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Expanded memory
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<p>In <a href="/facts/DOS_memory_management/EYvgYWs9">DOS memory management</a>, expanded memory is a system of <a href="/facts/Bank_switching/9y09qE2k">bank switching</a> that provided additional memory to <a href="/facts/DOS/sWwDXNmX">DOS</a> programs beyond the limit of <a href="/facts/Conventional_memory/hLcfWzlB">conventional memory</a> (640 KiB). </p><p><i>Expanded memory</i> is an umbrella term for several incompatible technology variants. The most widely used variant was the Expanded Memory Specification (EMS), which was developed jointly by <a href="/facts/Lotus_Software/8k8vj9x2">Lotus Software</a>, <a href="/facts/Intel/SMF0gJJX">Intel</a>, and <a href="/facts/Microsoft/nGIDDXdx">Microsoft</a>, so that this specification was sometimes referred to as "LIM EMS". LIM EMS had three versions: 3.0, 3.2, and 4.0. The first widely implemented version was EMS 3.2, which supported up to 8 MiB of expanded memory and uses parts of the address space normally dedicated to communication with peripherals (<a href="/facts/Upper_memory/CLE38IvM">upper memory</a>) to map portions of the expanded memory. EEMS, an expanded-memory management standard competing with LIM EMS 3.x, was developed by <a href="/facts/AST_Research/0zTdsr8b">AST Research</a>, <a href="/facts/Quadram/SK511oHv">Quadram</a> and <a href="/facts/Ashton-Tate/xFaCIAFC">Ashton-Tate</a> ("AQA"); it could map any area of the lower 1 MiB. EEMS ultimately was incorporated in LIM EMS 4.0, which supported up to 32 MiB of expanded memory and provided some support for DOS multitasking as well. IBM, however, created its own expanded-memory standard called XMA. </p><p>The use of expanded memory became common with games and business programs such as <a href="/facts/Lotus_1-2-3/tnkvSG3M">Lotus 1-2-3</a> in the late 1980s through the mid-1990s, but its use declined as users switched from DOS to <a href="/facts/Protected-mode/y5u3Gwqq">protected-mode</a> operating systems such as <a href="/facts/Linux/9FvCKSTq">Linux</a>, <a href="/facts/IBM_OS/2/uVBl6ItP">IBM OS/2</a>, and <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a>. </p>