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{{DISPLAYTITLE:Apple II<span style="font-size:75%">GS</span> emulators}}
{{Infobox console
|title=Apple II<span style="font-size:75%">GS</span>|image=AppleIIGSPC.png|imagecaption=An Apple II<span style="font-size:75%">GS</span> PC.|developer=[[Apple Inc.|Apple Computer, Inc.]]|type=[[:Category:Computers|Computers]]|release=September 1986|discontinued=December 1992|predecessor = [[Apple II line|Apple II]]|emulated={{✓}}
}}
The '''[[Apple II Lineline|Apple II]]<span style="font-size:75%">GS</span> ''' is a 16-bit PC produced by Apple Computer , Inc. It was created to compete with the [[Amiga Lineline|Amiga]] and the [[Atari ST Lineline|Atari ST]] lines of PCs.
Despite the Apple II<span style="font-size:75%">GS</span> name, it is a completely different architecture. The system has a chip called the “Mega II” which is an [[Apple II Lineline|Apple //e]] on a chip, making it fully backwards compatible with Apple ][ software. It was the first machine from Apple to use the Apple Desktop Bus and the first to provide a colour version of QuickDraw since the first colour Macintosh was not available until 1987. However it does not provide a high-resolution square pixel mode.
==Emulators==
{|class="wikitable" style="text-align:center"!scope="col"|Name!scope="col"|Operating systemPlatform(s)!scope="col"|Latest version! scope="col"|<abbr title="Free/Libre and Open-Source Software">FLOSS</abbr>!scope="col"|Active!scope="col"|[[Recommended Emulators|Recommended]]|-! colspan="7"|PC / x86
|-
|[[KEGS]]|Multi-platformalign=left|{{Icon|Linux|macOS}}|0[http://kegs.sourceforge.91net/ {{KEGSVer}}]| {{✓}}|{{✗✓}}|{{✓}}
|-
|[[GSplus]]|Multi-platformalign=left|{{Icon|Windows|Linux|macOS}}|0[https://github.14com/digarok/gsplus/releases {{GSplusVer}}]|{{✓}}| {{✗}}|{{~}}
|-
|[[https://david-schmidt.github.io/gsport GSport]]|Multialign=left|{{Icon|Windows|Linux|macOS}}| [https://github.com/david-platformschmidt/gsport/releases {{GSportVer}}]|0.31{{✓}}|{{✗}}|{{~✗}}
|-
|[[MAME]]|Multi-platformalign=left|{{Icon|Windows|Linux|macOS|FreeBSD}}|[http://www.mamedev.org/release.html {{MAMEVer}}]| {{✓}}|{{✓}}|{{✗}}
|}
==Processor==
The central processor is a 65816, a backwards-compatible 16-bit update to the 6502 that was also used in the Super Nintendo. It runs natively at 2.8Mhz but will slow down to ~1Mhz when in classic Apple II emulation mode or when writing to video memory.
==Graphics Capabilities==
In addition to RGB emulations of the existing Apple II artefact composite video modes, the IIgs adds 320x200 and 640x200 RGB colour modes; the former in various combinations of 16 colours per line and the latter at 4 colours per line (including a hardware dithering mode that acts a little like 16 colours per line). Each line may use any of 16 palettes, making a total of 256 colours on screen without raster-linked palette changes.
There is also some support for 'fill mode', in which colour 0 means "repeat the last non-zero colour", designed to aid in fast single-colour fills.
Colours are selected from a 12-bit RGB 4,096 colour palette; the IIGS therefore has the same total colour range as its contemporaries the Commodore Amiga, the Atari STE and the Acorn Archimedes.
However it is subject to a number of deficiencies: there is a single buffer for video only — double buffering is not supported — and it supports neither hardware scrolling nor hardware sprites; and as all writes into video memory clock the CPU down to 1Mhz these are expensive to perform in software.
==Audio Capabilities==
The IIGS provides a 32-channel wavetable Ensoniq sound chip, which uses 64kb for samples.
The OS by default configures this as 15 stereo channels and uses the remaining two channels as interrupt counters; the IIGS is therefore often described as a 15-channel machine.
{{Apple}}
[[Category:Computers]]
