CD and DVD care Tips

CD and DVD care Tips

01. discs kept in a cooler, less-humid environment and not subjected to extreme environmental changes should last longer. Optical discs stored in an optimal environment will outlast discs that are not.
02. Always keep your discs in their storage containers, until ready for use.
03. discs used frequently should be stored at a temperature similar to that of the environment in which they are to be used. This minimizes stress from frequent temperature changes.
04. Always keep your discs out of direct sunlight, as it is believed the sun's ultraviolet rays have enough energy to produce a photochemical reaction, altering the recording layer of the disc.
05. Any extended exposure to moisture resulting from a spill, humid air, or immersion allows fluid to become absorbed into the disc, where it may react with any of the layers. Returning the disc to a dry environment will allow the absorbed fluid to dissipate out of the disc over time. However, water or a water-based liquid may leave behind, within the disc, contaminants such as dyes or other dissolved minerals.
06. Fingerprints, smudges, dirt, or dust on the laser reading side of Cds and DVDs can disrupt disc play even more than a scratch can. Dirt or dust on the disc will block or reduce the ability of the laser to read data. If severe enough, it will cause the disc drive to miss data altogether. Fingerprints, smudges, or dirt cover wide areas of data and will cause the laser beam to go out of focus or lose intensity. They will also cause widespread misreading of data along the data lines or tracks, to an extent that exceeds the error correction capability of the disc drive. Dust can also spin off into the disc drive and collect on the laser head or other internal components. Fingerprints, smudges, and dirt are easier to remove than scratches; it is simply a matter of cleaning them off.
07. Bending the disc by any means, such as removing it from a jewel case or sitting on it, may harm the disc by causing stresses. The disc should be stored in its case and placed vertically, like a book, on a shelf. Long-term horizontal storage, particularly in a heated environment, can cause the disc to become permanently bowed. While the data may still be intact, the disc may not operate properly in the drive or permit the laser to follow the track.
08. Use a non-solvent-based felt-tip permanent marker to mark the label side of the disc. Never mark the play side of your disc.

Do:
01. Handle discs by the outer edge or the center hole.
02. Use a non-solvent-based felt-tip permanent marker to mark the label side of the disc.
03. Keep dirt or other foreign matter from the disc.
04. Store discs upright (book style) in plastic cases specified for CDs and DVDs.
05. Return discs to storage cases immediately after use.
06. Leave discs in their packaging to minimize the effects of environmental changes.
07. Open a recordable disc package only when you are ready to record data on that disc.
08. Store discs in a cool, dry, dark environment in which the air is clean.
09. Remove dirt, foreign material, fingerprints, smudges, and liquids by wiping with a clean cotton fabric in a straight line from the center of the disc toward the outer edge.
10. Use CD/DVD-cleaning detergent, isopropyl alcohol, or methanol to remove stubborn dirt or material.
11. Check the disc surface before recording.

Do Not:
01. Touch the surface of the disc.
02. Bend the disc.
03. Use adhesive labels.
04. Store discs horizontally for a long time (years).
05. Open a recordable optical disc package if you are not ready to record.
06. Expose discs to extreme heat or high humidity.
07. Expose discs to extremely rapid temperature or humidity changes.
08. Expose recordable discs to prolonged sunlight or other sources of ultraviolet light.
09. Clean by wiping in a direction going around the disc.

What is a proxy server, and how do they work?

What is a proxy server, and how do they work?

Proxies are store-and-forward caches. When you configure your web browser to use a proxy, it never connects to the URL. Instead, it always connects to the proxy server, and asks it to get the URL for you. Proxies can be used as a sort of firewall, because it isolates you from connecting to the Internet.

How does a proxy server work?
A proxy server receives a request for an Internet service (such as a Web page request) from a user. If it passes filtering requirements, the proxy server, assuming it is also a cache server, looks in its local cache of previously downloaded Web pages. If it finds the page, it returns it to the user without needing to forward the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user.
To the user, the proxy server is invisible; all Internet requests and returned responses appear to be directly with the addressed Internet server. (The proxy is not quite invisible; its IP address has to be specified as a configuration option to the browser or other protocol program.)

What are the advantages of using a proxy server?
An advantage of using a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy's cache, which will improve user response time. In fact, there are special servers called cache servers.
The functions of proxy, firewall, and caching can be in separate server programs or combined in a single package. Different server programs can be in different computers. For example, a proxy server may in the same machine with a firewall server or it may be on a separate server and forward requests through the firewall.
There are different types of proxy servers with different features, some are anonymous proxies, which are used to hide your real IP address and some are used to filter sites, which contain material that may be unsuitable for people to view.
When you connect to a web site, your true IP address will not be shown, but the proxy servers IP will, this does not mean that your completely anonymous. The proxy server will have logs of IP's that used the proxy server and the times.

So why should you use a proxy?
You can use a proxy server if you have a child and wish to restrict the sites they are viewing, you will need to make sure you get the correct type of proxy because not all proxies filter sites. You can use it to protect yourself, it can be used to hide your IP which is useful because it means hackers can not get info about you when using it. They will only get the proxy servers IP. Proxy servers are not hard to set up, no hardware or software is needed, you just need to configure your browser to connect through it.
Some ISP's (Internet Service Providers) make all their users use a proxy server, for example in the United Arab Emirates, the main ISP makes all users use a proxy server which blocks sites with unsuitable material. It does this using the meta tags in the HTML code used to make the web page. Some ISP's may give you a choice so you can use one or not. If you want to use a proxy server there are many around with different functions, you just have to get the one that suits your needs best.