The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo, was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic-core memory. Construction of the TX-0 began in 1955 and ended in 1956. It was used continually through the 1960s at MIT. The TX-0 incorporated around 3,600 Philco high-frequency surface-barrier transistors, the first transistor suitable for high-speed computers. The TX-0 and its direct descendant, the original PDP-1, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture. For MIT, this was the first computer to provide a system console which allowed for direct interaction, as opposed to previous computers, which required the use of punched card as a primary interface for programmers debugging their programs. Members of MIT's Tech Model Railroad Club, "the very first hackers at MIT", reveled in the interactivity afforded by the console, and were recruited by Marvin Minsky to work on this and other systems used by Minsky's AI group.

The surface-barrier transistor is a type of transistor developed by Philco in 1953 as an improvement to the alloy-junction transistor and the earlier point-contact transistor. Like the modern Schottky transistor, it offered much higher speed than earlier transistors and used metal–semiconductor junctions, but unlike the schottky transistor, both junctions were metal–semiconductor junctions.