Processor Choices

Because Linux has been ported to virtually every processor type and family, it’s unlikely that you’ll have to start from scratch and do all the work yourself. This also means that the available choices in terms of performance, cost, power consumption, and peripheral functions are nearly unlimited, and you won’t be forced to make giant compromises just to accommodate some obscure processor family.

It’s very important to do your homework on the processor you choose. For instance, it’s much easier to work with a processor that has a memory management unit (MMU) than a processor without one. A memory management unit provides differentiated address spaces for the kernel and each process, enforces memory protection, and provides for virtual memory. Without an MMU, these desirable features simply don’t exist.

The uClinux kernel fork was created specifically so you can use the MMU-less processors, but your application programs must behave quite differently when running in an MMU-less environment. For instance, because you can change any part of memory, including kernel memory, it’s quite easy for your application to completely freeze an MMU-less processor.