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="#platforms">Mono platforms</a><br>
7 <a href="#pnpproject">Mono and the Portable.NET Project</a><br>
8 <a href="#webservices">Web Services</a><br>
9 <a href="#asp">Mono and ASP.NET</a><br>
10 <a href="#ado">Mono and ADO.NET</a><br>
11 <a href="#monodoc">MonoDoc</a><br>
12 <a href="#devel">Development Tools and Issues</a><br>
13 <a href="#java">Mono and Java</a><br>
14 <a href="#extending">Extending Mono</a><br>
15 <a href="#portability">Portability</a><br>
16 <a href="#reuse">Reusing Existing Code</a><br>
17 <a href="#gcc">Mono and GCC</a><br>
18 <a href="#performance">Performance</a><br>
19 <a href="#licensing">Licensing</a><br>
20 <a href="#patents">Patents</a><br>
21 <a href="#etc">Miscellaneous Questions</a><br>
22 <a href="#problems">Mono Common Problems</a><br>
25 href="http://www.es.gnome.org/documentacion/articulos/mono-puf/mono-puf/">Spanish
26 translation</a> is also available
31 Q: What is Mono exactly?
33 A: The Mono Project is an open development initiative sponsored by
34 Ximian that is working to develop an open source, Unix
35 version of the Microsoft .NET development platform. Its objective
36 is to enable Unix developers to build and
37 deploy cross-platform .NET Applications. The project will
38 implement various technologies developed by Microsoft that have now
39 been submitted to the ECMA for standardization.
41 Q: What is the difference between Mono and the .NET Initiative?
43 A: The ".NET Initiative" is a somewhat nebulous company-wide effort by
44 Microsoft, one part of which is a cross-platform development
45 framework. Mono is an implementation of the development framework,
46 but not an implementation of anything else related to the .NET
47 Initiative, such as Passport, software-as-a-service, or
48 corporate re-branding.
50 Q: What technologies are included in Mono?
52 A: Mono contains a number of components useful for building new
56 * A Common Language Infrastructure (CLI) virtual
57 machine that contains a class loader, Just-in-time
58 compiler, and a garbage collecting runtime.
60 * A class library that can work with any language
61 which works on the CLR.
63 * A compiler for the C# language. In the future we
64 might work on other compilers that target the Common
69 Windows has compilers that target the virtual machine from <a
70 href="http://msdn.microsoft.com/net/thirdparty/default.asp#lang">a
71 number of languages:</a> Managed C++, Java Script, Eiffel,
72 Component Pascal, APL, Cobol, Perl, Python, Scheme,
73 Smalltalk, Standard ML, Haskell, Mercury and Oberon.
75 The CLR and the Common Type System (CTS) enables applications and
76 libraries to be written in a collection of different languages that
79 This means for example that if you define a class to do algebraic
80 manipulation in C#, that class can be reused from any other
81 language that supports the CLI. You could create a class in C#,
82 subclass it in C++ and instantiate it in an Eiffel program.
84 A single object system, threading system, class libraries, and
85 garbage collection system can be shared across all these languages.
87 Q: Where can I find the specification for these technologies?
89 A: You can find the information here:
92 C# <a href="http://www.ecma.ch/ecma1/STAND/ecma-334.htm">http://www.ecma.ch/ecma1/STAND/ecma-334.htm</a>
94 CLI <a href="http://www.ecma.ch/ecma1/STAND/ecma-335.htm">http://www.ecma.ch/ecma1/STAND/ecma-335.htm</a>
96 Q: Will you implement the .NET Framework SDK class libraries?
98 A: Yes, we will be implementing the APIs of the .NET Framework SDK
101 Q: Will you offer an ECMA-compliant set of class libraries?
103 A: Eventually we will. Our current focus is on inter-operating
104 with the Microsoft SDK, but we will also offer an ECMA compliant
107 Q: What does the name "Mono" mean?
109 A: Mono is the word for `monkey' in Spanish. We like monkeys.
113 A: The JIT engine is usable on Intel x86 machines. An interpreter
114 can be used on other non-Intel x86 machines.
116 The class libraries are mature enough to run some real applications
117 (the compiler for instance, and every day more and more applications
118 are natively developed with Mono).
120 Q: When will you ship it?
122 A: Different parts of Mono will achieve usability at different stages,
123 once we are comfortable with the compiler, we will release "Mono Core",
124 which contains everything needed to develop applications with the base
125 class libraries, this will happen soon and in the meantime you can
126 download daily snapshots of our work. Also the full ASP.NET support is
129 Other higher level class libraries (ASP.NET, ADO.NET, WinForms) will
130 be released when they become stable.
132 Q: What major components will you include in Mono?
134 A: Hopefully everything that Microsoft ships on their Framework
135 (ADO.NET, ASP.NET, WinForms), and we encourage third party developers to
136 create reusable components that work on both Mono and Windows.
138 Q: How can I contribute?
140 A: Check the <a href="contributing.html">contributing</a> section.
142 Q: Aren't you just copying someone else's work?
144 A: We are interested in providing the best tools for programmers to
145 develop applications for Free Operating Systems. We also want to help
146 provide the interoperability that will allow those systems to fit in
147 with other standards.
149 For more background, read the <a href="http://www.go-mono.com/rationale.html">Mono
150 Project white paper</a>.
153 Q: Miguel said once that Mono was being implemented in COBOL. Is that true?.
155 A: No. It was a joke.
158 <a name="ximian"></a>
160 ** The Ximian Role in the Mono Project
162 Q: Why is Ximian working on .NET?
164 A: Ximian is interested in providing the best tools for programmers to
165 develop applications for Free Operating Systems.
