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Amiga 音标拼音: [əm'igə] 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://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.
{(http://amiga.com/)}.
{Amiga Web Directory (http://cucug.org/amiga.html)}.
{amiCrawler (http://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)
Amiga: n A series of personal computer models originally sold by Commodore, based on 680x0 processors, custom support chips and an operating system that combined some of the best features of Macintosh and Unix with compatibility with neither. The Amiga was released just as the personal computing world standardized on IBM- PC clones. This prevented it from gaining serious market share, despite the fact that the first Amigas had a substantial technological lead on the IBM XTs of the time. Instead, it acquired a small but zealous population of enthusiastic hackers who dreamt of one day unseating the clones ( see Amiga Persecution Complex). The traits of this culture are both spoofed and illuminated in The BLAZE Humor Viewer. The strength of the Amiga platform seeded a small industry of companies building software and hardware for the platform, especially in graphics and video applications ( see video toaster). Due to spectacular mismanagement, Commodore did hardly any R& D, allowing the competition to close Amiga' s technological lead. After Commodore went bankrupt in 1994 the technology passed through several hands, none of whom did much with it. However, the Amiga is still being produced in Europe under license and has a substantial number of fans, which will probably extend the platform' s life considerably.
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