Digital Equipment Corporation — universally known as DEC — was founded in 1957 in a former woollen mill in Maynard, Massachusetts. It pioneered the minicomputer: machines far smaller and cheaper than mainframes that put real computing power within reach of individual labs, universities and companies.
PDP and VAX
DEC's PDP series, especially the PDP-8 (1965) and PDP-11, became the workhorses of science and engineering and the machines on which early Unix was written. The VAX (1977), with its VMS operating system, extended that success into a 32-bit architecture that ran a huge share of the world's technical computing through the 1980s. At its peak DEC was the second-largest computer company on earth, after IBM.
Missing the turn
DEC's culture was built around selling capable, expensive machines to institutions — and it was slow to take the personal computer seriously, viewing it as a toy. As cheap PCs and workstations grew powerful enough to replace minicomputers, DEC's core market eroded. After heavy losses it was acquired by Compaq in 1998 (which itself merged into HP in 2002), and the DEC name disappeared. It stands as a classic cautionary tale: a dominant company undone not by a competitor doing the same thing better, but by a cheaper technology it underestimated.