From: kentd@FtCollins.NCR.com (Kent Dalton)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Top 10 reasons why ...
Date: 13 Nov 92 10:49:11 GMT
	<1992Nov7.220845.14551@klaava.Helsinki.FI> <root.02pp@rkamiga.UUCP>
	<1992Nov9.222911.18961@usl.edu>
Organization: NCR Microelectronics, Ft. Collins, CO
In-reply-to: das9674@usl.edu's message of 9 Nov 92 22:29:11 GMT

>>>>> On 9 Nov 92 22:29:11 GMT, das9674@usl.edu (Stephenson Daniel A) said:

Dan> Why is it that Amiga hires mode seem to have LOTS higher horizontal
Dan> res than vertical res?

Dan> Ex: Resolution on the order of the 'super wooper duper productivity
Dan> mode' might be something like 1200X350 or something weird like
Dan> that.

Dan> Can someone explain to me why this is so different from the
Dan> marginal horizontal res edge in PC, Ex: 640X480,
Dan> 800X600,1024X768,1280X960,1280X1024.  If it were an Amiga with
Dan> similar horzontal resolution, they might read: 640X200,
Dan> 800X300,1024X350, 1280X450,1280X550,etc.  Note, these may/may NOT
Dan> be actually figures.

This is not really the case, the Amiga gfx modes you are talking about
are all non-interlace, every non-interlace mode the Amiga has a
corresponding interlace mode with 2x the vertical resolution, which
brings the majority of them in-line with the VGA style aspect ratios.

(The main exception being SuperHires which is still much wider than it is
tall. But I believe the primary purpose of that mode is specifically for
video titling applications.)

On "modern" Amigas (3000/1200/4000 any new machines which have AGA
chips.) the flicker associated with the interlaceness of  the
mode is a non-issue since they are all capable of outputting video
signals @ 31KHz horizontal scan rates.

Here's a listing of the more common Amiga display modes available:

	  Mode                     NTSC      PAL  
          =========================================
	  Lores                    320x200  320x256 
          Lores-Interlaced         320x400  320x512 
          Hires                    640x200  640x256
          Hires-Interlaced         640x400  640x512 
          Productivity             640x480  640x480 
          Productivity-Interlaced  640x960  640x960
          "Super VGA"              800x300  Not sure 
          "SVGA Interlace"         800x600  Not sure
          A2024-10Hz               1008x800 1008x1024
          A2024-15Hz               1008x800 1008x1024
          Super-Hires              1280x200 1280x256
          Super-Hires-Interlaced   1280x400 1280x512

Any Amiga with ECS or AGA (all current models being produced) and the
2.1 revision of the OS is capable of displaying all of the modes above
(Except the A2024 modes which require a seperate monitor though.)
Additionally the OS supports overscan for more resolution and "virtual"
scrolling workbenches of arbitrary size in all display modes.

I don't see any problem with having such a wide range of aspect ratios
to pick from, its just important that Amiga advocates keep people who
don't know much about the machine but are interested in its capabilities
(such as Dan) informed of the fact that the "odd" modes aren't the only
ones available.

--
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