Hi L4Ka::Pistachio developers,
I have read the source code of L4Ka::Pistachio-0.4. & found that some features defined in L4 eXperimental Kernel Reference Manual Version X.2 Revision 5 hasn't been implemented yet. For example, appoint redirector by SpaceControl, IO port mapping, etc.
I tried to checkout the newest source code from CVS, & the CVS server cvs.l4ka.org couldn't be reached.
When those features are going to be implemented? Now that those features are very important for implementing a flexible OS on L4 u-kernel.
Seems that there are so many differences between L4Ka::Pistachio and Fiasco. Is there a stardard L4 specification? I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so many complicated & inflexible policies inside L4 kernel?
BTW, has any OS or system been built on L4Ka::Pistachio? As I know, L4-Linux is built on Fiasco, but I don't like its design. I hope I can get a reference system based on L4Ka::Pistachio.
Best Regards, Darwin Yuan
-----Original Message----- From: l4-hackers-bounces@os.inf.tu-dresden.de [mailto:l4-hackers-bounces@os.inf.tu-dresden.de] On Behalf Of Frank Mehnert Sent: Wednesday, August 31, 2005 4:36 PM To: Mathias Krause Cc: l4-hackers@os.inf.tu-dresden.de Subject: Re: shared memory Beispiel?
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Hi Darwin Yuan,
it might be that you
1) posted to the wrong list since your question seems to be very specific to L4Ka. So please post to their mailing list (l4ka@ira.uni-karlsruhe.de)
2) wrongfully replied to a thread with has nothing to do with your question. Please create a new thread with a meaningful subject next time.
Thank you for your understanding!
To answer some of your statements:
On Wednesday 31 August 2005 11:36, yuan Darwin-r62832 wrote:
Seems that there are so many differences between L4Ka::Pistachio and Fiasco. Is there a stardard L4 specification? I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so many complicated & inflexible policies inside L4 kernel?
An interesting statement because you obviously did not read the L4 spec. Fiasco implements L4 version V2 and X0 with some extensions in the stable branch and X2 in a development branch. L4Ka::Pistachio implements X2. All three version can be found on
BTW, has any OS or system been built on L4Ka::Pistachio? As I know, L4-Linux is built on Fiasco, but I don't like its design. I hope I can get a reference system based on L4Ka::Pistachio.
L4Linux was originally built on L4 by Jochen Liedtke. AFAIK there are some implementations of L4Linux available for L4Ka::Pistachio -- see l4ka.org for details.
Sincerey yours,
Frank Mehnert
Hi,
yuan Darwin-r62832 wrote:
Hi L4Ka::Pistachio developers,
I have read the source code of L4Ka::Pistachio-0.4. & found that some features defined in L4 eXperimental Kernel Reference Manual Version X.2 Revision 5 hasn't been implemented yet. For example, appoint redirector by SpaceControl, IO port mapping, etc.
Please understand that both Pistachio and Fiasco are research prototypes and that the L4 eXperimental Kernel Reference Manual is indeed EXPERIMENTAL which means that it may change unnoticed and which also means that the prototypes may differ from the specification. The missing features that you state are published, e.g., at http://l4ka.org/projects/pistachio/ia32/ under the section Missing Features / Known Bugs for the Pistachio kernel , respectively at http://os.inf.tu-dresden.de/fiasco/status.html for Fiasco.
I tried to checkout the newest source code from CVS, & the CVS server cvs.l4ka.org couldn't be reached.
I had no problems reaching the server. Though I cannot confirm that it was up all the time.
When those features are going to be implemented?
Fiasco implements IO Flexpages. Neither Redirectors nor Clans and Chiefs are currently implemented in Fiasco and probably never will. I cannot speak for plans regarding Pistachio.
Now that those features are very important for implementing a flexible OS on L4 u-kernel.
Both redirectors and IO flexpages are not essential to get a system up and running. Their purpose is to control and restrict communication between threads respectively to prevent a thread from reading / writing IO-ports. Feel free to implement those features if you need them.
Can you elaborate on why you thing missing these features prevents someone building a flexible OS on L4?
Seems that there are so many differences between L4Ka::Pistachio and Fiasco. Is there a stardard L4 specification?
There is a standard L4 Specification: L4-V2 by Jochen Liedtke. Also there is the eXperimental specification you already found which is the defacto standard for L4-V4 kernels. The main difference between Pistachio and Fiasco is that the former implements L4-V4, the latter implements L4-V2 whereby some experimental features have been incorporated into Fiasco to better suite our user level software's needs. As you will see Fiasco already implements some parts of the L4-V4 specification.
I think L4Ka::Pistachio is more clean & flexible, why Fiasco put so many complicated & inflexible policies inside L4 kernel?
Which policies are you referring to? Can you elaborate on these points?
BTW, has any OS or system been built on L4Ka::Pistachio? As I know, L4-Linux is built on Fiasco, but I don't like its design. I hope I can get a reference system based on L4Ka::Pistachio.
Lets see, there is L4 Linux which runs on both Fiasco and Pistachio, L4 Env, Drops runs on Fiasco, Kenge, Iguana and Wombat on Pistachio. Also there is Mungi, Perseus, L4 Hurd, etc.
Have a look at l4hq.org and you may find out much more.
Why don't you like the design of L4Linux or do you mean Fiasco?
Some more final words: It is common practice on mailing lists to start a new topic if you are referring to a totally different topic.
Best regards
Marcus
[Marcus Völp]
When those features are going to be implemented?
Fiasco implements IO Flexpages. Neither Redirectors nor Clans and Chiefs are currently implemented in Fiasco and probably never will. I cannot speak for plans regarding Pistachio.
Just some notes for L4Ka::Pistachio: Support for I/O flexpages have been in the Pistachio CVS for some time now (I just updated the web page to reflect this). Clans & Chiefs are not part of the X2/V4 specification and will as such not be implemented. Redirectors are currently not implemented either. This is more out of lazyness than anything else, though. Things are often implemented on a whenever-we-need-it basis. It's not terribly hard to add support for it.
Seems that there are so many differences between L4Ka::Pistachio and Fiasco. Is there a stardard L4 specification?
There is a standard L4 Specification: L4-V2 by Jochen Liedtke. Also there is the eXperimental specification you already found which is the defacto standard for L4-V4 kernels. The main difference between Pistachio and Fiasco is that the former implements L4-V4, the latter implements L4-V2 whereby some experimental features have been incorporated into Fiasco to better suite our user level software's needs. As you will see Fiasco already implements some parts of the L4-V4 specification.
http://l4hq.org/kernels/ will give you a short introduction to the different kernel APIs, and which implementations exist for them.
eSk
l4-hackers@os.inf.tu-dresden.de
-
Espen Skoglund -
Frank Mehnert -
Marcus Völp -
yuan Darwin-r62832