The GA's

CGA
VGA/SVGA   XGA   SXGA   UXGA
WXGA   WSXGA

QXGA   QSXGA
QUXGA

NOTE:  all resolutions listed below are given as WxH (Width
x Height).  So the second number always refers to the number of horizontal
scan lines stacked vertically.

In the early days of monitors and video
adapters - the lack of a widely accepted standard for VGA pixel addressabilities
was a problem for manufacturers, system builders, programmers and end users
alike.

This was solved with the emergence of VESA
( Video Electronics Standards Association ).  VESA ia a consortium of
video adapter and monitor manufacturers whose goal is to standardize video
protocols - who developed a family of video standards that were backward
compatible with VGA but offered greater resolution and more colors. For a while
- prior to the emergence of the "XGA" family of definitions - VESA's VGA BIOS
Extensions (collectively known as Super VGA) were the closest thing to a
standard.

Here are the usual screen sizes, in pixels, for each of these
specifications:

VGA - 640 X 480

SVGA - 800 X 600

XGA - 1024 X 768

QVGA - 1280 X 960

SXGA+ - 1400 X 1050

UXGA - 1600 X 1200

QXGA - 2048 X 1536

QSXGA+ - 2800 X 2100

QUXGA - 3200 X 2400

The settings above all have an aspect ratio of 4:3. There are also a few
other funky settings, with either a 5:4 or 16:9 ratio:

WXGA - 1280 X 800

SXGA - 1280 X 1024

WSXGA+ - 1680 X 1050

WUXGA - 1920 X 1200

QSXGA - 2560 X 2048

Resolution is a term often used
interchangeably with addressability, but it more properly refers to the
sharpness, or detail, of the visual image. It is primarily a function of the
monitor and is determined by the beam size and dot pitch (sometimes referred to
as "line pitch"). An image is created when a beam of electrons strikes phosphors
which coat the base of the monitor's "screen. A group comprising one red, one
green and one blue phosphor is known as a pixel. A pixel represents the smallest
piece of the screen that can be controlled individually, and each pixel can be
set to a different color and intensity. A complete screen image is composed of
thousands of pixels and the screen's resolution - specified in terms of a row by
column figure - is the maximum number of displayable pixels. The higher the
resolution, the more pixels that can be displayed and therefore the more
information the screen can display at any given time. Resolutions generally fall
into predefined sets and the table below shows the series of video standards
since CGA, the first to support color/graphics capability:

Date

Standard

Description

Typical Resolution

Number of
Colors

1981

CGA

Color Graphics
Adapter

640x200
160x200

2
16

1984

EGA

Enhanced Graphics
Adapter

640x350

16 from 64

1987

VGA

Video
Graphics
Array

640x480
320x200

16
from 262,144
256

SVGA

Super
Video Graphics
Array

800x600

256 to
16.7 million

8514/A

IBM
interlaced standard

1024x768

16
from 262,144

1990

XGA

Extended Graphics Array

1024x768

16.7 million

SXGA

Super Extended Graphics Array

1280x1024

16.7 million

UXGA

Ultra XGA

1600x1200

16.7 million

WXGA

Wide
XGA

1366x768

16.7 million

XGA  4:3
Ratio

WXGA  16:9 or 16:10
Ratio

CGA (Color Graphics Adapter) - Introduced in 1981 by IBM, CGA was the first color graphics
system for IBM PCs. Designed primarily for computer games, CGA does not produce
sharp enough characters for extended editing sessions. CGA's highest-resolution
mode is 2 colors at a resolution of 640 by 200

EGA (Enhanced Graphics Adapter) -

VGA (Super Video Graphics Array) - developed by IBM. VGA has become
one of the de facto standards for PCs. In text mode, VGA systems provide a
resolution of 720 by 400 pixels. In graphics mode, the resolution is either 640
by 480 (with 16 colors) or 320 by 200 (with 256 colors). The total palette of
colors is 262,144.

Unlike earlier graphics standards for PCs -- MDA, CGA,
and EGA -- VGA uses analog signals rather than digital signals. Consequently, a
monitor designed for one of the older standards will not be able to use
VGA.  All computer/monitor systems today support and are backwards
compatible with VGA !!!

