Dinosaur

   In the [1]hacker jargon dinosaur is a type of a big, very old, mostly
   non-interactive ([2]batch), possibly partly mechanical computer, usually
   an IBM [3]mainframe from 1940s and 1950s (so called Stone Age). They
   resided in dinosaur pens (mainframe rooms).

   { This is how I understood it from the [4]Jargon File. ~drummyfish }

Links:
1. hacker.md
2. batch.md
3. mainframe.md
4. jargon_file.md