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

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3
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2answers
226 views

How does a bootloader and kernel interact after the kernel is loaded in memory?

I'm a little bit confused about the role of bootloader and its interaction with kernel, especially when talking wrt ARM Llnux. Once the Kernel is loaded into RAM, is there any job left for the ...
5
votes
1answer
2k views

Writing /dev/random to file?

If you ran the following, what would happen? cat /dev/random > ~/randomFile # don't run Would it be written until the drive runs out of space, or would the system see a problem with this and ...
3
votes
2answers
525 views

BSD Kernel Vs. Linux kernel? [closed]

I wanted to know in technical terms; what is the difference between BSD Kernel and Linux Kernel. In Linux, we can download the source kernel then patch it and make and make modules it. Even we have ...
12
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3answers
2k views

Why there are many BSD systems but only one Linux kernel?

Why there are many BSD systems but only one Linux kernel? I wonder why BSD was forked many times, but no such thing with Linux.
2
votes
1answer
51 views

How does the kernel know which file descriptor to write data to after fork() in a concurrent server?

Basic concurrent client/server architecture: There's a main loop listening for requests on a port (for example 3000), after accepting the connection the server spawns a child process that ends up ...
4
votes
1answer
97 views

How to relate a kernel config setting to the source files?

Here is an example that will explain better: I have a selected the audio driver from the picture and i would like to browse through its source. How do i get to the path of the source files from ...
3
votes
2answers
146 views

Using multiple layer of kernel modules for interfacing a hardware device?

I am trying to get a conceptual understanding of the purposes the kernel modules can have. The motivation for this question was a realization that interface to an actual hardware goes through multiple ...
0
votes
1answer
374 views

How can I install perf 3.4.25?

By installing perf using sudo apt-get install linux-tools-common sudo apt-get install linux-tools-3.2.0.23 gave me perf version 3.2.14 How can I install perf 3.4.25? Is it related to kernel ...
2
votes
1answer
365 views

How to get ondemand governor on fedora

In Ubuntu 13.10 on my (Dual Core i5 Lenovo G570) laptop, I recently discovered the wonders of indicator-cpufreq, so I can extend my battery life dramatically by setting it to 'ondemand' or 'powersave' ...
1
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0answers
156 views

How do I fix this boot-up error (attempt to read or write outside of partition)? [closed]

I just installed a version of ubuntu linux that I got from here, http://www.bauer-power.net/2013/06/bauer-puntu-1304-is-alive-download-it.html using vmware workstation. I have installed it before ...
30
votes
4answers
41k views

How to reload udev rules without reboot?

How should one reload udev rules, so that newly created one can function? I'm running Arch Linux, and I don't have a udevstart command here. Also checked /etc/rc.d, no udev service there.
1
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2answers
401 views

“select” vs “depends” in kernel Kconfig

What are the differences in dependencies between select and depends on in the kernels Kconfig files? config FB_CIRRUS tristate "Cirrus Logic support" depends on FB && (ZORRO || PCI) select ...
0
votes
1answer
50 views

How can I replace the default kernel with an earlier kernel?

I am working on petalinux, Linux for xilinx FPGAs. The source code is here This Linux is having 3.x kernel, and I have been asked to change the kernel to some earlier release version. What are the ...
3
votes
3answers
739 views

Self-built kernel: failed to mount /dev: No such device

I am trying to install a Linux kernel (3.8.1) from source in a Fedora distribution. The kernel is a vanilla one. I follow the kernel's build instructions closely that is: make menuconfig make sudo ...
1
vote
0answers
944 views

How to get back from “testing” to “stable” - Kernel downgrade

currently I am having lot's of fun with apt-get - and the bad thing is, it was my own fault. I had enabled the testing packages in /etc/apt/sources.list to install a certain package. And I told my ...
2
votes
2answers
154 views

How to measure PCI-Express bus usage?

I'm looking for a way to find out if PCIe bus is the bottleneck or not. It's not a problem to measure how much bytes was transferred through any particular NIC: Is there a way to find how much ...
4
votes
3answers
409 views

What distribution still supports the 2.6.x kernel?

