© 1997-2006
Gareth Knight
All Rights reserved
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What is a chipset?
A chipset is a number of custom chips that control certain parts of
the computer, such as the graphics or sound, meaning the processor
doesn't have to do the job and can get on with doing something
else. The Amiga has always had some kind of chipset since the A1000
in 1985, whilst the PC has only just caught on with the MMX
graphics chip.
What chipsets has the Amiga used?
The Amiga has used 3 main chipsets which were redesigned a number
of times to gain specific speed increases.
1985
The first chipset in the A1000 and A500 was called OCS (Original
ChipSet). It was made up Paula, Agnus and Denise. These allowed
graphics to be displayed in different resolutions up to 640x512,
and up to 4096 colours in HAM mode, as well as 4 channel stereo
sound.
1989
The OCS chipset was upgraded slightly to become ECS (Enhanced
ChipSet). The Agnus and Denise chips were upgraded, renaming it Fat
Agnus. These allowed higher resolutions to be displayed.
1992
The latest custom chipset is called the AA chipset (Advanced
Amiga). In many countries, particularly Europe and the UK it has
become known as AGA (Advanced Graphics Architecture) to avoid
conflict with a popular breakdown service, also known as the AA.
The Agnus chip was replaced by Alice (who the flip is Alice?), and
Lisa replaced Denise. This allowed resolutions of 1280x512 in VGA
and a palette of 16.8 million colours, of which 256,000 can be
displayed at the same time in HAM8 mode.
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Latest updates to the Amiga History Guide. (more)
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Other interesting items in the archive!
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