Monday, March 1, 2010

Anatomy of an Embedded Linux System - Kernel

As discussed earlier, the Linux kernel was created by a Finnish computer science student as a hobby project and was first released in August 1991. The operating system originally ran only on x86 hosts and was modeled on a teaching aid operating system, MINIX. The Linux kernel was first ported to the Motorola 68KB processor, a painful process resulting in Linus Torvalds designing the kernel for portability. By doing the right thing, he laid the groundwork for Linux being ported to nearly every major processor over the following decade.

Due to the maturity and wide device support of Linux, engineers spend less time doing kernel development work such as creating device drivers (for example, to drive an LCD) and more time and effort creating applications the user values (like displaying the current weather conditions). Some effort may go into customizing the kernel by removing unneeded components or making other tweaks to increase booting time, but generally you don’t need to do the low-level programming necessary to get the Linux kernel running in the first place.

Although it’s an essential and vital component, the kernel has a symbiotic3 relationship with the software it runs. The point isn’t to give the Linux kernel short shrift or minimize its importance! The point is to make clear how the kernel fits into the overall functioning of a Linux system. Without something to run, the kernel stops executing and panics. That’s where the root file system and your application come into play.

Source of Information : Pro Linux Embedded Systems (December 2009)

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