Linux 2.6 is the next major release of the Linux kernel development cycle, and it contains powerful features aimed at improved performance on high-end enterprise servers as well as support for several embedded devices. This release is not yet a stable release but only a beta release: anyway there are many new features that will be introduced with this release.

Linux 2.6 is a big step for Linux on enterprise servers as well as for embedded systems. For high-end machines, new features target performance improvements, scalability, throughput, and NUMA support for SMP machines. For the embedded world, new architectures and processor types have been added -- including support for MMU-less systems that do not have a hardware-controlled memory management scheme. And, as usual, a whole new set of drivers for audio and multimedia have been added to cater to the desktop crowd.

In this new release is support for ACPI (Advanced Configuration and Power Interface), for CPU scaling (the ability to vary the CPU clock frequency under varying loads to conserve power) and software suspension (this feature is still being tested); moreover IPSec (IP Security) support has been added to the kernel. The IPSec feature uses the new crypto API provided by the kernel. This crypto API includes various popular algorithms like MD4, MD5 DES, and so on. Support for the new NFSv4 (Network File System) client/server has been added.

Other important features are the new scheduler and the kernel preemption.
The 2.6 Linux kernel uses a new scheduler algorithm, developed by Ingo Molnar. It should perform notably well under high loads and it scales well with a large number of processors.
The kernel preemption patch has been merged into the 2.5 series and subsequently will make it into 2.6. This should significantly lower latencies for user interactive applications, multimedia applications, etc. This feature is especially good for real-time systems and embedded devices.

Do you need more details? See The Wonderful World of Linux 2.6