Introduction to the Linux Kernel 2.6

ForThe Fraser Valley Linux Users Group

By Alan Bailward<alan@ufies.org>

Overview

What is a “kernel”What does this release meanNifty new thingsBack-end changesUpgradingQuestion TimeResources

What is a Kernel

● Core of the OS● Controls all input and output● In development since 1991● Works in conjunction with your shell, tools and

applications

What 2.6 Means

● The 2.6 designation means that this is a stable kernel

● Almost● Currently (12/7/2003) at 2.6.0-test11● Linus is anticipating the full release by the end

of the year● Already very stable and many are using it● More “industry strength” features● Improved user experience

Nifty New Things

● New menu systems (gtk and qt)

Nifty New Things Cont...

● New build system– No more compile messages! (unless you use V=1)

Back-end Changes

● Hardware Support– better embedded support– better NUMA (non-uniform memory access... think

SMP++) support– Hyperthreading

● Scalability– PAE (physical address extension to allow x86 to

access up to 64G of ram)– higher limits on PIDs and device major and minor

numbers

Back-end Changes 2

● Interactivity– preemptible

● kernel operations can be interrupted● improves responsiveness ● “feels faster”● supposedly better than the 2.4 preempt patches

– threading ● start and stop 100,000 threads in 2 seconds (vs 14:58

before)

Back-end Changes 3

● Modules renamed to .ko● Stability improvements to the module subsystem● ISA, EISA, PCI systems are modules● Hotplug improvements● New filesystem sysfs

– /sys– joins /proc, /dev (devfs) and devpts– has all known attributes of the device (irq, dma,

power status, etc)

Back-end Changes 4

● Better PnP● USB 2.0 (“high speed”)● Wireless support merged into single subsystem

– amateur radio AX.25– wireless 802.11

● Infrared updates● Bluetooth updates● IDE updates and scalability improvements● No more ide-scsi for CD writing!● New Serial ATA drivers● SCSI updates

Back-end Changes 5

● Ext2/3 extended attributes– meta-data and finer grained permissions– catching up to windows in this respect!

● XFS added● NFS improvements, r/w better but still

experimental● Quota support more scalable

Back-end Changes 6

● Human Interface layer– create a completely headless system – complete modularity for video, keyboard, mouse, and

all things human (ph34r the machines!)● Touch screens● Strange mice● Braille devices● Magic sysrq key now not only from a console● ALSA (advanced linux sound architecture)

merged

Back-end Changes 7 (last one!)

● Networking updates– many small changes here and there– IPSEC support

● allows for transparent cryptography through ipv4 and ipv6– VLAN (for routers) support no longer experimental

● Network filesystem updates– NFSv4 support – CIFS (streamlined SMB)

● Many security updates– alternate security modules begun

● User mode Linux● APM/ACPI improvements

The “Gotchas”

● Not all non-open source packages are updated yet● May need patches for

– vmware– nvidia

● My own personal experience:– mouse speed changed– mouse buttons stopped working– vga=791 frame-buffer no longer worked

● have heard of problems with CD burning● some apps aren't updated yet● Gentoo changes with devfs and ptyfs

Upgrading

● module-init-tools● mkdir /sys● ensure keyboard and video are loaded in● pty filesystem

Questions?

Resources

● http://kniggit.net/wwol26.html● http://kernel.org● http://www.nyetwork.org/wiki/LinuxKernel● http://forums.gentoo.org/viewtopic.php?t=70838● http://kerneltrap.org/node/view/799● http://developers.slashdot.org/article.pl?sid=02/09/21/2024247● http://thomer.com/linux/migrate-to-2.6.html