l4-hackers April 2002

l4-hackers@os.inf.tu-dresden.de

9 participants
5 discussions

DE use
by luke.hart＠sysmedia.com 02 May '02

02 May '02

All, The latest version of L4 (from CVS) and probably earlier ones, check for the debug extensions. Does it actually use them? I ask this since Bochs, does not set the DE bit in the CPUID or support these extensions. I have done a search for usage of DRx (where x is 0-7) in the source, but couldn't find any references. Is it safe to just remove the check for DE? Thanks for any info., Luke

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L4 SCSI driver
by dmiller 19 Apr '02

19 Apr '02

Gernot a quick question does any version of L4 have an adaptec SCSI driver? we are trying to add an adaptec 2940UW SCSI driver to Sombrero thanks for any info you have on this don -- Donald S. Miller Associate Professor Computer Science and Engineering Department Arizona State University Tempe, AZ 85287-5406 email: donald.miller(a)asu.edu http://www.eas.asu.edu/~sasos phone: (480)-965-5935 Fax: 480/965-2751 --

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L4 for asm-free OS'es?
by William A. Gatliff 09 Apr '02

09 Apr '02

Guys: I'm an L4 newbie. I've booted it on my PC, I've read a lot of the online docs, and I've looked at some of the code. But I've been doing embedded systems for more than ten years now, so I know a thing or two about computers and operating systems. I'm interested in using L4 as a foundation for a new, yet-to-be-written Linux replacement intended primarily for use in embedded systems. My main motivations are for an OS that is portable, is understandable, has low interrupt latency, and has a small memory footprint. I'm thinking along the same lines as L4-Linux, but my OS would probably be written in C++ and make more use of L4 servers for hardware i/o. Here are my questions: One of the L4 manuals I've read says that when an OS running under L4 starts, it should take all free memory from sigma0 and then manage the pages itself. To me, this means that the OS has to know how to interact with the host CPU's MMU hardware, which is obviously hardware-dependent and therefore undesirable in a portable OS. It also appears to be redundant--- sigma0 already knows how to work the MMU. Performance issues aside, would letting sigma0 do page mapping and unmapping eliminate the need for an OS running under it to know how the MMU interface works, and thereby make the OS a little more portable? Is this a reasonable approach? What is the likelihood that an L4-based OS would need no assembly language at all, other than the syscall interface? I'm thinking along the lines of "to port this OS to your CPU, just port L4 and then recompile the OS sources." I'm eyeing ARM, MIPS, SH and x86 targets--- all of which I work with every day. I have single-board computers representing all four architectures in my lab here right now, and I'm doing something with all of them almost all the time. That's why portability is important to me. My customers think Linux is great because it's more portable than the alternatives, but I think it isn't nearly portable enough. And it scores low marks for understandability, interrupt latency and footprint. Oh, and debuggability---I love your "KD:" prompt! :^) Thanks! b.g. -- Bill Gatliff bgat(a)billgatliff.com

5 6

RE: L4 for asm-free OS'es?
by Josh English 09 Apr '02

09 Apr '02

I was told that BeOS used a similar C++ structure. Though I have no idea how it was really implemented. - Josh -----Original Message----- From: Patrick Strasser [mailto:past@sbox.tugraz.at] Sent: Monday, April 08, 2002 5:29 PM To: bgat(a)billgatliff.com Cc: l4ka(a)ira.uka.de; l4-hackers(a)os.inf.tu-dresden.de Subject: Re: L4 for asm-free OS'es? William A. Gatliff wrote: > A lot of what I see happening in the C parts of Linux could be done > *so* much better with C++. I'm thinking of an OO-oriented driver > model as an example, rather than just a soup of C functions that you > have to invoke in the proper order for things to work right. "Want to > right a USB driver? Well then just inherit from USBDriver and fill in > these functions for the bulk transfers." You know, like that. :^) You probaly want to have a look at MacOS X / Darwin and its IOKit. Thats exactly what they do. Patrick _______________________________________________ l4-hackers mailing list l4-hackers(a)os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers

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IDL4 0.8.1 released
by Andreas Haeberlen 06 Apr '02

06 Apr '02

Hello L4 hackers, IDL4 is now available for download from the L4Ka home page. IDL4 is a stub-code generator for the L4 platform. It generates communication stubs from interface definitions written in a specification language such as CORBA IDL or DCE IDL. It also uses knowledge about the hardware platform and the microkernel to optimize the performance of the generated code. Some features: o Supports CORBA IDL (recommended) and DCE IDL o Backends available for Hazelnut and Pistachio o Client stubs use CORBA C language mapping o Type import from C/C++ code o Modular design; easily extensible For more information please visit http://l4ka.org/projects/idl4/ - Andreas --- Andreas Haeberlen System Architecture Group, University of Karlsruhe, Germany haeberlen(a)ira.uka.de, phone: +49 (721) 608-4055

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l4-hackers April 2002