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Started by Info-Graphics moderator Andy Cro...
Sun, 10 May 1987 10:00
Info-Graphics Digest
Author: Info-Graphics moderator Andy Cro...
Date: Sun, 10 May 1987 10:00
Date: Sun, 10 May 1987 10:00
362 lines
16336 bytes
16336 bytes
Info-Graphics Digest Sun May 10 03:00:26 PDT 1987
- Send submissions to Info-Graphics@ADS.ARPA
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Today's Topics:
Re: Distributed Computation for Computer Animation
Looking for PHIGS and GKS-3D standards
Distributed animation summary
IBM Graphics Cards and Monitors
Addition
----------------------------------------------------------------------
Tue, 5 May 87 10:30:45 +0100
Date: Tue, 5 May 87 10:22:42 -0100
From: unido!gmdzi!hops@seismo.CSS.GOV (Peter Seuffert)
Subject: Re: Distributed Computation for Computer Animation
peterson@cs.utah.edu (John W Peterson):
>
>
> I'd like to thank all the people who responded to my "Distributed
> computation for computer animation" survey. I received several
> interesting responses. Since the summary of these responses was
> rather long, I've mailed it directly to the people who requested a
> summary rather than post it. If you'd like a copy, send me e-mail and
> I'll send one off.
>
> Cheers,
> John Peterson
>
> peterson@cs.utah.edu
> {ihnp4,decvax,seismo}!utah-cs!peterson
>
Interested. Please send me a summary.
Greetings,
Peter "hops" Seuffert
------------------------------
Date: Wed, 6 May 87 12:08:23 edt
From: ho@rti.rti.org (Don Rich)
Subject: Looking for PHIGS and GKS-3D standards
Does anyone know where I can get copies of the (proposed?) standards
for PHIGS and GKS-3D ? Or, if standardized, what the magic ANSI or NBS
numbers for them are? Thanks,
ho@rti.rti.org
---
Don Rich, Research Triangle Institute, Box 12194, Res. Tri. Park, NC 27709
------------------------------
Date: Thu, 7 May 87 11:03:19 EST
From: munnari!goanna.oz!gl@seismo.CSS.GOV (Leachie)
Subject: Distributed animation summary
Could you please send me a copy of the summary?
Ta
Geoff Leach
Department of Computing
RMIT
Melbourne, Australia
------------------------------
Date: Wed, 6 May 87 17:05 EST
From: INTORCIO%ecs.umass.edu@RELAY.CS.NET
Subject: IBM Graphics Cards and Monitors
X-Vms-To: CSNET%"Info-Graphics@ADS.ARPA"
>I have just started looking at all these graphics cards for PC's (we have
>zeniths with IBM cards here at Queens) and am frankly getting quite confused
>about all the different standards (CGA, EGA, HERC, ...the new IBM standard)
>as well as what screen works with what (monochrome, high-res, ttl...)
>
>I have some vendor documentation but it's difficult to see the forest for the
>trees. Is there any article or reference out there that gives a clear,
>simple overview of the whole subject of graphics cards/standards/monitors?
In response, I offer a bulletin that I prepared for an MS-DOS bulletin
board that I am associated with. It's somewhat dated in that it was
written before the PS/2 line came out and, as such, contains no onformation
on the new displays and adapters. It may, however, prove a worthwhile
introduction:
= W H A T A R E M D A, C G A, E G A, A N D H E R C D I S P L A Y S ? =
Although the technical details are beyond the scope of this bulletin,
it may serve to clarify the some of the differences between the various
types of display adapters available for he IBM PC and its compatibles.
There are other display adapters available and this does not claim to
be an exhaustive survey but rather an introduction.
Monochrome Display Adapter (MDA)
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
This adapter provides only monochrome text on a monochrome monitor.
It will will not work properly with a color monitor. This adapter
is not capable of displaying any "bit mapped" graphics whatsoever.
It is important to realize that the ASCII line characters such as B
and G are not true graphics but are merely characters that may be
put together to resemble graphics. In fact, such displays are
often referred to as "character graphics". So, even on a
monochrome display adapter which cannot display graphics, graphs
such as the following are possible:
Sales of Personal Computers
4
3 ZDDD?
4 3 3
3 3 3
4 3 3
3 3 3 ZDDD?
