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

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9
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5answers
8k views

Is it possible to put root in LVM without using initrd?

I have just set up a Gentoo base system (which means I can boot and log in and do stuff with it now). My root partition is in an LVM2 virtual group (with a separated /boot partition). In order to boot ...
3
votes
2answers
409 views

Buffer overflow attacks

I just learnt today in a Distributed Systems class that there is an address space allocated for every user by the kernel, and if a user wants to get the su privilege, he needs to shift to the kernel ...
9
votes
1answer
6k views

What is the loopback interface

What is the loopback interface and how does it differ from the eth0 interface? And why do I need to use it when mounting an ISO or running a service on localhost?
6
votes
1answer
782 views

Patching Linux kernel on-line (i.e. without rebooting)

Sorry - I don't remember the exact name. I know there is mechanism to patch the kernel at runtime by loading modules without need of the reboot as long as the structures involved are not affected. It ...
3
votes
2answers
878 views

Does the Linux PreemptRT patch benefit desktop users?

Does the PREEMPT_RT patch (real-time kernel) have any benefit for regular desktop users?
13
votes
5answers
6k views

Benefit of kernel module compiled inside kernel?

What's the benefit of compiling kernel modules into the kernel (instead of as loadable modules)?
2
votes
1answer
337 views

Kernel memory allocator patch

Is there any patch for Linux kernel to use different memory allocators, such as ned allocator or TLSF allocator?
12
votes
6answers
8k views

Compiling GNU/Linux with -O3 optimization

It's said that compiling GNU tools and Linux kernel with -O3 gcc optimization option will produce weird and funky bugs. Is it true? Has anyone tried it or is it just a hoax?
11
votes
2answers
2k views

Heavy write activity on SSD nukes system performance

I've noticed that when I do heavy write applications, the whole system slows down. To test this further I ran this to do a (relatively) low-CPU, high disk activity: john -incremental > file_on_SSD ...
2
votes
1answer
402 views

Sometimes no sound in flash videos after boot?

Sometimes after I boot up the machine, I get no sound in flash videos. First I didn't know why it was happening, but as I read a few articles here and there, I found out it was because of my USB ...
9
votes
6answers
4k views

How to find information about the system/machine in Unix?

I have always found it difficult to find information about the system itself in Unix, whether it be Which OS I am using (version number and all, to compare it with the latest available builds)? ...
3
votes
8answers
1k views

Oldest Linux machine you still run [closed]

What is your oldest machine you ever installed Linux on and currently still run? What are the specs, kernel version or distro, and for what purpose?
40
votes
7answers
29k views

Linux Kernel: Good beginners' tutorial [closed]

I'm interested in modifying the kernel internals, applying patches, handling device drivers and modules, for my own personal fun. Is there a comprehensive resource for kernel hacking, intended for ...
6
votes
1answer
407 views

Linux kernel 2.6 on ARM

I have compiled and installed the 2.6 kernel on an ARM board. I am using the ARM mini2440 board. I would like to know if there is already a way to access the General Purpose I/O port pins? Or will ...
76
votes
13answers
13k 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?
12
votes
3answers
1k views

What does it mean when code is executed in [kernel|user] mode?

The title says everything.
8
votes
3answers
804 views

Why does it makes sense to cache swap?

It sounds quite counter-productive to me to cache pages that are swapped out. If you swap pages in, what is the advantage to first cache them in memory, only to have to than move them to the right ...
4
votes
3answers
2k views

How can I tweak the kernel for total swap out?

I would like to deploy the following swapping policy: By default all pages in memory should also be in swap space. When a page in memory is changed (i.e. dirty), the page should be written out as ...
5
votes
1answer
1k views

Is it safe to disable OOM killer in a web server/reverse proxy?

I have Linux machine dedicated to serving static contents and PHP pages with Apache. Apache also work as a reverse proxy in a subdomain. I moved the PostgreSQL database to another Linux machine. Is ...
27
votes
12answers
3k views

How can I tweak my Linux desktop to be more responsive?

I have the experience that Linux works fine until the physical memory is exhausted. As soon as swap space is used the performance is severely degraded and the GUI becomes unresponsive. This problem ...
11
votes
3answers
3k views

How should I configure grub for booting linux kernel from a USB hard drive?

I have a laptop hard drive in an external enclosure which I use as a large pendrive. For an added twist, I have installed Linux on it, so I can boot any machine with my distribution of choice (e.g. ...