From: bcoleman@hayes.com (Bill Coleman)
Newsgroups: comp.sys.mac.advocacy
Subject: Re: Multiple Video (was: Re: 7.1 vs. OS/2 and Windows NT)
Date: 13 Oct 92 14:37:00 EDT
Organization: Hayes Microcomputer Products, Norcross, GA

In article <TOMSTER.92Oct12212307@bigwpi.WPI.EDU>, tomster@bigwpi.WPI.EDU (Thomas Richard Dibble) writes:
> In article <6173.2ad5a923@hayes.com> bcoleman@hayes.com (Bill Coleman) writes:
> 
>    I have yet to see a PC with a two-page display. Squeezing 1240 by 1024 on a
>    16" monitor doesn't cut it.
> 
> Well, actually, I *have* seen a few PC's with two *seperate* displays, if that
> is what you're talking about.  Does two-page refer to the monitor being
> Radius-like (tall), or using one monitor to squeeze in two monitors of info
> or what?

Well, I think this proves that such a beast doesn't exist for the PC, since you
obviously don't know what one is.

A two-page display is one that is large enough to show two full pages of
text. The Radius display shows one page. If you use like a 21" screen and
small (75 dpi) pixels, you have enough space to show two pages at a nominal
72 ppi. (I may have one of the dimensions wrong, but we're talking 10 1/2"
tall, and 17" wide -- and at 72 dpi, that's about 756 by 1224 minimum)

> 
>    Further, it isn't cost effective to have one giant monitor. I think the best
>    combination for programming is a 13" 24-bit color monitor (for all those
>    color applications), and a b/w full page display (for all that code and
>    debugging windows). 
> 
> Very true.  However, this is the *only* setup which works well in DOS.  (Not
> sure about 24-bit, though)

Except DOS doesn't have anything close. You can't get a full page display
for DOS. DOS is 24 (or 25) by 80. 25 lines is barely a third of a page.

>    You can probably buy such a setup for around $1500, maybe less. However,
>    to buy the equivalent space in form of a 2-page, 24-bit color monitor would
>    set you back about $4000. Ouch.
> 
> Well, assumming you already had the color monitor, a good b&w monitor is
> $80-90, and a cheap video card (the one you piggy-back to your delux one)
> will run you up to $65.  

An ordinary 13" color monitor won't cut it. It isn't big enough. You've gotta
have room for two pages on the screen. An ordinary 13" monitor barely has
the space to show half a page.

> Total add-on to upgrade from whatever you have
> to a two-monitor syustem in DOS is ~$150, all figures being somewhat rounded.

Except you added on the wrong thing.

> To trade in your current monitor and get a bigger one ... no figures, but
> a vague grasp of monitor prices says that even without the double-paging
> doohicky it will cost you much more.

Which is exactly why I said multiple monitors are more cost effective.

>    > Anyway, here are possible setups:
>    > Monitor one    Monitor two
>    > XGA            XGA
> 
>    (I don't think this will work)
> 
>    > 8514           VGA
> 
>    I've seen this. The VGA repeats the 8514 display in character mode. (Hence,
>    it is just a duplicate of the same monitor) In graphics mode, the 8514
>    dominates. You can't run both in graphics mode with Windows or OS/2. Sorry,
>    it isn't the same thing.
> 
>    > VGA            EGA (or maybe MDA, monochrome text)
> 
>    I've seen this, too. EGA won't work. You have to use an MDA. That's a
>    character interface only. Again, it isn't the same thing as multiple
>    monitors on the Mac.
> 
> Hmm...  Seems to me that the doc file in 'MahJonng' says that the second
> display is used to show graphically how many tiles are left.  I may be wrong,
> seeing as how its been months since I read that.  

I think you are. The problem is that VGA and EGA cards use the same memory
addresses to the processor. There's no solution to that addressing
conflict.

>    > Of course, I've never done any of this, but I've heard it done.  
> 
>    Well, I've seen the first two. I haven't heard of using two XGAs, and I
>    feel that you'd probably run into an address conflict. So I doubt it
>    would work. 
> 
>    > I think that neither OS/2 nor Windows has the ability to virtualize
>    > monitor 2 as part of monitor 1, producing one big monitor (a la mac). 
> 
>    And that is exactly the problem.
> 
> The thing I don't get is *why* the limitation is still there.  Especcially
> with the newfound popularity of Windows.  

Because it is a hardware problem. All graphics adapters use the same address
for the video refresh RAM. On the Mac, each card slot has its own unique
address space, so this problem can be easily resolved.

Now, it is possible to resolve this on an MCA machine, but it doesn't work
that way. 

Face it. PCs don't work this way. They just don't.

> I would expect to see this void filled
> in the next few years within the pc industry as a whole, either by the
> Intel-baseds learning how to map across monitors or by others taking their
> place in the market.  To tell the truth, I had hoped for it with at least
> *one* of the new os's coming out, but it seems even the mac-clone / catch-
> all NT has missed this boat ...  oh, well.

It won't happen. It is a hardware deficiency in the PC architecture. It can't
change unless the existing hardware base is abandoned. Because of the huge
inertia (note the term) of the PC market, this isn't likely to happen.

-- 
Bill Coleman, AA4LR                ! CIS: 76067,2327    AppleLink: D1958
Principal Software Engineer        ! Packet Radio: AA4LR @ W4QO
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Disclaimer: "My employer doesn't pay me to have opinions."
Quote: "The same light shines on vineyards that makes deserts." -Steve Hackett.

Newsgroups: comp.sys.mac.advocacy