Burroughs and RCA announce the first mainframe computer families based on monolithic integrated circuit technology.

Large electronic data processing systems for business and scientific applications are called “mainframe” computers. In the 1960s mainframe vendors distinguished their systems in the marketplace through proprietary hardware, operating systems, and applications software. They demanded components offering unique features and significantly faster speed (1961 Milestone) than general-purpose logic solutions. (1963 Milestone) As mainframe systems offered the highest production volume business opportunities, teams of engineers at Fairchild, Motorola, Signetics, TI, and others handcrafted families of custom and special ICs for these customers.

Two of the earliest mainframe designs to use monolithic ICs were the RCA Spectra 70 series (1965) and the Burroughs B2500/3500 (1966) machines. RCA developed Current Mode Logic (CML) circuits internally and worked with IC vendors to manufacture them. Burroughs engineers cooperated with Robert Seeds at Fairchild to develop a Complementary Transistor Logic (CTL) family that also powered Hewlett-Packard’s 3000 Series. IBM produced the majority of its needs in-house while CDC, General Electric, Honeywell, NCR, SDS, and Univac contracted for custom design services.

In 1962 Jan Narud led the development of Motorola"s MECL (Motorola Emitter Coupled Logic) family, a monolithic implementation of IBM"s transistor-based very high speed logic circuits. Although offered as standard products, expensive multi-layer p.c. boards and system cooling requirements limited ECL usage largely to high-performance scientific computer applications at Control Data Corporation, Cray, GE, Hitachi, ICL, and others. In 1976 each Cray 1 machine consumed 250,000 dual F100K ECL gate packages from Fairchild that offered switching times of under 1ns per gate.