4 3 3 3 3
3 3 3 3 3
@DDDDDDDADDDADDDDDDADDDADDDDDD
IBM Other
(If the above looks like garbage, chances are you're not working on
an IBM compatible machine. My apologies for the mess. Try to
imagine that as a nice little graph.)
Again, this is not a true graphic. The MDA can display only the 256
characters which make up the IBM standard character set.
The MDA will work only with a monochrome monitor. Further, the
monochrome monitor most accept TTL (Transistor-Transistor Logic)
input. The MDA is connected to the monitor with a cable (usually
attached to the monitor) equipped with a DB-7 plug.
The MDA will function only with software that does not require a
graphics display. A database or wordprocessing program for example
would likely function just fine with an MDA. A graphics oriented
program such as the AutoCAD drafting system would not function with
an MDA.
Hercules Graphics Card (HGC)
DDDDDDDDDDDDDDDDDDDDDDDDDDDD
The Hercules Co. was the first to introduce a display adapter
which could produce bit mapped graphics on a monochrome monitor.
They made a fortune. HGC now refers to cards from a number of
manufacturers which implement the Hercules graphics standard.
In addition to being able to do all that the MDA does, this card
can display bit mapped graphics with a resolution of 720 x 348.
To understand what that means, just look real close at you screen.
You'll see that each character is made up of lots of little dots.
The number of little dots that an adapter/monitor combination can
display is know as the resolution and is expressed as "seven-twenty
by three-forty-eight" or "six-forty by four-hundred". The first
number is the number of little dots horizontally across the screen
and the second, the number vertically. Each dot is an individually
addressable location that, at least for monochrome, may either be
"on" (have a bit value of 1) or "off" (have a bit value of 0). The
pattern of bits in the computer which represents the display gives
rise to the term "bit mapped graphics".
The fact that the HGC can display "bit mapped graphics" or merely
"graphics" means that it is especially desirable to those who wish
to use a program such as Lotus 1-2-3 which has the ability to draw
pie charts and other graphs or AutoCAD which allows the user to
draw any number of shapes. The pseudo-graphics provided by the
ASCII characters are not sufficient for such applications.
Again, the HGC will work only with a monochrome monitor. Further,
the monochrome monitor most accept TTL (Transistor-Transistor
Logic) input. The HGC is connected to the monitor with a cable
(usually attached to the monitor) equipped with a DB-7 plug.
The HGC is the display adapter most often provided with discount
IBM pc compatibles. It will operate with most software and is
widely supported amongst the commercial vendors. The notable
exception is most game software which will not function with the
HGC without the use of special software to "fool" the game program.
Color Graphics Adapter (CGA)
DDDDDDDDDDDDDDDDDDDDDDDDDDDD
The IBM CGA is perhaps considered the industry standard display
adapter. It can operate in one of six display modes:
1. BW80 Where it acts the same as the MDA and displays only
characters and only in white on black.
2. BW40 Where again only monochrome characters are displayed
but this time at double width, only 40 characters
per line.
3. CO80 Character mode with 80 characters per line but this
time with eight colors at two intensity levels
effectively providing 16 colors.
4. CO40 Same as above but with only 40 characters per line.
5. MEDIUM "Medium" resolution graphics mode providing a
resolution of 320 x 200 with four colors (one of
which is black) from a choice of two pallets (one
provides cyan-magenta-white, the other,
yellow-red-green).
6. HIGH "High" resolution graphics mode providing a
resolution of 640 x 200 but with only two colors
(white on black).
The CGA will work with either an RGB or Composite color monitor or
a composite monochrome monitor. It displays only monochrome images
on the monochrome monitor, not shades of gray (The Compaq portables
have been available with a special type of monochrome monitor that
functions with a CGA compatible card to provide shades of green
instead of colors.). It connects to a composite color or
monochrome monitor with a coaxial cable equipped with RCA plugs and
to an RGB monitor with a DB-7 plug.
Enhanced Graphics Adapter (EGA)
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
The EGA card is IBM's latest offering in the graphics adapter line.
Now being offered by other manufacturers as well, it's still high
priced but it does do much more than any of the other adapters
discussed so far. Being new, there's still a lot of confusion
around about what it is and what it does. (This author being among
the confused, much of what appears here is excerpted from several
articles appearing in PC Magazine.)
