# random-access memory

> form of computer data storage

**Wikidata**: [Q5295](https://www.wikidata.org/wiki/Q5295)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Random-access_memory)  
**Source**: https://4ort.xyz/entity/random-access-memory

## Summary
Random-access memory (RAM) is a form of computer data storage that serves as the primary memory for a digital device, holding information for immediate use. As a type of volatile memory, it requires constant electrical power to maintain the data it stores; if power is lost, the information is erased. RAM allows stored data to be accessed directly in any random order, making it significantly faster than storage media that reads data sequentially.

## Key Facts
- **Common Acronym:** Commonly known by the acronym RAM.
- **Classification:** RAM is a type of computer hardware and is classified as volatile storage.
- **Core Function:** It is used to store information for immediate use in a digital electronic device.
- **Primary Types:** The two main types are dynamic random-access memory (DRAM), which stores data in capacitors, and static random-access memory (SRAM), which uses flip-flops.
- **Volatility:** Most RAM is volatile, meaning it needs constant power to prevent data from being erased. Non-volatile RAM (NVRAM) is a separate class that retains information when power is off.
- **Historical Form:** Magnetic-core memory was the predominant form of random-access computer memory for approximately 20 years, from 1955 to 1975.
- **Notable Manufacturers:** Major manufacturers include Micron Technology, Samsung Electronics, Kingston Technology, and Corsair Gaming.

## FAQs
### Q: What is the difference between RAM and other computer storage?
A: RAM is a form of volatile memory used for immediate data access, meaning it loses its contents when the power is turned off. This differs from non-volatile storage like hard drives or read-only memory (ROM), which retain data without power and are used for long-term storage.

### Q: Is RAM volatile or non-volatile?
A: Standard RAM is volatile, which means it requires a constant power supply to maintain the information stored in it. There is a separate class called non-volatile random-access memory (NVRAM) that retains its data when power is turned off, but this is distinct from conventional DRAM and SRAM.

### Q: What are the main types of RAM?
A: The two fundamental types are static random-access memory (SRAM) and dynamic random-access memory (DRAM). Modern computers primarily use types of DRAM, including generations like DDR, DDR2, DDR3, DDR4, and DDR5 SDRAM, as well as LPDDR for mobile devices.

## Why It Matters
Random-access memory is a critical component in modern computing, acting as the high-speed "working memory" for a computer's central processing unit (CPU). Its significance lies in its ability to read and write data at extremely high speeds and in any order (randomly), which is essential for running operating systems, applications, and processing data in real-time. Without RAM, a computer would have to rely on much slower long-term storage devices, like hard drives, for every calculation, making modern multitasking and high-performance computing impossible. The amount and speed of RAM in a device directly impact its overall performance, determining how many applications can run simultaneously and how quickly they can operate. It solves the problem of the speed gap between the ultra-fast processor and slower permanent storage, enabling the seamless and responsive user experience we expect from today's digital devices.

## Notable For
- **Random Access:** Unlike sequential storage media, any piece of data in RAM can be accessed directly and quickly, regardless of its physical location in the memory. This property is fundamental to its high performance.
- **Volatility:** The volatile nature of most RAM, requiring constant power to hold data, distinguishes it from non-volatile storage like SSDs, hard drives, and read-only memory (ROM).
- **Role as Primary Memory:** RAM functions as the main or primary memory of a computer system, holding the operating system, active programs, and current data for rapid access by the processor.
- **Evolution of Standards:** RAM technology has evolved through numerous distinct standards, most notably the generations of Synchronous Dynamic RAM (SDR SDRAM) and Double Data Rate SDRAM (DDR, DDR2, DDR3, DDR4, DDR5), each offering significant performance increases.

## Body
### ### Classification and Characteristics
Random-access memory is a physical component of a computer, classified as **computer hardware** and **volatile storage**. Its primary use is as **computer memory**, a device that stores information for immediate use. The defining characteristic of most RAM is its volatility; it requires a constant supply of power to maintain the stored information. If the power is interrupted, the data is lost. This is in contrast to **non-volatile random-access memory**, a separate class that retains its information when power is turned off.

### ### Major Types of RAM
The source material identifies several key types and standards of RAM:
- **Static Random-Access Memory (SRAM):** A type of semiconductor memory that uses flip-flops to store each bit of data.
- **Dynamic Random-Access Memory (DRAM):** Stores each bit of data in a separate capacitor within an integrated circuit. It is the basis for most modern system memory.
- **Synchronous Dynamic RAM (SDRAM):**
    - **SDR SDRAM:** The first generation of synchronous dynamic RAM.
    - **DDR SDRAM:** The first generation of double-data-rate SDRAM.
    - **DDR2 SDRAM:** The second generation.
    - **DDR3 SDRAM:** The third generation.
    - **DDR4 SDRAM:** The fourth generation.
    - **DDR5 SDRAM:** The fifth generation.
- **LPDDR:** A series of memory standards designed for laptops and mobile devices.
- **RDRAM:** A type of synchronous dynamic RAM developed by Rambus.

### ### Specialized and Historical Forms
- **Magnetic-Core Memory:** Was the predominant form of RAM for 20 years, between approximately 1955 and 1975.
- **Video Memory (VRAM):** A type of computer memory specifically used to store image data for a computer display.
- **Tag RAM:** A special memory module on a computer's motherboard.
- **NVDIMM:** A type of non-volatile random-access memory for computers.
- **Soviet Integrated Circuits:** Several series of integrated circuits produced in the Soviet Union were specifically for RAM, including:
    - **185 series:** RAM circuits.
    - **188 series:** The first Soviet series of CMOS RAM ICs.
    - **307 series:** PZT (segnetoelectric) RAM circuit.
    - **505 series:** Contained both ROM and RAM integrated circuits (inception 1970).
    - **565 series:** RAM integrated circuits (inception 1970).

### ### Manufacturers
The source material lists several companies as manufacturers of random-access memory:
- Corsair Gaming
- Kingston Technology
- Micron Technology
- Mushkin
- Samsung Electronics

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## References

1. Integrated Authority File
2. [Source](https://computerhope.com/jargon/r/ram.htm#:~:text=Alternatively%20referred%20to%20as%20main,and%20retrieved%20on%20a%20computer.&text=Because%20information%20is%20accessed%20randomly,access%20times%20are%20much%20faster.)
3. BabelNet
4. Quora
5. National Library of Israel
6. KBpedia
7. GF WordNet
8. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)