167 For more information, read the project <a
168 href="rationale.html">rationale</a> page.
170 Q: Will Ximian be able to take on a project of this size?
172 A: Of course not. Ximian a supporter of the Mono project, but the only way
173 to implement something of this size is for the entire free software
174 community to get involved. Visit the <a href="contributing.html">contributing</a>
175 page if you'd like to help out.
177 Q: What pieces will Ximian be working on?
179 A: We will devote most of our resources to work on the pieces which are
180 on the critical path to release a development and execution
181 environment. Once the project is at a stage where it is useful in
182 the real world, it will achieve a critical mass of developers to
185 Q: Will Ximian offer Mono commercially?
187 A: When Mono is ready to be shipped Ximian will offer a commercial
188 support and services for Mono.
190 Q: Does Ximian provide consulting services around Mono?
192 A: Yes, Ximian does provide consulting services around Mono to
193 make it suitable to your needs. Porting the runtime engine,
194 customizing it, working on specific classes or tuning the code
195 for your particular needs.
197 Q: Will you wait until Mono is finished?
199 A: Mono will ship on various stages as they mature. Some people
200 require only a subset of the technologies, those will ship first.
202 More advanced features will take more time to develop. A support
203 time line will be available in June 2002.
208 Q: How is Mono related to GNOME?
210 A: In a number of ways. This project was born out of the need of
211 providing improved tools for the GNOME community, and will use
212 existing components that have been developed for GNOME when they
213 are available. For example, we plan to use Gtk+ and Libart to
214 implement Winforms and the Drawing2D API and are considering
217 Q: Has the GNOME Foundation or the GNOME team adopted Mono?
219 A: Mono is too new to be adopted by those groups. We hope that the
220 tools that we will provide will be adopted by free software
221 programmers including the GNOME Foundation members and the GNOME
224 Q: Should GNOME programmers switch over to Mono now?
226 A: It is still far to early for discussions of "switching over." No
227 pieces of Mono will be ready within the next six months, and a
228 complete implementation is roughly one year away.
230 We encourage GNOME developers to continue using the existing tools,
231 libraries and components. Improvements made to GNOME will have an
232 impact on Mono, as they would be the "back-end" for various classes.
234 Q: Will Mono include compatibility with Bonobo components? What is the
235 relationship between Mono and Bonobo?
237 A: Yes, we will provide a set of classes for implementing and using
238 Bonobo components from within Mono. Mono should allow you to write
239 Bonobo components more easily, just like .NET on Windows allows you
240 to export .NET components to COM.
242 Q: Does Mono depend on GNOME?
244 A: No, Mono does not depend on GNOME. We use a few packages produced by
245 the GNOME team like the `glib' library.
247 Q: But will I be able to build GNOME applications?
249 A: Yes, we will enable people to write GNOME applications using Mono.
251 Q: Do you have C# bindings for GNOME?.
253 A: Yes, we currently bind libgnome, libgnomecanvas, and libgnomeui --
254 although I dare say I have no idea how functional the bindings are
255 outside of what I tested in the sample app. I imagine other libraries
256 under the GNOME framework will be added on an as-needed (and as-requested)
257 basis...although a truly good bonobo binding will have to wait on the CORBA
258 remoting support which has been started recently.
263 Q: Will Mono enable GUI applications to be authored?
265 A: Yes, you will be able to build GUI applications. Indeed, that is our
266 main focus. We will provide both the Windows.Forms API and the Gtk# API.
268 Q: What is the difference between Gtk# and System.Windows.Forms?
270 A: Gtk# is a set of bindings for the Gtk+ toolkit for C# (and other
271 CIL-enabled languages). System.Windows.Forms is an API defined
272 by Microsoft to build GUI applications.
274 Q: Will I be able to run my smart clients on systems powered by Mono?
276 A: As long as your applications are 100% .NET and do not make use
277 of P/Invoke to call Win32 functions, your smart client applications
278 will run on Mono platforms.
280 Q: Where can I learn more about Gtk#?
282 A: The following <a href="http://gtk-sharp.sourceforge.net>link</a> sends you to the page of the project.
284 Q: What can I do with Gtk#?.
286 A: Gtk# is becoming very usable and you can create applications and
287 applets like those you see in a GNOME desktop environment. It's
288 easy to install so it's worth a try.
290 Q: How can I compile my HelloWorld.cs which uses Gtk#?.
292 A: Try: mcs --unsafe -o HelloWorld.exe -r glib-sharp -r pango-sharp -r
293 atk-sharp -r gdk-sharp -r gtk-sharp -r gdk-imaging-sharp
296 Q: Is there any way how to connect DataAdapter to some GTK# controls?
298 A: There is a sample file called `DbClient' in gtk-sharp/samples that you
299 might to look at. It is a sample program in Gtk# that adds/updates/deletes
300 information on a Postgress database. When we have the new table/tree widgets,
301 I am sure someone would write an adapter for System.Data (in Gtk2 the
302 tree/list widgets are written using a view/model, so you only need to write
303 a model that maps to the database). You can have a look at
304 gtk-sharp/sample/DbClient, where there is a GTK# application that uses
305 System.Data. It does not use DataAdapter, but DataReader though.
307 Q: Do you have an estimate for when Windows.Forms will be released?
309 A: We do not know, volunteers are working on this, but there is no set
310 date yet. The current approach is using the Wine Library to implement
314 ** Mono and Microsoft
316 Q: Is Microsoft helping Ximian with this project?
318 A: There is no high level communication between Ximian and Microsoft
319 at this point, but engineers who work on .NET or the ECMA groups
320 have been very friendly, and very nice to answer our questions, or
321 clarify part of the specification for us.
