As with anything in technology that’s nearly 30 years old, the ARM architecture has gone through many phases, many changes, many names through the decades as the architecture evolved from the ARM1 to the ARM11. With the switch to the ARM Cortex series, there’s even more complexity. ARM processor cores are key elements in the development of a lot of SoCs these days, so perhaps you might like to see a concise explanation of how the ARM architectural evolutionary tree looks and how it got to be that way.
Although you could easily write a book about this subject (and maybe I will some day), Bryon Moyer at the Electronic Engineering Journal has written an excellent blog that analyzes the topic. Moyer writes:
“So this is my attempt to make sense out of the ARM processor line. If you’ve ever thought that the ARM offering can be confusing, you’re right: it is. There are codes and numbers that aren’t well understood – even within the company, and things that you would think would be natural boundaries – like fundamental architecture changes and major product family changes – turn out not to coincide. ”
You’ll find Moyer’s excellent blog entry here.