title: How is floating point stored? When does it matter?
body: <p>In follow up to <a href="https://stackoverflow.com/questions/56820/round-in-python-doesnt-seem-to-be-rounding-properly">this question</a>, it appears that some numbers cannot be represented by floating point at all, and instead are approximated.</p>
  
  <p>How are floating point numbers stored?</p>
  
  <p>Is there a common standard for the different sizes?</p>
  
  <p>What kind of gotchas do I need to watch out for if I use floating point?</p>
  
  <p>Are they cross-language compatible (ie, what conversions do I need to deal with to send a floating point number from a python program to a C program over TCP/IP)?</p>