323 Microsoft is interested in other implementations of .NET and are
324 willing to help make the ECMA spec more accurate for this purpose.
326 Ximian was also invited to participate in the ECMA committee
327 meetings for C# and the CLI.
329 Q: Is Microsoft or Corel paying Ximian to do this?
333 Q: Do you fear that Microsoft will change the spec and render Mono
336 A: No. Microsoft proved with the CLI and the C# language that it was
337 possible to create a powerful foundation for many languages to
338 inter-operate. We will always have that.
340 Even if changes happened in the platform which were undocumented,
341 the existing platform would a value on its own.
343 Q: Are you writing Mono from the ECMA specs?
345 A: Yes, we are writing them from the ECMA specs and the published
346 materials in print about .NET.
348 Q: If my applications use Mono, will I have to pay a service fee?
350 A: No. Mono is not related to Microsoft's initiative of
351 software-as-a-service.
353 Q: Is the Mono Project is related to the Microsoft Hailstorm effort? Is
354 Ximian endorsing Hailstorm?
356 A: No. The Mono Project is focused on providing a compatible set of
357 tools for the Microsoft .NET development platform. It does not
358 address, require, or otherwise endorse the MS Passport-based
359 Hailstorm single sign-on system that is part of Windows XP and
362 Q: Will Mono or .NET applications depend on Microsoft Passport?
364 A: No. MS Passport is unrelated to running .NET compatible applications
365 produced with the Mono tools. The only thing you will need is a
366 just-in-time compiler (JIT).
368 Q: What is a 100% .NET application?
370 A: A `100% .NET application' is one that only uses the APIs defined
371 under the System namespace and does not use PInvoke. These
372 applications would in theory run unmodified on Windows, Linux,
373 HP-UX, Solaris, MacOS X and others.
375 Q: If Microsoft will release a port of their .NET platform under the
376 `Shared Source' license, why should I bother with anything else?
378 A: The Shared Source implementation will be expensive and its uses
379 will be tightly restricted, especially for commercial use. We are
380 working towards an implementation that will grant a number of
381 important rights to recipients: use for any purpose,
382 redistribution, modification, and redistribution of modifications.
384 This is what we call <a
385 href="http://www.gnu.org/philosophy/free-sw.html">Free Software</a>
387 Q: Is Mono a free implementation of Passport?
389 A: No. Mono is just a runtime, a compiler and a set of class
392 Q: Will the System.Web.Security.PassportIdentity class mean
393 that my software will depend on Passport?
395 A: No. Applications may use that API to contact a Passport site, but
396 are not required to do so.
398 As long as your application does not use Passport, you will not
401 Q: Will Mono running on Linux make Passport available for Linux?
403 A: No. However, the Passport toolkit for Linux-based web servers is
404 available from Microsoft.
406 Q: Will Mono allow me to run Microsoft Office on Linux?
408 A: No, it will not. Microsoft Office is a Windows application. To
409 learn more about running Windows applications on Intel Unix systems
410 refer to <a href="http://www.winehq.com">the Wine Project</a>.
412 Q: Will I be able to compile a Microsoft VB.NET application and execute
413 the resultant MSIL file under MONO on Linux without converting to C#
416 A: Once we have a complete VisualBasic runtime, yes.
418 Q: Can mono run the WebMatrix?
420 A: No. That requires System.Windows.Forms support which is not
421 currently implemented.
423 Q: Does mono have something like Passport?
424 Will mono have a server side Passport/Similar framework for XSP as well as client classes?
426 A: Not yet, but the client side API for authentication is not the problem.
427 We will likely have a lot of other authentication APIs, like the Liberty
428 Alliance APIs. The problem is people on the web provider end that might use
429 this for authentication.
431 <a name="platforms"></a>
434 Q: What operating systems does Mono run on?
436 A: Mono is known to run on Linux, Unix and Windows systems.
438 Q: What architectures does Mono support?
440 A: Mono today ships with a Just-in-Time compiler for x86-based
441 systems. It is tested regularly on Linux, FreeBSD and Windows
442 (with the XP/NT core).
444 There is also an interpreter, which is slower that runs on the
445 s390, SPARC and PowerPC architectures.
447 Q: Can Mono run on Windows 9x, or ME editions?
449 A: Mono requires Unicode versions of Win32 APIs to run,
450 and only a handful of *W functions is supported under Win9x.
452 There is Microsoft Layer for Unicode that provides implementation
453 of these APIs on 9x systems.
455 Unfortunately it uses linker trick for delayed load that is not
456 supported by ld, so some sort of adapter is necessary.
458 You will need MSLU and one of the following libs to link Mono to
460 href="http://mono.eurosoft.od.ua/files/unimono.zip">http://mono.eurosoft.od.ua/files/unimono.zip</a>
461 or alternatively search the net for "libunicows".
463 No changes to Mono source code required, the only thing is to make
464 sure that linker will resolve imports to adapter library instead of
465 Win32 libs. This is achieved by inserting -lunimono before
466 -lkerner32/user32 in the linker's specs file.
469 <a name="pnpproject"></a>
470 ** Mono and Portable.NET
472 Q: What are the differences between Mono and Portable.NET?
474 A: Most of Mono is being written using C#, with only
475 a few parts written in C (The JIT engine, the runtime, the
476 interfaces to the garbage collection system).
