Read–write memory, or RWM is a type of
computer memory
In computing, memory is a device or system that is used to store information for immediate use in a computer or related computer hardware and digital electronic devices. The term ''memory'' is often synonymous with the term ''primary storage ...
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 may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
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 division of 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 identifie ...
, 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 typic ...
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 the digital data is stored in logical pools, said to be on "the cloud". The physical storage spans multiple servers (sometimes in multiple locations), and the physical environment is t ...
,
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 platters coated with magnet ...
or
CD-RW
CD-RW (Compact Disc-Rewritable) is a digital media, digital optical disc data storage device, storage format introduced in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written.
CD-RWs, as opposed to CDs, require ...
s,
DVD-RWs,
SD card
Secure Digital, officially abbreviated as SD, is a proprietary non-volatile flash memory card format developed by the SD Association (SDA) for use in portable devices.
The standard was introduced in August 1999 by joint efforts between SanDis ...
s,
Solid State Drive
A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data Persistence (computer science), persistently, typically using flash memory, and functioning as secondary storage in the Computer ...
,
SRAM, and
DRAM
Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...
, or other
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
ry.
History
San Francisco in 1956,
IBM 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 Read-mostly memory (RMM) is a type of memory that can be read fast, but written to only slowly.
Historically, the term was used to refer to different types of memory over time:
In 1970, it was used by Intel and Energy Conversion Devices to refer ...
(RMM)
*
Random-access memory
Random-access memory (RAM; ) is a form of 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, random-access memory device allows data items to b ...
(RAM)
References
Footnotes
Computer memory
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