Mapping memory between kernel and user space — Linux Kernel Newbies. Linuxdd. Inside the Linux boot process. In the early days, bootstrapping a computer meant feeding a paper tape containing a boot program or manually loading a boot program using the front panel address/data/control switches.
Today's computers are equipped with facilities to simplify the boot process, but that doesn't necessarily make it simple. Let's start with a high-level view of Linux boot so you can see the entire landscape. Then we'll review what's going on at each of the individual steps. A Simple Block Driver for Linux Kernel 2.6.31 « Superpatterns. Linux Device Drivers, 3rd Edition My current work involves writing my first Linux block device driver.
Going to the web to find a sample, I discovered Jonathan Corbet's Simple Block Driver article with its associated block driver example code. It's a nice succinct implementation of a ramdisk - pretty much the simplest working block device.