The kernel of operating systems popularly known as Linux, or sometimes GNU/Linux.

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What does Linux's “nointremap” option do?

Ubuntu 12.10 alpha 2 works perfectly on my new 11" 2012 Macbook Air, but only when I boot with the "nointremap" option. Supposedly this is not good to use as a permanent solution. What exactly does ...
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0answers
101 views

“nopage” method for ISA vs PCI [closed]

This is with reference to LDD3 ch. 15, section "Mapping memory with nopage". I am having trouble understanding the third paragraph on page 429. It says: Note that this implementation works for ISA ...
2
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0answers
89 views

How to deal with closed source modules when configuring a new kernel build

I found this command very useful: make localmodconfig However, having some closed source drivers/modules ends up being a problem because this command can't find an appropriate way of including the ...
5
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5answers
420 views

Which tasks to learn and which books to read to become more skilled at Unix/Linux internals? [closed]

I recently interviewed at a major company and did well on programming questions such as: "What is the time complexity of quicksort? What is the opposite in C of malloc? What is the opposite in ...
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2answers
938 views

can't initialise/detect 16550A UART at unusual io port address

I've got a board based on the Vortex86DX CPU which is an x86 based microcontroller. It has five 16550A UARTS, four (COM1-COM4) of which are at the usual io port addresses (0x3f8, 0x2f8, 0x3e8, 0x2e8) ...
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1answer
751 views

Hurd vs Plan9 vs Linux vs eCos vs FreeRTOS what are the main differences specially with Hurd?

Hurd is actually not Unix nor Linux. But more superior says. Where Plan9 and Linux are in the range of Unix/Linux. eCos and FreeRTOS is also completely not unix/linux. What is the main differences ...
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1answer
933 views

IO Error in rsync while doing everyday backup

I have a sample NAS server (QNAP TS-210), with very limited Linux on-board (although a bit reinforced with Optware/IPKG). I'm a Linux newbie. After digging through Internet I was able to write my own ...
5
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1answer
377 views

Does the kernel delete entries in /dev on an initramfs?

I have a fully custom, minimal, embedded Linux (vanilla, 3.3.8, i486, Vortex86dx) system that boots from an initramfs image. No standard distribution scripts are used, just a single rcS file that does ...
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3answers
442 views

“Modules not found” error during kernel install

I have a question regarding a kernel installation. I downloaded a new version of net-next kernel source and I performed the following steps: make allyesconfig make -j16 make modules_install make ...
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2answers
736 views

Entry point of linux kernel [closed]

In the linux kernel is there a file that I can start to add my code, ex. load libraries? thanks
19
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2answers
17k views

Linux: How to find the device driver used for a device?

If my target has one device connected and many drivers for that device loaded, how can I understand what device is using which driver?
5
votes
1answer
3k views

How do I convert a kernel .config file from 32-bit to 64-bit?

At this page you can download a configuration file that lets you target a particular notebook architecture during the compilation of a new 32-bit Linux kernel. I need a 64 bit version. What do I ...
5
votes
2answers
2k views

how is the file /proc/net/dev filled?

So, I'm writing a kernel module that needs stats about local network interfaces and I came up with the following code ... everything works fine except for the part where I try to read wireless device ...
3
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0answers
588 views

How extended (4MB) and regular (4KB) paging coexist?

On x86 architecture, "Extended paging" allows page frames (physical memory) to be 4 MB instead of 4 KB. The book "Understanding the Linux Kernel, 3rd" at chapter 2 "Memory Addressing", sub-chapter ...
3
votes
2answers
963 views

Where can I find the Linux driver for headphones in the kernel tree?

I have headphones with three buttons on them which allow me to control my music player with my phone. I want to write a driver for my headphones to make it control my music player on my pc (Ubuntu ...
2
votes
3answers
499 views

Why does Linux on sparc64 architecture use 32-bit pointers in user-space and 64-bit pointers in kernel-space?

