Big iron, as the hacker's dictionary the Jargon File defines it, "refers to large, expensive, ultra-fast computers. It is used generally for number crunching supercomputers such as Crays, but can include more conventional big commercial IBM mainframes".
The term is often used in reference to IBM mainframes, often when discussing their comeback/survival after the assault of lower cost Unix systems. More recently the term is also applied to powerful computer servers and computer ranches, whose steel racks naturally invoke the same association.
The expression may be compared with the slang expression for heavy handguns, derived from the slang "iron" for a handgun ("shooting iron"), as exemplified by the classic country music ballad Big Iron by Marty Robbins about "the ranger with the big iron on his hip".
Famous quotes containing the words big and/or iron:
“It is not only a question of who is responsible for very young children. There is no longer anyone home to care for adolescents and the elderly. There is no one around to take in the car for repair or to let the plumber in. Working families are faced with daily dilemmas: Who will take care of a sick child? Who will go to the big soccer game? Who will attend the teacher conference?”
—Fran Sussner Rodgers (20th century)
“By the flow of the inland river,
Whence the fleets of iron have fled,
Where the blades of the grave-grass quiver,
Asleep are the ranks of the dead:—”
—Francis Miles Finch (1827–1907)