PC Magazine: Linux Reborn: Kernel 2.4Mar 31, 2001, 14:00 (7 Talkback[s])
(Other stories by Rich Dragan)
[ Thanks to Brian Hunt for this link. ]
"The reliability of Linux is already legendary, and that reputation is arguably based on the strength of its small, efficient kernel. It has traditionally been limited, however, by its failure to scale onto symmetric multiprocessor (SMP) systems. Although multithreading was added in January, 1999 to the Linux kernel in 2.2, it's been an open secret that this older kernel didn't scale very well beyond two CPUs on a single system. "The scalability fell off after two processors," says Darren Davis, VP of technology strategy at Caldera. The new kernel promises performance for four CPUs and beyond."
"For overcoming obstacles to scalability, the makers of Linux (including its inventor, Linus Torvalds) rewrote the kernel code that worked with such system resources as spin locks, which coordinate access to system resources across multiple CPUs. If implemented inefficiently, spin locks can slow down a multiprocessor system. Kernel subsystems like the networking stack and file i/o are now fully multithreaded...."
"Other enterprise-level improvements include a fully journaled file system (available in 2.4.1 of this release with the Riser [sic] file system), which eliminates the need for time-consuming file system consistency verification on reboots. (This feature contributes to increased server availability.)"