The main component of most operating systems, the kernel manages most of a computer's communication between hardware and software. Typically, the kernel is the lowest level of abstraction a programmer can have to a resource.

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Stuck on GRUB command prompt after regular kernel update

I am running Debian Wheezy. Update Manager suggest to install kernel update. After update, I reboot system but instead of listing all the kernels (bootloader), it gave me a GRUB command prompt: grub&...
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Why is there an extra HDD under /dev being added in my Linux Kernel?

I have created a Linux kernel and for some reason an extra drive is always added at bootup. My hard drive is listed as /dev/sdb. /dev/sda is created too, and it is 8 MB in size. I can't find ...
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WD Green Hard Drive and home linux server

Are newer WD Green Hard Drives still a problem for Linux nowadays? The discussion here is focused on home linux servers, not NAS or data centers. Here is a summary of my research from googling. "...
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Hairpinning in Linux

I have a router in which I installed a Linux system. I want my router to support NAT hairpinning. Does a such feature exists in Kernel Linux? If yes how to activate it? Are there a patch to apply it ...
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device driver and kernel

Are device drivers part of a OS kernel, or outside the kernel, or some are part of the kernel and others are outside the kernel? If the third is correct, what devices' drivers are usually part of ...
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Why do Linux installers install more than one kernel?

For instance, my boot menu has three kernel versions, each with a recovery option. Are these extra options for debugging and troubleshooting?
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Possible to boot Linux kernel without initrd?

Is it possible to boot a Linux kernel (say 2.6.35) without initrd these days? I seem to remember that this is possible before (early 2.6.x and 2.4). I mean, in theory, if a kernel has all hardware ...
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How do I digitally sign a 64-bit kernel mode driver?

I have a kernel mode driver and I have to install it on 64 bit win 7. It needs to be digitally signed. I digitally signed it using the dseo13b.exe. But when I load the driver I get error in the system ...
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FreeBSD sysctl.conf kernel.panic parametr?

There is a kernel.panic param in Linux's /etc/sysctl.conf to auto-reboot the OS when the kernel crashes. Is there anything like this in FreeBSD?
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How to make bootable USB with Linux Kernel alone?

I would like to boot the Linux kernel alone and run busybox, not including a GUI. How can I do that? How can I make a custom bzImage, initrd.img and how can I change the file structures in that ...
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Pipe kernel messages to another process as they occur

I have an OLED screen on my laptop that I have configured to show status information. The current driver I have installed in Linux for it is able to display messages by sending them to a script as an ...
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IPTables module ip_tables not found for root

We got a custom build Linux distribution from a vendor, which is not shipped with iptables enabled. root@xxxx:~# iptables -L modprobe: FATAL: Module ip_tables not found. iptables v1.4.21: can't ...
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Problems with mounting HFS+ drives

I have a problem mounting some hfsplus drives. I just need them mounted readonly. (disabling journal is not an option) I did a lot of research and found out that due to changes from kernel version 2.6....
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Home wireless router as a PC

Is it possible to install a small program on a cheap home router that runs a Linux kernel and run it? I mean can I use a router that runs a Linux OS as a small computer to run arbitrary code on it? I'...
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Computer crashes constantly after upgrading from Debian Wheezy to Jessie

I’m on a Lenovo ThinkPad T430 which had Debian Wheezy running solid/stable. No crashes, ever. Upgraded to Debian Jessie recently and been having crashes; it seems like Gnome crashes. By crash, it ...
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What does `apt-get install linux-headers-generic` do

Looking for explanation on apt-get install linux-headers-generic. What does installing linux-headers for a kernel do ? The significance of that command at the time of kernel installation and after a ...
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Logitech M560 mouse on linux sends messed up input events

My friend bought yesterday a Logitech M560 mouse (you can see it here) and tried it on her Ubuntu system. It seems to be a relatively new model, so there is no info about it anywhere, except for ...
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Error while validating for Ubuntu 12.10 Kernel headers

I have my VMware Player (v 5.0.0 build-812388) all up and running Ubuntu (12.10) from my Windows (Win 7) machine. When I launch sudo vmware-config-tools.pl, it tries to search for kernel Searching ...
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Linux Kernel Messages: ata1.00: status: { DRDY ERR }

I am receiving a lot of these messages. Is my HD going to die tomorrow morning? ata1: link is slow to respond, please be patient (ready=0) ata1: device not ready (errno=-16), forcing hardreset ata1: ...
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Who's crashing my kernel?

Symptoms Suddenly, a message saying "A problem in the kernel package has been detected" started appearing after I login upon boot. A new message is shown every second, incessantly (translation below)....
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How can I display a static image while Debian Linux is booting up?

I need to show a static image with the logo of our department while Debian boots. Is there any easy way or tool to do this? (Any parameter of the kernel maybe?) It doesn't have to be anything fancy (...
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Where did SELinux go?

I am compiling a new kernel, and want to enable SELinux but don't see it in menuconfig anywhere. The only framework under security options is Tomoyo.....so I ask, what happened to SELinux? Both 2.6.33....
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Backing Up Kernel Modules from a GNU/Linux installation

How can I create a backup of all the driver modules (especially those that are not part of the original kernel yet) from an installation of GNU/Linux OS? The original source of the proprietary ...
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628 views

FreeBSD compatibility layer on Linux

I am aware of Linux mode on FreeBSD, where Linux binaries can seamlessly be executed in FreeBSD. From the FreeBSD handbook: In effect, there is a Linux kernel in the FreeBSD kernel. The various ...
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How to disable device in Linux Debian (Wheezy)

I need to force the kernel to not load drivers for the Intel NIC in my PC to see if this helps on performance issues I have by using the second NIC that is on the same motherboard. How can I do this? ...
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Forward/backward compatibility of glibc and the kernel

Suppose you have glibc 2.5 compiled with kernel headers 2.6.18 Is it safe to run this glibc with Linux kernel 2.6.32? Is it safe to run this glibc with Linux kernel 2.6.9?
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How to distinguish 'syscalls' form 'int 80h' when using ptrace

As far as I know, ptrace can only get syscall number by PTRACE_SYSCALL, but syscall number is different in x86 and x64. So is there any way to figure out where this syscall real origin? I am now ...
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Does 'urandom' share the same entropy of 'random'?

