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How do I...?
Terminology: What is...?
Search Engine
A web site that is used for the purpose of searching information on
the World Wide Web by using words or phrases describing the subject area
being sought. (back to top)
Digital Cameras and Mega Pixels
Resolution refers to the number of dots per
inch (dpi) that are contained in an image. This number is often
quantified in millions of pixels. The quality of an image depends on
the presence of a sufficient number of pixels, and what is sufficient
depends on the size of the image and the output device (monitor or
printer) used. When printing is the desired finished product, a
digital camera capable of 3 mega pixel photos is optimum. When the
image will be used in email or on a web site, a camera capable of only 1
to 2 mega pixels is necessary. (back to top)
BMP's (Bitmap Images)
The images you see on your computer are composed of bitmaps. A bitmap is
a map of dots, or bits (hence the name), that looks like a picture as
long you are sitting a reasonable distance away from the screen. Common
bitmap file types include BMP (the raw bitmap format), JPEG, GIF, and
TIFF. (back to top)
GIF, TIFF, or JPEG?
When saving an image for use in a web site or
email message it is actually being compressed so that it will use less
memory space while not losing the dimensions of the image. The
format to use depends on the type of image. Photographs and
graphics with lots of color fields, especially those that blend and fade
into one another, are best saved as a JPEG file. Images with flat
color fields, like most clip art, will compress well in the GIF format.
(back to top)
GIF's (Graphics Interchange Format) are based on indexed colors, which
is a palette of at most 256 colors. This helps greatly reduce their file
size. These compressed image files can be quickly transmitted over a
network or the Internet, which is why you often see them on web pages.
GIF files are great for small icons and animated images, but they lack
the color range to be used for high-quality photos.
JPEG's (Joint Photographic Experts Group) images are not limited to a
certain amount of color, like GIF images are. Therefore, the JPEG format
is best for compressing photographic images. A large, colorful image on
the web is most likely a JPEG file. However, JPEG is a "lossy" format,
which means some quality is lost when the image is compressed. If the
image is compressed too much, the graphics become noticeably "blocky."
Like GIF's, JPEGs are cross-platform, meaning the same file can be
viewed equally on both a Mac and PC.
TIFF's (Tagged Image File Format) are the graphics file format created in
the 1980's to be the standard image format across multiple computer
platforms, but since the original TIFF standard was introduced, people
have been making many small improvements to the format, so there are now
around 50 variations of the TIFF format. Recently, JPEG has become the
most popular universal format, because of its small file size and
Internet compatibility. (back to top)
Kilobytes, Megabytes, and Gigabytes
One byte = approximately
one character (or 8 bits)
One kilobyte (KB) = 1024 (or
210) bytes
One megabyte (MB) = 1024 KB (or 1,048,576 bytes, or 220 bytes)
One gigabyte (GB) = 1024 MB (or 1,073,741,824
bytes, or 230
bytes)
(back to top)
Bandwidth
Bandwidth is the measurement of the quantity
of information a network can carry. Think of a computer network as
a highway, and each message as a car. The more lanes in the highway, and
the higher the speed limit, the more traffic it can carry. So the wider
the bandwidth of a network, and the faster its speed, the more
information it can carry. (back to top)
InTERnet vs. InTRAnet
The inTERnet is the information highway which
is now known as the world wide web (www). An inTRAnet may use
similar software and navigation tools found on the www, but is used only
within a private office network for the sharing of information within
the office environment without public links. (back to
top)
Memory (RAM) vs. Hard Drive
RAM (Random Access Memory) is temporary storage for the Operating
System (i.e., Windows), plus any applications and data you may be using. RAM
holds this information in place only while the computer is powered on. The hard
drive permanently stores all the applications and data on your computer for use and
retrieval, whether powered-up or not. Think of it this way:
RAM is the computer's memory, which goes completely blank when the
system is shut down. The hard drive is like a paper journal where
information can be "written down" and reread whenever necessary. Since
the computer does everything "in its head" (RAM), it must read necessary
information (OS, applications and data) from the hard disk into memory
(RAM) before being used. Any changes to data you with to retain must be
saved (written) back to the hard drive before the system is shut down.
(back to top)
What is a virus?
A virus is a small malicious program, typically hidden inside a larger
(carrier) program. When the carrier program is opened or started, the
virus program also starts. The instructions in the virus program can be
as innocuous as simply displaying a silly message, to as destructive as
erasing data and disabling systems. One thing that nearly every virus
does have in common is that they propagate; some by rapidly traversing
networks, others by adding their code to new carrier programs.
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