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Z-buffer
The z-buffer is a reserved portion of video
memory that holds depth information (as opposed to color information) for every pixel being displayed on the screen.
When a polygon is rendered with z buffering, each of its pixels depth (z-value) is compared with the corresponding
value stored in the z-buffer. If the value stored in the z-buffer is less than the depth of the new arriving pixel,
it is decided that this pixel is visible and should therefore be rendered. The z-buffer is then updated with the
pixel s depth. If however, the value is greater, the pixel is rejected and will not be rendered, as this means
it is behind of what has already been drawn. Z-buffering is used to ensure that objects are rendered in the
right order, that is, objects in the back should not appear in front of objects that are in the front.
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ZIP
A Microsoft Windows based compressed file. Can contain one or many files as well as a directory structure.
On the Internet large graphics and programs are usually compressed into ZIP files and then made avaliable for download.
After you download this file you need to use a decompression software program to "UNZIP" the file. Several
popular tools exist for zipping: PKZIP in the DOS operating system, WinZip and NetZIP in Windows, MacZip for Macintosh
users, and Zip and UnZip in UNIX systems.
To zip a file is to compress it into an archive so that it occupies less disk space.
Zip archive
An archive of one or more Zip-compressed files. When used as a noun, Zip is typically capitalized. Compressed files
can come in many formats besides Zip.
Zip file
A Zip archive that Windows presents as a single file. In
general, the contents can not be accessed unless the archive is decompressed.
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Zone (Internet security zones)
Internet Explorer divides the Internet world into zones, so that you can assign a Web site to a zone with a suitable
security level. You can tell which zone the current Web page is in by looking at the right side of the Internet
Explorer status bar. Whenever you attempt to open or download content from the Web, Internet Explorer checks the
security settings for that Web site's zone.
There are four different zones:
Internet zone: By default, this zone contains anything that is not on your computer or an intranet, or assigned
to any other zone. The default security level for the Internet zone is Medium.
Local intranet zone: This zone
typically contains any addresses that don't require a proxy server, as defined by the system administrator. These
include sites specified on the Connections tab, network paths (such as \\server\share), and local intranet sites
(typically addresses that don't contain periods, such as http://internal). You can also add sites to this zone.
The default security level for the Local intranet zone is Medium.
Trusted sites zone: This zone contains sites
you trust - sites that you believe you can download or run files from without worrying about damage to your computer
or data. You can assign sites to this zone. The default security level for the Trusted sites zone is Low.
Restricted sites zone: This zone
contains sites you don't trust - that is, sites that you're not sure whether you can download or run files from
without damage to your computer or data. You can assign sites to this zone. The default security level for the
Restricted sites zone is High.
In addition, any files already on your local computer are assumed to be very safe, so minimal security settings
are assigned to them. You cannot assign a folder or drive on your computer to a security zone.
If you want, you can change the security level for a zone; for example, you might want to change the security setting
for your Local intranet zone to Low. Or, you can customize the settings within a zone from the default settings
in Low, Medium Low, Medium, and High.
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