What are the advantages of deviating from the norm; that is 64-bit pointers in both user and kernel space for a 64-bit architecture? Reference: http://lwn.net/images/pdf/LDD3/ch11.pdf (Page 2)
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0answers
424 views

Booting linux from SD Card on a Leopard board (Ti DM365)

I have a Leopard board with Ti DM365 processor. Problem is that I tried to flash the bootloader (uboot) to nand and landed up corrupting the NAND. Now I can't use the NAND to bring up the board. So I ...
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votes
1answer
156 views

Linux kernel compiling commands [closed]

I'm trying to make a mini operating system (using the linux kernel). I'm planning on it being for x86 and I'm trying to make it so that it not only runs on qemu but also on a real device. What are the ...
0
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1answer
1k views

Can the Linux kernel be compiled on Mac OS X 10.6.8?

I have a Macbook Pro and I want to build the Linux Kernel. Can I build 3.3.6 on my Mac? How?
2
votes
1answer
377 views

Binding lsmod module name with kernel configuration menu entry

Lets suppose I have a module named "mptsas". How can I find out, what kernel configuration menu entry (make menuconfig inside /usr/src/linux) corresponds to that module? By 'corresponds' I mean what ...
3
votes
1answer
3k views

Search through kernel make menuconfig configuration menu entries

When I run make menuconfig inside /usr/src/linux directory, the kernel configuration wizard appears. How can I search through the menu entries inside the make menuconfig wizard? I've tested /, but / ...
3
votes
1answer
119 views

LILO vga option

In LILO config file (/etc/lilo.conf) what's the difference between specifying vga option in Global section and when specifying it in per-image section.
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4answers
1k views

Difference between bootable and non-bootable partitions

What is the difference between a bootable and non-bootable partition? I know that a user cannot boot a system from a partition marked non-bootable and can from one marked bootable. I want to know ...
24
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1answer
2k views

High CPU usage with CFS?

I asked a previous question to try and isolate the source of an increase in CPU usage when moving an application from RHEL 5 to RHEL 6. The analysis that I did for that seems to indicate that it is ...
2
votes
1answer
683 views

Learning how to build my own linux kernel

Reference - http://www.linode.com/wiki/index.php/PV-GRUB#Building_Your_Own_Kernel In order to work with Xen, a number of options that must be selected: CONFIG_PARAVIRT_GUEST=y CONFIG_XEN=y ...
4
votes
3answers
587 views

Does the linux kernel (specifically 2.6 onwards) have any recursive function?

Given the limited fixed size of kernel stack, my guess is that although theoretically we might have a recursive function if its recursion doesn't go too deep, pragmatism would suggest to do away with ...
9
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1answer
3k views

Isolating cause of higher CPU usage on RHEL 6 vs RHEL 5

I'm currently looking to move our system from RHEL 5 to RHEL 6, but I've run into a snag with unexpectedly high CPU usage on the RHEL 6 machines. It appears that this may be due at least in some part ...
3
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0answers
231 views

When would I use FBDEV vs DRM vs DSS?

I'm new to Linux graphics, and I'm interested in developing a graphics driver. I see that Linux supports three methods for writing graphics to the display device FBDEV DRM DSS2 When would I use ...
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2answers
232 views

Why does boot fail with my custom kernel at the mknod step?

I want to build a custom kernel under Ubuntu. I configured and built the new kernel. The new kernel hasn't initrd and comes from vanilla source. I build this new monolithic kernel only with drivers it ...
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2answers
488 views

NAND flash memory wear & virtual memory page swap

For a linux kernel with virtual memory and disk storage, pages are swapped back and forth into swap area. But embedded systems generally use NAND flash instead of disk. A NAND flash has a limited ...
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0answers
549 views

How do I create more /dev/tty entries and /dev/ptmx on boot up?

