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="#winforms">Mono and WinForms</a><br>
6 <a href="#msft">Mono and Microsoft</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="#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>
25 Q: What is Mono exactly?
27 A: The Mono Project is an open development initiative sponsored by
28 Ximian that is working to develop an open source, Unix
29 version of the Microsoft .NET development platform. Its objective
30 is to enable Unix developers to build and
31 deploy cross-platform .NET Applications. The project will
32 implement various technologies developed by Microsoft that have now
33 been submitted to the ECMA for standardization.
35 Q: What is the difference between Mono and the .NET Initiative?
37 A: The ".NET Initiative" is a somewhat nebulous company-wide effort by
38 Microsoft, one part of which is a cross-platform development
39 framework. Mono is an implementation of the development framework,
40 but not an implementation of anything else related to the .NET
41 Initiative, such as Passport, software-as-a-service, or
44 Q: What technologies are included in Mono?
46 A: Mono contains a number of components useful for building new
50 * A Common Language Infrastructure (CLI) virtual
51 machine that contains a class loader, Just-in-time
52 compiler, and a garbage collecting runtime.
54 * A class library that can work with any language
55 which works on the CLR.
57 * A compiler for the C# language. In the future we
58 might work on other compilers that target the Common
63 Windows has compilers that target the virtual machine from <a
64 href="http://msdn.microsoft.com/net/thirdparty/default.asp#lang">a
65 number of languages:</a> Managed C++, Java Script, Eiffel,
66 Component Pascal, APL, Cobol, Oberon, Perl, Python, Scheme,
67 Smalltalk, Standard ML, Haskell, Mercury and Oberon.
69 The CLR and the Common Type System (CTS) enables applications and
70 libraries to be written in a collection of different languages that
73 This means for example that if you define a class to do algebraic
74 manipulation in C#, that class can be reused from any other
75 language that supports the CLI. You could create a class in C#,
76 subclass it in C++ and instantiate it in an Eiffel program.
78 A single object system, threading system, class libraries, and
79 garbage collection system can be shared across all these languages.
81 Q: Where can I find the specification for these technologies?
83 A: You can find the work-in-progress documentation from the T3G ECMA
86 <a href="http://www.dotnetexperts.com">http://www.dotnetexperts.com</a>
88 Q: Will you implement the .NET Framework SDK class libraries?
90 A: Yes, we will be implementing the APIs of the .NET Framework SDK
93 Q: Will you offer an ECMA-compliant set of class libraries?
95 A: Eventually we will. Our current focus is on interoperating
96 with the Microsoft SDK, but we will also offer an ECMA compliant
99 Q: What does the name "Mono" mean?
101 A: Mono is the word for `monkey' in Spanish. We like monkeys.
105 A: The JIT engine is usable on Intel x86 machines. An interpreter
106 can be used on other non-Intel x86 machines.
108 The class libraries are mature enough to run some real applications
109 (the compiler for instance, and every day more and more applications
110 are natively developed with Mono).
112 Q: When will you ship it?
114 A: Different parts of Mono will achieve usability at different stages,
115 once we are comfortable with the compiler, we will release "Mono Core",
116 which contains everything needed to develop applications with the base
117 class libraries. This should be available at some point during 2002.
119 Other higher level class libraries (ASP.NET, ADO.NET, Windows.Forms) will
120 be released when they become stable.
122 Q: What major components will you include in Mono?
124 A: Hopefully everything that Microsoft ships on their Framework
125 (ADO.NET, ASP.NET, Windows.Forms), and
126 we encourage third party developers to create reusable components that
127 work on both Mono and Windows.
129 Q: How can I contribute?
131 A: Check the <a href="contributing.html">contributing</a> section.
133 Q: Aren't you just copying someone else's work?
135 A: We are interested in providing the best tools for programmers to
136 develop applications for Free Operating Systems. We also want to help
137 provide the interoperability that will allow those systems to fit in
138 with other standards.
