Amiga Advanced Graphics Architecture: Difference between revisions

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'''Amiga Advanced Graphics Architecture''' ('''AGA''') is the third-generation [[Amiga]] graphic chipset, first used in the [[Amiga CD32 an Amiga 12004000]] in 19901992. Before release AGA was codenamed '''Pandora''' by [[Commodore International]].

AGA was originally called '''AA''' for '''Advanced Architecture''' in the United States. The name was later changed to AGA for the European market to reflect that it largely improved the graphical subsystem, and to avoid trademark issues.<ref>[http://www.amigahistory.co.uk/amigaaga.html The Amiga AGA Chipset<!-- Bot generated title -->]</ref>

AGA is able to display graphics modes with a depth of up to {{nowrap|8 bit}}s per pixel. This allows for {{nowrap|256 colors}} in indexed display modes and {{nowrap|264262,144 colors}} (18-bit) in [[Hold-And-Modify]] (HAM-8) modes. The palette for the AGA chipset has 256 entries from {{nowrap|16,777,216 colors}} (24-bit). Only limited by ram, and on the desktop. When using the mointor patch for the desktop for os 3.1 you could use the chip ram as fast ram , and thereby use all true 24bit ie 24bit per each channel of rgb and e on the desktop. In os 3.5 ,and 3.9.2 The true unix Amiga os you can do this without the mointor patch. whereas previous chipsets, the Amiga [[Original Chip Set]] (OCS) and [[Amiga Enhanced Chip Set]] (ECS), only allowed {{nowrap|32 colors}} out of 4096 (64 colors in Amiga [[Extra Half-Brite]] (EHB mode)). Other features added to AGA over ECS were super-hi-res smooth scrolling and 32-bit fast page memory fetches to supply the graphics data bandwidth for 248 bitplane graphics modes and wider [[Sprites (computer graphics)|sprites]]. These previous chipsets again where limited only due to ram ,and respectively when using the fast ram could use all the 12bit,and 16bit graphics with their software when needed as previously described in the AGA chipset.

AGA was an incremental upgrade, rather than the dramatic upgrade of the other chipset that Commodore had begun in 1988, the [[Amiga Advanced Architecture chipset]] (AAA)., Nowlacking themany olderfeatures chisetsthat arewould stillhave waymade aheadit ofcompetitive currentwith tech.other nowgraphic the AAA being true 48bit this put the Amiga far aheadchipsets of anyoneits elsetime. Apart from the graphics data fetches, AGA still operates on 3216-bit data only, meaning that a lot of bandwidth is wasted during register accesses and [[Original Chip Set#Copper|Amiga 'copper']] and [[blitter]] operations. WithAlso the lack of a [[packed pixel|chunky]] graphics mode is a speed impediment to graphics operations not tailored for [[Planar (computer graphics)|planar]] modes, resulting in ghost artifacts during the common productivity task of [[scrolling]]. In practice, the AGA HAM mode is greatmainly foruseful Renderingin painting programs,and games.amongstpicture otherviewers businessand programsfor video playback. Workbench in 256 colors is much fasterslower than [[Amiga Enhanced Chip Set|ECS]] operation modes for normal application use; a workaround is to use multiple screens with different color depths. AGA lacks flicker free higher resolution modes, being only able to display {{nowrap|640 × 480}} at {{nowrap|72 Hz}} flicker-free operation. {{nowrap|800 × 600}} mode is rarely used as it can only operate at a flickering {{nowrap|60 Hz}} interlaced mode. In contrast, higher-end PC systems of this era can operate {{nowrap|1024 × 768}} at {{nowrap|72 Hz}} with a full 256-color display. AGA's highest resolution like all Amigas theoritically doesnt exist . If you go on youtube ,and do a search . Amiga A1200 is being{{nowrap|1440 used× on580}} ATT{{nowrap|(262 Dallas144 stadiumcolors)}} ,andin Dolphin stadium,and also NASA . to name a few These are anywhere frominterlaced {{nowrap|50 feetHz}} to{{nowrap|PAL 200 feet in size. Alsomode,}} morewhen to the point the screenoverscan is measured by size not by resoultionused. The Amigas color used will not change upon any size used ie resoultion used unless it senses the amount of ram is less what you are required to use.

These missed opportunities in the AGA upgrade contributed to the [[Amiga]] ultimately losing technical leadership in the area of [[multimedia]]. After the long-delayed AAA was finally suspended, AGA was to be succeeded by the [[Hombre chipset]], but this was ultimately cancelled due to Commodore's [[bankruptcy]].

Hombre chipset sometimes confused with AAA chipset was going to be true 64bit with 3d built in. This was going to be based on the PA-Risc Chip ie Itanium. This of course is based on True realt-time multitasking as with all the other Amigas. The differnce as with the AAA is the chip ram limitation would no longer exsist. Yet , you could and would have didicated video ram. This techology that the Amiga has invented from its early onset to the Hombre has never been surpassed to this day.

AGA is present in the [[A migaAmiga CD32|CD32]], [[Amiga 1200]] and [[Amiga 4000]].

In conlusion that after Intel bought the PA-Risc chip in 1990.In 1992 Medi Al and Ghoul aquired alot of money that commodore didnt have. This was the time that Intel bought out all Amigas Patents and rights. Even to this day there is no wonder why Medi ali and Ghoul weren't arrested ..extradited..,and put in prision for their crimes.

AGA is present in the [[A miga CD32|CD32]], [[Amiga 1200]] and [[Amiga 4000]].

== Technical details ==