Re: New hardware ... new video card idea

[Rubywand <rubywand@swbell.net>]

Roy and/or Janet Miller wrote:
> 
> Rubywand wrote:
> 
> >
> > > PS What do you think of a VGA card for the gs? Complete with hdb15 jack,
> > > like is used on pc monitors?
> >
> >      The traditional snag in new IIgs video card designs has been what to do
> > about current display modes, especially super-res. Since the interface signals
> > you would like to have are not conveniently available, you end up with either a
> > complex, costly design or having to tell users to keep their standard GS
> > monitor attached.
> >
> 
> <snip>
> 
> >      Most likely, there would be no problem with any of the older display
> > formats-- in fact, the displays would probably look better; and, based upon
> > viewing tests on a composite color monitor, 320-mode super-res would almost
> > certainly be at least adequate.
> >
> >      The big question is how would 640-mode super-res turn out? If it's good
> > enough to satisfy users, the problem of dealing with current display formats in
> > new IIgs video card designs is pretty much eliminated.
 ....
> 
> IBM in 1987 came out with both the VGA and the MCGA display modes. The MCGA modes
> would work on VGA monitors. The MCGA did 320X200 with up to 256 colors (sound
> familiar?) and a 640X200 with (I think) up to 16 colors. These modes were the only
> modes built into the "Baby" PS/2, the Model 25, which couldn't display VGA -
> but it can. Bill Malcom of the AppleLinc
> club (who is doing some hardware projects of his
> own) too two old Model 25s that I gave him, and turned them into VGA 12" monitors.
> They aren't great, but they will do the basic VGA displays.
> 
> Now, here is where my ignorance leads me blightly onward. If those VGA monitors
> could do 320X200 and 640X200 with colors like the IIGS... well, it is an
> interesting thought isn't it?
 ....

     In fact, I'm pretty sure there's been something posted about using some Sony
multi-sync monitors on a IIgs with an adaptor. The main requirement is being able to
lock into the IIgs's relatively low-frequency horizontal sync.

     So, I guess, your idea is to find monitors which could display both New Card
video and IIgs RGB video. This would eliminate the need for doing a VBOX or other
conversion. You would have a switch (which could be separate or part of the new video
card) to select between 'regular IIgs RGB' and 'New Card VGA video'. 

     Kind of a nice 'cutting the Gordian Knot' approach. The main problem is that you
would probably not be able to find many  modern monitors which can handle the GS's
low H-sync frequency with any kind of decent stability. And, the trend for future
monitor modeal is likely to be to design for only higher frequencies.

     Another drawback is that monitors able to sync down to work for GS 640 x 200 RGB
probably would not handle higher resolutions, such as 1024 x 768.

     Although the VBOX conversion approach could be a little more costly, it does let
the user attach a current model SVGA monitor which can display the higher resolution
modes. So, the new video card would be able to offer the high performance video one
would want for applications like a net browser.



Rubywand