140 For more background, read the <a href="http://www.go-mono.com/rationale.html">Mono
141 Project white paper</a>.
144 Q: Miguel said once that Mono was being implemented in COBOL. Is that true?.
146 A: No. It was a joke.
149 <a name="ximian"></a>
151 ** The Ximian Role in the Mono Project
153 Q: Why is Ximian working on .NET?
155 A: Ximian is interested in providing the best tools for programmers to
156 develop applications for Free Operating Systems.
158 For more information, read the project <a
159 href="rationale.html">rationale</a> page.
161 Q: Will Ximian be able to take on a project of this size?
163 A: Of course not. Ximian a supporter of the Mono project, but the only way
164 to implement something of this size is for the entire free software
165 community to get involved. Visit the <a href="contributing.html">contributing</a>
166 page if you'd like to help out.
168 Q: What pieces will Ximian be working on?
170 A: We will devote most of our resources to work on the pieces which are
171 on the critical path to release a development and execution
172 environment. Once the project is at a stage where it is useful in
173 the real world, it will achieve a critical mass of developers to
176 Q: Will Ximian offer Mono commercially?
178 A: When Mono is ready to be shipped Ximian will offer a commercial
179 support and services for Mono.
181 Q: Does Ximian provide consulting services around Mono?
183 A: Yes, Ximian does provide consulting services around Mono to
184 make it suitable to your needs. Porting the runtime engine,
185 customizing it, working on specific classes or tuning the code
186 for your particular needs.
188 Q: Will you wait until Mono is finished?
190 A: Mono will ship on various stages as they mature. Some people
191 require only a subset of the technologies, those will ship first.
193 More advanced features will take more time to develop. A support
194 timeline will be available in June 2002.
199 Q: How is Mono related to GNOME?
201 A: In a number of ways. This project was born out of the need of
202 providing improved tools for the GNOME community, and will use
203 existing components that have been developed for GNOME when they
204 are available. For example, we plan to use Gtk+ and Libart to
205 implement Winforms and the Drawing2D API and are considering
208 Q: Has the GNOME Foundation or the GNOME team adopted Mono?
210 A: Mono is too new to be adopted by those groups. We hope that the
211 tools that we will provide will be adopted by free software
212 programmers including the GNOME Foundation members and the GNOME
215 Q: Should GNOME programmers switch over to Mono now?
217 A: It is still far to early for discussions of "switching over." No
218 pieces of Mono will be ready within the next six months, and a
219 complete implementation is roughly one year away.
221 We encourage GNOME developers to continue using the existing tools,
222 libraries and components. Improvements made to GNOME will have an
223 impact on Mono, as they would be the "backend" for various classes.
225 Q: Will Mono include compatibility with Bonobo components? What is the
226 relationship between Mono and Bonobo?
228 A: Yes, we will provide a set of classes for implementing and using
229 Bonobo components from within Mono. Mono should allow you to write
230 Bonobo components more easily, just like .NET on Windows allows you
231 to export .NET components to COM.
233 Q: Does Mono depend on GNOME?
235 A: No, Mono does not depend on GNOME. We use a few packages produced by
236 the GNOME team like the `glib' library.
238 Q: But will I be able to build GNOME applications?
240 A: Yes, we will enable people to write GNOME applications using Mono.
245 Q: Will Mono enable GUI applications to be authored?
247 A: Yes, you will be able to build GUI applications. Indeed, that is our
248 main focus. We will provide both the Windows.Forms API and the Gtk# API.
250 Q: What is the difference between Gtk# and System.Windows.Forms?
252 A: Gtk# is a set of bindings for the Gtk+ toolkit for C# (and other
253 CIL-enabled languages). System.Windows.Forms is an API defined
254 by Microsoft to build GUI applications.
256 Q: Will I be able to run my smart clients on systems powered by Mono?
258 A: As long as your applications are 100% .NET and do not make use
259 of P/Invoke to call Win32 functions, your smart client applications
260 will run on Mono platforms.
