Strictly speaking, you do not really need an OS, it is just highly recommended.
Your options are:
(a) Do it all yourself. This is nothing
and hacking it bare-metal.
You can reference some of the bootloaders like whoosh or u-boot SPL, and do it all yourself. It usually starts with setting up memory timings etc.
(b) The middle way. U-boot bootloader can act as a very rudimentary operating system. Think early MS-DOS.
You have memory setup, drivers for many but not all interfaces, but you will lack things like multi-threading, MMU memory protection, and will be limited to a single core.
Many things have to be done hacking bare metal registers.
You can compile applications for u-boot using the mkimage tool, a part of the u-boot project.
(c) The recommended way. Load an operating system and treat your Wandboard as a real computer.
Regardless, starting with our pre-compiled images is probably a good idea regardless, to familiarize yourself with the hardware.
pianoman wrote:You mention I'll need a graphics toolkit for Linux. Does this mean a toolkit that develops apps that run on Linux or a toolkit that runs on Linux and can also be used to make apps?
Ment the latter. A set of libraries that allow applications to run on Linux, and a set of headers that allow you to develop for said libraries.
The use of IDE and choice of editors is more heterogenous among Linux programmers than for Windows programmers.
Usually people only refer to libraries and headers needed/used, understanding that everyone's development environemnet is different, even unique, and suited for their own needs and personal preferences.