(Random Access Memory) A type of computer memory that provides direct access to any single location (any byte). RAM chips are "byte addressable." The contents of any byte can be read or written without regard to the bytes before or after it. The term generally refers to main memory, which is the computer's workspace, and the most common type of RAM is the DRAM chip (see dynamic RAM and memory module). To learn more about how memory works, see computer and memory.|
RAM read and write speeds are generally the same, taking no longer to write a byte than it does to read one. In contrast, writing to flash memory takes longer than reading (see flash memory). Also in contrast, hard disk drives are not byte addressable. The smallest unit of data that can be read or written to a hard disk is typically 512 bytes (see magnetic disk). See future memory chips, memory types and static RAM.
Hardly a chip, this magnetic drum was the memory in the IBM 650 computer in the mid-1950s. About a foot and a half long, it held 20,000 digits. That much memory today would easily fit within this letter "o," with room to spare. See also