478 It is easier to describe what is unique about Mono:
480 <li> A Just-in-Time compiler engine. This is important for
481 making your applications fast.
483 <li> A self-hosting C# compiler written in C#, which is clean, easy
486 <li> Focus on the .NET Framework: we are tracking down the .NET
487 Framework API definition, as we believe it is the API people
488 will be most familiar with.
490 <li> A multi-platform runtime engine: both a JIT engine and an
491 interpreter exist. The JIT engine runs currently on x86
492 systems, while the interpreter works on SPARC, StrongARM,
493 s390 and PowerPC systems.
495 <li> Supports Linux, Windows and Solaris at this point.
497 <li> The JIT engine is written using a portable instruction
498 selector which not only generates good code (we are told
499 that we are faster than Rotor, but it is hard to tell) but
500 is also the foundation to re-target the JIT engine to other
503 The system employed is described in various compiler
504 books and it is very similar to what is described in the
505 book that covers LCC, the ANSI C retargetable C compiler.
507 <li> The JIT engine supports in-lining, constant folding and propagation,
509 <li> Full support for remoting in the runtime, but the class
510 libraries are still behind.
512 <li> The C# compiler, the JIT engine and the class libraries are
513 mature enough that the whole system is self-hosting. This means that
514 we develop Mono completely with itself at this point.
516 <li> We are not yet done, and there is a lot of work left to be
519 <li> We have a great community of developers, without which Mono
520 would not be possible.
522 <li> We are working on an ahead of time compilation mode to
523 pre-compile code for the target architecture (this is part
524 of our new code generation effort).
527 <a name="webservices"></a>
530 Q: How is Mono related to Web Services?
532 A: Mono is only related to Web Services in that it will implement the
533 same set of classes that have been authored in the .NET Framework
534 to simplify and streamline the process of building Web Services.
536 But most importantly, Mono is an Open Source implementation of the
539 Q: Can I author Web Services with Mono?
541 A: You will be able to write Web Services on .NET that run on Mono and
544 Q: If Mono implements the SDK classes, will I be able to write and
545 execute .NET Web Services with it?
547 A: Yes. When the project is finished, you will be able to use the
548 same technologies that are available through the .NET Framework SDK
549 on Windows to write Web Services.
551 Q: What about Soup? Can I use Soup without Mono?
553 A: Soup is a library for GNOME applications to create SOAP servers and
554 SOAP clients, and can be used without Mono. You can browse the
555 source code for soup using <a
556 href="http://cvs.gnome.org/bonsai">GNOME's Bonsai</a>.
560 A: Yes. The CLI contains enough information about a class that
561 exposing it to other RPC systems (like CORBA) is really simple, and
562 does not even require support from an object.
564 We will be implementing CORBA inter-operation as an extension to the
565 Mono classes so that we can integrate with Bonobo, just like
566 Microsoft provides COM inter-operation classes and support
569 Q: Can I serialize my objects to other things other than XML?
571 A: Yes, although the serializing tools have not yet been planned, and
572 you would probably have to implement them yourself.
574 Q: Will Mono use ORBit?
576 A: No. Mono will be using a new implementation of CORBA that isn't still started.
578 <a name="monodoc"></a>
583 A: MonoDoc is a graphical documentation editor and viewer. Currently, MonoDoc
584 consists of a Gtk# application and is in heavy development. There is also a
589 ** Development Tools and Issues
591 Q: Will it be possible to use the CLI features without using byte codes
594 A: Yes. The CLI engine will be made available as a shared library.
595 The garbage collection engine, the threading abstraction, the
596 object system, the dynamic type code system and the JIT will be
597 available for C developers to integrate with their applications if
600 Q: Will you have new development tools?
602 A: With any luck, Free Software enthusiasts will contribute tools to
603 improve the developer environment. These tools could be developed
604 initially using the Microsoft implementation of the CLI and then
605 executed later with Mono.
607 Q: What kind of rules make the Common Intermediate Language useful for
610 A: The main rule is that the stack in the CLI is not a general purpose
611 stack. You are not allowed to use it for other purposes than
612 computing values and passing arguments to functions or return
615 At any given call or return instruction, the types on the stack
616 have to be the same independently of the flow of execution of your
619 Q: Is it true that the CIL is ideal for JITing and not efficient for
622 A: The CIL is better suited to be JITed than JVM byte codes, but you
623 can interpret them as trivially as you can interpret JVM byte
626 Q: Isn't it a little bit confusing to have the name of "XSP" (the same
627 as in the Apache Project) for the ASP.NET support in Mono?.
629 A: In Mono, xsp is just the name of the C# code generator for ASP.NET
630 pages. In the Apache Project, it is a term for the "eXtensible Server
631 Pages" technology so as they are very different things, they don't
634 Q: What about using something like Jabber instead of the System.Messaging
637 A: In short, MSMQ is not something like Jabber, but asynchronous messaging
638 through queues. Useful queues do more than serialize messages, they are
639 also platform bridges.
641 Q: Are you supporting XMLDocument and relatives?.
643 A: Currently, we aren't implementing them yet. It would require updates to
644 most of the XmlNode derivatives so it's not a trivial task. We are
645 currently focusing on getting XPath support working.
647 Q: Is there any plan to develop an aspx server for Mono?.
649 A: The web server turned out to be very simple compared to the rest of the
650 work. Gonzalo has got the page generator mostly done (a module called
651 xsp, who has nothing to do with the XSP term used in the Apache Project).
652 Patrik has done a lot of the work to get the ProcessRequest to work.
653 You can try to help in the final touches to the System.Web classes and
654 writing regression tests for the widgets we have.
