mono run the WebMatrix?
415 A: No. That requires System.Windows.Forms support which is not
416 currently implemented.
418 Q: Does mono have something like Passport?
419 Will mono have a server side Passport/Similar framework for XSP as well as client classes?
421 A: Not yet, but the client side API for authentication is not the problem.
422 We will likely have a lot of other authentication APIs, like the Liberty
423 Alliance APIs. The problem is people on the web provider end that might use
424 this for authentication.
426 <a name="pnpproject"></a>
427 ** Mono and Portable.NET
429 Q: What are the differences between Mono and Portable.NET?
431 A: Most of Mono is being written using C#, with only
432 a few parts written in C (The JIT engine, the runtime, the
433 interfaces to the garbage collection system).
435 It is easier to describe what is unique about Mono:
437 <li> A self-hosting C# compiler written in C#, which is clean, easy
440 <li> A multi-platform runtime engine: both a JIT engine and an
441 interpreter exist. The JIT engine runs currently on x86
442 systems, while the interpreter works on SPARC, StrongARM and
445 <li> Supports Linux, Windows and Solaris at this point.
447 <li> The JIT engine is written using a portable instruction
448 selector which not only generates good code (we are told
449 that we are faster than Rotor, but it is hard to tell) but
450 is also the foundation to re-target the JIT engine to other
453 The system employed is described in various compiler
454 books and it is very similar to what is described in the
455 book that covers LCC, the ANSI C retargetable C compiler.
457 <li> The JIT engine supports in-lining, constant folding and propagation,
459 <li> Full support for remoting in the runtime, but the class
460 libraries are still behind.
462 <li> The C# compiler, the JIT engine and the class libraries are
463 mature enough that the whole system is self-hosting. This means that
464 we develop Mono completely with itself at this point.
466 <li> We are not yet done, and there is a lot of work left to be
469 <li> We have a great community of developers, without which Mono
470 would not be possible.
472 <li> We will provide an ahead of time compilation mode in the
476 <a name="webservices"></a>
479 Q: How is Mono related to Web Services?
481 A: Mono is only related to Web Services in that it will implement the
482 same set of classes that have been authored in the .NET Framework
483 to simplify and streamline the process of building Web Services.
485 But most importantly, Mono is an Open Source implementation of the
488 Q: Can I author Web Services with Mono?
490 A: You will be able to write Web Services on .NET that run on Mono and
493 Q: If Mono implements the SDK classes, will I be able to write and
494 execute .NET Web Services with it?
496 A: Yes. When the project is finished, you will be able to use the
497 same technologies that are available through the .NET Framework SDK
498 on Windows to write Web Services.
500 Q: What about Soup? Can I use Soup without Mono?
502 A: Soup is a library for GNOME applications to create SOAP servers and
503 SOAP clients, and can be used without Mono. You can browse the
504 source code for soup using <a
505 href="http://cvs.gnome.org/bonsai">GNOME's Bonsai</a>.
509 A: Yes. The CLI contains enough information about a class that
510 exposing it to other RPC systems (like CORBA) is really simple, and
511 does not even require support from an object.
513 We will be implementing CORBA inter-operation as an extension to the
514 Mono classes so that we can integrate with Bonobo, just like
515 Microsoft provides COM inter-operation classes and support
518 Q: Can I serialize my objects to other things other than XML?
520 A: Yes, although the serializing tools have not yet been planned, and
521 you would probably have to implement them yourself.
523 Q: Will Mono use ORBit?
525 A: No. Mono will be using a new implementation of CORBA that isn't still started.
528 ** Development Tools and Issues
530 Q: Will it be possible to use the CLI features without using byte codes
533 A: Yes. The CLI engine will be made available as a shared library.
534 The garbage collection engine, the threading abstraction, the
535 object system, the dynamic type code system and the JIT will be
536 available for C developers to integrate with their applications if
539 Q: Will you have new development tools?
541 A: With any luck, Free Software enthusiasts will contribute tools to
542 improve the developer environment. These tools could be developed
543 initially using the Microsoft implementation of the CLI and then
544 executed later with Mono.
