BOEL update

HOWTO: update SystemImager kernel (a.k.a. BOEL)

Copy the previous config file from patches/linux.<ARCH>.config into the new kernel source directory. For example:

 $ cp patches/linux.i386.config src/linux-2.6.16/.config

Try to make the kernel, cloning the previous configuration:

$ cd src/linux-2.6.16 && make xconfig

Surely you will get some errors here, due to the differences of the previous configuration parameters, but that's not a problem.

Using the xconfig interface simply choose a configuration compatible with the new kernel you want to use and remember the following guidelines.

compile only the minimum functionalities to boot and to reach the image server via the network (compile all the available network drivers statically in the kernel)
compile storage drivers and file systems as kernel modules (they'll be included in boel_binaries.tar.gz)
do not use SLOB allocator: rsync becomes very slow with that! (better to use SLAB)
compile RAM disk support statically in the kernel
compile these filesystems statically in the kernel: cramfs, procfs', sysfs, tmpfs (aka virtual memory filesystem), ISO 9660, UDF
enable support for large block devices
enable support for largest memory size (in some systems with a lot of memory users could want to use tmpfs staging of the whole image)
regarding networking and storage be more general as you can: BOEL should support all the available network cards and disk controllers
remember that the target environment is mainly a single-user and single-task system (a preemptible kernel will only provide lower performance)
do not enable sound and multimedia stuff

Moreover remember to update the kernel patches and remove those that are no more needed. The patches are constituted of the following files:

 patches/linux.<ARCH>.<PATCH_NAME>.patch

Save the new generated .config in patches/linux.<ARCH>.config and make the systemimager package to check if there's something wrong:

 $ cp src/linux-2.6.16/.config patches/linux.i386.config
 $ make