262 Q: Where can I learn mora about Gtk#?
264 A: The following <a href="http://gtk-sharp.sourceforge.net>link</a> sends you to the page of the project.
266 Q: What can I do with Gtk#?.
268 A: Gtk# is becoming very usable and you can create applications and
269 applets like those you see in a GNOME desktop environment. It's
270 easy to install so it's worth a try.
272 Q: How can I compile my HelloWorld.cs which uses Gtk#?.
274 A: Try: mcs --unsafe -o HelloWorld.exe -r glib-sharp -r pango-sharp -r
275 atk-sharp -r gdk-sharp -r gtk-sharp -r gdk-imaging-sharp
278 <a name="winforms"></a>
281 Q: Can you tell me why aren't you implementing WinForms?.
283 A: (This is based in an original mail to mono-list written by Miguel de
284 Icaza. You should read it for completion, but the core part is here).
286 First, Windows.Forms is packed with quirks and is not that great of a
287 toolkit in the first place. Up to the point of the unconfirmed rumor
288 that Microsoft is working on a replacement for it.
290 Once the runtime is done, we will very likely start contributing to
291 the Gtk# project ourselves, and we will likely start doing feasibility
292 work on getting Mono used by Gnome developers: full gnome apps and
293 extending existing applications.
295 Those interested in hacking on Windows.Forms are welcome to do so,
296 but Ximian will not likely look at it in the near future; if there is
297 enough demand, or I can be convinced that Windows.Forms is useful for
298 something Ximian might re-evaluate our resource allocation for this
301 By doing native ports, we could use the same API on all those systems.
302 Also, Gtk is mature enough, we know this because we have built an entire
303 desktop (and all sorts of very window system-specific hacks), and we
304 have built a bunch of productivity applications with it.
308 Someone mentioned VCL. The only problem with the VCL is that it can
309 only be used for GPL applications (or I guess you could license it from
310 Borland for your app), and would have to be ported from Delphi to C#
311 (or someone would have to write a CIL compiler for it).
314 ** Mono and Microsoft
316 Q: Is Microsoft helping Ximian with this project?
318 A: No. Ximian CTO Miguel de Icaza had a friendly conversation with
319 Microsoft software architect David Stutz, but that's about the
320 extent of the contact. Microsoft is interested in other
321 implementations of .NET and are willing to help make the ECMA spec
322 more accurate for this purpose.
324 Ximian representatives have also spoken with Sam Ruby at the ECMA
325 TG3 committee to discuss the same issues.
327 Q: Is Microsoft or Corel paying Ximian to do this?
331 Q: Do you fear that Microsoft will change the spec and render Mono
334 A: No. Microsoft proved with the CLI and the C# language that it was
335 possible to create a powerful foundation for many languages to
336 interoperate. We will always have that.
338 Even if changes happened in the platform which were undocumented,
339 the existing platform would a value on its own.
341 Q: Are you writing Mono from the ECMA specs?
343 A: Yes, we are writing them from the ECMA specs and the published
344 materials in print about .NET.
346 Q: If my applications use Mono, will I have to pay a service fee?
348 A: No. Mono is not related to Microsoft's initiative of
349 software-as-a-service.
351 Q: Is the Mono Project is related to the Microsoft Hailstorm effort? Is
352 Ximian endorsing Hailstorm?
354 A: No. The Mono Project is focused on providing a compatible set of
355 tools for the Microsoft .NET development platform. It does not
356 address, require, or otherwise endorse the MS Passport-based
357 Hailstorm single sign-on system that is part of Windows XP and
360 Q: Will Mono or .NET applications depend on Microsoft Passport?
362 A: No. MS Passport is unrelated to running .NET compatible applications
363 produced with the Mono tools. The only thing you will need is a
364 just-in-time compiler (JIT).
366 Q: What is a 100% .NET application?
368 A: A `100% .NET application' is one that only uses the APIs defined
369 under the System namespace and does not use PInvoke. These
370 applications would in theory run unmodified on Windows, Linux,
371 HP-UX, Solaris, MacOS X and others.
373 Q: If Microsoft will release a port of their .NET platform under the
374 `Shared Source' license, why should I bother with anything else?
