We have had several letters from Linux readers which begged to differ with IBM over SMP plans for the OS. But, on the other hand, nearly all were thankful IBM was doing the necessary driver porting work. Earlier today, we posted a story saying that IBM had undertaken a massive drivers project for the Linux OS on Netfinity servers. (Story: IBM gives Linux helping hand) One Linux fan said: "IBM's statement about linux being only 'two way' are incorrect. According to the Linux SMP FAQ, Alan Cox states that even Linux 2.0 has been tested with four CPU systems. Linux 2.2 supports up to 16 processors (the same as 2.0), but due to kernel changes, can handle more than two more efficiently than 2.0". However, the fan added: "It Does seem like IBM will do some nice stuff for Linux. Look out billyboi!" Another reader wrote: "The Linux that IBM is supporting on its Netfinity servers is Red Hat 5.2, which is indeed only two-way since it is based on the older 2.0.3x Linuxk kernel. Red Hat does not yet support the newer 2.2 kernel released mid-last month which has significantly improved SMP capability. "The newer Linux 2.2 kernel does support up to 16-way, but keep in mind, this only means that it boots on a 16-way. Actual scalability has yet to be demonstrated. That means there is little or no evidence that performance actually increases when you add more processors. There has been no public demonstration of scalability (e.g. published benchmarks from trade press or independent benchmark organisations) of improved performance to even four-way as far as I am aware of, as I've been keeping an eye out for that." ®