Everything about UNIX kernels: development, configuration, compilation, design, etc.

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13
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3answers
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What does the vm.swappiness parameter really contol?

Per the kernel documentation: This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase agressiveness, lower values decrease the amount of swap. ...
5
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1answer
607 views

User Kernel split in 64bit Linux

What is the default user/kernel split in the 64bit linux ? I read Documentation/x86_64/mm.txt (which someone pointed out), but I could not make out. Can somebody provide a direct answer (something ...
4
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1answer
70 views

Timescales of any task in linux kernel?

I am studying how Linux kernel works and getting interested in the timescale of anything that happens in the kernel. Of course I know it depends on the HW, but would like to get an example. For ...
2
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1answer
2k views

i686 versus i486 kernel on an Intel Core i3

I had installed Debian 6 Squeeze on my laptop a couple of weeks ago. Coming from Ubuntu, I did this by downloading the hybrid i386 image and booting it off a USB drive. Now on GRUB, I'm presented ...
2
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1answer
203 views

Writing Linux Kernel module for non-MSDOS disk labels/partition tables

Linux supports a set of different disk label or partition table formats. For example, Sun Disk Labels and MS-DOS partition tables are both disk labels that contain (largely) the same information ...
1
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1answer
953 views

How to have CoreAudio from Mac to Linux/Unix?

After using Alsa and PulseAudio for a while, I feel they are not yet strong enough for Audio capture and audio playback. When I test with loud-speaker and microphone, there is self feedback-loop. ...
1
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1answer
244 views

Does CentOS fall into System V family? How is it considered to be while comparing with Unix System V family?

CentOS is "derived entirely from the Red Hat Enterprise Linux (RHEL) distribution" (more here). Does it fall into any UNIX System V family? Such as PDP-11 or etc? If not, where does CentOS stands ...
2
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1answer
161 views

Why is kernel-default 114MB on SUSE Studio?

I see that $ du -h /boot/initrd-2.6.37.6-0.5-pae 3.9M /boot/initrd-2.6.37.6-0.5-pae $ du -h /boot/vmlinuz-2.6.37.6-0.5-pae 4.1M /boot/vmlinuz-2.6.37.6-0.5-pae $ du -sh /boot 17M /boot ...
5
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2answers
622 views

Are kernel threads really kernel processes?

I've read in many places that Linux creates a kernel thread for each user thread in a Java VM. (I see the term "kernel thread" used in two different ways: a thread created to do core OS work and a ...
2
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2answers
3k views

Kernel Panic - not syncing: VFS: Unable to mount root fs after new kernel compile

So I've been at this for a while and have been poking around for an answer for a few days, and figure it's about time to ask for help. I am running Ubuntu 10.10 in VMWare Fusion, and have downloaded ...
5
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1answer
3k views

Can vmlinux be used instead of uImage?

I want to use an uncompressed kernel image and boot the BeagleBoard. Generally I use uImage to boot the kernel which is in compressed format. How do I use an uncompressed kernel image?
3
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1answer
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getrusage system call: what is “maximum resident set size”

man getrusage 2 says ru_maxrss (since Linux 2.6.32) This is the maximum resident set size used (in kilobytes). For RUSAGE_CHILDREN, this is the resident set size of the largest ...
2
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2answers
2k views

Undefined reference to symbol 'acs_map' when running makeconfig

I get a linker error when I try to configure the Linux kernel with menuconfig: # make menuconfig HOSTLD scripts/kconfig/mconf /usr/local/bin/ld: scripts/kconfig/lxdialog/checklist.o: undefined ...
0
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1answer
157 views

I need kernel headers for 2.6.21.5 [closed]

Preferably in slackware module format(lzm). Can't seem to find it. Can anyone help me?
1
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1answer
96 views

Removing generic kernel updates from aptitude post custom kernel install

I've updated my Mint 12 system to be running a kernel built from Linus' git repo. Now, whenever I run apt-get upgrade, I see that linux*-generic are still on the update list (they're being "kept ...
6
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1answer
1k views

Why is my initial ramdisk so big?

