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Computing On
The Big Screen
Forget about CAD & desktop publishing on a small
screen. To really work with these programs, you need a
large-screen, high-resolution monitor.
By JIM SHARPLES*
The recent popularity of
others , such as desktop pubGUis (Graphical User Interlishing, CAD and graphics,
faces) and WYSIWYG (What
larger screens are almost a
You See Is What You Get)
necessity. If you try doing a
has resulted in a marked
2-page layout in PageMaker
decrease in the prices of
or Ventura, for example, the
monitors, particularly the
resulting display is practicolour models.
cally unusable. Or what
The advent of Windows
about trying to design a
3.0 in the IBM PC compatlarge double-sided board on
a small screen. It is possiible market has created a
ble but not the most effihuge demand for colour
cient way.
monitors capable of dis playing higher resolutions
Colour or mono?
than ordinary VGA. These
higher resolutions are reEighteen months ago the
ferred to as "Super VGA"
price gap between colour
and can not only display
and monochrome monitors
the 640 x 480 pixel resoluwas fairly substantial and
tion of standard VGA , but
if the application didn't abThe Philips 4CM2799 20-inch colour monitor supports
also 800 x 600 and 1024 x
solutely require colour, then
resolutions up to 1280 x 1024 & can be used with a wide
768 resolutions. Many of
monochrome was certainly
range of video driver cards.
the larger monitors also supthe most economical purchase. Now, however, the
port 1280 x 1024 but there
there is a corresponding demand for
are not (yet) many video cards able to
price gap has narrowed to the point
larger monitors. It's very nice having
where monochrome would not be a
display at this resolution.
a 14-inch monitor displaying Win- wise choice, particularly as many
Most of the recent monitors are the
"multisync" type; ie, they synchro- dows or CAD (Computer Aided De- newer programs rely on colour to make
sign) in 1024 x 768 resolution but
nise at multiple frequencies. This
them easier to use. Menus, grids, tools,
everything is so small! Just try using a
icons, selection areas and many asmeans that IBM compatible users
14-inch monitor, swap to a large moniaren't the only ones to score - Mac,
pects of the programs use colour to
tor for a week or so, then return to the
Amiga and other computers can use
make the user's job more instinctive
14-inch monitor. You'll really miss
and obvious.
the same monitors.
that large screen.
Windows 3.0 is a good example.
Larger monitors
For some applications, the smaller Whereas Windows 2.0 hardly needed
size is not much of a problem but for
With the increase in resolution,
colour and indeed, it was just a 1uxury,
16
SILICON CHIP
Windows 3.0 was designed to use colour. In fact, it is somewhat difficult to
use quite a few applications in monochrome!
CAD is another software category
where colour is almost essential, particularly with multi-layered applications such as circuit board design.
Drawings quickly become confusing
and hard on one's concentration.
But what about the difference in
quality between monochrome and
colour? Let's face it - monochrome
will beat colour hands down in a contest where resolution is the same. It's
much easier having one electron gun
than trying to align three at once.
Again, things are changing. The
resolution of colour monitors is improving all the time, to the point where
it doesn't really make that much of a
practical difference, and in any case
the advantages of colour outweigh the
clarity of monochrome.
How large?
OK. We've decided on a large colour monitor. What is the best size to
go for? Well, here's where personal
taste steps in. In my view, a 17-inch
monitor is ideal for the broadest range
of applications, whether they be textbased (eg, wordprocessing or database under MS-DOS) or graphicsbased as in Microsoft Windows. Text-
based applications can be rather overpowering when viewed on a 21-inch
monitor, unless you happen to be very
short-sighted, in which case they are
a great idea. I know of one person
who bought a 20-inch monitor for this
very purpose.
(By the way, notice how we still
persist in measuring monitor diagonal sizes in inches? Obviously, this is
the strong influence from the American computer industry).
17-inch monitors
As mentioned, this is the best general purpose monitor size. They have
the added advantage of taking up a
little less space on the desktop, though
even a 17-inch monitor seems huge
after a standard 14-inch one. There
haven't been many of this size monitor around until a recent flurry of
announcements by various manufacturers. It seems they all suddenly realised that this would be the logical
choice for many users and announcements have been appearing hard on
the heels of one another.
Another curiosity is that they have
appeared with almost the same specifications: flat screen, 1280 x 1024
maximum resolution, 0.26mm dot
pitch and very similar horizontal and
vertical scan rates and bandwidth.
These specs are pretty good for this
A video glossary
Autosizing: this is the ability of the
monitor to maintain a constant image
size across different video modes.
For example, this is important when
entering Windows in 1024 x 768
non-interlaced mode from the normal
DOS VGA mode. If this is not
available, either automatically or as
a user-programmable option, then
the user must change the size and
position of the image every time
another mode is entered.
