Read–write memory, or RWM, is a type of
computer memory
Computer memory stores information, such as data and programs, for immediate use in the computer. The term ''memory'' is often synonymous with the terms ''RAM,'' ''main memory,'' or ''primary storage.'' Archaic synonyms for main memory include ...
that can be easily written to as well as read from using electrical signaling normally associated with running a software, and without any other physical processes. The related storage type
RAM
Ram, ram, or RAM most commonly refers to:
* A male sheep
* Random-access memory, computer memory
* Ram Trucks, US, since 2009
** List of vehicles named Dodge Ram, trucks and vans
** Ram Pickup, produced by Ram Trucks
Ram, ram, or RAM may also ref ...
means something different; it refers to memory that can access any memory location in a constant amount of time.
The term might also refer to memory locations having both read and write permissions. In modern computer systems using
memory segmentation
Memory segmentation is an operating system memory management technique of dividing a computer's primary memory into segments or sections. In a computer system using segmentation, a reference to a memory location includes a value that identifies ...
, each segment has a length and set of permissions associated with it.
Types
Read–write memory is composed of either
volatile or
non-volatile
Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data.
Non-volatile memory typ ...
types of storage. Volatile memory is usually in the form of a microchip or other hardware that requires an external power source to enable data to persist. Non-volatile memory is considered static, or storage-type memory. This means that you can write data to it, and that information will persist even in the absence of a power source. Typically read-write speeds are limited to its
bandwidth
Bandwidth commonly refers to:
* Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range
* Bandwidth (computing), the rate of data transfer, bit rate or thr ...
or have mechanical limitations of either rotation speeds and arm movement delays for storage types such as
Cloud Storage
Cloud storage is a model of computer data storage in which data, said to be on "the cloud", is stored remotely in logical pools and is accessible to users over a network, typically the Internet. The physical storage spans multiple servers (so ...
,
Hard Disk Drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, pla ...
or
CD-RW
RW (Compact Disc-Rewritable) is a digital media, digital optical disc data storage device, storage format introduced by Ricoh in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written.
CD-RWs, as opposed to CDs, r ...
s,
DVD-RWs,
SD card
Secure Digital (SD) is a proprietary, non-volatile, flash memory card format developed by the SD Association (SDA). Owing to their compact size, SD cards have been widely adopted in a variety of portable consumer electronics, including dig ...
s,
Solid-State Drive
A solid-state drive (SSD) is a type of solid-state storage device that uses integrated circuits to store data persistently. It is sometimes called semiconductor storage device, solid-state device, or solid-state disk.
SSDs rely on non- ...
,
SRAM, and
DRAM
Dram, DRAM, or drams may refer to:
Technology and engineering
* Dram (unit), a unit of mass and volume, and an informal name for a small amount of liquor, especially whisky or whiskey
* Dynamic random-access memory, a type of electronic semicondu ...
, or other
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
ry.
History
San Francisco in 1956,
IBM
International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...
was the first company to develop and sell the first commercial
Hard Disk Drive (HDD). The drive was the Model 350 disk storage unit, which was 3.75 megabytes of data storage capacity and had fifty 24-inch diameter disks stacked on a spindle and sold to
Zellerbach paper.
See also
*
Read-mostly memory (RMM)
*
Random-access memory
Random-access memory (RAM; ) is a form of Computer memory, electronic computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A random-access memory device allows ...
(RAM)
References
Footnotes
Computer memory
{{compu-hardware-stub