376 A: The Shared Source implementation will be expensive and its uses
377 will be tightly restricted, especially for commercial use. We are
378 working towards an implementation that will grant a number of
379 important rights to recipients: use for any purpose,
380 redistribution, modification, and redistribution of modifications.
382 This is what we call <a
383 href="http://www.gnu.org/philosophy/free-sw.html">Free Software</a>
385 Q: Is Mono a free implementation of Passport?
387 A: No. Mono is just a runtime, a compiler and a set of class
390 Q: Will the System.Web.Security.PassportIdentity class mean
391 that my software will depend on Passport?
393 A: No. Applications may use that API to contact a Passport site, but
394 are not required to do so.
396 As long as your application does not use Passport, you will not
399 Q: Will Mono running on Linux make Passport available for Linux?
401 A: No. However, the Passport toolkit for Linux-based web servers is
402 available from Microsoft.
404 Q: Will Mono allow me to run Microsoft Office on Linux?
406 A: No, it will not. Microsoft Office is a Windows application. To
407 learn more about running Windows applications on Intel Unix systems
408 refer to <a href="http://www.winehq.com">the Wine Project</a>.
410 <a name="pnpproject"></a>
411 ** Mono and Portable.NET
413 Q: What are the differences between Mono and Portable.NET?
415 A: Most of Mono is being written using C#, with only
416 a few parts written in C (The JIT engine, the runtime, the
417 interfaces to the garbage collection system).
419 It is easier to describe what is unique about Mono:
421 <li> A self-hosting C# compiler written in C#, which is clean, easy
424 <li> A multi-platform runtime engine: both a JIT engine and an
425 interpreter exist. The JIT engine runs currently on x86
426 systems, while the interpreter works on Sparc, StrongARM and
429 <li> Supports Linux, Windows and Solaris at this point.
431 <li> The JIT engine is written using a portable instruction
432 selector which not only generates good code (we are told
433 that we are faster than Rotor, but it is hard to tell) but
434 is also the foundation to retarget the JIT engine to other
437 The system employed is described in various compiler
438 books and it is very similar to what is described in the
439 book that covers LCC, the Ansi C retargetable C compiler.
441 <li> The JIT engine supports inlining, constant folding and propagation,
443 <li> Full support for remoting in the runtime, but the class
444 libraries are still behind.
446 <li> The C# compiler, the JIT engine and the class libraries are
447 mature enough that the whole system is self-hosting, ie, that
448 it can be fully developed with itself at this point.
450 <li> We are not yet done, and there is a lot of work left to be
453 <li> We have a great community of developers, without which Mono
454 would not be possible.
456 <li> We will provide an ahead of time compilation mode in the
460 <a name="webservices"></a>
463 Q: How is Mono related to Web Services?
465 A: Mono is only related to Web Services in that it will implement the
466 same set of classes that have been authored in the .NET Framework
467 to simplify and streamline the process of building Web Services.
469 But most importantly, Mono is an Open Source implementation of the
472 Q: Can I author Web Services with Mono?
474 A: You will be able to write Web Services on .NET that run on Mono and
477 Q: If Mono implements the SDK classes, will I be able to write and
478 execute .NET Web Services with it?
480 A: Yes. When the project is finished, you will be able to use the
481 same technologies that are available through the .NET Framework SDK
482 on Windows to write Web Services.
484 Q: What about Soup? Can I use Soup without Mono?
486 A: Soup is a library for GNOME applications to create SOAP servers and
487 SOAP clients, and can be used without Mono. You can browse the
488 source code for soup using <a
489 href="http://cvs.gnome.org/bonsai">GNOME's Bonsai</a>.
493 A: Yes. The CLI contains enough information about a class that
494 exposing it to other RPC systems (like CORBA) is really simple, and
495 does not even require support from an object.
497 We will be implementing CORBA interoperation as an extension to the
498 Mono classes so that we can integrate with Bonobo, just like
499 Microsoft provides COM interoperation classes and support
502 Q: Can I serialize my objects to other things other than XML?
504 A: Yes, although the serializing tools have not yet been planned, and
505 you would probably have to implement them yourself.
