The Linux kernel version 3.5 has been released and is now available for download. New features include support for hybrid graphics, security fixes, and other enhancements.
From the kernelnewbies change log:
This release includes support for metadata checksums in ext4, userspace probes for performance profiling with tools like Systemtap or perf, a sandboxing mechanism that allows to filters syscalls, a new network queue management algorithm designed to fight bufferbloat, support for checkpointing and restoring TCP connections, support for TCP Early Retransmit (RFC 5827), support for Android-style opportunistic suspend, btrfs I/O failure statistics, and SCSI over Firewire and USB. Many small features and new drivers and fixes are also available.
This article provides an overview of the most important changes in Linux version 3.5:
Together with a new version of X Server, Linux 3.5 will offer improved hybrid graphics support. The new kernel supports "FireWire Target Disk Mode", which is a familiar Mac feature, and performance monitoring components can now keep an eye on userspace software.