chairman is the biggest in a company. he's the one who approve
your paycheck every month, doesn't do anything much and can don't
even need to be technically knowledgable in the product/service the
company is selling/providing. 
a CEO is the 2nd biggest. he basically runs the whole show and
decides on the company policies. he need not be technically
knowledgable in the product/service the company is
selling/providing as well.
then below CEO we have the senior vice-president, vice-president,
assistant vice-president then followed by senior managers,
managers. these are the poeple must be technically knowledgable in
the product/service the company is selling/providing. if not then
something is very wrong. 