I'm running Ubuntu 11.10, which came with kernel version 3.0.0-14. I downloaded and built a kernel from the 3.1.0 branch. After installing the new kernel, I see that my /boot/initrd.img-3.1.0 file is ...
2
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1answer
149 views

Running a script every time a new kernel is installed

I'm currently having to recompile my wireless driver from source every time I get a new kernel release. Thinking it would be awesomely hackerish to automate this process, I symlinked my Bash build ...
2
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1answer
660 views

Compiling a distribution unspecific kernel on two different distributions

I downloaded kernel 3.2.1 from the kernel.org. Compiled it "successfully" on OpenSuse 11.3 64 bit. When I tried to compile the same kernel source on Ubuntu 11.10, I got: ERROR: ...
4
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2answers
354 views

Is it normal that a restart is required to mount USB after a kernel upgrade?

Sometimes I see the Linux kernel being mentioned in the list of upgrades, when running pacman -Syu (updating my packages in Arch Linux). Whenever this happens, after installation of the packages, I ...
4
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2answers
703 views

Not enough space on / to install new kernel update

During a recent update I received this: Installing: kernel-default-2.6.37.6-0.11.1 [error] Installation of kernel-default-2.6.37.6-0.11.1 failed: (with --nodeps --force) Error: Subprocess failed. ...
3
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1answer
6k views

How to get a list of installed external kernel modules?

From the documentation of Linux kernel 3.2 (Documentation/kbuild/modules.txt) === 5. Module Installation Modules which are included in the kernel are installed in the directory: ...
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1answer
2k views

__modver_version_show undefined error during make

Platform: Ubuntu 11.10 64bit Kernel to be compiled: 3.2.1 Error after make: ERROR: "__modver_version_show" [drivers/staging/rts5139/rts5139.ko] undefined! To solve this I copied the .config file of ...
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2answers
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modprobe: Module ext4 not found. WARNING: no dependencies for kernel module 'ext4' found

I rebooted a compiled kernel 3.1.0, and those are the errors that I am getting: linux-dopx:/usr/src/linux-3.1.0-1.2 # make install sh /usr/src/linux-3.1.0-1.2/arch/x86/boot/install.sh 3.1.0 ...
2
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2answers
264 views

Precautions to be taken while make oldconfig

If a previous kernel (assuming it is not from the stone age) compiles successfully, does it make sense to assume that old config file if copied to the new kernel, will compile successfully too? What ...
2
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2answers
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Updating /boot/grub/menu.lst on OpenSuSe 11.3

I compiled the latest kernel, and the menu.lst is updated as follows. My aim is to keep the other kernel around, so that if the new one fails we can still boot from the other one. Is this the correct ...
5
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2answers
7k views

How to create an initrd image on OpenSuSE linux?

/usr/src/linux-3.2.1 # make install scripts/kconfig/conf --silentoldconfig Kconfig sh /usr/src/linux-3.2.1/arch/x86/boot/install.sh 3.2.1-12-desktop arch/x86/boot/bzImage \ System.map ...
4
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1answer
406 views

Compiling the kernel with default configurations

Assumptions: The platform: anisha@linux-dopx:~/> uname -a Linux linux-dopx 2.6.34-12-desktop #1 SMP PREEMPT 2010-06-29 02:39:08 +0200 x86_64 x86_64 x86_64 GNU/Linux The kernel downloaded is the ...
3
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2answers
2k views

Kernel Panic - Can't find root filesystem / error mounting /dev/root

From here: http://fedoraproject.org/wiki/Common_kernel_problems#Can.27t_find_root_filesystem_.2F_error_mounting_.2Fdev.2Froot A lot of these bugs end up being a broken initrd due to bugs in ...
0
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2answers
828 views

critical section for linux

In linux or a library for linux, is there an equivalent to critical section in win32? I am aware of Mutex, but it is not the same as critical section since a critical section uses user-mode spinlock ...
5
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1answer
185 views

What do the kernel options in braces mean?

I saw a kernel option today in menuconfig that used braces for its checkbox. {*} Button This isn't listed in the legend at the top of the screen. [*] built-in [ ] excluded <M> module ...
4
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2answers
944 views

Multiple root options in Linux command line

My kernel command line looks like this: root=31:0 ro noinitrd console=ttyS0,115200 root=/dev/mtdblock2 rootfstype=squashfs I think the first root entry identifies a disk by its major and minor ...
7
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3answers
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How do I tell what version of Gentoo & Linux is running?

