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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

1711.0. "Amiga 2000 new chip set bad rumor" by LEMAN::BLANC (Phil Lausanne-CH DSC 22-SEP-1988 10:03) Thu Sep 22 1988 08:08

T.RTitleUserPersonal
Name
DateLines
1711.1False RumorTLE::RMEYERSRandy MeyersThu Sep 22 1988 19:3326
Re: .0

I haven't heard that rumor, and considering that various other aspects
of the chip set have been discussed openly, I believe the rumor to be
false.

The new chip set is supposed to support all existing graphics modes.
However, in the new non-interlaced 400 line graphics mode, the color
palette is reduced from 4096 to some small number that escapes me at
the moment.

This aspect surprises almost everybody (it surprised me!).  The reason
is that memory bandwidth is the deciding factor in limiting graphics
modes.  The number of colors that can be used from the palette is
decided by the number of bit planes you can use, and the number of
bit planes you can use is decided by how much memory the system can
access quickly enough to paint the display tube.

So, no one was surprised when it was announced that the new display modes
would allow you to have a maximum of four colors, but was very surprised
about the new modes having a smaller palette.  It tuns out that inside
the video chip the color registers can not run fast enough to deliver
12 bits of RGB information.  So, the registers are used in a truncated
form and the palette is thus reduced.

None of this affects the already existing graphics modes.
1711.2BAGELS::BRANNONDave BrannonThu Sep 22 1988 21:5916
    re:.1
    
    the palette size you couldn't remember is 64 colors.
    
    Seemed real strange to me too, almost like beating a dead horse
    to see if there is anything else you can squeeze out of it (sorry,
    it's been an interesting day).
    
    CBM needs to support add-on graphics cards for higher resolutions.
    640x400 non-interlace is nice, but the world is passing that by
    in favor of 640x480 and greater.
    
    I've already heard comments like "it only does CGA resolution 
    non-interlaced? (320x200, 640x200)"
    
    -dave
1711.3And I have oneTLE::RMEYERSRandy MeyersThu Sep 22 1988 22:158
Re: .2

>    CBM needs to support add-on graphics cards for higher resolutions.
>    640x400 non-interlace is nice, but the world is passing that by
>    in favor of 640x480 and greater.


They do: it's called a flickerFixer and supports 720 by 470 non-interlaced.
1711.4not quite what I had in mindBAGELS::BRANNONDave BrannonThu Sep 22 1988 23:1017
    re:.3
    
    470 isn't 480.  Flickerfixer is just giving you a non-flickering
    400 line mode with overscan.  Not the same thing.  Imagine starting
    with 640x480 and then adding overscan.  The 640x480 gives you that
    1:1 aspect ratio that desktop publishing likes so much.
    
    Flickerfixer does provide the full palette in that mode, unlike
    the future CBM chips.
    
    I'm hoping that somebody, who knows maybe the Flickerfixer folks,
    will figure out some way to interface a VGA card or chipset to the 
    Amiga 2000 (NOT thru the bridgeboard) without disabling the Amiga
    chip set.  Somehow treat it as an additional graphics cooprocessor.
    
    -Dave
    
1711.5VGA doesn't make that much differenceTLE::RMEYERSRandy MeyersFri Sep 23 1988 19:4437
Re: .4

>Flickerfixer is just giving you a non-flickering 400 line mode with
>overscan.  Not the same thing.

Yep, with overscan, its a 470 line mode.  It still displays as much
text as a VGA card minus one line.  Not a big deal.  If you are
complaining about the interlace motion artifact, I concede that
problem.

>The 640x480 gives you that 1:1 aspect ratio that desktop publishing
>likes so much.

Actually, all of the VGA and multi-sync monitors have looked at have
height and width controls that easily produce a 1:1 ratio even though
your are missing 10 scan lines.

When I was looking for a monitor for my flixerFixer, I carried my
2000 into a clone shop near my house to try the multi-sync monitor
they sell.  I was trying a lot of different display modes and programs,
a some of the store staff and a customer wandered over to see what
I was doing.  They were unimpressed with low res and medium res
screens, but the ray traced picture Glass blew them away, and their
response to a high-res de-interlaced display was, "Wow, that's fine
resolution.  So it does have a 640 by 480 display mode."

>I'm hoping that somebody, who knows maybe the Flickerfixer folks,
>will figure out some way to interface a VGA card or chipset to the 
>Amiga 2000 (NOT thru the bridgeboard) without disabling the Amiga
>chip set.

I've seen frame buffers for the Amiga designed to increase the number
of colors, but I think that it isn't being produced because of high
ram prices.

Really, though, I hope that they come out with an Amiga 3000 that
uses video ram for chip ram, and move video output to a plug-in card.
1711.6LEDS::ACCIARDIFri Sep 23 1988 20:1816
    
    Randy is correct regarding aspect ratio adjustment on multisync
    monitors.
    
    If I want to view a perfect circle in a CAD program, I just adjust
    the height until the circle looks round.  Printing or plotting a
    round circle isn't a problem, since a bitmap isn't even used in
    object oriented programs.
    
    Since I now use an interlaced display exclusively, I usually elongate
    the display vertically to that an 8 piont font doesn't look quite
    as 'squashed'.
    
    I do agree with Dave that 640 x 480 would have made more sense,
    but what the hell, I'm not going to fuss.