507 Q: Will Mono use ORBit?
509 A: No. Mono will be using a new implementation of CORBA that isn't still started.
512 ** Development Tools and Issues
514 Q: Will it be possible to use the CLI features without using bytecodes
517 A: Yes. The CLI engine will be made available as a shared library.
518 The garbage collection engine, the threading abstraction, the
519 object system, the dynamic type code system and the JIT will be
520 available for C developers to integreate with their applications if
523 Q: Will you have new development tools?
525 A: With any luck, Free Software enthusiasts will contribute tools to
526 improve the developer environment. These tools could be developed
527 initially using the Microsoft implementation of the CLI and then
528 executed later with Mono.
530 Q: What kind of rules make the Common Intermediate Language useful for
533 A: The main rule is that the stack in the CLI is not a general purpose
534 stack. You are not allowed to use it for other purposes than
535 computing values and passing arguments to functions or return
538 At any given call or return instruction, the types on the stack
539 have to be the same independently of the flow of execution of your
542 Q: Is it true that the CIL is ideal for JITing and not efficient for
545 A: The CIL is better suited to be JITed than JVM byte codes, but you
546 can interpret them as trivially as you can interpret JVM byte
549 Q: Isn't it a little bit confusing to have the name of "XSP" (the same
550 as in the Apache Project) for the ASP.NET support in Mono?.
552 A: In Mono, xsp is just the name of the C# code generator for ASP.NET
553 pages. In the Apache Project, it is a term for the "eXtensible Server
554 Pages" technology so as they are very different things, they don't
557 Q: What about using something like Jabber instead of the System.Messaging
560 A: In short, MSMQ is not something like Jabber, but asynchronous messaging
561 through queues. Usefull queues do more than serialize messages, they are
562 also platform bridges.
564 Q: Are you supporting XMLDocument and relatives?.
566 A: Currently, we aren't implementing them yet. It would require updates to
567 most of the XmlNode derivatives so it's not a trivial task. We are
568 currently focusing on getting XPath support working.
570 Q: Is there any plan to develop an aspx server for Mono?.
572 A: The webserver turned out to be very simple compared to the rest of the
573 work. Gonzalo has got the page generator mostly done (a module called
574 xsp, who has nothing to do with the XSP term used in the Apache Project).
575 Patrik has done a lot of the work to get the ProcessRequest to work.
576 You can try to help in the final touches to the System.Web classes and
577 writing regression tests for the widgets we have.
579 Q: Is there any way I can develop the class libraries using linux yet?
581 A: Yes. Some class libraries can be developed on Linux. Search for
582 Paolo's post (he lists which classes can be compiled fine now).
584 Q: Is there any way I can install a known working copy of mono in /usr,
585 and an experimental copy somewhere else, and have both copies use
586 their own libraries? (I'm still not very good at library paths in
589 A: Yes. Just use two installation prefixes.
595 Q: Is Mono supporting ASP.NET?
597 A: Yes. The development of the support for ASP.NET comes in various stages,
598 here is what Gonzalo has been working on: 1. The Parser. 2. Getting the
599 parser to generate output compatible with ASP.NET. 3. Running the sample
600 output with the real Microsoft runtime but using our generated page. 4.
601 Running the sample with our classes with the .NET runtime. 5. Running
602 our sample code with our classes with our runtime. This is the process
603 we are following. Currently Gonzalo has reached point 5.
608 Q: Why don't you use Java? After all, there are many languages that
611 A: You can get very good tools for doing Java development on free
612 systems right now. <a href="http://www.redhat.com">Red Hat</a> has
613 contributed a <a href="http://gcc.gnu.org">GCC</a> <a
614 href="http://gcc.gnu.org/java">frontend for Java</a> that can take
615 Java sources or Java byte codes and generate native executables; <a
616 href="http://www.transvirtual.com">Transvirtual</a> has implemented
617 <a href="http://www.kaffe.org">Kaffe</a> a JIT engine for Java;
618 Intel also has a Java VM called <a
619 href="http://www.intel.com/research/mrl/orp">ORP</a>.