Dot Pitch: the distance between
the holes in the shadow mask in a
colour monitor. The shadow mask
(which sits behind the screen) ensures that each electron beam (from
the red, green and blue guns in the
tube's neck) hits the correct dot in
each triad of red, green and blue
phosphors. The smaller the dot pitch,
the finer the grain of the image.
Horizontal Frequency: how often
the monitor scans a horizontal line,
measured in kHz. VGA is standardised at 31.SkHz, while Super VGA
varies depending on the vertical refresh rate of the graphics adaptor.
Multisync: a term originated by
NEC to indicate that the monitor
can synchronise to any horizontal
line frequency within a given range.
Some cheaper monitors are actually "multiple fixed frequency" which
means that they synchronise to particular modes, usually VGA 800 x
600 and 1024 x 768.
Pixel: the smallest triad or group of
triads, depending on the resolution
selected.
Triad: a triad comprises three phosphor dots - red, green and blue arranged in a triangle. Each of the
three electron guns is assigned a
particular colour and that gun excites only its own phosphor dot in
the triad. The combination of excited dots determines pixel colour.
Vertical Frequency or Refresh
Rate: how often the monitor scans
a compete screen, measured in Hz
(cycles per second). The higher the
refresh rate, the less flicker is noticeable. Standard VGA has a vertical frequency of 60 or 70Hz, while
Super VGA should be an absolute
minimum of 56Hz but preferably
70Hz or higher.
This 19-inch high-resolution monochrome monitor from Radius is ideal for
desktop publishing & graphics design. It is fully VGA compatible & can be used
with either PC or Macintosh systems.
Video Bandwidth: the highest video
input frequency the monitor can accept, measured in MHz. This determines the maximum resolution .
MAY 1992
17
size of monitor and should make them
a popular choice.
benefit from a larger view of all those
figures .
19 & 21-inch monitors
Portrait & 'full page' monitors
These are the big ones, needing
plenty of desk space. Don't try to use
them on a narrow desk - you'll land
up with the keyboard in your lap!
And do a weightlifting course before
moving the monsters. They are definitely in the heavyweight class.
Once in place however, the view is
worth it. Both graphics and text are
easier to see and manipulate, reducing the need to zoom in on working
details. There is a corresponding saving in screen redraw time between
the zoom levels. Monitors in this class
usually have a 0.31mm dot pitch,
which is quite acceptable, though
some go as low as 0.28mm:
This is the ideal monitor size for
those working almost exclusively in
high-resolution graphics mode,
whether it be CAD, desktop publishing, animation or even large spreadsheets. Maybe accountants could also
What is a 'full page' monitor? A
number of times I have been asked to
recommend a monitor to fit this vague
notion and when pressed to clarify
the request, the customer usually answers: "a monitor that displays an A4
page". My answer is almost always in
the form of another question: "What
size would you like your A4 page to
be?".
The person wanting a full page
monitor usually needs it for a desktop
publishing application and I have to
point out that even a 12-inch monitor
can display a full A4 page. But if they
want it displayed full size, the options are limited and are pretty expensive.
I also point out that unless they are
working solely on publications where
only a single page view is necessary,
the portrait or 'full page' monitor can
be a liability when viewing two pages
fllc
Edit
l2plloni ,eage
Iypc
Elemcnl
Window
Help
J
Computirig'On
•I
The l3ig Screen
Forget about t,AD & desktop publisll.Ufg on a small
screen. ToreaD~ work ~ilhthesep~og,JpDl~,youneeda
large-screenh,gh-resolution "f°:nil'or.
~:,- JIM SHARPLES
'
These two captured screen images
from PageMaker show how much
more information is displayed at
higher resolutions. At top left is a
1280 x 1024 display, while at bottom
right is a 640 x 480 (standard VGA)
screen capture. The text is directly
readable on-screen in the highresolution mode but has "Greeked"
in the low-resolution mode.
18
SILICON CHIP
side-by-side, or using other applications.
The only exception to my prejudice against portrait monitors is a
rather curious animal - the Radius
Full Page Pivot monitor. This colour
monitor acts as its name suggests - it
pivots between portrait and landscape
modes, using software drivers to
change the orientation when the monitor is pivoted. Portrait mode can only
be used in applications for which a
driver exists and these include some
CAD, wordprocessing and spreadsheet programs, plus Microsoft Windows. A Mac version is also available.
The Pivot measures 15-inches diagonally, so it does not really fit into the
"large monitor" category.
VESA & Swedish standards
The Video Electronics Standards
Association has defined standards for
Super VGA signals to reduce flicker.
This can be particularly noticeable
when the screen background is white,
as in Microsoft Windows. The official
standard requires the vertical refresh
rate to be 72Hz at 800 x 600 resolution
and 60Hz at 1024 x 768 resolution.