546 Q: What kind of rules make the Common Intermediate Language useful for
549 A: The main rule is that the stack in the CLI is not a general purpose
550 stack. You are not allowed to use it for other purposes than
551 computing values and passing arguments to functions or return
554 At any given call or return instruction, the types on the stack
555 have to be the same independently of the flow of execution of your
558 Q: Is it true that the CIL is ideal for JITing and not efficient for
561 A: The CIL is better suited to be JITed than JVM byte codes, but you
562 can interpret them as trivially as you can interpret JVM byte
565 Q: Isn't it a little bit confusing to have the name of "XSP" (the same
566 as in the Apache Project) for the ASP.NET support in Mono?.
568 A: In Mono, xsp is just the name of the C# code generator for ASP.NET
569 pages. In the Apache Project, it is a term for the "eXtensible Server
570 Pages" technology so as they are very different things, they don't
573 Q: What about using something like Jabber instead of the System.Messaging
576 A: In short, MSMQ is not something like Jabber, but asynchronous messaging
577 through queues. Useful queues do more than serialize messages, they are
578 also platform bridges.
580 Q: Are you supporting XMLDocument and relatives?.
582 A: Currently, we aren't implementing them yet. It would require updates to
583 most of the XmlNode derivatives so it's not a trivial task. We are
584 currently focusing on getting XPath support working.
586 Q: Is there any plan to develop an aspx server for Mono?.
588 A: The web server turned out to be very simple compared to the rest of the
589 work. Gonzalo has got the page generator mostly done (a module called
590 xsp, who has nothing to do with the XSP term used in the Apache Project).
591 Patrik has done a lot of the work to get the ProcessRequest to work.
592 You can try to help in the final touches to the System.Web classes and
593 writing regression tests for the widgets we have.
595 Q: Is there any way I can develop the class libraries using Linux yet?
597 A: Yes. Some class libraries can be developed on Linux. Search for
598 Paolo's post (he lists which classes can be compiled fine now).
600 Q: Is there any way I can install a known working copy of mono in /usr,
601 and an experimental copy somewhere else, and have both copies use
602 their own libraries? (I'm still not very good at library paths in
605 A: Yes. Just use two installation prefixes.
607 Q: How should I write tests or a tests suite?
609 A: If you do a test suite for C#, you might want to keep it
610 independent of the Mono C# compiler, so that other compiler
611 implementations can later use it.
613 Q: Would it be too terrible to have another corlib signed as mscorlib?
615 A: We rename corlib to mscorlib also when saving the PE files, in fact,
616 the runtime can execute program created by mono just fine.
618 Q: Is there a relatively straightforward way to repeat the steps taken
619 by Paolo to get Mono completely self-hosted on Linux?
621 A: To build the compiler and class libraries in Linux, run:
622 <ul><li>make -f makefile.gnu. To install them, run: </li>
623 <li>make -f makefile.gnu install prefix=/opt/mono</li>
626 If you want to produce and distribute a monocharge tarball, run:
627 make -f makefile.gnu dist
628 Of course you have to run these in the top level mcs directory.
630 Q: Is it possible to build a C# file to some sort of intermediate format which
631 can linked into a final module, like the traditional .c -> .o -> .so path?
633 A: You could do: mcs /target:module file1.cs, mcs /target:module file2.cs,
634 mcs /target:exe file1.dll file2.dll /out:mybin.exe
636 Q: Is there any plans for implementing remoting in the near future?, When will
637 work in System.Runtime.Remoting.dll start?
639 A: The remoting infrastructure is in place. Some of the channels and
642 Q: I'm wondering if there are any plans to start using nant to build the
643 class lib + test lib. i think that every project need/should use an
644 automated build process and nant + a couple of tools enables this. is
645 the problem that the compiler can't run nant yet?
647 A: Maybe well be doing some sort of automated build process + testing when
653 Q: Is Mono supporting ASP.NET?
655 A: Yes. The development of the support for ASP.NET comes in various stages,
656 here is what Gonzalo has been working on: 1. The Parser. 2. Getting the
657 parser to generate output compatible with ASP.NET. 3. Running the sample
658 output with the real Microsoft runtime but using our generated page. 4.
659 Running the sample with our classes with the .NET runtime. 5. Running
660 our sample code with our classes with our runtime. This is the process
661 we are following. Currently Gonzalo has reached point 5.
