IBM 1401

The processor cabinet of an IBM 1401 at the Computer History Museum in California, where the museum's restoration team has brought 1401 systems back to working order. The 1401 swapped vacuum tubes for smaller, cheaper transistors and brought a computer within reach of ordinary businesses, not just governments and large labs. IBM built more than 12,000 of them, and by the mid-1960s nearly half the computers in the world were 1401s, which makes it the first real workhorse of office computing.