Line printer
A high-speed impact printer that stamps out a whole line of text at once — the mainframe's workhorse from the 1950s to the 1980s.
Where a typewriter lays down one character at a time, a line printer commits an entire row, typically 132 columns, in a single hammer stroke. Speeds ranged from 600 to well over 1200 lines per minute, fast enough to spew payroll runs, account statements and compiler listings without leaving the mainframe idle. IBM's 1403 (1959) became the archetype: a cabinet-sized machine that sounded like rolling thunder.
The characters rode on a spinning drum, a chain or a band that swept past a bank of hammers; the right hammer fired the instant the right glyph lined up. Paper was continuous, folded in a zig-zag and dragged along by a tractor feed. Laser printers took the office in the 1980s, but line printers lingered in machine rooms into the 1990s wherever raw volume mattered more than typography.