After building kernel 3.2.13 and installing via RPM on my system, I have this problem: There is no /dev/ptmx which the rest of my system is expecting. There is actually a /dev/tty/ptmx device ...
1
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1answer
76 views

Good ways to host or distribute my patch for the Linux Kernel Mailing List

I have an approximately 1500 line patch for the Linux kernel - introducing a new file system. I have lots of problems with posting a patch straight to the kernel mailing list (gmail mangles the ...
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votes
2answers
253 views

Linux kernel headers' organization

While I was doing some reading on system calls, I did a search for "syscalls.h" to find the header file in LXR. The search results puzzled me. There is a dozen of "syscalls.h" files coming from ...
7
votes
3answers
9k views

mptscsih: ioc0: task abort: SUCCESS (rv=2002) causes 30 seconds freezing

I/O to my software RAID6 often freezes for around 30 seconds after which everything is back to normal. After the freeze is over this is put into syslog: Mar 14 18:43:57 server kernel: [35649.816060] ...
7
votes
2answers
2k views

What is the appropriate value of vm.swappiness when using zram?

I'm using zram on my computer as a compressed RAM-backed swap. When the system needs to swap something out, swapping it to a zram-backed swap file is more or less equivalent to compressing that data ...
4
votes
3answers
724 views

How to compile my own linux kernel? [duplicate]

I want to learn about compiling a kernel from scratch. How can I download the latest stable Linux kernel from http://kernel.org/, compile it, and install it in a VMware virtual machine? This is just ...
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0answers
73 views

Linux Operating system-NOT A KERNEL CHANGE [closed]

I tried to make an operating system with my on custom built kernel. It didn't work out to well. I am using ubuntu and have downloaded linux 3.2.7 from kernel.org . I am not trying to change the kernel ...
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2answers
335 views

Can't switch to console using my own compiled kernel

In my Ubuntu, I can't switch to console through Ctrl+Alt+Fx using my own compiled kernel, and a black screen appears. I can switch back through Ctrl+Alt+F7. Using the default Ubuntu kernel, I can ...
7
votes
1answer
1k views

How to debug system freeze?

I'm experiencing strange bug when I close lid of my laptop - system freezes (no reaction on keys, no response form ssh) hard and displays some strange colour effects. The kernel log (after reboot) ...
1
vote
1answer
281 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 ...
4
votes
1answer
159 views

How/why can Firefox packages work on all Linuxes?

How/why can a Firefox 64bit (or 32bit) package work on different Linux distributions since each Linux distribution has a different version for gcc, glibc, linux kernel, etc. ?
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votes
1answer
410 views

illegal seek,system call [closed]

here is my test_code: And,when i run it,it prompt: Anyone can show me why?thx
8
votes
3answers
4k 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?
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votes
0answers
290 views

network device module equivalent to ping

I have made a module which is transmitting but I don't know whether the packet which I am transmitting is a ping packet or not. Code is shown below: icmp.type = 8; icmp.code = 0; ...
6
votes
2answers
5k views

How to list console and kernel fonts?

I have a number of console fonts installed in /lib/kbd/consolefonts/ installed. How do I list them (obviously all I can do, is just look at the filenames, but not at a list at available fonts). How ...
0
votes
1answer
311 views

Difference between vmlinuz-2.6.32-34-generic and vmlinuz-2.6.32-34-generic-pae

Can someone please tell me the difference between these two vmlinuz images ?
7
votes
2answers
236 views

Linux /proc/sys/kernel: where are the files sysrq-sticky, sysrq-key, and sysrq-timer?

Documentation for Red Hat Enterprise Linux 3 (section 5.3.9.3) mentions these files in /proc/sys/kernel/: sysrq sysrq-key sysrq-sticky sysrq-timer The documentation for RHEL 5 also mentions them. ...
2
votes
0answers
144 views

Need good ideas about improving any Linux service [closed]

I have a project assigned to me by OS teacher to choose any Linux service and improve it. Currently I am totally blank in this. I am not sure which service should I use which can easily be implemented ...
4
votes
1answer
216 views

After re-compiling the kernel, my grub stop after the bios

After recompiling my kernel, I copied the corresponding files to /boot, and my /boot directory looks like: Then, I inserted a new item in grub, and /boot/grub/menu.lst now looks like: After ...
6
votes
2answers
9k views

Where is the struct task_struct definition in the 2.6.30.5 Linux Kernel?

In the version 2.6.15 kernel, I got that I can rewrite the task_struct in the file (include/linux/sched.h),like: struct task_struct { unsigned did_exec:1; pid_t pid; pid_t tgid; ...