663 Q: Do I need install cygwin to work on ASP.NET in mono or Linux is enough since
664 it is self host right now.
668 Q: Any plan to make ASP.NET in mono works with Apache in Linux?.
670 A: Yes, we have plans to do so, but we need to wait for Patrik's patches to
671 HttpRuntime. Once that is there, writing a mod_mono should be trivial
672 (look at mono/samples/embed for a sample embedded application).
677 Q: What is the status of ADO.NET support?. Could I start migrating
678 applications from MS.NET to Mono?.
680 A: You could start right now using the ADO.NET support in mono, of course,
681 if you want to help filling the missing gaps while you develop your app
682 :-) Well, what I mean is that we're not that far to having full ADO.NET
683 support in Mono, and we've got a lot of working things, so if we could
684 get more help, we'd finish it really soon :-)
686 Q: In developing the data architecture for the application are there and
687 objects I should stay away from in order to insure the smoothest possible
688 transition (minimum code rewrite) to Mono's ADO.NET implementation? (For
689 example, strongly typed datasets versus untyped datasets, etc...)
691 A: We are implementing all the classes in Microsoft .NET's System.Data, so
692 you can be sure that things will work the same in Mono as with the Microsoft
698 Q: Why don't you use Java? After all, there are many languages that
701 A: You can get very good tools for doing Java development on free
702 systems right now. <a href="http://www.redhat.com">Red Hat</a> has
703 contributed a <a href="http://gcc.gnu.org">GCC</a> <a
704 href="http://gcc.gnu.org/java">front-end for Java</a> that can take
705 Java sources or Java byte codes and generate native executables; <a
706 href="http://www.transvirtual.com">Transvirtual</a> has implemented
707 <a href="http://www.kaffe.org">Kaffe</a> a JIT engine for Java;
708 Intel also has a Java VM called <a
709 href="http://www.intel.com/research/mrl/orp">ORP</a>.
711 The JVM is not designed to be a general purpose virtual machine.
712 The Common Intermediate Language (CIL), on the other hand, is
713 designed to be a target for a
714 wide variety of programming languages, and has a set of rules
715 designed to be optimal for JITers.
717 Q: Could Java target the CLI?
719 A: Yes, Java could target the CLI. We have details on a <a
720 href="ideas.html#guavac">project</a> that someone could take on to
723 Microsoft has an implementation of the Java language called J# that
724 can target the CIL execution engine.
726 Q: Is it possible to write a JVM byte code to CIL converter?
728 A: Yes, it is possible. Here are a few starting point:
731 * A byte code representation is really a flattened forest of
732 trees. Look at the Mono JIT engine to see how we compute
733 the basic blocks (this is used to figure out the "trees").
735 The forest is just an array of trees.
737 Indeed, run the JIT engine with -d (mono -d prog.exe) and
738 you will see how these trees look like.
740 You will have to do something similar for Java.
742 * Each "forest of trees" has a meaning. This meaning can now
743 be translated into the equivalent "meaning" in CLR-land.
746 Q: Could mono become a hybrid CIL/java platform?
748 A: No. It is quite far from the philosophy of the project. The idea of Mono
749 is, to have only _one_ VM, on which all can run. And if there existing a
750 binary-converter from Java-.class to IL and if there existing something
751 like J-Sharp on Mono, you can write programs in Java, which than can run
752 on Mono. You do not need two bindings (like your example: GTK-Sharp _and_
753 Java-Gnome). You need only _one_ of it (GTK-Sharp). Thats the idea of Mono.
754 An other point is, that there are no people, who use Open Source-JVMs. They
755 all prefer Suns original. But for Unix there don't exist a .NET-Framework.
756 So it is possible, that in the future Mono is the standard .NET for Unixes.
758 Q: Do you plan to implement a Javascript compiler?
760 A: Yes. Eto Demerzal has started a Rhino port to C#.
761 After this is completed, we will begin developing
762 the JavaScript compiler.
