As is customary, Torvalds announced version 2.6.16 on the Linux kernel mailing list Monday.
Linux is technically just a kernel, but the term often is used to refer to the entire operating system built around that kernel. Linux sellers such as Red Hat and Novell use their own variations of the kernel that Torvalds releases at kernel.org, but they generally are reluctant to deviate too far from what amounts to a standard.
The Cell support should mean an easier time for IBM as it tries to encourage people to buy Cell servers later this year. The unusual processor also is used in Sony's upcoming PlayStation 3 game console, but IBM expects it to be used for high-performance computing tasks such as medical image processing as well. Cell has a main PowerPC processing engine supplemented by eight special-purpose cores that run tiny programs of their own.
Programming Cell is tough, but support in Linux could ease the challenges. The new kernel includes the SPU (synergistic programming unit) file system, which lets software control and communicate with the different processor cores.
Cell isn't the only multicore processor where Linux work is taking place. Torvalds accepted a number of patches Tuesday so Linux will run on Sun Microsystems' UltraSparc T1 "Niagara"-based servers, according to David Miller, the lead Linux-on-Sparc programmer, who posted the news on his blog.
The UltraSparc T1 has eight cores. Though it typically runs Sun's Solaris operating system, Sun wants to build support for Linux as well.
The new kernel has the Oracle Cluster File System as well. This software governs how a single pool of data is shared by a group of servers, a crucial element of Oracle efforts to make clusters of low-end computers a viable database alternative to expensive multiprocessor servers.
OCFS version 2 is part of Suse Linux Enterprise Server, but Red Hat has its own open-source alternative, the Global File System. GFS isn't part of the mainline kernel, according to the KernelNewbies site.
Linux is most widely used on low-end computers, but work is still under way to adapt it for large multiprocessor systems. One change in this domain is improvement in how Linux handles NUMA--nonuniform memory access.
Large servers most often divide memory so it's in patches near different processors. An operating system tries to make sure a computing task on one processor uses the nearby memory, but sometimes it needs data from a distant, slower-responding area--thus the term "nonuniform" is used to describe access speeds.
The new kernel can move information stored in memory so it's close to the relevant processor without stopping the process using that memory.
[nt]
