The Linux Kernel Christoph Lameter, Ph.D. Technical Advisory Board The Linux Foundation

Overview Who am I The origin of the Kernel Encountering Linux for the first time. Freedom to innovate makes it fun. But …. can one make a living off it? What is the kernel. Future outlook and dangers

Origins In 1991 Linus first publishes the kernel In 1992 someone uploaded Linux-0.14 to my BBS the Water Fountain. Trouble with Quickview, MSDOS and Windows 3.1 Linux worked sort of but needed fixing.

Encountering Linux for the first time There is a bug in the OS!! Was able to fix it. But the bug needed fixing for all users. So I sent it to Linus. Discussion aobut Posix standard and how exactly to fix this issue. Linus accepted the path after discussion. Next kernel release worked fine with my BBS.

Freedom to innovate Experiences with MS-Basic on PET 2001: Computers never really operate they way they need to. Novell Netware Writing compilers, Forth OS Problem was that all of these endeavors were very work intensive. No easy task for an isolated developer. Linux allowed access to experts that could help us organize and bundle our efforts. Became an entry point into Open Source community for me. And since I am lazy I stuck to it.

Can you make a Living with it? Linux as a hobby while studying Theology Linux as an Enterprise Solution: From BSD/i to Debian at Fuller Seminary Monitoring: Silicon Valley Startup hired me TelemetryBox: Tried my own distribution : Embedded Linux: Customizing Linux for a NAS device Supercomputers: Silicon Graphics: Principal Engineer for the Linux Kernel Working in the financial industry in Chicago.

The role of the Kernel in the Open Source Movement Central element of the Linux OS Central to the Open Source community Other projects take cues from Kernel community The kernel as the Cultural Center? Evolution of the movement mostly seen in the Kernel

Technical Features of the Kernel Isolates software (User space) from hardware. Any software can run on any hardware (well only if its the same basic architecture, arch or platform) Source level compatibility across architectures. Rebuild with an arch specific compiler is necessary to run it on a different platform

Architectures and Platforms Linux (kernel) supports the largest number of architectures. On each architecture another large selection of hardware is supported. Embedded architectures: ARM, MIPS, Sparc.... PC based architectures: x86 (32 and 64 bit) High Performance Computing: PowerPC, IA64, S/390, Sparc Linux basically runs everywhere from small devices (watch, gumstick) to the large supercomputers of NASA and the mainframes popularized by IBM. Easy to port provided there is a version of the GNU C compiler available for a platform.

Kernel features Features are increasing with every release. Largest amount of features of any OS. Only in specialized areas are other OSes better. Scratch the itch approach leads to features being added as the need becomes evident.

Kernel Limitations Processors: 1 to 4096 processors. Potentially 64k in two years. Memory: 16 Megabyte to 4 Petabyte (RAM not disk space!) Flexible configuration scheme. Switching off features reduces code size and simplifies the kernel. Major basic kernel configurations: SMP, Preemption, NUMA

Pragmatic Open Source Philosophy FSF has an idealized approach to source code. They use the term free software Linus and the Linux kernel use a pragmatic approach. Open source is useful and leads to superior software through better cooperation. Gets the dysfunctional corporate communication processes out of the way. Linux comes from below. It is usually present in all organization in some form. Management may not be aware of the use of Linux. An evil OS comes from above. Management often dictates its use.

What has Linux become now Major player in the High Performance Computing Market Dominates Server on the Internet. Mainframe are increasingly running Linux. IBM is fully on the Linux track. Dominates embedded devices Most Wifi routers, switches and other network devices are Linux based in some form or another.

Future Dangers Embedded market Servers HPC Where is the competition? BSD? Solaris? We need more competition. Progress becomes stifled. We need more innovative ideas.

Summarize Open Source is the best development approach to software. We dominate several industries already. Proprietary software is increasing showing problems. Proprietary software is dangerous for businesses. Governments show a tendency to require open source approaches for software.