What is kernel in linux ubuntu

Kernel

The kernel is the software that directly manages your hardware, allowing application libraries and software like GNOME and Firefox to run on many types of hardware without much difficulty. Because the Linux kernel is the core component of a GNU/Linux system, a full restart is required to complete the kernel update.

Types

Ubuntu packages the Linux kernel for a variety of architectures, including several variants of the x86 architecture. These include a 386 version, a 686 version, and versions for the AMD k6 and k7 processors. While most software for x86 processors in Ubuntu is compiled for 386 or better instruction sets, the kernel and a few other packages are specifically compiled for certain processors for speed reasons. Check the package documentation to determine what type of kernel will perform best for your processor.

Versions

Ubuntu currently packages the 3.8 kernel for optimal desktop speed and features.

SMP

Some motherboards have more than one processor on them, and some processors have multiple cores. If your computer is like this, then the SMP kernel is for you. Non-SMP kernels will not be able to take advantage of your multiple processors. However, if you do not have multiple processors, the additional code in an SMP kernel will only slow you down. Naturally, Ubuntu provides both SMP and non-SMP kernels for all supported architectures.

PAE

PAE (Physical Address Extension) allows the 32 bit version of Ubuntu to access up to 64 Gb of memory and is the standard for all members of the Ubuntu family from release 12.10 and beyond, as the non-PAE version has been dropped. For more on this please see here.

If your hardware does not support PAE, refer to the PAE pages with topics like installing, upgrading and enabling (with) PAE.

HowTo Upgrade or Recompile Kernel

The precompiled kernels that are supplied with your distro should be fine however if you wish to update or optimise (or standardise) for your platform :

• 1) You can Kernel/Upgrade easily using Ubuntu. 2) You can also Kernel/Compile it yourself from LinuxKernelSource or UbuntuKernelSource. 3) Run the following Terminal commands to install a new Ubuntu kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline/

sudo apt-get install python-bs4 python-apt

cd /tmp; rm -rf medigeek-kmp*; wget --no-check-certificate https://github.com/medigeek/kmp-downloader/tarball/master -O kmpd.tar.gz; tar xzf kmpd.tar.gz; cd medigeek-*

Just press instead of a number if you get stuck on a certain question in the python script.

The script by default filters out (i.e. does not show) the release candidates. If you want the latest release candidates, please use: python kmpd.py -d

How to Remove unwanted Kernels from your system

• Open the Synaptic package manager from the System->Administration menu. Click the “Search” button on the tool bar and search for «linux-image-2». The results should show every available and installed kernel. A green box on the left indicates that the package is installed. The only linux-image you want installed is the latest one. Find the package corresponding to the kernel to you running currently (this is the kernel you found in the terminal window). Make sure you keep that one. Now you can uninstall the old kernels from the list by clicking their boxes and selecting “Mark for Removal”.

Or you can uninstall kernels using the ubuntu-tweak Ubuntu PPA package.

Experimental Kernel Options

• As per the Ubuntu Kernel Team, their typical Kernel configuration policy is that options marked EXPERIMENTAL are disabled by default, until a request has been made to justify enabling it. For example, one may find out if an option is marked this way via:

config RT2800USB_RT35XX bool "rt2800usb - Include support for rt35xx devices (EXPERIMENTAL)" depends on EXPERIMENTAL default y ---help--- This adds support for rt35xx wireless chipset family to the rt2800usb driver. Supported chips: RT3572

See also

Kernel (последним исправлял пользователь ckimes 2017-09-26 21:10:21)

The material on this wiki is available under a free license, see Copyright / License for details
You can contribute to this wiki, see Wiki Guide for details

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Ubuntu Wiki

This set of wiki pages is primarily focused on assisting new Ubuntu Kernel developers, packagers, testers, and bug triagers.

If you are considering updating these pages please see the Kernel/WikiGardening guide. The project to revamp the kernel pages can be found on the Kernel/WikiToDo.

Mission

The Ubuntu Kernel Team aims to provide the highest quality Linux kernel for Ubuntu and the Ubuntu family of products. The Linux Kernel is the core of Ubuntu and is the rock upon which we base all other Ubuntu technology, and is a usable, high-quality desktop & server operating system for users around the world. It strives to be the best free software development platform in existence.

