I thought about bringing this up as well.  I&#x27;m not sure what you mean by &quot;C&#x27;s machine is quite different from a real machine&quot;.  Do you mean (as I was thinking) that even assembly language is frequently not close enough to the machine to be used to guide the programmer trying to write high efficiency code?<p>I&#x27;m constantly surprised by how poorly documented the actual operation of current processors is, and how few people seem to care.  In one way, this means that the abstraction is working, and no longer does anyone need to look behind the curtain.  In another way, like the move to teaching only higher level languages, it feels like something essential is being lost.