Answer:
1) Special Purpose Computers
A special-purpose computer is designed to be task specific and most of the times their job is to solve one particular problem. They are also known as dedicated computers, because they are dedicated to perform a single task over and over again.
2) Non-electric computers
A mechanical computer is built from mechanical components such as levers and gears, rather than electronic components.
3) Mainframe Computers ~ VAX 8842, CDC 6600, IBM 4381
Mini Computers ~ PDP - 11, VASPARC