621 The JVM is not designed to be a general purpose virtual machine.
622 The Common Intermediate Language (CIL), on the other hand, is
623 designed to be a target for a
624 wide variety of programming languages, and has a set of rules
625 designed to be optimal for JITers.
627 Q: Could Java target the CLI?
629 A: Yes, Java could target the CLI. We have details on a <a
630 href="ideas.html#guavac">project</a> that someone could take on to
633 Microsoft has an implemenation of the Java language called J# that
634 can target the CIL execution engine.
636 Q: Is it possible to write a JVM byte code to CIL convertor?
638 A: Yes, it is possible. Here are a few starting point:
641 * A byte code representation is really a flattened forest of
642 trees. Look at the Mono JIT engine to see how we compute
643 the basic blocks (this is used to figure out the "trees").
645 The forest is just an array of trees.
647 Indeed, run the JIT engine with -d (mono -d prog.exe) and
648 you will see how these trees look like.
650 You will have to do something similar for Java.
652 * Each "forest of trees" has a meaning. This meaning can now
653 be translated into the equivalent "meaning" in CLR-land.
656 Q: Could mono become a hybrid cil/java platform?
658 A: No. It is quite far from the philosophy of the project. The idea of Mono
659 is, to have only _one_ VM, on which all can run. And if there existing a
660 binary-converter from Java-.class to IL and if there existing something
661 like J-Sharp on Mono, you can write programs in Java, which than can run
662 on Mono. You do not need two bindings (like your example: GTK-Sharp _and_
663 Java-Gnome). You need only _one_ of it (GTK-Sharp). Thats the idea of Mono.
664 An other point is, that there are no people, who use OpenSource-JVMs. They
665 all prefer Suns original. But for Unix there don't exist a .NET-Framework.
666 So it is possible, that in the future Mono is the standard .NET for unixes.
668 <a name="extending"></a>
671 Q: Would you allow other classes other than those in the
674 A: Yes. The Microsoft class collection is very big, but it is by no
675 means complete. It would be nice to have a port of `Camel' (the
676 Mail API used by Evolution inspired by Java Mail) for Mono
679 You might also want to look into implementing CORBA for Mono. Not
680 only because it would be useful, but because it sounds like a fun
681 thing to do, given the fact that the CLI is such a type rich
684 For more information on extending Mono, see our <a
685 href="ideas.html">ideas</a> page.
687 Q: Do you plan to Embrace and Extend .NET?
689 A: Embracing a good technology is good. Extending technologies in
690 incompatible ways is bad for the users, so we do not plan on
691 extending the technologies.
693 If you have innovative ideas, and want to create new classes, we
694 encourage you to make those classes operate correctly well in both
697 Q: Is there any way I can develop the class libraries using linux yet?
699 A: Yes. Some class libraries can be developed on Linux. Search for
700 Paolo's post (he lists which classes can be compiled fine now).
702 Q: Is there any way I can install a known working copy of mono in /usr,
703 and an experimental copy somewhere else, and have both copies use
704 their own libraries? (I'm still not very good at library paths in
707 A: Yes. Just use two installation prefixes.
710 <a name="portability"></a>
713 Q: Will Mono only work on Linux?
715 A: Currently, we are doing our work on Linux-based systems and
716 Windows. We do not expect many Linux-isms in the code, so it
717 should be easy to port Mono to other UNIX variants.
719 Q: What about Mono on non Linux-based systems?
721 A: Our main intention at Ximian is to be able to develop GNOME
722 applications with Mono, but if you are interested in providing a
723 port of the Winform classes to other platforms (frame buffer or
724 MacOS X for example), we would gladly integrate them, as long
725 they are under an open source license.
727 Q: What operating systems/CPUs do you support
729 A: Mono currently runs on Linux, Windows, Solaris and FreeBSD.
730 There is a JIT engine available for x86 processors that can
731 generate code and optimizations tailored for a particular CPU.