764 <a name="extending"></a>
767 Q: Would you allow other classes other than those in the
770 A: Yes. The Microsoft class collection is very big, but it is by no
771 means complete. It would be nice to have a port of `Camel' (the
772 Mail API used by Evolution inspired by Java Mail) for Mono
775 You might also want to look into implementing CORBA for Mono. Not
776 only because it would be useful, but because it sounds like a fun
777 thing to do, given the fact that the CLI is such a type rich
780 For more information on extending Mono, see our <a
781 href="ideas.html">ideas</a> page.
783 Q: Do you plan to Embrace and Extend .NET?
785 A: Embracing a good technology is good. Extending technologies in
786 incompatible ways is bad for the users, so we do not plan on
787 extending the technologies.
789 If you have innovative ideas, and want to create new classes, we
790 encourage you to make those classes operate correctly well in both
793 Q: Is there any way I can develop the class libraries using Linux yet?
795 A: Yes. Some class libraries can be developed on Linux. Search for
796 Paolo's post (he lists which classes can be compiled fine now).
798 Q: Is there any way I can install a known working copy of mono in /usr,
799 and an experimental copy somewhere else, and have both copies use
800 their own libraries? (I'm still not very good at library paths in
803 A: Yes. Just use two installation prefixes.
806 <a name="portability"></a>
809 Q: Will Mono only work on Linux?
811 A: Currently, we are doing our work on Linux-based systems and
812 Windows. We do not expect many Linux-isms in the code, so it
813 should be easy to port Mono to other UNIX variants.
815 Q: What about Mono on non Linux-based systems?
817 A: Our main intention at Ximian is to be able to develop GNOME
818 applications with Mono, but if you are interested in providing a
819 port of the Winforms classes to other platforms (frame buffer or
820 MacOS X for example), we would gladly integrate them, as long
821 they are under an open source license.
823 Q: What operating systems/CPUs do you support
825 A: Mono currently runs on Linux, Windows, Solaris and FreeBSD.
826 There is a JIT engine available for x86 processors that can
827 generate code and optimizations tailored for a particular CPU.
829 Interpreters exist for the SPARC, PowerPC and StrongARM CPUs.
831 Q: Does Mono run on Windows?
833 A: Yes. You can get pre-compiled
834 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
836 Q: Does Mono run on Linux?
838 A: Yes. You can get pre-compiled
839 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
841 Q: Will I require Cygwin to run mono?
843 A: No. Cygwin is only required to build Mono.
845 Q: Will Mono depend on GNOME?
847 A: It will depend only if you are using a particular assembly (for
848 example, for doing GUI applications). If you are just interested
849 in Mono for implementing a `Hello World Enterprise P2P Web
850 Service', you will not need any GNOME components.
852 Q: Is anyone working on porting Mono to IA-64?
854 A: Nobody is working on such port.
856 Q: If I were about to start a Mono port to IA-64,would the same lburg code
857 generator work for IA-64 also? or anything else need to be used for code
858 generation(as the processor architecture is totally different from IA32)
860 A: The lburg approach can be use for any processor architecture. But you might
861 think in another better approach.
863 Q: Do you plan to port Rhino to C#?.
865 A: Eto Demerzal has started a Rhino port to C#.
867 Q: Has anyone succeeded in building a Mac version of the C# environment.
868 If so can you explain how?
870 A: You could try to check with the Darwin people, or the Fink people.
871 Mono/C# is self hosting on Linux/PPC which is the hard part, so it
872 should be relatively simple to get it to work on MacOS
875 ** Reusing Existing Code
877 Q: What projects will you reuse or build upon?
879 A: We want to get Mono in the hands of programmers soon. We are
880 interested in reusing existing open source software.
882 Q: What about Intel's research JIT framework, ORP?
884 A: At this time, we are investigating whether we can use elements of
885 ORP for Mono. ORP is a research JIT engine that has a clearly
886 defined API that splits the JIT from the GC system and the actual
887 byte code implementation.
889 We are using some pieces of ORP (Their code generation interface)
890 and we use it as a source of inspiration for optimizations. Paolo
891 and Dietmar consider ORP as being one of the best JIT engines out
892 there (and their research work and papers are very useful if you are
893 interested in JIT technology).
895 Q: What about using GNU Lightning?
897 A: We are not using GNU Lightning. Our JIT is using an instruction
898 selector based on tree-pattern matching, and a code generation
899 interface that is very tied to the current architecture.
