If you could kill someone by tipping it over on them, it might be a
mainframe.

If the only mouse it has is the one living inside it, it might be a
mainframe.

If you need earth-moving equipment to relocate it, it might be a
mainframe.
If youve ever lost an oscilloscope inside of it, it might be a
mainframe.

If its big enough to be used as an apartment, it might be a
mainframe.

If it has ever had a card-punch designed for it, it might be a
mainframe.

If it weighs more than an RV, it might be a mainframe.

If lights in the neighborhood dim when its powered up, it might be a
mainframe.

If it arrived in its own moving van, it might be a mainframe.

If its disk platters are big enough to cook pizzas on, it might be a
mainframe.

If Michael Jordan would need his entire annual salary to buy one, it
might be a mainframe.

If keeping all of the manuals together creates a fire hazard, it might
be a mainframe.

If its so large that a dropped pen will slowly orbit it, it might be a
mainframe.

If its ever been mistaken for a refrigerator, (or if the disk drive
has ever been mistaken for a washing machine), it might be a
mainframe.

If anyone has ever frozen to death in the room where its kept, it
might be a mainframe.

If it has a power supply thats bigger than your car, it might be a
mainframe.

If it has its own postal code, it might be a mainframe.

If the operators considered the addition of COBOL to be an upgrade, it
might be a mainframe.

If it was designed before you were born, it might be a mainframe.

If its main power cable is thicker than your neck, it might be a
mainframe.

If the designers have since died from old age, it might be a
mainframe.