The Linux Kernel is the fundamental component of Linux OS.
Linux boasts features found in modern fully-fledged Unix including true multitasking, virtual memory, demand loading, shared libraries, shared copy-on-write executables, proper memory management, and multistack networking (IPv4 and IPv6). Originally developed for 32-bit x86-based PCs, the operating system now supports numerous architectures such as Compaq Alpha AXP, Sun SPARC and UltraSPARC, PowerPC, PowerPC64, ARM, Hitachi SuperH, IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS, and Renesas M32R.
It's easily portable to most general-purpose 32- or 64-bit architectures with paged memory management units and a port of the GNU C compiler (gcc) as an essential requirement. Although limited functionality is expected for most architectures without a PMMU. Those interested in additional information can check out the µClinux project.
Version 2.6.32 RC7: N/A