ERA 1101 drum memory Computers  Engineering Research Associates of Minneapolis built the ERA 1101, the first commercially produced computer; the company's first customer was the U.S. Navy. It held 1 million bits on its magnetic drum, the earliest magnetic storage devices. Drums registered information as magnetic pulses in tracks around a metal cylinder. Read/write heads both recorded and recovered the data. Drums eventually stored as many as 4,000 words and retrieved any one of them in as little as five-thousandths of a second. SEAC Computers  The National Bureau of Standards constructed the SEAC (Standards Eastern Automatic Computer) in Washington as a laboratory for testing components and systems for setting computer standards. The SEAC was the first computer to use all-diode logic, a technology more reliable than vacuum tubes, and the first stored-program computer completed in the United States. Magnetic tape in the external storage units (shown on the right of this photo) stored programming information, coded subroutines, numerical data, and output. SWAC Computers  The National Bureau of Standards completed its SWAC (Standards Western Automatic Computer) at the Institute for Numerical Analysis in Los Angeles. Rather than testing components like its companion, the SEAC, the SWAC had an objective of computing using already-developed technology. Pilot ACE Computers  Alan Turing's philosophy directed design of Britain's Pilot ACE at the National Physical Laboratory. "We are trying to build a machine to do all kinds of different things simply by programming rather than by the addition of extra apparatus," Turing said at a symposium on large-scale digital calculating machinery in 1947 in Cambridge, Mass. Start of project: 1948 Completed: 1950 Add time: 1.8 microseconds Input/output: cards Memory size: 352 32-digit words Memory type: delay lines Technology: 800 vacuum tubes Floor space: 12 square feet Project leader: J. H. Wilkinson
		© The Computer Museum History Center.   All images are digitally watermarked.