screensavers

A screensaver is a computer program originally designed to conserve the image quality of computer displays by blanking the screen or filling them with moving images or patterns when the computers are not in use. Today, screensavers are primarily for entertainment or security purposes.

Purpose - Until recently, most computer screens depended on cathode ray tubes (CRTs). CRT images are generated using electron beams which are "launched" from the back of the monitor and "draw" images continuously on the screen. Most computer programs paint images in the screen. Some of these images (letters, pictures, animations, menus) are usually moving or changing, and never stay in the same place for long. But some portions of the screen (like the Start bar in Microsoft Windows, or the typical upper "score" bar of some video games) are always in the same place, sometimes for hours or even days or months. Particularly with older CRTs, these sorts of images, continuously drawn in the same place for a long time, could damage the screen because the electron rays always hit the same points on the screen. Damage would consist of poor image quality, and those fixed images could remain "burned in" to the same place like "ghost lines" even if the image eventually changed. This is commonly known as "phosphor burn-inscreen burn". This effect could be observed in some older video game machines; after displaying the same image for years on end, "ghost images" could be seen to be "burnt" into the display. Screensaver programs were originally designed to help avoid these effects by automatically changing the images on the screen when the computer was not in use. They can be usually set up to launch automatically, waiting a specified amount of time after the last keystroke or the last mouse movement made by a user. Then the screensaver switches the image to black, or sometimes produces some animation effects, thus avoiding any "fixed" images. The screensaver remains active until a user enters a keystroke or makes a mouse movement. At that moment, the screensaver closes and the former screen contents are restored, to allow the user to work again.Modern CRTs are much less susceptible to burn-in than older models. Flat panel displays are used in all laptop computers and are gradually replacing CRTs on the desktop. Flat panels are burn-in resistant because they use a fluorescent bulb or similar light source instead of an electron beam. For this reason, screensavers today primarily are decorative or for entertainment, and usually feature moving images or patterns and sometimes sound effects.

LCD considerations - Using a screensaver with a flat panel or TFT LCDLCD screen actually ''reduces'' the lifetime of the display, since the fluorescent backlight remains lit and ages faster than it would if the screen was turned off completely. As fluorescent tubes age they grow progressively dimmer and are expensive to replace. (In most cases, the tube is an integral part of the LCD and the entire assembly needs to be replaced.)

Entertainment - After Dark was an early screensaver for the Apple MacintoshMacintosh platform featuring whimsical designs such as flying toasters. Perhaps in response to the workplace environment in which they are often viewed, many screensavers continue this legacy of whimsy by populating the idle monitor with animals or fish, Computer and video gamegames, and visual expressions of obscure mathematics equations such as fractals.The ability of screensavers to divert and entertain is used for Promotional (marketing)promotional purposes, especially to build buzz for "event-based" products such as filmfeature films. Taking this development a step further, Idle Time is an art project and screensaver that uses the screensaver medium as a form of filmcinema.Screensavers have also been used as shared computing applications, such as the SETI@home project.

Security - Screensaver software also has been adapted as a security measure. Many screensavers can be configured to ask users for a password (called "locking the workstation"), before permitting the user to resume work. Beware that a user might be able to circumvent the password by restarting the computer.Screensavers are not to be confused with power management features, which place the computer in a low power state after it has been idle for a specified amount of time. In fact, screensavers can actually waste power, because they can prevent the computer from entering the lower power (or sleep) state, and they often cause the Central processing unitCPU and !Graphics_processing_unit GPU to perform more calculations, and keep the hard disk running for longer than if the computer were idle.Some screensavers activate a useful background task, such as a anti-virus softwarevirus scan or a distributed computing application.

History - The first screensaver was allegedly written for the original IBM PC by John Socha, best known for creating the Norton Commander; he also coined the term ''screen saver''. The screensaver, uncreatively named ''scrnsave'', was published in December 1983 issue of the Softalk magazine. It simply blanked the screen after three minutes of inactivity (an interval which could be changed only by recompiling the program).

Security risks for Microsoft Windows screensavers - Users of the Microsoft Windows operating systems should be aware that the native screensaver format has the potential to install a virus when run. It is recommended that end users not open any email attachment with the file suffix ".scr". Windows will execute .scr (screensaver) files automatically — this has the potential to allow a virus (computer)virus or malware to install itself as the default screensaver. Such malicious software will then be automatically executed when the screensaver kicks in.

Underlying architecture - Screensavers are usually designed and coded using a variety of programming languages as well as graphics interfaces. Typically the authors of screensavers use the C programming language, along with OpenGL or DirectX, to craft their final products. The screensaver interfaces indirectly with the operating system to cause the physical display screen to be overlayed with one or more graphic 'scenes'. The screensaver typically terminates after receiving a message from the operating system that the mouse has been moved or a key has been pressed.

External links -

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X-Screensaver
X-Screensaver : The Best Erotic Screensavers and wallpapers
http://www.x-screensaver.com/

Maldive Isle - Maldives Guide
Maldives Travel and Tourism Guide - with sections on business and society,
http://www.maldiveisle.com/

Internet Gateway: E-cards, Freebies, Games, News, Resources, Shopping
Designed to get you the Best of the Web without searching..from Books to Fitness, News to E-greetings, Education to Travel
http://www.lynx-cosmos.com/

GoDesktop
Free Celebrity and entertainment download stuff, features wallpapers, screensavers, desktop themes and skins.
http://www.godesktop.com/

Paul Johnson Interactive
Flash and Illustration Solutions for Web Development.
http://www.pj-i.com/

Arterran.com
Woodcarvings and digital art and design by Canadian Westcoast artist, Terran Ambrosone.
http://www.arterran.com

arx.net S.A.
ASP in Greece for internet and wireless services
http://www.arx.gr/

3D Nature Screensaver Downloads - FancyBytes Software
Only original 3D screensavers. 3D Nature Aquarium, Space Voyage, Holiday Screensavers and more! Turn your desctop into a breathtaking 3D view with realistic sounds and real-time animation.
http://www.fancybytes.com/

Peacock Cards
free ecards, desktop wallpapers, screensavers, links to personalized gifts, T-shirts, and more.
http://www.peacockcards.com/

Tech TV
The on-air, online network for the digital lifestyle. Get tech help, product reviews, news, and entertainment. Includes streaming video and radio.
http://www.techtv.com/

Screensaver.com
This site features top quality screen savers complete with descriptions for each.
http://www.screensaver.com/

The Screensavers TV Show
Television show for those who enjoy technology. Co-hosted by Leo Laporte, Patrick Norton, Megan Morrone, Jessica Corbin, Yoshi DeHerrera and Kevin Rose.
http://www.thescreensavers.com

ScreensaverShot.com
Sorted by theme with ratings, descriptions, and preview images. Categories cover; personalites, animals, nature, machines, TV and movies, art, music, sports and Holidays.
http://www.screensavershot.com/

Freesaver.Com
Listed either alphabetically or grouped in categories, all with thumbnail previews and short descriptions.
http://www.freesaver.com/

JoBlo's Movie Emporium
Reviews of films new to theatres and DVD. Includes film preview news.
http://www.joblo.com/