733 Interpreters exist for the SPARC, PowerPC and StrongARM cpus.
735 Q: Does Mono run on Windows?
737 A: Yes. The Compiler and the runtime both run on Windows.
739 Q: When will mono and mcs compile on Linux?.
741 A: That happend a long time ago. Know you can download and compile
742 them or even install them from already made binary packages for
743 Windows and for Linux (RPM/DEB).
745 Q: Will I require Cygwin to run mono?
747 A: No. While you'll need it to compile it, it runs without cygwin and does not even require cygwin1.dll
749 Q: Will Mono depend on GNOME?
751 A: It will depend only if you are using a particular assembly (for
752 example, for doing GUI applications). If you are just interested
753 in Mono for implementing a `Hello World Enterprise P2P Web
754 Service', you will not need any GNOME components.
756 Q: Is anyone working on porting Mono to IA-64?
758 A: Nobody is working on such port.
760 Q: If I were about to start a Mono port to IA-64,would the same lburg code
761 generator work for IA-64 also? or anything else need to be used for code
762 generation(as the processor architecture is totally different from IA32)
764 A: The lburg approach can be use for any processor architecture. But you might
765 think in another better approach.
768 ** Reusing Existing Code
770 Q: What projects will you reuse or build upon?
772 A: We want to get Mono in the hands of programmers soon. We are
773 interested in reusing existing open source software.
775 Q: What about Intel's research JIT framework, ORP?
777 A: At this time, we are investigating whether we can use elements of
778 ORP for Mono. ORP is a research JIT engine that has a clearly
779 defined API that splits the JIT from the GC system and the actual
780 byte code implementation.
782 We are using some pieces of ORP (Their code generation interface)
783 and we use it as a source of inspiration for optimizations. Paolo
784 and Dietmar consider ORP as being one of the best JIT engines out
785 there (and their research work and papers are very useful if you are
786 interested in JIT technology).
788 Q: What about using GNU Lightning?
790 A: We are not using GNU Lightning. Our JIT is using an instruction
791 selector based on tree-pattern matching, and a code generation
792 interface that is very tied to the current architecture.
794 Q: Will I be able to use Microsoft SQL Server 2000 or will I need to switch
795 to a specific Open Source Database. Will I need to recode?
797 A: There should not be any need to recode.
799 Q: What do I need to watch out for when programming in VB.NET so that I'm
800 sure to be able to run those apps on Linux?
802 A: Not making any PInvoke or DLL calls should and not using anything in
803 the Microsoft.* namespaces should suffice. Also do not use any
804 Methods/Classes marked as "This type/method supports the .NET Framework
805 infrastructure and is not intended to be used directly from your code."
806 even if you know what these classes/methods do.
808 Q: Will built-in reporting be supported for crystal reports? This is a
809 heavily used part of our system.
811 A: Probably not. Crystal Reports are propriety. Someone may try to emulate
812 the behaviour, but no-one has yet volunteered.
814 Q: Who about writing to the registry? As I understand it, Linux does not have
815 a counterpart to the registry. Should I avoid relying on that feature?
817 A: Try to avoid it. Although there would be a emulation for registry in
818 Mono too. GNOME does have a registry like mechanism for configuration. But
819 Even if gnome has a configuration system similar to the registry, the keys
820 will not be equal, so you will probably end up having to do some runtime
821 detection, and depending on this load an assembly that has your
822 platform-specific hacks.
827 Q: Are you working on a GCC front-end to C#? A GCC backend that will
828 generate CIL images? What about making a front-end to GCC that
829 takes CIL images and generates native code?
831 A: We are currently seeking volunteers for those projects.
832 Visit the <a href="contributing.html">contributing</a> section if
835 Q: But would this work around the GPL in the GCC compiler and allow
836 people to work on non-free front-ends?
838 A: People can already do this by targeting the JVM byte codes (there
839 are about 130 compilers for various languages that target the JVM).
