TX-0, a transistor computer with a 256 by 256 memory

Synopsis: TX-0 is a high-speed digital computer which was built at Lincoln Laboratory to demonstrate and operationally test 5-megapulse transistor circuitry and a 65,536-word magnetic-core memory. The word length is 19 bits; 1 bit is a parity check bit for memory, 16 bits are assigned to memory addressing, and the 2 remaining bits are used to select among three memory-reference instructions and one microprogramming instruction. The logic is performed by standardized packages using surface barrier transistors. Fig. 1 shows TX-0 with the arithmetic element just beyond the console and the memory on the far left. Part I of this paper covers the TX-0 memory, and Part II the TX-0 circuitry.