The Computer That Half the World Was Running

On October 5, 1959, IBM announced a small mainframe called the 1401 with a starting monthly lease of $2,500. Comparable machines from competitors leased for around $10,000. In the first five weeks, IBM took 5,200 orders — more than the company expected the entire 1401 lifetime to produce.

The pitch was less about speed than about cost-of-entry. The 1401 ran on diode-transistor logic packaged onto pluggable Standard Modular System cards, with germanium-alloy transistors instead of vacuum tubes. It was small enough to sit in a back office, cool enough to run without industrial chillers, and reliable enough that a mid-sized insurance firm could keep one alive on its own.

Its native job was punch-card work — payroll, billing, inventory — moved off the cards onto the much faster magnetic tape drives sold alongside it. Programs were written in Autocoder or RPG, then loaded from a deck. Characters were six bits, with parity and a word-mark bit that doubled as a string terminator, an idea that quietly anticipated the null-terminated strings of the next decade.

By the mid-1960s, more than half of the computers installed worldwide were 1401-family machines. Over 12,000 units shipped before IBM officially retired the line on February 8, 1971. A computer that started as a low-end side bet ended up being the machine most of the working world first met.