I'm trying to use a Khepera III robot. The documentation says I need a Linux OS with kernel 2.6.x. An Ubuntu 8 image was provided at the website. When I created a virtual machine with that image, I ...
0
votes
1answer
62 views

Why my cpu spend so much time on system? [closed]

top - 08:58:42 up 20 days, 8:23, 1 user, load average: 67.17, 58.94, 62.75 Tasks: 630 total, 40 running, 524 sleeping, 0 stopped, 66 zombie Cpu(s): 57.3%us, 41.6%sy, 0.0%ni, 0.0%id, 0.0%wa, ...
1
vote
2answers
60 views

CentOS 6 with Linux-Libre kernel?

I understand that CentOS ships with nonfree blobs in it's kernel. It seems that a "nonfree blob" free kernel exists, a.k.a. Linux-Libre. Is it possible to somehow get CentOS to use Linux-Libre ...
3
votes
3answers
134 views

Is it mandatory to have a file system and MMU in Linux? [closed]

Suppose I do not need a filesystem and I have only applications where data reloading may not be required - so MMU may be redundant. Can I remove these two items from Linux, and boot the OS ...
6
votes
3answers
375 views

Is there a file for each socket?

"Everything is a file" in the UNIX World. Above sentence is famous. When I run echo "hello programmer" >> /dev/tty1 , I can watch the given string on TeleType 1 , .... What and where is file ...
1
vote
0answers
119 views

D-Link usb dongle detection problem [ Debian Wheezy ]

according to this topic,I was upgrade kernel from 3.2 to 3.12 (using .deb backport),But at installation process I get some error message like this : # dpkg -Ri kernel3.12 Selecting previously ...
17
votes
1answer
820 views

Configuring, compiling and installing a linux kernel

I'd like to try using a kernel other than the one provided by my distro -- either from somewhere else, or as customized by me. Is this difficult or dangerous? Where do I start?
1
vote
1answer
90 views

Debian/Ubuntu:How to compile a Linux kernel on one machine and use on other machines (same architecture)

Debian/Ubuntu: How to compile a Linux kernel on one machine and use on other machines (same architecture)? I know how to do it on the same machine. But to use a compiled kernel other machines, is ...
0
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0answers
30 views

Problems configuring kernel

Trying to recompile my kernel and getting the following error to support Xen PCI Passthrough.It almost makes it through the whole build then flops out when building the image. dh_testdir ...
1
vote
3answers
84 views

How to create a kernel source tree?

I am reading a book on creating drivers on Linux, I do not have too much experience with Linux, I have installed a quite a few distros before but I have always used windows as my main operating ...
6
votes
4answers
1k views

Given a kernel ATA exception, how to determine which physical disk is affected?

I woke up this morning to a notification email with some rather disturbing system log entries. Dec 2 04:27:01 yeono kernel: [459438.816058] ata2.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6 ...
1
vote
0answers
56 views

How to disable PAE feature of kernel, after installation?

I am using RHEL 5.3(x86) as a base platform for my development purpose.My machine's spec is as follows: Intel, Core-i3 Processor @ 2.5GHz 4GB RAM Problem is whenever I am attempting to install the ...
0
votes
2answers
44 views

How do you check the support for a specific CPU in the Linux or BSD kernel?

Assuming that I have the sources for my kernel and I know the name of a SoC or a CPU, how I can check that the hardware is supported without compiling and running ?
1
vote
1answer
591 views

Driver install, kernel source not found

I am trying to install a NVidia Cuda driver on a Amazon EC2. GPU instance (Amazon Linux AMI (HVM) 2013.09.2 - ami-e9a18d80) following the instructions laid out in a blog. It worked for the last two ...
3
votes
3answers
381 views

Why does MemTotal in /proc/meminfo change?

I monitor value from /proc/meminfo file, namely the MemTotal: number. It changes if a ram module breaks, roughly by size of the memory module - this is obvious. I know the definition for the field ...
1
vote
0answers
30 views

Patching the kernel source through git

I'm trying to understand how the patching of the kernel source works. I found the patch that I would like to try an apply on the following page. I found no .patch files that I can use to apply the ...
1
vote
1answer
86 views

What does this key code qualifier mean?

