actions vs. avm instructions in actionscript

My questıon is that, what are actions and what are avm instructions. I've been reading these two documents:

ht开发者_高级运维tp://www.adobe.com/devnet/swf/pdf/swf_file_format_spec_v10.pdf

http://www.adobe.com/devnet/actionscript/articles/avm2overview.pdf

but I couldn't get the concept of it. Could anyone with more understanding of it explain this please?

With AVM2 and ActionScript 3 Adobe essentially stopped using actions as the primary vehicle for programming in SWFs. What they did was to introduce the DoABC tag which contains within it AVM instructions.