Both monitors and video boards must
be able to conform to or exceed these
standards.
Sweden's National Board for Measurement and Testing (MPR) has pub-
A 17-inch colour monitor is a good compromise between size & cost for many
applications. The multi-sync CMl 7MBD from Tatung features 0.26mm dot pitch,
1280 x 1024 resolution (max.), a flat dark-tinted CRT & a microprocessor-based
control system for automatic screen configuration. It can be used with a wide
range of driver cards for both PC & Macll computers.
lished standards for monitor emissions, designed to reduce health risks
and eye stress. Many manufacturers
are designing monitors to conform to
the standards, though there is still
some controversy over the supposed
health risks.
Video graphics boards
When discussing high resolution
monitors, one part of the equation
that cannot be left out is the board
generating the screen graphics, and
here I will restrict discussion to PC
compatibles. A series of simple calculations will show these results:
Resolution
640 x 480 (VGA)
800 X 600
1024 X 768
Pixels
307,200
480,000
789,504
It is obvious that at the common
high resolution of 1024 x 768 the
number of pixels is over three-quarters of a million! And the poor graphics board has to frequently redraw
most of them! Standard VGA has a
limit of 16 colours, whereas high resolution boards can usually generate 256
colours. This means that the high resolution board is manipulating five times
as much information as VGA.
The question of which graphics
board to use is therefore an important
one if you want your screen updates
to happen at an acceptable pace. Basically there are two types of high-resolution boards: those with graphics
coprocessors and those without. The
most popular and possibly fastest of
the boards without coprocessors are
those based on the Tseng Labs ET 4000
chipset. Apart from Tseng Labs themselves, quite a number of manufacturers produce boards using this chipset.
A better option for those using large
monitors at high resolutions are the
coprocessor based boards. IBM ini-
The Radius Pivot Display System is
a colour monitor that pivots between
portrait & landscape modes to suit
your application. Versions are
available to suit both the PC & the
Macintosh family.
tially produced the 8514/A coprocessor for 1024 x 768 interlaced resolution and others have subsequently
cloned this chip, adding extended features like 1024 x 768 non-interlaced
and higher scanning frequencies (see
glossary for an explanation of some of
the terrris).
Another popular coprocessor is the
Texas Instruments TMS34010 and
TMS34020, and boards designed
around these chips can respond to
TIGA, the Texas Instruments Graphics Architecture software interface. In
terms of speed, there is not much to
choose between the 8514/ A and
MAY 1992
19
There are also some lower-cost
boards appearing which contain the
Sierra DAC (Digital-to-Analog Converter), which is 15-bit and generates
32,768 colours, and then there are
other 16-bit adapters such as IBM's
XGA which generate 65,536 colours.
For most purposes, a 256-colour
board based on the S3 chip would be
my choice, both in terms of speed and
economy.
What should you look for?
Hitachi's Model CM2187 is a 21-inch multi-sync colour monitor with a 0.31mm
dot pitch & a resolution ofup to 1600 x 1200 (non-interlaced). It is compatible
with a wide range of graphics standards & features microprocessor control.
TMS340x0, though the 8514/A-based
boards tend to be a little cheaper.
A new contender is the 86C911 chip
produced by S3 Inc. The boards based
on the S3 are particularly exciting,
not only because of their fast speed,
but because they cost about half the
price of the other two types.
Most graphics boards available gen-
erate 16 and/or 256 colours (4 and 8
bits per pixel), though there are other
more expensive boards available
which can generate 16.8 million colours (24 bits per pixel). These boards
would only entice the most demanding users who need photographic-like
images and can afford the thousands
of dollars required to purchase them.
16-inch Colour Display for the Mac
Apple's new Macintosh 16-inch Color Display
features 832 x 624 resolution & is supported by all
current Apple video cards & by the on-board video
interface of the Quadra CPUs. Alternatively, users
can choose the 8.24 GC card (not needed for
Quadras) which offers 32,768 colours & graphics
acceleration.
20
SILICON CHIP
Dot pitch is important - newer 17inch monitors are 0.26mm, while a
20-inch monitor should be 0.31mm
or less.
Autosizing is a definite requirement
if you will be changing modes and
may be either automatic or user-programmable.
Colour-correction may be important
depending on the type of work you
do. The new NEC FG series is one of
the few monitors available with this
feature built-in.
Non-interlacing at higher resolutions can increase viewer comfort but
it is important to match graphics card
capabilities to that of the monitor.
Finally, spend a reasonable amount
of time looking for the monitor you
need and don't skimp on price and
quality - you will spend long periods
looking at the screen.
SC
•Jim Sharples runs Computrack, a company that supplies PC-based desktop publishing equipment. Phone (02) 451 2521.
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