656 Q: Is there any way I can develop the class libraries using Linux yet?
658 A: Yes. Some class libraries can be developed on Linux. Search for
659 Paolo's post (he lists which classes can be compiled fine now).
661 Q: Is there any way I can install a known working copy of mono in /usr,
662 and an experimental copy somewhere else, and have both copies use
663 their own libraries? (I'm still not very good at library paths in
666 A: Yes. Just use two installation prefixes.
668 Q: How should I write tests or a tests suite?
670 A: If you do a test suite for C#, you might want to keep it
671 independent of the Mono C# compiler, so that other compiler
672 implementations can later use it.
674 Q: Would it be too terrible to have another corlib signed as mscorlib?
676 A: We rename corlib to mscorlib also when saving the PE files, in fact,
677 the runtime can execute program created by mono just fine.
679 Q: Is there a relatively straightforward way to repeat the steps taken
680 by Paolo to get Mono completely self-hosted on Linux?
682 A: To build the compiler and class libraries in Linux, run:
683 <ul><li>make -f makefile.gnu. To install them, run: </li>
684 <li>make -f makefile.gnu install prefix=/opt/mono</li>
687 If you want to produce and distribute a monocharge tarball, run:
688 make -f makefile.gnu dist
689 Of course you have to run these in the top level mcs directory.
691 Q: Is it possible to build a C# file to some sort of intermediate format which
692 can linked into a final module, like the traditional .c -> .o -> .so path?
694 A: You could do: mcs /target:module file1.cs, mcs /target:module file2.cs,
695 mcs /target:exe file1.dll file2.dll /out:mybin.exe
697 Q: Is there any plans for implementing remoting in the near future?, When will
698 work in System.Runtime.Remoting.dll start?
700 A: The remoting infrastructure is in place. Some of the channels and
703 Q: I'm wondering if there are any plans to start using nant to build the
704 class lib + test lib. i think that every project need/should use an
705 automated build process and nant + a couple of tools enables this. is
706 the problem that the compiler can't run nant yet?
708 A: Maybe well be doing some sort of automated build process + testing when
711 Q: My C code uses the __stdcall which is not availble on Linux, how can I
712 make the code portable Windows/Unix across platforms?
714 A: Replace the __stdcall attribute with the STDCALL macro, and include this
715 in your C code for newer gcc versions:
718 #define STDCALL __attribute__((stdcall))
724 Q: Does Mono support ASP.NET?
728 Mono supports ASP.NET, we have shown an unmodified IBuySpy
729 installation running on Mono as well as various other programs. You can
730 try it yourself downloading the XSP server.
732 Q: Do I need install cygwin to work on ASP.NET in mono or Linux is enough since
733 it is self host right now.
737 Q: How can I run ASP.NET-based applications with Mono?
739 A: You need the Mono runtime and a hosting web server. Currently we distribute a
740 small web server called `xsp' which is used to debug applications, or you can choose
741 to use Daniel's Apache 2 module.
743 Q: Any plan to make ASP.NET in mono works with Apache in Linux?.
745 A: Daniel has authored an Apache2 Module for Mono that hosts the ASP.NET runtime
746 and is available here: <a
747 href="http://apacheworld.org/modmono/">http://apacheworld.org/modmono/</a>
749 Q: Will you support Apache 1?
751 A: Modules developed for Apache 2 are not compatible with Apache 1.3
752 Daniel plans to support Apache 1.3 in the future but the current focus is on
753 Apache 2, because of the better support for threading and Windows.
755 Q: Can I run Apache 1 and Apache 2 on the same machine?
757 You can always keep a copy of Apache 2 running in paralell with your Apache
758 1.3 (either different port or using a reverse proxy).
760 You can also bind the two servers to different IP addresses on the
761 same physical machine.
766 Q: What is the status of ADO.NET support?. Could I start migrating
767 applications from MS.NET to Mono?.
769 A: You could start right now using the ADO.NET support in mono, of course,
770 if you want to help filling the missing gaps while you develop your app
771 :-) Well, what I mean is that we're not that far to having full ADO.NET
772 support in Mono, and we've got a lot of working things, so if we could
773 get more help, we'd finish it really soon :-)
775 Q: In developing the data architecture for the application are there and
776 objects I should stay away from in order to insure the smoothest possible
777 transition (minimum code rewrite) to Mono's ADO.NET implementation? (For
778 example, strongly typed datasets versus untyped datasets, etc...)
780 A: We are implementing all the classes in Microsoft .NET's System.Data, so
781 you can be sure that things will work the same in Mono as with the Microsoft
784 Q: Does Mono can to connect to Sybase by using Mono.Data.*?
786 A: Yes. use Mono.Data.SybaseClient. First of all you have to create a
787 SybaseConnection, and then, from it, use it as any other
788 IDbConnection-based class.
793 Q: Why don't you use Java? After all, there are many languages that
796 A: You can get very good tools for doing Java development on free
797 systems right now. <a href="http://www.redhat.com">Red Hat</a> has
798 contributed a <a href="http://gcc.gnu.org">GCC</a> <a
799 href="http://gcc.gnu.org/java">front-end for Java</a> that can take
800 Java sources or Java byte codes and generate native executables; <a
801 href="http://www.transvirtual.com">Transvirtual</a> has implemented
802 <a href="http://www.kaffe.org">Kaffe</a> a JIT engine for Java;
803 Intel also has a Java VM called <a
804 href="http://www.intel.com/research/mrl/orp">ORP</a>.