Is there a way to tell from Bash what distro version # I'm running and also what Kernel version is included?
3
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1answer
419 views

Compiling and installing a kernel.org kernel to a custom volume on disk

I want to compile and install a kernel.org kernel on a custom HDD volume, say /dev/sda5, instead of being merged with my current Ubuntu's directories. I can find information about configuration and ...
3
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1answer
886 views

How does the Linux kernel decide how much bandwidth to allocate to Isochronous USB endpoints?

As far as I'm aware, USB endpoints that use isochronous transfers have a 'wMaxPacketSize' parameter associated with them that is used by the kernel to guarantee a certain amount of bandwidth for the ...
2
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1answer
5k views

What does the 'i8042.nomux=1' kernel option do during booting of Ubuntu?

I have a laptop with a multi guesture touchpad. My touchpad never works in any Linux distro such as Ubuntu, Fedora, openSUSE, Linux Mint, Knoppix, Puppy, Slitaz and lots more. I have tried lots of ...
2
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1answer
751 views

kernel panic error after recompilation

I am completely blocked, but temporarily. I have an Ubuntu 11.10 in good condition, in this one I installed VirtuelBox. I installed on VirtuelBox as Ghest Debian Squeeze with Kernel 2.6.32-5-686. ja ...
4
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2answers
636 views

How does X map from kernel key scan codes to a keysym?

According to this page there is no direct mapping from udev key mappings to X, it has its own mappings. X has a (quasi) total independent way of mapping keys: X reads the kernel keycode table at ...
4
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1answer
95 views

Is it the process that cleans itself on termination or the kernel?

Recently I found this in a powerpoint presentation: When a program is compiled and linked, the linker inserts some extra code in the program. It is this code that calls the main function about the ...
8
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4answers
2k views

How can same fd in different processes point to the same file?

Say I have process 1 and process 2. Both have a file descriptor corresponding to the integer 4. In each process however the file descriptor 4 points to a totally different file in the Open File Table ...
4
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1answer
408 views

System call invokation methods in new kernel

I read that in the newer kernels system calls are invoked using the INT X80 instruction and also using the sysenter instruction. And also the sysenter instruction gives faster invocation as compared ...
2
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1answer
293 views

Unable to access linux/skbuff.h

I am writing a kernel module where I need to access sk_buff variables. But when I write #include <linux/skbuff.h> Netbeans says it can't locate that header file.
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1answer
511 views

Best method for testing android kernel

I would like to test some of the features of android kernel like inserting a module and collecting certain parameters for research purpose. What would you think the best method for that?
0
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1answer
83 views

What's a NM thread?

I am studying OCFS2 kernel source code and I found this comment of function dlm_lanuch_thread in file fs/ocfs2/dlm/dlmthread.c: /* Launch the NM thread for the mounted volume */ So what does the ...
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5answers
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Any way to restart a Linux machine via SSH if the root filesystem is not working?

Just as a curiosity; something went wrong with a Linux machine, making the root file system show up as "64Z". A few commands work, like top, df, and kill, but others like reboot come up with "command ...
4
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2answers
5k views

Cleaning log files under linux

I am using a kvm ubuntu 10.04 virtual machine to test some features of a kernel module. I grep through the /var/log files to observe the kernel messages about that module. To start from a clean ...
0
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1answer
559 views

Is there any X windows system, which is HTML, CSS, Javascript? Such as Web Browser?

For dacades X windows system is either BASH, C or etc. But is there any X windows system or any wrapper which can interpret HTML, CSS, Javascript to general Windows system? I would like to build ...
4
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2answers
1k views

Installing OpenVPN to replace Cisco VPN because Cisco will not work with the kernel I am on or downgrade instead?

I had difficulties installing Cisco5.0 VPN on my Ubuntu 10.04 LTS. I asked for assistance in this question: link to previous question. The answer is that this Cisco program will run on only older ...
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0answers
343 views

How is the Linux kernel stack organised for ARM architecture?

Can any one explain how exactly linux kernel stack organisation is handled? When a child process is created using the fork() system call, how is the kernel stack space initialized?
3
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2answers
408 views

Choosing a device name under /dev from the kernel command line

I am booting CentOS via a USB install. The boot method is simply booting the ISO from GRUB2 installed on the USB Key. The USB key always gets the "name" /dev/sda. Can I change that name from the ...
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2answers
700 views

How to install kernel on debian with no internet connection

I'm trying to install a newer kernel version on my Debian (squeeze) machine as I need it to get my wireless card working. I have Debian on one partition of my hard drive, Fedora on the other. I'm ...