# Extended memory

> Section of computer memory in PC compatibles

**Wikidata**: [Q1143380](https://www.wikidata.org/wiki/Q1143380)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Extended_memory)  
**Source**: https://4ort.xyz/entity/extended-memory

## Summary
Extended memory is a convention that defines a section of memory in PC-compatible computers beyond the first megabyte, enabling use of additional physical RAM. It is commonly referenced by the alias XMS and adheres to standardized specifications for accessing memory beyond conventional limits.

## Key Facts
- Extended memory is an instance of a convention (instance_of: convention).
- It is a subclass of computer memory (subclass_of: computer memory).
- Aliases include EXtended Memory Specification, Memoire etendue, Erweiterter Speicher, XMS, and 扩展内存.
- Its freebase ID is /m/026bpv (referenced in Wikidata).
- It has a Microsoft Academic ID of 171675096 (discontinued).
- It is distinct from the entity with Wikidata ID Q120767163.
- It has 18 sitelinks across Wikipedia editions.
- Available in 10 Wikipedia languages: az, ca, cs, de, en, es, fr, it, ja, kk.

## FAQs
### Q: What is Extended memory used for?
A: Extended memory is used to access physical RAM beyond the first megabyte in PC-compatible computers, enabling larger applications and data processing beyond conventional memory limits.

### Q: What does XMS stand for?
A: XMS stands for EXtended Memory Specification, which is the formal designation for the extended memory convention.

### Q: How does Extended memory differ from conventional memory?
A: Extended memory operates beyond the first 640KB addressable in conventional memory, utilizing a standardized convention to access additional RAM in PC-compatible systems.

## Why It Matters
Extended memory revolutionized personal computing by overcoming the 640KB conventional memory barrier in early PCs. This convention provided a standardized method to utilize additional RAM, enabling more complex software, larger datasets, and multitasking capabilities. Without it, the evolution of modern operating systems and applications would have been severely constrained by hardware limitations, fundamentally shaping PC architecture and software development. Its adoption as XMS became a cornerstone of MS-DOS and early Windows memory management.

## Notable For
- Defining the first standardized approach to accessing RAM beyond the first megabyte in PC compatibles.
- Establishing the widely recognized XMS alias that became synonymous with extended memory.
- Being implemented as a critical memory management convention in MS-DOS and early Windows systems.
- Having representation across 10 language editions of Wikipedia, indicating its global technical significance.
- Maintaining a distinct identity from related memory entities, such as the one identified by Q120767163.

## Body
### Definition
Extended memory refers to a specific section of computer memory in PC-compatible systems, managed through a standardized convention. It addresses the physical RAM located beyond the first 640KB boundary that was historically inaccessible due to architectural constraints.

### Naming and Aliases
- Officially known as Extended Memory Specification (XMS).
- International aliases include Memoire etendue (French), Erweiterter Speicher (German), and 扩展内存 (Chinese).
- Widely recognized by the abbreviation XMS in technical documentation.

### Technical Classification
- Instance of: Convention (specifying memory access rules).
- Subclass of: Computer memory (broader category for physical storage devices).
- Distinct from entity Q120767163 (related but separate memory concept).

### Identification and References
- Freebase ID: /m/026bpv (referenced in Wikidata).
- Microsoft Academic ID: 171675096 (discontinued ID from Microsoft's academic database).
- Wikipedia title: "Extended memory".
- Featured in 18 Wikipedia sitelinks across languages like German (de), Japanese (ja), and Spanish (es).

### Role in PC Architecture
- Provides standardized protocols for accessing RAM beyond conventional memory limits.
- Critical for enabling applications requiring more than 640KB of memory, such as graphics processing and database management.
- Forms the basis for memory managers in early PC operating systems like MS-DOS and Windows 3.x.

## References

1. Freebase Data Dumps. 2013
2. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)