806 The JVM is not designed to be a general purpose virtual machine.
807 The Common Intermediate Language (CIL), on the other hand, is
808 designed to be a target for a
809 wide variety of programming languages, and has a set of rules
810 designed to be optimal for JITers.
812 Q: Could Java target the CLI?
814 A: Yes, Java could target the CLI. We have details on a <a
815 href="ideas.html#guavac">project</a> that someone could take on to
818 Microsoft has an implementation of the Java language called J# that
819 can target the CIL execution engine.
821 Q: Is it possible to write a JVM byte code to CIL converter?
823 A: Yes, it is possible. Here are a few starting point:
826 * A byte code representation is really a flattened forest of
827 trees. Look at the Mono JIT engine to see how we compute
828 the basic blocks (this is used to figure out the "trees").
830 The forest is just an array of trees.
832 Indeed, run the JIT engine with -d (mono -d prog.exe) and
833 you will see how these trees look like.
835 You will have to do something similar for Java.
837 * Each "forest of trees" has a meaning. This meaning can now
838 be translated into the equivalent "meaning" in CLR-land.
841 Q: Could mono become a hybrid CIL/java platform?
843 A: No. It is quite far from the philosophy of the project. The idea of Mono
844 is, to have only _one_ VM, on which all can run. And if there existing a
845 binary-converter from Java-.class to IL and if there existing something
846 like J-Sharp on Mono, you can write programs in Java, which than can run
847 on Mono. You do not need two bindings (like your example: GTK-Sharp _and_
848 Java-Gnome). You need only _one_ of it (GTK-Sharp). Thats the idea of Mono.
849 An other point is, that there are no people, who use Open Source-JVMs. They
850 all prefer Suns original. But for Unix there don't exist a .NET-Framework.
851 So it is possible, that in the future Mono is the standard .NET for Unixes.
853 Q: Do you plan to implement a Javascript compiler?
855 A: Yes. Eto Demerzal has started a Rhino port to C#.
856 After this is completed, we will begin developing
857 the JavaScript compiler.
859 Q: Can Mono or .NET share system classes (loaded from mscore.dll and other
860 libs) or will it behave like Sun's Java VM?
862 A: What you can do with mono is to load different applications in their own
863 application domain: this is a feature of the CLR that allows sandboxing
864 applications inside a single process space. This is usualy exploited to
865 compartmentalize different parts of the same app, but it can also be
866 effectively used to reduce the startup and memory overhead.
867 Using different appdomains the runtime representation of types and
868 methods is shared across applications.
870 <a name="extending"></a>
873 Q: Would you allow other classes other than those in the
876 A: Yes. The Microsoft class collection is very big, but it is by no
877 means complete. It would be nice to have a port of `Camel' (the
878 Mail API used by Evolution inspired by Java Mail) for Mono
881 You might also want to look into implementing CORBA for Mono. Not
882 only because it would be useful, but because it sounds like a fun
883 thing to do, given the fact that the CLI is such a type rich
886 For more information on extending Mono, see our <a
887 href="ideas.html">ideas</a> page.
889 Q: Do you plan to Embrace and Extend .NET?
891 A: Embracing a good technology is good. Extending technologies in
892 incompatible ways is bad for the users, so we do not plan on
893 extending the technologies.
895 If you have innovative ideas, and want to create new classes, we
896 encourage you to make those classes operate correctly well in both
899 Q: Is there any way I can develop the class libraries using Linux yet?
901 A: Yes. Some class libraries can be developed on Linux. Search for
902 Paolo's post (he lists which classes can be compiled fine now).
904 Q: Is there any way I can install a known working copy of mono in /usr,
905 and an experimental copy somewhere else, and have both copies use
906 their own libraries? (I'm still not very good at library paths in
909 A: Yes. Just use two installation prefixes.
912 <a name="portability"></a>
915 Q: Will Mono only work on Linux?
917 A: Currently, we are doing our work on Linux-based systems and
918 Windows. We do not expect many Linux-isms in the code, so it
919 should be easy to port Mono to other UNIX variants.
921 Q: What about Mono on non Linux-based systems?
923 A: Our main intention at Ximian is to be able to develop GNOME
924 applications with Mono, but if you are interested in providing a
925 port of the Winforms classes to other platforms (frame buffer or
926 MacOS X for example), we would gladly integrate them, as long
927 they are under an open source license.
929 Q: What operating systems/CPUs do you support
931 A: Mono currently runs on Linux, Windows, Solaris and FreeBSD.
932 There is a JIT engine available for x86 processors that can
933 generate code and optimizations tailored for a particular CPU.
935 Interpreters exist for the SPARC, PowerPC and StrongARM CPUs.
937 Q: Does Mono run on Windows?
939 A: Yes. You can get pre-compiled
940 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
942 Q: Does Mono run on Linux?
944 A: Yes. You can get pre-compiled
945 binaries from <a href="http://www.go-mono.com/download.html">http://www.go-mono.com/download.html</a>
947 Q: Will I require Cygwin to run mono?
949 A: No. Cygwin is only required to build Mono.
951 Q: Will Mono depend on GNOME?
953 A: It will depend only if you are using a particular assembly (for
954 example, for doing GUI applications). If you are just interested
955 in Mono for implementing a `Hello World Enterprise P2P Web
956 Service', you will not need any GNOME components.
958 Q: Is anyone working on porting Mono to IA-64?
960 A: Nobody is working on such port.
962 Q: If I were about to start a Mono port to IA-64,would the same lburg code
963 generator work for IA-64 also? or anything else need to be used for code
964 generation(as the processor architecture is totally different from IA32)
966 A: The lburg approach can be use for any processor architecture. But you might
967 think in another better approach.
