By Jason Brooks  |  Posted 2004-03-08 Print this article Print

-Emptive Measures"> Pre-Emptive Measures

Another major change in Linux 2.6 is that the kernel is now pre-emptible, which means that tasks running in the kernel can be interrupted by other tasks. This capability benefits embedded implementations of Linux because it enables the kernel to behave more like a real-time operating system. This modification also benefits desktop Linux users, as it can make the system feel more responsive to mouse clicks and other user actions.

Linux 2.6 includes support for access control lists through extended file system attributes, a feature that previously required applying patches to the kernel. There are plenty of potentially interesting uses for these extended attributes within Linux, but until applications begin taking specific advantage of them, this support will most directly benefit companies interoperating through Samba with Microsoft Corp.s Windows systems with NTFS.

Linux now includes JFS (journaling file system) and XFS (extended file system) support, and the ext3 file system that comes with 2.6 has indexed directory support that can deliver considerable speed gains for directories with large numbers of files. The 2.6 kernel also includes an improved NTFS driver, although write support for NTFS is still considered experimental.


While its possible to upgrade any Linux system to the latest kernel release, most enterprise customers will want to wait until their Linux distributions are updated with the 2.6 kernel. Following is the schedule for the major distros:
  • Knoppix 3.4: End of month
  • Red Hat Fedora Core: April
  • Mandrake Linux 10.0: April or May
  • SuSE Linux Enterprise Server 9: Late spring/early summer
  • Red Hat Enterprise Linux 4: Fall
  • Debian Linux: No firm date set for the next stable release, Sarge, nor is it certain that Sarge will include the 2.6 kernel
  • The newest version of Linux sees the merge of the uClinux project into the kernel. This code targets embedded devices that lack a memory management unit, bringing support for processors such as Hitachi Ltd.s H8/300, NEC Corp.s v850 and Motorola Inc.s m68k into the mainstream development effort.

    In addition to the architectures supported by the uClinux merge, the 2.6 kernel has added support for Advanced Micro Devices Inc.s x86-64 and IBMs ppc64 architectures, as well as for User-Mode Linux. The latter allows users to run Linux in a virtual machine within a Linux system, which can be useful for kernel testing and for segregating server tasks into their own virtual machines for security reasons.

    Linux 2.6 can handle a variety of new hardware, including serial ATA drives and USB (Universal Serial Bus) 2.0 devices. Linux 2.6 also ships with support for Bluetooth and has improved support for IrDA.

    Linux 2.6 sports a new sound system, ALSA (Advanced Linux Sound Architecture), which widens sound device support and improves performance compared with the previous sound system. ALSA has been a popular add-on for Linux for some time now, but one that required kernel patching.

    Along similar lines, 2.6 includes Video for Linux 2, a second-generation video capture and overlay API within Linux that comes into play with devices such as video capture cards.

    Linux 2.6s boosted support for peripheral hardware and multimedia devices should be of particular benefit for desktop Linux users.

    Also new in Linux 2.6 is a cleaned-up kernel configuration and compilation process, which includes GTK (The GIMP Toolkit) and the Qt-based version of the graphical kernel configuration utility. Both make it much easier to select what to compile into the kernel.

    Senior Analyst Jason Brooks can be reached at

    As Editor in Chief of eWEEK Labs, Jason Brooks manages the Labs team and is responsible for eWEEK's print edition. Brooks joined eWEEK in 1999, and has covered wireless networking, office productivity suites, mobile devices, Windows, virtualization, and desktops and notebooks. JasonÔÇÖs coverage is currently focused on Linux and Unix operating systems, open-source software and licensing, cloud computing and Software as a Service. Follow Jason on Twitter at jasonbrooks, or reach him by email at

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