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:
“The name of the town isn’t important. It’s the one that’s just twenty-eight minutes from the big city. Twenty-three if you catch the morning express. It’s on a river and it’s got houses and stores and churches. And a main street. Nothing fancy like Broadway or Market, just plain Broadway. Drug, dry good, shoes. Those horrible little chain stores that breed like rabbits.”
—Joseph L. Mankiewicz (1909–1993)
“Should the German people lay down their arms, the Soviets ... would occupy all eastern and south-eastern Europe together with the greater part of the Reich. Over all this territory, which with the Soviet Union included, would be of enormous extent, an iron curtain would at once descend.”
—Joseph Goebbels (1897–1945)