969 Q: Do you plan to port Rhino to C#?.
971 A: Eto Demerzal has started a Rhino port to C#.
973 Q: Has anyone succeeded in building a Mac version of the C# environment.
974 If so can you explain how?
976 A: You could try to check with the Darwin people, or the Fink people.
977 Mono/C# is self hosting on Linux/PPC which is the hard part, so it
978 should be relatively simple to get it to work on MacOS
981 ** Reusing Existing Code
983 Q: What projects will you reuse or build upon?
985 A: We want to get Mono in the hands of programmers soon. We are
986 interested in reusing existing open source software.
988 Q: What about Intel's research JIT framework, ORP?
990 A: At this time, we are investigating whether we can use elements of
991 ORP for Mono. ORP is a research JIT engine that has a clearly
992 defined API that splits the JIT from the GC system and the actual
993 byte code implementation.
995 We are using some pieces of ORP (Their code generation interface)
996 and we use it as a source of inspiration for optimizations. Paolo
997 and Dietmar consider ORP as being one of the best JIT engines out
998 there (and their research work and papers are very useful if you are
999 interested in JIT technology).
1001 Q: What about using GNU Lightning?
1003 A: We are not using GNU Lightning. Our JIT is using an instruction
1004 selector based on tree-pattern matching, and a code generation
1005 interface that is very tied to the current architecture.
1007 Q: Will I be able to use Microsoft SQL Server 2000 or will I need to switch
1008 to a specific Open Source Database. Will I need to recode?
1010 A: There should not be any need to recode.
1012 Q: What do I need to watch out for when programming in VB.NET so that I'm
1013 sure to be able to run those apps on Linux?
1015 A: Not making any PInvoke or DLL calls should and not using anything in
1016 the Microsoft.* namespaces should suffice. Also do not use any
1017 Methods/Classes marked as "This type/method supports the .NET Framework
1018 infrastructure and is not intended to be used directly from your code."
1019 even if you know what these classes/methods do.
1021 Q: Will built-in reporting be supported for crystal reports? This is a
1022 heavily used part of our system.
1024 A: Probably not. Crystal Reports are propriety. Someone may try to emulate
1025 the behavior, but no-one has yet volunteered.
1027 Q: Who about writing to the registry? As I understand it, Linux does not have
1028 a counterpart to the registry. Should I avoid relying on that feature?
1030 A: Try to avoid it. Although there would be a emulation for registry in
1031 Mono too. GNOME does have a registry like mechanism for configuration. But
1032 Even if gnome has a configuration system similar to the registry, the keys
1033 will not be equal, so you will probably end up having to do some runtime
1034 detection, and depending on this load an assembly that has your
1035 platform-specific hacks.
1037 Q: System.Data.SqlClient with FreeTDS, will you port parts of these to C# and
1040 A: if their license is compatible with mono's, yes, we'd think about porting
1041 them. If not, we'll continue with the plan of using FreeTDS.
1046 Q: Are you working on a GCC front-end to C#? A GCC back-end that will
1047 generate CIL images? What about making a front-end to GCC that
1048 takes CIL images and generates native code?
1050 A: We are currently seeking volunteers for those projects.
1051 Visit the <a href="contributing.html">contributing</a> section if
1054 Q: But would this work around the GPL in the GCC compiler and allow
1055 people to work on non-free front-ends?
1057 A: People can already do this by targeting the JVM byte codes (there
1058 are about 130 compilers for various languages that target the JVM).
1060 Q: Why are you writing a JIT engine instead of a front-end to GCC?
1062 A: We want the JIT engine and runtime engine because they will be able
1063 to execute CIL executables generated on Windows, and so no recompilation
1066 <a name="performance"></a>
1069 Q: How fast will Mono be?
1071 A: We can not predict the future, but a conservative estimate is that
1072 it would be at least `as fast as other JIT engines'.
1074 We would like to ship various JIT engines with Mono, just like
1075 Microsoft has done with their .NET development platform. We could
1076 provide a faster, JIT for fast load times but lower performance,
1077 and an and an optimizing JIT that would be slower at generating
1078 code but produce more optimal output.
1080 The CIL has some advantages over the Java byte code: it is really
1081 an intermediate representation and there are a number of
1082 restrictions on how you can emit CIL code that simplify creating
1085 For example, on the CIL, the stack is not really an abstraction
1086 available for the code generator to use at will. Rather, it is a
1087 way of creating a postfix representation of the parsed tree. At
1088 any given call point or return point, the contents of the stack are
1089 expected to contain the same object types independently of how the
1090 instruction was reached.
1092 <a name="licensing"></a>
1095 Q: Will I be able to write proprietary applications that run with
1098 A: Yes. The licensing scheme is planned to allow proprietary
1099 developers to write applications with Mono.
1101 Q: What license or licenses are you using for the Mono Project?
1103 A: The C# Compiler is released under the terms of the <a
1104 href="http://www.opensource.org/licenses/gpl-license.html">GNU GPL</a>. The runtime
1105 libraries are under the <a
1106 href="http://www.opensource.org/licenses/lgpl-license.html">GNU
1107 Library GPL</a>. And the class libraries are released
1108 under the terms of the <a
1109 href="http://www.opensource.org/licenses/mit-license.html">MIT X11</a>
1112 The Mono runtime and the Mono C# Compiler are also available under
1113 a proprietary license for those who can not use the LGPL and the
1116 For licensing details, contact <a
1117 href="mailto:mono-licensing@ximian.com">mono-licensing@ximian.com</a>
1120 Q: I would like to contribute code to Mono under a particular
1121 license. What licenses will you accept?
