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:
“O, pluck was he to the backbone and clear grit through and through;
Boasted and bragged like a trooper; but the big words wouldn’t do;
The boy was dying, sir, dying, as plain as plain could be,
Worn out by his ride with Morgan up from the Tennessee.”
—Constance Fenimore Woolson (1840–1894)
“Already the iron door of the north
Clangs open: birds, leaves, snows
Order their populations forth,
And a cruel wind blows.”
—Stanley Jasspon Kunitz (b. 1905)