Does the entropy pool /dev/random used the same to /dev/urandom? I want to mknod /dev/random 1 9 to replace the slow random, I think the current entropy is randomly enough, if urandom is based on ...
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Is the Windows kernel considered an “application”?

If it is true that all Windows files with the ".exe" file extension are considered "applications", is NTOSKRNL.exe, the Windows kernel, an "application", or is this an exception to the rule? What ...
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Does a software like VMware run in user space or kernel space?

Vmware is a user installed software. So it should run in user space given by the underlying OS. Yet its runs OS-es which are fully operational and need to run in kernel mode. So where does it run?
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Linux: obtain current # of jiffies since reboot

Linux's /proc/PID/stat lists several metrics that are measured in jiffies. Is there a way to get the current # of jiffies since reboot? Jiffies I also assume to be seconds times the USER_HZ value. ...
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Linux kernel scheduler for a pen drive - noop or deadline?

I run Debian Live as a persistent system on a 16 GB pen drive. This is my workhorse every day system. I was earlier plagued with continual delays and freezes due to slow write speeds. I have ...
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How to load previous kernel via ssh?

I work remotely on my work computer. I am also the root of the workstation that I am sharing with my colleague. Yesterday, I upgraded the kernel to 2.6.31-17 when asked by the update manager but ...
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Linux kernel, Nvidia: Turning off graphics in Ubuntu

How can you turn off graphics at Ubuntu's GRUB -bootloader such that you can access and see terminal? I have a 5-year-old Nvidia graphics-card which is not anymore compatible with Linux kernel 2..18 ...
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Writing directly to /proc versus using sysctl -w

I am trying to configure the kernel of my Linux server so that it will not act as router, for more security. The point is not to forward packets. I have found this: echo 0 > /proc/sys/net/ipv4/...
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Linux Mint 14 severe overheating

I've tried switching to Mint (it was Mint 12) about 6 months ago, but failed to do it due to enormous overheating which made it virtually impossible to run any applications more complex than Gedit. ...
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753 views

Difference between gnu and darwin and mach

These terms belong to the Mac OS X architecture topic and I'm confused about the following: mach is said to be a microkernel Darwin and XNU are mentioned to be a kernel So ...can you help me to ...
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How to keep Linux running after hard drive removal?

I am working on an embedded Linux device with a USB hard drive. There is a swap file on this drive. The hard drive may be powered down at any moment before being powered back on few seconds later. ...
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Will applications running in root mode be able to overwrite OS's or other program's memory section?

I read here that any application running in root mode can issue a kernel call and execute in kernel mode. Is is possible that ANY application running in root mode can make a kernel call, go to kernel ...
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how to bring network up at boot time in linux

I am working on an embedded linux system, my aim is to activate ethernet interface at boot time. I am using u-boot as bootloader. I passed ip= and eth= u-boot environment variables to the linux kernel ...
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negative effect of running PAE kernel?

Fedora, and other distros install a PAE kernel if the hardware supports it. Are there any negative effect on running a PAE kernel on a machine with less than 3-4Gb ram ?
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CPU cores remain offline after hotplug

When my UPS triggers an "on-battery" event, I want all cores to switch off to conserve power. The PC has 8 cores on two chips, UPS batteries need replacement every 3 months because of high current ...
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771 views

Why will dmesg have message from user space?

you can use dmesg -u to see log from userspace. In my case, I have log from systemd and lvm. Why is this happening, why userspace program can print to kernel buffer ring?
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On certain Linux boxes, variables in the stack seems to be initialized to 0 - why?

I have a buggy program that pushes a variable onto stack and may use it without initialization. I take the same binary and run it on different Linux boxes. Those boxes have different CPUs (i5, i7), ...
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109 views

How is battery charge reported to the operating system?

This feels like a stack exchange EE question, but it seems like it belongs here instead. How is the charge of a notebook computer's battery reported to the operating system? Since all laptop ...
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How can I get the number of threads running in a process from /proc/[pid]/stat in Linux?

I have the pid of the process. I would like to know the current number of thread running in the process. I know I can read /proc/pid/stat for this information, but I'm not sure how to specifically get ...
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How do I find out which files were used in insmod in Linux?

I'm working on a script which runs on various types of CentOS/Redhat servers where it needs to find out which files were loaded into the kernel. Running lsmod provides me with the name of the module (...
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Disabling kextcache on 10.5.8 and 10.6.3

We use Radmind to manage our Mac OS X loadsets and, as such, often run into difficulty when new OS releases come out due to, among other things, updated kernel extensions. The workflow in the past (OS ...
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Pressing Alt+Left/Right causes screen flicker

I run Arch Linux with a "normal" Xorg desktop, that is, using LightDM as login manager and the i3 Window Manager (with some components from Xfce, GNOME and KDE as needed). The graphics is the ...
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Does Installing a driver increase linux kernel memory footprint?

I have read that linux kernel is monolithic kernel and it contains drivers within it, in a single file. For example, I have two linux kernels 3.16.0.40 and 3.16.0.50 Currently booted system with 3.16....