资料来源 : Free On-Line Dictionary of Computing

Amiga
     
         A range of home computers first released by
        {Commodore Business Machines} in early 1985 (though they did
        not design the original - see below).  Amigas were popular for
        {games}, {video processing}, and {multimedia}.  One notable
        feature is a hardware {blitter} for speeding up graphics
        operations on whole areas of the screen.
     
        The Amiga was originally called the Lorraine, and was
        developed by a company named "Amiga" or "Amiga, Inc.", funded
        by some doctors to produce a killer game machine.  After the
        US game machine market collapsed, the Amiga company sold some
        {joysticks} but no Lorraines or any other computer.  They
        eventually floundered and looked for a buyer.
     
        Commodore at that time bought the (mostly complete) Amiga
        machine, infused some money, and pushed it through the final
        stages of development in a hurry.  Commodore released it
        sometime[?] in 1985.
     
        Most components within the machine were known by nicknames.
        The {coprocessor} commonly called the "Copper" is in fact the
        "{Video} Timing Coprocessor" and is split between two chips:
        the instruction fetch and execute units are in the "Agnus"
        chip, and the {pixel} timing circuits are in the "Denise" chip
        (A for address, D for data).
     
        "Agnus" and "Denise" were responsible for effects timed to the
        {real-time} position of the video scan, such as midscreen
        {palette} changes, {sprite multiplying}, and {resolution}
        changes.  Different versions (in order) were: "Agnus" (could
        only address 512K of {video RAM}), "Fat Agnus" (in a {PLCC}
        package, could access 1MB of video RAM), "Super Agnus"
        (slightly upgraded "Fat Agnus").  "Agnus" and "Fat Agnus" came
        in {PAL} and {NTSC} versions, "Super Agnus" came in one
        version, jumper selectable for PAL or NTSC.  "Agnus" was
        replaced by "Alice" in the A4000 and A1200, which allowed for
        more {DMA} channels and higher bus {bandwidth}.
     
        "Denise" outputs binary video data (3*4 bits) to the "Vidiot".
        The "Vidiot" is a hybrid that combines and amplifies the
        12-bit video data from "Denise" into {RGB} to the {monitor}.
     
        Other chips were "Amber" (a "flicker fixer", used in the A3000
        and Commodore display enhancer for the A2000), "Gary" ({I/O},
        addressing, G for {glue logic}), "Buster" (the {bus
        controller}, which replaced "Gary" in the A2000), "Buster II"
        (for handling the Zorro II/III cards in the A3000, which meant
        that "Gary" was back again), "Ramsey" (The {RAM} controller),
        "DMAC" (The DMA controller chip for the WD33C93 {SCSI adaptor}
        used in the A3000 and on the A2091/A2092 SCSI adaptor card for
        the A2000; and to control the {CD-ROM} in the {CDTV}), and
        "Paula" ({Peripheral}, Audio, {UART}, {interrupt} Lines, and
        {bus Arbiter}).
     
        There were several Amiga chipsets: the "Old Chipset" (OCS),
        the "Enhanced Chipset" (ECS), and {AGA}.  OCS included "Paula",
        "Gary", "Denise", and "Agnus".
     
        ECS had the same "Paula", "Gary", "Agnus" (could address 2MB
        of Chip RAM), "Super Denise" (upgraded to support "Agnus" so
        that a few new {screen modes} were available).  With the
        introduction of the {Amiga A600} "Gary" was replaced with
        "Gayle" (though the chipset was still called ECS).  "Gayle"
        provided a number of improvments but the main one was support
        for the A600's {PCMCIA} port.
     
        The AGA chipset had "Agnus" with twice the speed and a 24-bit
        palette, maximum displayable: 8 bits (256 colours), although
        the famous "{HAM}" (Hold And Modify) trick allows pictures of
        256,000 colours to be displayed.  AGA's "Paula" and "Gayle"
        were unchanged but AGA "Denise" supported AGA "Agnus"'s new
        screen modes.  Unfortunately, even AGA "Paula" did not support
        High Density {floppy disk drives}.  (The Amiga 4000, though,
        did support high density drives.)  In order to use a high
        density disk drive Amiga HD floppy drives spin at half the
        rotational speed thus halving the data rate to "Paula".
     
        Commodore Business Machines went bankrupt on 1994-04-29,
        the German company {Escom AG} bought the rights to the Amiga
        on 1995-04-21 and the Commodore Amiga became the Escom
        Amiga.  In April 1996 Escom were reported to be making the
        {Amiga} range again but they too fell on hard times and
        {Gateway 2000} (now called Gateway) bought the Amiga brand
        on 1997-05-15.
     
        Gateway licensed the Amiga operating system to a German
        hardware company called {Phase 5} on 1998-03-09.  The
        following day, Phase 5 announced the introduction of a
        four-processor {PowerPC} based Amiga {clone} called the
        "{pre\box}".  Since then, it has been announced that the
        new operating system will be a version of {QNX}.
     
        On 1998-06-25, a company called {Access Innovations Ltd}
        announced {plans (http://www.micktinker.co.uk/aaplus.html)} to
        build a new Amiga chip set, the {AA+}, based partly on the AGA
        chips but with new fully 32-bit functional core and 16-bit AGA
        {hardware register emulation} for {backward compatibility}.
        The new core promised improved memory access and video display
        DMA.
     
        By the end of 2000, Amiga development was under the control of
        a [new?] company called {Amiga, Inc.}.  As well as continuing
        development of AmigaOS (version 3.9 released in December
        2000), their "Digital Environment" is a {virtual machine} for
        multiple {platforms} conforming to the {ZICO} specification.
        As of 2000, it ran on {MIPS}, {ARM}, {PPC}, and {x86}
        processors.
     
        {Home (http://www.amiga.com/)}.
     
        {Amiga Web Directory (http://www.cucug.org/amiga.html)}.
     
        {amiCrawler (http://www.amicrawler.com/)}.
     
        Newsgroups: {news:comp.binaries.amiga},
        {news:comp.sources.amiga}, {news:comp.sys.amiga},
        {news:comp.sys.amiga.advocacy},
        {news:comp.sys.amiga.announce},
        {news:comp.sys.amiga.applications},
        {news:comp.sys.amiga.audio}, {news:comp.sys.amiga.datacomm},
        {news:comp.sys.amiga.emulations}, {news:comp.sys.amiga.games},
        {news:comp.sys.amiga.graphics},
        {news:comp.sys.amiga.hardware},
        {news:comp.sys.amiga.introduction},
        {news:comp.sys.amiga.marketplace}, {news:comp.sys.amiga.misc},
        {news:comp.sys.amiga.multimedia},
        {news:comp.sys.amiga.programmer},
        {news:comp.sys.amiga.reviews}, {news:comp.sys.amiga.tech},
        {news:comp.sys.amiga.telecomm}, {news:comp.Unix.amiga}.
     
        See {aminet}, {Amoeba}, {bomb}, {exec}, {gronk}, {guru
        meditation}, {Intuition}, {sidecar}, {slap on the side},
        {Vulcan nerve pinch}.
     
        (2003-07-05)