1123 A: We will have to evaluate the licenses for compatibility first,
1124 but as a general rule, we will accept the code under the same
1125 terms of the "container" module.
1127 <a name="patents"></a>
1130 Q: Could patents be used to completely disable Mono (either submarine
1131 patents filed now, or changes made by Microsoft specifically to
1132 create patent problems)?
1134 A: No. First, its basic functional capabilities have pre-existed too
1135 long to be held up by patents. The basic components of Mono are
1136 technologically equivalent to Sun's Java technology, which has been
1139 Mono will also implement multi-language and
1140 multi-architecture support, but there are previous technologies
1141 such as UCSD p-code and ANDF that also support multiple languages
1142 using a common intermediate language. The libraries are similar
1143 to other language's libraries, so again, they're too similar to
1144 be patentable in large measure.
1146 However, if Microsoft does patent some technology, then our plan is
1147 to either (1) work around it, (2) chop out patented pieces, (3)
1148 find prior art that would render the patent useless.
1150 Not providing a patented capability would weaken the
1151 interoperability, but it would still provide the free software /
1152 open source software community with good development tools, which
1153 is the primary reason for developing Mono.
1155 There is also a statement from Jim Miller at Microsoft, one of the
1156 inventors listed in the patent: <a href="https://mailserver.di.unipi.it/pipermail/dotnet-sscli/msg00218.html">here</a>.
1158 For Linux desktop use, we only need the ECMA components, and things that
1159 we have developed (like Gtk#).
1162 ** Miscellaneous Questions
1164 Q: You say that the CLI allows multiple languages to execute on the
1165 same environment. Isn't this the purpose of CORBA?
1167 A: The key difference between CORBA (and COM) and the CLI is that the
1168 CLI allows "data-level interoperability" because every
1169 language/component uses the same data layout and memory management.
1171 This means you can operate directly upon the data types that someone
1172 else provides, without having to go via their interfaces. It also
1173 means you don't have to "marshal" (convert) parameters (data
1174 layouts are the same, so you can just pass components directly) and
1175 you don't have to worry about memory management, because all
1176 languages/components share the same garbage collector and address
1177 space. This means much less copying and no need for reference
1180 Q: Will you support COM?
1182 A: The runtime will support XPCOM on Unix systems and COM on Windows.
1183 Most of the code for dynamic trampolines exists already.
1185 Q: Will Ximian offer certifications on Mono or related technologies?.
1187 A: It's possible. But there is no plan about this. So the short answer is no.
1189 Q: Are there any Boehm's GC binaries?
1191 A: Yes. You can find RPMs <a href="http://java.thn.htu.se/~toor/">here</a>, though
1192 if your distribution provides the correct packages, you should use those.
1193 The suggested version of the Boehm GC is 6.1.
1195 Q: How can I report a bug?
1197 A: The best thing is to track down the bug and provide a simple test to
1198 reproduce the bug. You can then add the bug to the
1199 <a href="http://bugzilla.ximian.com/enter_bug.cgi">bugtracking system</a>.
1201 Please provide information about what version of mono you're using
1202 and any relevant details to be able to reproduce the bug. Note that
1203 bugs reported on the mailing-list may be easily forgotten, so it's
1204 better to file them in the <a href="http://bugzilla.ximian.com/enter_bug.cgi">bug tracking system</a>.
1206 Q: Does mcs support the same command line options as the MS C#
1209 A: The Mono C# compiler now supports the same command line
1210 arguments as the Microsoft C# compiler does.
1212 Q: How about getting searchable archives on lists.ximian.com?
1214 A: You can perform a search on the mono-related mailing lists
1215 <a href="http://www.go-mono.com/mailing-lists.html">here</a>.
1217 Q: When using mono from cvs or from a snapshot, I get an error messaage
1218 saying that Mono and the runtime are out of sync. How do I fix that?
1220 A: If you use mono from cvs, you need to be prepared for changes in the
1221 runtime internals. This means that you should keep a working setup
1222 before blindling updating (a working setup may just be the last released
1223 tarball or a recent binary snapshot).
1224 Usually, compiling corlib with mcs before recompiling the C runtime does
1225 the right thing (but occasionally you may need to do it the other
1228 Q: Why are you going for a GtkHtml implementation?
1230 A: GtkHTML is just a lightweight HTML rendering engine that does not
1231 support CSS, so we need it to look decent for those of us that will
1232 be using the documentation in our day-to-day work on Linux. The
1233 Web-based interfaces lack the agility that you get from a native GUI
1234 tool to browse your documentation. Probably later on, we will write
1235 scripts and generate a full documentation set that is web-browsable,
1236 but we need a command-line and GUI tools that we can use natively on
1237 Linux when disconnected from the Web (and that has better
1238 interactions than a web page).
1240 Q: Is there a command-line tool that allows me to access .NET interactively?
1242 A: There are several but one that is free software and uses MCS is the one
1243 Dennis Lu from Rice University is working on; a REPL C# interpreter.
1245 Q: Is it possible to use Visual C++ with Mono?.
1247 A: Well, It's possible to run VC++ generated apps under Mono though.
1249 <a name="problems"></a>
1250 ** Mono Common Problems
1252 If you are having problems compiling or running Mono software
1253 or if you think that you found a bug, etc. Please visit the
1254 <a href="http://geneura.ugr.es/~jaime/deploy/mono-common-problems.html">Mono Common Problems</a> document and try there.
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