Invention of RANDOM ACCESS MEMORY (RAM) (1968)

Dennard combines a transistor with a capacitor in a revolutionary memory cell.  RAM, a random Access Memory, the short-term, high-speed ‘working’ memory of a computer, has existed since the invention of magnetic core memory in 1949.  Modern RAM, though, owes its invention to Texan Robert Dennard (b. 1932).

In 1966, Dennard was working at IBM’s Thomas Watson Research Centre.  IBM knew that magnetic core memory was too blocky, power-hungry and slow, and that transistors would be the answer to replacing it.  They had reduced the problem of storing a single bit of memory to a cell that used to only six transistors.  Added to a silicon chip, this cell was already tine compared to a magnetic core.  Dennard, though simplified the memory cell even more to a single transistor and a capacitor, a component that can hold an electric charge.  The memory was used to read and write it.  Capacitors “leak” charge through so the memory had to be continuously refreshed, many times a second.  Because of this constant forgetting and refreshing, Dennard’s system is called “Dynamic” RAM or DRAM.

Despite its need to be refreshed, DRAM had a world-beating advantage.  With only two components, which could be placed side in the thousands on a single silicon chip, it was the smallest memory ever made.  The computer industry quickly took advantage of Dennard’s invention and fledging company Intel relased the first commercial DRAM chip in 1970.  Magnetic Core memory became the technology of yesteryear almost as soon as Intel began to ship its new chip.