Computer Memory

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Computer Memory

RCA Magnetic Core Memory Ad (1964)

Early computers in the 1940's used vacuum tubes to store memory. But the memory would be lost if power was taken away, this type of memory is known as Volatile memory.

Efforts began in the late 1940s to find a way to create non-volatile memory. Jay Forrester, Jan A. Rajchman and An Wang would be credited with the development of magnetic core memory, which would allow for recall of memory after power loss. Magnetic core memory would become the dominant form of memory until the development of transistor based memory in the late 1960s.

NCR's "Rod Memory' was released in 1968 for use in it's business computers. Rod memory was similar to core memory. This type of memory would not last but a few short years, it couldn't compete with transistor technology.

By 1970, Transistor based RAM & ROM memory on Integrated Circuits became the industry standard in computer memory. This new technology offered a much smaller component size and cheaper cost than the earlier core memory. Non-volatile Read-only memory (ROM) was now able to store program code. Volatile Random-access memory (RAM) was able to store data.

A few companies, including Intel, Western Electric, Texas Instruments, Hitachi & Sharp, produced a new form of nonvolatile memory in the 1970's known as Bubble memory. Bubble memory technology used a thin film of magnetic material to hold small magnetized areas known as bubbles. Each bubble was capable of storing one bit of data. Bubble memory started out as a promising new data storage technology in the 1970's but failed commercially as hard disk prices fell rapidly in the 1980's.

Other types of non-volatile memory including erasable programmable read only memory (EPROM) in the 1970's, and electrically erasable programmable read-only memory (EEPROM or Flash ROM) in the 1980's. These types of memory can be erased and reprogrammed, but it was a slow process.

Flash memory created in the 1990's works like the earlier EPROMs, allowing non-volatile reprogrammable storage, but allows data to now be erased and reprogrammed thousands of times at very high speeds.