The EGA standard provides for 12 graphics modes (for some silly
reason, they're numbered 0 through 7 and 13 through 16). Which of
those modes is actually available depends on the monitor to which
the EGA is attached.
With a TTL Monochrome monitor:
Mode Type Resolution Colors Comments
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
7 Text 720 x 350 4 Compatible with MDA
15 Graphics 640 x 350 4 (The four colors are black
and three shades of green)
With and RGB color monitor:
Mode Type Resolution Colors Comments
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
0&1 Text 320 x 200 16 CGA Compatible - 40 Char
2&3 Text 640 x 200 16 CGA Compatible - 80 Char
4&5 Graphics 320 x 200 4 CGA Compatible
6 Graphics 640 x 200 2 CGA Compatible
13 Graphics 320 x 200 16
14 Graphics 640 x 200 16
With an Enhanced color monitor:
Mode Type Resolution Colors Comments
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
0&1 Text 320 x 200 16 CGA Compatible - 40 Char
2&3 Text 640 x 200 16 CGA Compatible - 80 Char
4&5 Graphics 320 x 200 4 CGA Compatible
6 Graphics 640 x 200 2 CGA Compatible
13 Graphics 320 x 200 16
14 Graphics 640 x 200 16
16 Graphics 640 x 350 4 or 16 The number of colors
depends on the amount of
graphics memory installed
on the EGA card. 64k gives
4 colors, 128k gives 16.
These modes are for the IBM version of the EGA adapter. Many other
manufacturers produce cards with other modes as well. It should
also be noted that although the EGA claims compatibility with
software written for the MDA and CGA, that compatibility is not
absolute and some programs written for the CGA or MDA will not
function with the EGA. Most notable of these are Flight Simulator
from Microsoft and Lotus 1-2-3 Release 1A. Also, the card may have
additional memory beyond 128k which will not provide additional
colors in the high resolution mode but will provide faster display
of complicated images and faster scrolling.
Other Graphics Adapters (OGA's?)
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
Of course, other than the above "standards" there are a whole bunch
of other cards around. Some things to be aware of follow:
Other EGA Cards
There are a lot of companies making IBM EGA compatible cards
these days and some have approved upon the original IBM design.
Even IBM itself is due to release a revised EGA. Some things
to look for are an added mode which mimics the HGC (Quadram
QuadEGA+, Video-7 Vega, etc.), the ability to display more
modes on monochrome and standard color monitors (ATI's
EGAWonder which even supports composite color monitors), 132
column modes, etc. Additionally, although the IBM EGA was a
full length board, many of the other cards on the market are
half length or shorter.
Many of these cards offer much improved compatibility with the
MDA, CGA, and HGC cards and some are even able to detect what
type of adapter the software is looking for and switch into
that mode (Paradise AutoSwitch etc.).
CGA Like Cards
Other display adapters are available that offer graphics
similar to the CGA but with enhancements which allow for more
colors at higher resolution. Some notable cards include the
Tecmar Graphics Master offer 640 x 400 with 16 colors and the
Plantronics card offering 4 colors at 640 x 200.
Professional Graphics Adapter (PGA)
Another high resolution high cost offering from IBM, this card
is priced out of reach of most home users and was aimed at the
serious CAD users.
Higher Resolution Cards
There are cards available, at higher prices, that will provide
the user with resolutions of 1024 x 1024 or better (Number
Nine, BNW Graphics, etc.). These cards generally have a
standard mode which emulates the CGA and offer the enhanced
graphics modes only to programs specifically written to take
advantage of their abilities. AutoCAD for example supports
many of these cards.
I hope that all of this is helpful. I hope it's fairly accurate as
well. Please drop a note if you find any mistakes and we'll try to
pick 'em up. Enjoy reading!
>>> John <<<
2/5/87
===============================================================================
------------------------------
Date: Thu, 7 May 87 16:52:27 CDT
From: Kevin Black <MEPCOM-IM@STL-HOST1.ARPA>
Subject: Addition
Please add me to your mailing list.
Thank you in advance
Regards,
Kevin Black
-------
------------------------------
End of INFO-GRAPHICS
********************
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