What is expanded memory? - Definition from WhatIs.com
Part of the Computing fundamentals glossary:

Expanded memory, also know as EMS (Expanded Memory Specification) was a method used to increase the 640KB upper limit of MS-DOS to 1MB using a gated memory riser card.

After the advent of extended memory, programs written to use EMS would be redirected by driver emulation to use extended memory instead, which did not rely upon special hardware but just increasing RAM capacities. Extended memory can only be addressed by software running in protected mode as all but the small portion of high memory are unreadable by programs running in standard real mode.

Expanded memory is a distinct technology from the similarly named extended memory, which replaced EMS with greater capacity when it was introduced with the Intel 80286.

Fun fact: The 640KB upper limit of DOS is the alleged source of the often-quoted but steadfastly denied Bill Gates statement: “640KB ought to be enough for anyone.”

This was last updated in February 2014
Contributor(s): Matthew Haughn
Posted by: Margaret Rouse

Related Terms

Definitions

  • IS (information system or information services)

    - An information system (IS) is the collection of technical and human resources that provide the storage, computing, distribution, and communication for the information required by all or some part o... (WhatIs.com)

  • distributed

    - Computing is said to be "distributed" when the computer programming and data that computers work on are spread out over more than one computer, usually over a network.Cloud computing is a particula... (WhatIs.com)

  • greedy algorithm

    - A greedy algorithm is a mathematical process that looks for simple, easy-to-implement solutions to complex, multi-step problems by deciding which next step will provide the most obvious benefit. (WhatIs.com)

Glossaries

  • Computing fundamentals

    - Terms related to computer fundamentals, including computer hardware definitions and words and phrases about software, operating systems, peripherals and troubleshooting.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question. Find an Answer.Powered by ITKnowledgeExchange.com

Ask An IT Question

Get answers from your peers on your most technical challenges

Ask Question

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.