title: What is the difference between machine code and opcode?
body: <p>The question is mostly related to PHP because IMHO opcode is mostly mentioned in PHP context.  According to this <a href="http://blog.golemon.com/2008/01/understanding-opcodes.html" rel="nofollow">description</a>, here's a transformation process of php code into opcode: </p>
  
  <p>php text -> scanning/parsing -> result = tokens -> compiling > result = opcode</p>
  
  <p>Several questions here: </p>
  
  <p>1) Is opcode just a portion of machine code, does machine code consist of opcodes? 
  2) Thinking in the context of Wamp server, what PHP module is responsible for? Is that module  just PHP interpreter who transforms PHP code into tokens or is it also a compiler who compiles tokens into opcode that is executed on the hardware (processor)?</p>