SVGA (Super Video
Graphics Array) - a set of graphics
standards designed to offer greater resolution than VGA. SVGA supports 800 x 600
resolution, or 480,000 pixels.  In general, the larger the diagonal screen
measure of an SVGA monitor, the more pixels it can display horizontally and
vertically. Small SVGA monitors (14in diagonal) usually use a resolution of
800x600 and the largest (20in+ diagonal) can display 1280x1024, or even
1600x1200, pixels..  Supports the display of 16 million colors, but the
number of colors that can be displayed simultaneously is limited by the amount
of video memory installed in a system. The greater number of colors, or the
higher the resolution or, the more video memory will be required. However, since
it is a shared resource reducing one will allow an increase in the
other.

8514/A - A
high-resolution video standard for PCs developed by IBM in 1987. It is designed
to extend the capabilities of VGA. The 8514/A standard provides a resolution of
1,024 by 768 pixels, which gives it about 2.5 times the pixels of VGA (640 by
480). Like VGA, 8514/A provides a palette of 262,000 colors, of which 256 can be
displayed at one time. On monochrome displays, 8514/A provides 64 shades of
gray. In its original version, 8514/A relies on interlacing, a technique that
makes it possible to provide resolution at low cost. Interlacing, however,
carries a performance penalty, so many manufacturers produce noninterlaced
8514/A clones.

XGA (Extended
Graphics Array) - XGA replaced 8514/A
and was non-interlaced, developed by IBM and was originally used to describe
proprietary graphics adapters designed for use in Micro Channel Architecture
expansion slots. It has subsequently become the standard used to describe cards
and displays capable of displaying resolutions up to 1024x768 pixels.  It
has 768 horizontal scan lines.

SXGA (Super
Extended Graphics Array) - this
standard is used to describe the next screen size up - 1280x1024. SXGA is
notable in that its standard ratio is 5:4, while VGA, SVGA, XGA and UXGA are all
the traditional 4:3 aspect ratio found on the majority of computer
monitors.

Pixels are smaller at higher resolutions and prior to
Windows 95 - and the introduction of scaleable screen objects - Windows icons
and title bars were always the same number of pixels in size whatever the
resolution. Consequently, the higher the screen resolution, the smaller these
objects appeared - with the result that higher resolutions worked much better on
physically larger monitors where the pixels are correspondingly larger. These
days the ability to scale Windows objects - coupled with the option to use
smaller or larger fonts - affords the use far greater flexibility, making it
perfectly possible to use many 15in monitors at screen resolutions of up to
1024x768 pixels and 17in monitors at resolutions up to 1600x1200.

WXGA (Wide Extended Graphics Array) -  resolution can vary depending on the size of the
screen. WXGA basically means wide screen, the aspect ratio is 16:9 or 16:10
versus the more box like 4:3 aspect ratio of a standard laptop. If you're a
movie fanatic who wishes you could watch that great DVD collection while on the
road/plane/lunch break then you may want to take a look at laptop computers with
this type of screen. There are variations on this such as WSXGA or WUXGA which
are wide screen versions of the higher resolution modes.

WSXGA (Wide Super XGA) - a resolution that
supports 1600 by 900 pixels or 1600 by 1024 pixels.

UXGA (Ultra Extended Graphics Array) - a display
specification that is capable of displaying 1600 x 1200 resolution, or
approximately 1.9 million pixels.  It has 1200 horizontal scan
lines.

UXGA (Ultra Extended Graphics Array) - resolution of 1600x1200. This is featured on mainly high end
laptops which have medium to large screens (15.4 inch or greater). Like SXGA+
this resolution is great for when you need to see more of the screen at once
such as with spreadsheets or editing large photos, etc.

QXGA (Quad Extended Graphics Array)* - a display
specification that is capable of supporting 2048 x 1536 resolution, or
approximately 3.2 million pixels. (2048 by 1536 pixels; 1.33:1 aspect
ratio)

QSXGA (Quad Super XGA)* - a Display Standard referring to a
video adapter capable of a resolution of up to 2560 by 2048 pixels. (2560 by
2048 pixels; 1.25:1 aspect ratio)

QUXGA (Quad Ultra XGA)* - 3200 by 2400 pixels;
1.33:1 aspect ratio

* these high-resolution screens are made possible by a
new screen technology called TFT

TFT (Thin Film Transistor) - also referred to as
active matrix or even used at the same time such as “TFT Active Matrix LCD!”.
You would be hard pressed to find a modern laptop that doesn't use this type of
screen, it has become the standard for bright and colorful screens, although
“bright” and “colorful” may vary from each manufacturer.

LCD (Liquid Crystal Display) - LCD's are found in
countless gadgets that require a small or flat screens such as cell phones,
handheld game systems, computer monitors, etc.