901 Q: Will I be able to use Microsoft SQL Server 2000 or will I need to switch
902 to a specific Open Source Database. Will I need to recode?
904 A: There should not be any need to recode.
906 Q: What do I need to watch out for when programming in VB.NET so that I'm
907 sure to be able to run those apps on Linux?
909 A: Not making any PInvoke or DLL calls should and not using anything in
910 the Microsoft.* namespaces should suffice. Also do not use any
911 Methods/Classes marked as "This type/method supports the .NET Framework
912 infrastructure and is not intended to be used directly from your code."
913 even if you know what these classes/methods do.
915 Q: Will built-in reporting be supported for crystal reports? This is a
916 heavily used part of our system.
918 A: Probably not. Crystal Reports are propriety. Someone may try to emulate
919 the behavior, but no-one has yet volunteered.
921 Q: Who about writing to the registry? As I understand it, Linux does not have
922 a counterpart to the registry. Should I avoid relying on that feature?
924 A: Try to avoid it. Although there would be a emulation for registry in
925 Mono too. GNOME does have a registry like mechanism for configuration. But
926 Even if gnome has a configuration system similar to the registry, the keys
927 will not be equal, so you will probably end up having to do some runtime
928 detection, and depending on this load an assembly that has your
929 platform-specific hacks.
931 Q: System.Data.SqlClient with FreeTDS, will you port parts of these to C# and
934 A: if their license is compatible with mono's, yes, we'd think about porting
935 them. If not, we'll continue with the plan of using FreeTDS.
940 Q: Are you working on a GCC front-end to C#? A GCC back-end that will
941 generate CIL images? What about making a front-end to GCC that
942 takes CIL images and generates native code?
944 A: We are currently seeking volunteers for those projects.
945 Visit the <a href="contributing.html">contributing</a> section if
948 Q: But would this work around the GPL in the GCC compiler and allow
949 people to work on non-free front-ends?
951 A: People can already do this by targeting the JVM byte codes (there
952 are about 130 compilers for various languages that target the JVM).
954 Q: Why are you writing a JIT engine instead of a front-end to GCC?
956 A: We want the JIT engine and runtime engine because they will be able
957 to execute CIL executables generated on Windows, and so no recompilation
960 <a name="performance"></a>
963 Q: How fast will Mono be?
965 A: We can not predict the future, but a conservative estimate is that
966 it would be at least `as fast as other JIT engines'.
968 We would like to ship various JIT engines with Mono, just like
969 Microsoft has done with their .NET development platform. We could
970 provide a faster, JIT for fast load times but lower performance,
971 and an and an optimizing JIT that would be slower at generating
972 code but produce more optimal output.
974 The CIL has some advantages over the Java byte code: it is really
975 an intermediate representation and there are a number of
976 restrictions on how you can emit CIL code that simplify creating
979 For example, on the CIL, the stack is not really an abstraction
980 available for the code generator to use at will. Rather, it is a
981 way of creating a postfix representation of the parsed tree. At
982 any given call point or return point, the contents of the stack are
983 expected to contain the same object types independently of how the
984 instruction was reached.
986 <a name="licensing"></a>
989 Q: Will I be able to write proprietary applications that run with
992 A: Yes. The licensing scheme is planned to allow proprietary
993 developers to write applications with Mono.
995 Q: What license or licenses are you using for the Mono Project?
997 A: The C# Compiler is released under the terms of the <a
998 href="http://www.opensource.org/licenses/gpl-license.html">GNU GPL</a>. The runtime
999 libraries are under the <a
1000 href="http://www.opensource.org/licenses/lgpl-license.html">GNU
1001 Library GPL</a>. And the class libraries are released
1002 under the terms of the <a
1003 href="http://www.opensource.org/licenses/mit-license.html">MIT X11</a>
1006 The Mono runtime and the Mono C# Compiler are also available under
1007 a proprietary license for those who can not use the LGPL and the
1010 For licensing details, contact <a
1011 href="mailto:mono-licensing@ximian.com">mono-licensing@ximian.com</a>
1014 Q: I would like to contribute code to Mono under a particular
1015 license. What licenses will you accept?