Topics

• Kernel/FAQ — Frequently Asked Questions
• Kernel/Debugging — debugging and triaging issues with the kernel
• Kernel/Testing — testing the kernel
• Kernel/BugTriage — Triaging bugs assigned to the kernel team
• Kernel/KernelBisection — How to use bisection to find a bug among many commits
• Kernel/Dev — developing against the Ubuntu kernel
• Kernel/Handbook — documentation on how things are done within the team
• Kernel/Reference — reference manuals and information
• KernelTeam — about the team behind the kernel and how to contact them
• KernelTeam/Meeting — kernel progress meeting agenda and minutes
• Kernel/Investigations — various kernel related investigations (config choices, sub-system performance)

Kernel (последним исправлял пользователь brad-figg 2012-01-10 16:49:25)

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Ubuntu kernels from Canonical

At the core of the Ubuntu operating system is the Linux kernel, which manages and controls the hardware resources like I/O (networking, storage, graphics and various user interface devices, etc.), memory and CPU for your device or computer. It is one of the first software programs a booting device loads and runs on the central processing unit (CPU). The Linux kernel manages the system’s hardware environment so other programs like the operating system’s user space programs and application software programs can run well without modification on a variety of different platforms and without needing to know very much about that underlying system.

Identifying a kernel

The easiest way to determine the kernel you’re running is to type cat /proc/version_signature on the terminal. For example:

Ubuntu 5.4.0-12.15-generic 5.4.8

This output provides important information about the kernel:

• Canonical adds » Ubuntu «
• Ubuntu kernel-release = 5.4.0-12.15-generic
  • kernel version is 5.4 , which is identical to upstream stable kernel version
  • .0 is an obsolete parameter left over from older upstream kernel version naming practices
  • -12 application binary interface (ABI) bump for this kernel
  • .15 upload number for this kernel
  • -generic is kernel flavour parameter, where -generic is the default Ubuntu kernel flavour

  Kernel and OS releases

  Canonical provides long-term support (LTS) kernels for Ubuntu LTS releases. Canonical also provides interim operating system releases with updated kernels every 6 months.

  For customers and business partners that don’t have specialised bleeding-edge workloads or latest hardware needs, the latest LTS release «-generic» kernel is the best option for them such as the 4.15 default kernel in Ubuntu 18.04 LTS. Customers who need the latest hardware support capability can install the latest HWE kernel such as the ones contained in interim releases, keeping in mind the shorter support lifespan associated with these kernels (9 months). HWE kernel customers are recommended to upgrade to a newer LTS release that supports their hardware and/or software needs as soon as it is available. Another option for customers is to use point releases. For example, there is an 18.04.4 point release as of February 2020, which includes an updated 5.3.x kernel but is also considered LTS, exactly like the original GA 4.15 kernel in 18.04.

  Kernel security

  The Canonical Kernel Team’s primary focus is the careful maintenance of kernels and their variants for regular delivery via the Ubuntu SRU process and the Canonical livepatch service. This includes rigorous management of all Linux kernel Common Vulnerabilities and Exposures (CVE) lists (with a focus on patching all high and critical CVEs) review and application of all relevant patches for all critical and serious kernel defects in the mailing lists and then rigorously testing newly updated kernels end-to-end each SRU cycle.

  General Availability (GA) and variant Ubuntu kernels

  The complete functionality of any given kernel is determined by the included modules and the kernel configuration for both hardware and the expected workloads that are run on it.

  Kernel modules are binary programs that extend a kernel’s ability to control the computing system’s hardware or add additional system capabilities like high-performance networking or non-standard graphics, etc. The GA kernel that is shipped by default, with the Canonical Ubuntu Long Term Support (LTS) and Hardware Enablement (HWE) releases, are tuned for stable, reliable, secure, high-performance operation over a wide variety of hardware platforms and workloads.

  A kernel variant is a kernel that deviates from the generic GA kernel by changes to its configuration, and/or by having modules added and/or removed.

  Optimised kernels

  Canonical advocates for customers to use the GA kernel shipped with Ubuntu as the best and most cost-effective option in their business environment. We also offer the option for customers to customize their own Ubuntu kernels. Several of our enterprise, Telco and cloud provider customers have systems and workload needs, which justify both the time investment to optimise their kernels and the pay to develop and maintain those optimised kernels over time.

  © 2023 Canonical Ltd. Ubuntu and Canonical are registered trademarks of Canonical Ltd.

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