IBM System/370 Model 145

In a major departure from conventional computer technology, International Business Machines Corporation on September 23, 1970 introduced its first computer using a main memory made entirely of monolithic circuits. To store its data and instructions, the new IBM System/370 Model 145 uses silicon memory chips, rather than the magnetic core technology that has been the mainstay of computer memories for the past 15 years. More than 1,400 microscopic circuit elements are etched onto each one-eighth-inch-square chip.