I know that in general this means that I have a "bad disk". But I'm after a more specific reason for why I am getting these messages from the kernel: sd 15:0:0:0: [sda] Attached SCSI disk sd ...
5
votes
1answer
6k views

disable transparent hugepages

We are installing SAP HANA in a RAID machine. As part of the installation step, it is mentioned that, To disable the usage of transparent hugepages set the kernel settings at runtime with echo ...
1
vote
0answers
54 views

kernel 3.1x and optimus support

I have encountered a negative observation regarding bumblebee. Namely, using optirun the performance of the GPU seems to be an order of magnitude lower than it should be. To be more specific: I have ...
1
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0answers
1k views

kernel: “echo 0 > /proc/sys/kernel/hung_task_timeout_secs”

I got this errors in syslog. Any idea what does it mean? The system is running on Ubuntu 12.04, kernel: 3.8.0-35-generic #52~precise1 It looks to me like failure when trying to write to disk... ...
6
votes
2answers
234 views

what's the format spec for `ss -D `?

Background of the question: I am trying to sum up the total bandwidth, but ss -i cleverly converted numbers to more readable format like Kbps/s or Mbps/s, which is not accurate. So does ss -o with ...
2
votes
0answers
196 views

graph TCP connection performance based on `ss -i`

A nearby question has brought to my attention the ss utility on Linux, another utility to investigate sockets. It would appear that it may be a great tool to monitor the performance of, say, an ssh ...
2
votes
1answer
938 views

After upgrading the kernel, the sound no longer works

I have updated the Linux kernel on my system to Linux 3.11-2-amd64 #1 SMP Debian 3.11.10-1 (2013-12-04) x86_64 GNU/Linux. Having done that, the sound no longer works. Distribution Info(cat ...
3
votes
2answers
1k views

How to add more /dev/loop* devices on Fedora 19

How to add more /dev/loop* devices on Fedora 19? I do: # uname -r 3.11.2-201.fc19.x86_64 # lsmod |grep loop # ls /dev/loop* /dev/loop0 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 /dev/loop5 ...
4
votes
2answers
148 views

What does it mean to install a kernel?

What does it mean to install a new version of the kernel. My Linux box gave me this message when I was updating, NOTE, 3.8.13 was the last maintained maintenance release by Greg Kroah-Hartman. ...
0
votes
1answer
42 views

Patching linux kernel fails?

From what I understand, I can easily upgrade my kernel by applying patches to it, opposed to recompiling the kernel every time. I'm trying to go from kernel 3.2.51 to 3.2.54 by applying all the ...
0
votes
1answer
54 views

cc1 not in the PATH

I 'm trying to configure kernel via make menuconfig [Angstrom distribution] on BeagleBoard-xM, but I get these errors: make: Warning: File `/usr/src/linux-2.6.32.61/arch/arm/Makefile' has ...
0
votes
1answer
45 views

How to install kernel sources

I 'm running Angstrom distribution (console only) on BeagleBoard-xM. Image was build on Narcissus, with Bootloader Files (x-load/u-boot/scripts) added. I noticed that usr/src directory is empty. I ...
0
votes
1answer
122 views

NFS: failed to create MNT RPC client status = -101

I am trying for network file system (NFS) booting between two systems. I am using dhcp server to assign IP-address for client. And my kernel and root file system are present in server. My client is ...
65
votes
12answers
7k views

What is the benefit of compiling your own linux kernel?

What benefit could I see by compiling a Linux kernel myself? Is there some efficiency you could create by customizing it to your hardware?
2
votes
1answer
141 views

Finding and reloading driver from kernel

I am using Crunchbang 64 bit O.S. with a ASUS N150 wireless adapter. Everytime I close my laptop and it enters sleep mode, when I "wake it up" I am unable to connect back using the wireless adapter, I ...
0
votes
1answer
89 views

Questions about behaviour of running LiveCD Linux after unmounting a CD-ROM

Could anyone explain what happens in system after unplugging CD-ROM during working with LiveCD session? Suppose that I'm using Ubuntu LiveCD and suddenly by accident the CD-ROM disconnect for a ...
1
vote
1answer
175 views

I want to understand Buildroot - the 3 compression config options (kernel, initramfs & rootfs)

I'm using buildroot to generate my images and for sure there is the option of compression with the help of different methods (LZO, LZMA, gzip, ...). So far i found these 3 compression options in ...
0
votes
1answer
70 views

Ubuntu Kernel Compilation?

I'm trying to compile and install kernel 3.13.1 on ubuntu 13.10 using following commands: sudo apt-get install gcc sudo apt-get install libncurses5-dev cd Downloads/ sudo tar -xvf ...