l4-hackers March 2011

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

20 participants
15 discussions

Samsung R&D - Full-time OS Researcher Position
by Daniel Waddington 10 Mar '11

10 Mar '11

Samsung R&D, San Jose - CA, is recruiting full-time researchers in the area of Operating Systems (OS) for future cyber-physical systems. We are looking for individuals with a passion for systems research and the desire to follow through from concept to pre-transition prototype. Position: Full-time Researcher for the Systems Research Group Summary: The Systems Research Group is developing new OS and software platform designs that can meet the needs of future computing platforms based on multicore, manycore and cloud technologies. We are currently developing a solution based on L4 microkernel technology that will readily scale from sensors-to-servers, whilst providing advanced support for transparent distributed processing, Quality-of-Service (QoS) guarantees for co-located real-time and best-effort applications, and the "first-class" integration of parallel programming technologies. We are looking for highly motivated and creative individuals to join the San Jose research team and to augment existing system research expertise. This is an excellent opportunity to join a new team advancing state-of-the-art software technologies for Samsung's current and future business. Duties and Responsibilities: . Research and develop micro-kernel based solutions for next generation products. . Research and develop innovative technologies to directly address scalability limitations of existing solutions. . Research and develop ideas around the single-system image concept. . Research and develop new ideas in OS-level and language-level support for heterogeneous processor platforms. . Develop ideas around the support of fine-grained resource management and QoS monitoring, policing and adaptation in the context of real-time cyber-physical applications. . Build proof-of-concept prototypes. . Write research papers and technical articles publishing work and results in top-tier conferences and journals. Necessary Skills/Attributes: . Ph.D. in Computer Science or related area with 0-5 years of practical experience. . A track record in OS research pertaining to the above areas of interest with high-quality publications in the field. . Hands-on experience with low-level systems prototyping and development - a true hacker at heart. . Proficiency with C/C++ and Linux-based development including multi-threaded programming. . Excellent communication and team working skills are required with a willingness to work with an international team to deliver an integrated solution. . A willingness to learn new things and take on new challenges. Desirable Skills/Attributes: . Experience with L4 or other similar microkernel technology (e.g., QNX, Integrity) . Experience with embedded systems development. . Experience building OS sub-systems such as memory managers, and task schedulers. . Experience with the use of machine-learning to drive system optimization. . Experience with distributed and parallel computing. . Experience developing on TILE processors and programming with TILE assembly. . Experience developing on ARM processors and programming with ARM assembly. Contact: Please send resumes and enquiries to Dr. Daniel Waddington (d.waddington(a)samsung.com)

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Re: Genode OS framework and kernel-specific features
by Valery V. Sedletski 09 Mar '11

09 Mar '11

On Sun, 06 Mar 2011 09:29:52 +1200 (MSK), Valery V. Sedletski wrote: > >PS: maybe, offtopic, but I'm in trouble a bit. > Already googled the Linux Framebuffer HOWTO and several articles. It seems that vesafb will not work for me (I have Matrox G400 card, on which I get a message "Cannot set vga mode, press Enter..." when booting Linux. Also, it supports VESA 2.0, but GRUB sees only modes not higher than 800x600). I also found some drivers in ./kernel/drivers/video/matrox, will check them.

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Can L4 modules be accessed as files from L4Linux?
by Dan Haim 07 Mar '11

07 Mar '11

Hi, I'm trying to find a solution to the following scenario - I want to have an L4Linux instance running (from a CD) where the root filesystem is several hundred MB's big, so it is not feasible to run it from a ramdisk (the filesystem is larger than the amount of RAM available) - I need to run it directly from the CD. A possible solution I'm thinkning about is to give the L4Linux instance access to the CD-ROM drive, then store a SquashFS image as a file on the drive and UnionFS it with a tmpfs when the system starts. Now here's the catch - While this solution may technically work, it is still not 'good enough' because I can't give the L4Linux instance direct access to the CD-ROM drive - I need to have it completely isolated so a user working on the L4Linux instance will not have access to any files stored on the CD (other than the SquashFS image) even if he/she has root access over the L4Linux instance. I was thinking - is it possible to specify the SquashFS image as an L4 module and then somehow mount it from within L4Linux in-place (i.e. without completely loading it to RAM)? Is there any other way to accomplish what's needed in this scenario? Thank you all, Dan.

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Genode OS framework and kernel-specific features
by Valery V. Sedletski 05 Mar '11

05 Mar '11

Hi all. I am now giving a try to the Genode OS framework. I like it's concepts and ideas and its elegant design, and maybe, will migrate to it eventually. -- I was developing an OS/2 clone based on Fiasco microkernel and l4env. Now they're discontinued. So, I must probably, migrate to something else. The most probable candidates are L4Re or Genode. I like Genode because of its kernel-neutrality (It can work on any L4 flavour, it is very attractive feature) and has interesting ideas regarding the scalability and capability to build a hierarchy of subsystems, minimising the application-specific Trusted Computing Bases. So, as I understood, it abstracts the kernel specifics from a developer. But in some cases, it can be desirable to make some kernel-specific implementations. For example, Fiasco kernel based on l4v2 API has 'segments' feature which, for example, is actively used by L4Linux. We use this feature too. One of our objectives is a binary compatibility with existing OS/2 applications. And OS/2 application ABI includes a convention that FS register for Ring3 application, holds a selector of a structure named Thread Info Block. Though the application can obtain this structure by calling an DosGetInfoBlocks() API, the C startup code generated by many compilers, relies on the convention that FS must contain the TIB selector. So, if we try to implement this feature on L4, we must have the means to allocate GDT selectors and get the allocated selector. On Fiasco, this can be done by filling the registers in a special way and issuing a 'LLDT' instruction, or, by calling a fiasco_gdt_set() function, and get the allocated selector by fiasco_gdt_get_entry_offset() (which is the same, but through a 'l4sys' package). On Fiasco.OC, this can be done similar way (not through LLDT instruction, though). My question is: Can be the underlying kernel determined under Genode, and then try doing kernel-specific things? Or, maybe, there is a more elegant way to do kernel-specific things? Thanks in advance, valery. PS: On Pistachio, as I heard, the application also can operate on GDT selectors, but this possibility has even more limitations. (It seems, only LDT selectors can be altered, but not GDT ones, or something)

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Compiling l4re for BeagleBoard
by Ivan Bludov 04 Mar '11

04 Mar '11

Hello, I'm trying to compile l4re for ARM (beagleboard). I used the cross-toolchain for AMR (from CodeSourcery and toolchain downloaded from your site), but I got errors during making configuration of l4 : =========================================================== set -e; X="tmp.$$$RANDOM.c" ; echo 'int main(void){}'>$X ; \ rm -f $X.out ; LD_PRELOAD=libgendep.so LD_LIBRARY_PATH=/home/ibludov/Downloads/l4re-snapshot-2011022209.0/src/l4/build/tool/gendep/64: GENDEP_SOURCE=$X \ GENDEP_OUTPUT=$X.out arm-linux-gcc -c $X -o $X.o; \ test -e $X.out; echo INT_CPP_NAME=`cat $X.out` \ >>/home/ibludov/Downloads/l4re-snapshot-2011022209.0/src/l4/build/.config.all; \ rm -f $X $X.{o,out}; ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ERROR: ld.so: object 'libgendep.so' from LD_PRELOAD cannot be preloaded: ignored. ============================================================ These errors appear only when I use the arm-linux compiler and do not appear when I use host compiler. Is it a problem of toolchan or some other system libraries? Can you make some advise to fix it? Ivan Bludov

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l4-hackers March 2011