[Rustington] Raspberry Pi speed up tip for Raspberry Pi users

[Martin Webb]

The Raspberry PI has 256MB of memory which is split between the operating
system and the GPU. As it is a small amount of memory by modern standards
the way it is split is done really matters. The distributions for the Pi by
default splits the memory 50/50 which works well for a lots of things but
means that web browsing is pretty hopeless. In most machines you would
change this split by changing a setting in the BIOS, but the Pi does not
have a BIOS so the method is different.

On the boot partition there are several files that end in ".elf". The
Broadcom system-on-a-chip on the device looks for a file named "start.elf"
before loading the operating system. This file also decides how the split
is done. Several other ".elf" files exist these start with "arm128",
"arm192" and "arm224". The number in these files is how much memory will be
given to the OS (the remaining memory goes to the video chip). The more
memory you give to the video chip the more it can do, but less is available
to the OS so it consequently can do less and so on. How you split depends
on what you are doing, a set top box type use might go for a 50/50 split, a
desktop might want more memory for the OS. I backed up the old "start.elf"
file to "old_start.elf" and copied "arm192_start.elf" to "start.elf" and
rebooted. The difference was dramatic, Midori was now able to browse web
pages in a pretty respectable fashion. I even tried it with some Javascript
heavy sites and it coped. It is not as fast as browsing the web on a
laptop, but is usable.
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