841 Q: Why are you writing a JIT engine instead of a front-end to GCC?
843 A: We want the JIT engine and runtime engine because they will be able
844 to execute CIL executables generated on Windows, and so no recompilation
847 <a name="performance"></a>
850 Q: How fast will Mono be?
852 A: We can not predict the future, but a conservative estimate is that
853 it would be at least `as fast as other JIT engines'.
855 We would like to ship various JIT engines with Mono, just like
856 Microsoft has done with their .NET development platform. We could
857 provide a faster, JIT for fast load times but lower performance,
858 and an and an optimizing JIT that would be slower at generating
859 code but produce more optimal output.
861 The CIL has some advantages over the Java byte code: it is really
862 an intermediate representation and there are a number of
863 restrictions on how you can emit CIL code that simplify creating
866 For example, on the CIL, the stack is not really an abstraction
867 available for the code generator to use at will. Rather, it is a
868 way of creating a postfix representation of the parsed tree. At
869 any given call point or return point, the contents of the stack are
870 expected to contain the same object types independently of how the
871 instruction was reached.
873 <a name="licensing"></a>
876 Q: Will I be able to write proprietary applications that run with
879 A: Yes. The licensing scheme is planned to allow proprietary
880 developers to write applications with Mono.
882 Q: What license or licenses are you using for the Mono Project?
884 A: The C# Compiler is released under the terms of the <a
885 href="http://www.opensource.org/licenses/gpl-license.html">GNU GPL</a>. The runtime
886 libraries are under the <a
887 href="http://www.opensource.org/licenses/lgpl-license.html">GNU
888 Library GPL</a>. And the class libraries are released
889 under the terms of the <a
890 href="http://www.opensource.org/licenses/mit-license.html">MIT X11</a>
893 Q: I would like to contribute code to Mono under a particular
894 license. What licenses will you accept?
896 A: We will have to evaluate the licenses for compatibility first,
897 but as a general rule, we will accept the code under the same
898 terms of the "container" module.
900 <a name="patents></a>
903 Q: Could patents be used to completely disable Mono (either submarine
904 patents filed now, or changes made by Microsoft specifically to
905 create patent problems)?
907 A: No. First, its basic functional capabilities have pre-existed too
908 long to be held up by patents. The basic components of Mono are
909 technologically equivalent to Sun's Java technology, which has been
910 around for years. Mono will also implement multi-language and
911 multi-architecture support, but there are previous technologies
912 such as UCSD p-code and ANDF that also support multiple languages
913 using a common intermediate language. The libraries are similar
914 to other language's libraries, so again, they're too similar to
915 be patentable in large measure.
917 However, if Microsoft does patent some technology, then our plan is
918 to either (1) work around it, (2) chop out patented pieces, (3)
919 find prior art that would render the patent useless.
921 Not providing a patented capability would weaken the
922 interoperability, but it would still provide the free software /
923 open source software community with good development tools, which
924 is the primary reason for developing Mono.
927 ** Miscellaneous Questions
929 Q: You say that the CLI allows multiple languages to execute on the
930 same environment. Isn't this the purpose of CORBA?
932 A: The key difference between CORBA (and COM) and the CLI is that the
933 CLI allows "data-level interoperability" because every
934 language/component uses the same data layout and memory management.
936 This means you can operate directly upon the datatypes that someone
937 else provides, without having to go via their interfaces. It also
938 means you don't have to "marshall" (convert) parameters (data
939 layouts are the same, so you can just pass components directly) and
940 you don't have to worry about memory managment, because all
941 languages/components share the same garbage collector and address
942 space. This means much less copying and no need for reference
945 Q: Will you support COM?
947 A: The runtime will support XPCOM on Unix systems and COM on Windows.
948 Most of the code for dynamic trampolines exists already.
950 Q: Will Ximian offer certifications on Mono or related technologies?.
952 A: It's possible. But there is no plan about this. So the short answer is no.
954 Q: Are there any Boehm's gc binaries?
956 A: Yes. You can find them <a href="http://java.thn.htu.se/~toor/">here</a>