big iron

from Jargon File (4.4.4, 14 Aug 2003)

big iron
 n.

   [common] Large, expensive, ultra-fast computers. Used generally of
   {number-crunching} supercomputers, but can include more conventional
   big commercial IBMish mainframes. Term of approval; compare {heavy
   metal}, oppose {dinosaur}.

from The Free On-line Dictionary of Computing (8 July 2008)

big iron
heavy metal

   <jargon> (Or "heavy metal [Cambridge]) Large, expensive,
   ultra-fast computers.  Used generally of {number crunching}
   {supercomputers} such as {Crays}, but can include more
   conventional big commercial {IBM}ish {mainframes}.  The term
   implies approval, in contrast to "{dinosaur}".

   [{Jargon File}]

   (2000-11-09)