read/write memory
[′rēd ′rīt ‚mem·rē] (computer science)
A computer storage in which data may be stored or retrieved at comparable intervals.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
RAM
(Random Access Memory) The main memory in a computer, smartphone or tablet. RAM is the temporary workspace where instructions are executed and data are processed. What makes RAM "random access" is its capability of reading and writing any single byte. This "byte addressability" differs from storage devices such as hard drives and solid state drives (SSDs) that read and write many bytes (sectors or pages) at one time. In addition, RAM is used as a temporary space for the software, while storage is permanent until deleted by the user. To learn how RAM is used, look at the memory examples in computer. Also see memory, memory module and future memory chips.RAM Is Mostly DRAM
The most common type of RAM is dynamic RAM (DRAM). When a computer data sheet states 8GB of memory or 8GB RAM, it refers to DRAM (see dynamic RAM). Higher-speed SRAM is also used as an internal staging area (see static RAM).
Memory Is Often Not RAM!
A smartphone or tablet's specification of 16, 32, 64 or 128GB of memory does not refer to RAM; rather it is the unit's flash memory capacity for storing apps and data. The amount of internal RAM in a mobile device (typically 2GB to 6GB) is published on a tech specs Web page (see storage vs. memory).
 |
| Old Fashioned RAM - 1950s |
|---|
| This magnetic drum was the memory in the IBM 650 computer in the mid-1950s. About 18 inches long, it held the equivalent of 20,000 bytes (20KB). That much RAM today would fit inside this letter "o" with plenty of room to spare. (Image courtesy of the Hagley Museum and Library.) |
 |
| Core Memory - 1960s |
|---|
| In 1967, this 30-inch-high Dataram core memory module provided a whopping 16KB for a Data General minicomputer. Women in third-world countries were hired to string the cores together using a microscope. See core storage and early memory. |
 |
| Fifty Years Later |
|---|
| Compared to the Dataram example above, two thousand times as much RAM is available in two memory modules. |
Copyright © 1981-2025 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.