Computer memory
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Computer memory stores information, such as data and programs, for immediate use in the computer; instructions fetched by the computer, and data fetched and stored by those instructions, are located i
![DDR4 SDRAM module. As of 2021[update], over 90 percent of computer memory used in PCs and servers was of this type.](https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/RAM_Module_%28SDRAM-DDR4%29.jpg/500px-RAM_Module_%28SDRAM-DDR4%29.jpg)
DDR4 SDRAM module. As of 2021[update], over 90 percent of computer memory used in PCs and servers was of this type.
Electromechanical memory used in the IBM 602, an early punch multiplying calculator
Detail of the back of a section of ENIAC, showing vacuum tubes
Williams tube used as memory in the IAS computer c. 1951
Random-access memory
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Random-access memory is a form of electronic computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data
Example of writable volatile random-access memory: Synchronous dynamic RAM modules, primarily used as main memory in personal computers, workstations, and servers.
A 64 bit memory chip die, the SP95 Phase 2 buffer memory produced at IBM mid-1960s, versus memory core iron rings
8GB DDR3 RAM stick with a white heatsink
These IBM tabulating machines from the mid-1930s used mechanical counters to store information.