Digital Equipment Corporation introduced the PDP-1 in November 1960, the world's first small, interactive computer.
The PDP-1 sold for about $120,000, which made it one of the most inexpensive computers of that time.
The PDP also utilized a keyboard that allowed the operator to "talk" to it and change the programming mid-stream, if necessary. The PDP-1 was relatively small and did not require specialized air conditioning.
The PDP-1 was an 18 bit machine, developed by Benjamin Curley. The PDP-1 used Digital's own system modules, which came from the existing range of 10MC logic released in late 1959.
Some of the early PDP-1's included graphic display systems as peripherals. These were the first commercially available computer graphics terminals.
A total of 53 PDP-1's were made. As late as 1970, Digital Equipment Corporation reported that all 53 were still in operation. The last PDP-1 was reportedly built in 1969. DEC PDP-1 applications included message switching, instrument control and special purpose time-sharing.