1017 A: We will have to evaluate the licenses for compatibility first,
1018 but as a general rule, we will accept the code under the same
1019 terms of the "container" module.
1024 <a name="patents"></a>
1027 Q: Could patents be used to completely disable Mono (either submarine
1028 patents filed now, or changes made by Microsoft specifically to
1029 create patent problems)?
1031 A: No. First, its basic functional capabilities have pre-existed too
1032 long to be held up by patents. The basic components of Mono are
1033 technologically equivalent to Sun's Java technology, which has been
1036 Mono will also implement multi-language and
1037 multi-architecture support, but there are previous technologies
1038 such as UCSD p-code and ANDF that also support multiple languages
1039 using a common intermediate language. The libraries are similar
1040 to other language's libraries, so again, they're too similar to
1041 be patentable in large measure.
1043 However, if Microsoft does patent some technology, then our plan is
1044 to either (1) work around it, (2) chop out patented pieces, (3)
1045 find prior art that would render the patent useless.
1047 Not providing a patented capability would weaken the
1048 interoperability, but it would still provide the free software /
1049 open source software community with good development tools, which
1050 is the primary reason for developing Mono.
1053 ** Miscellaneous Questions
1055 Q: You say that the CLI allows multiple languages to execute on the
1056 same environment. Isn't this the purpose of CORBA?
1058 A: The key difference between CORBA (and COM) and the CLI is that the
1059 CLI allows "data-level interoperability" because every
1060 language/component uses the same data layout and memory management.
1062 This means you can operate directly upon the data types that someone
1063 else provides, without having to go via their interfaces. It also
1064 means you don't have to "marshal" (convert) parameters (data
1065 layouts are the same, so you can just pass components directly) and
1066 you don't have to worry about memory management, because all
1067 languages/components share the same garbage collector and address
1068 space. This means much less copying and no need for reference
1071 Q: Will you support COM?
1073 A: The runtime will support XPCOM on Unix systems and COM on Windows.
1074 Most of the code for dynamic trampolines exists already.
1076 Q: Will Ximian offer certifications on Mono or related technologies?.
1078 A: It's possible. But there is no plan about this. So the short answer is no.
1080 Q: Are there any Boehm's GC binaries?
1082 A: Yes. You can find RPMs <a href="http://java.thn.htu.se/~toor/">here</a>, though
1083 if your distribution provides the correct packages, you should use those.
1084 The suggested version of the Boehm GC is 6.1.
1086 Q: How can I report a bug?
1088 A: The best thing is to track down the bug and provide a simple test to
1089 reproduce the bug. You can then add the bug to the
1090 <a href="http://bugzilla.ximian.com/enter_bug.cgi">bugtracking system</a>.
1092 Please provide information about what version of mono you're using
1093 and any relevant details to be able to reproduce the bug. Note that
1094 bugs reported on the mailing-list may be easily forgotten, so it's
1095 better to file them in the <a href="http://bugzilla.ximian.com/enter_bug.cgi">bug tracking system</a>.
1097 Q: Does mcs support the same command line options as the MS C#
1100 A: The Mono C# compiler now supports the same command line
1101 arguments as the Microsoft C# compiler does.
1103 Q: How about getting searchable archives on lists.ximian.com?
1105 A: You can perform a search on the mono-related mailing lists
1106 <a href="http://www.go-mono.com/mailing-lists.html">here</a>.
1108 Q: When using mono from cvs or from a snapshot, I get an error messaage
1109 saying that Mono and the runtime are out of sync. How do I fix that?
1111 A: If you use mono from cvs, you need to be prepared for changes in the
1112 runtime internals. This means that you should keep a working setup
1113 before blindling updating (a working setup may just be the last released
1114 tarball or a recent binary snapshot).
1115 Usually, compiling corlib with mcs before recompiling the C runtime does
1116 the right thing (but occasionally you may need to do it the other
1121 <a name="problems"></a>
1122 ** Mono Common Problems
1124 If you are having problems compiling or running Mono software
1125 or if you think that you found a bug, etc. Please visit the
1126 <a href="http://geneura.ugr.es/~jaime/deploy/mono-common-problems.html">Mono Common Problems</a> document and try there.