screensaver

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 -

dmoz.org - DMOZ - Screen SaversCategory:Display !technologyde:Bildschirmschoner es:Protector? de pantallahe:שומר !מסךnl:Schermbeveiligingja:� ��クリーンセーバーpl:W ygaszacz? ekranu

TrialMe.com
software downloads site include: DVD software, game, Audio MP3 software, CD burner, DVD Burner, DVD ripper, DVD copy, CD ripper, DVD converter, Screensaver, arcade games, puzzle game, multimedia and design, home and education, ActiveX, utilities, internet tools, web authoring, finance and business, Security and Encryption and more.
http://www.trialme.com/

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

Sfondi per Desktop e Screensaver
Sfondi Desktop e Screensaver per PC da scaricare gratis
http://www.sfondissimo.com/

Medevial Traumzeit-Tarot Kartenorakel, online Orakel und esoterische Beratung
Medevial Traumzeit Tarot, Große und Kleine Arkana, die TAROT-Website des KÜNSTLERS selber mit dessen Eingebungen zu den Geheimnissen des Lebens und der Seelenreise in einfacher bildlicher Symbolik. Die Symbolik ist verschiedenen Kulturen, Epochen, esoterischen Traditionen wie Traumdeutung und Astrologie entnommen und beschreibt eine neue These spirituell vernetzter und uneingeschränkter Wahrnehmungsfähigkeit
http://www.corporatearts.de/

AXXIS - The german cult rockband !
AXXIS - the german rockband online. One of the most successful rockbands in Germany are presenting their homepage with a lot of interactivity to fans and visitors.
http://www.axxisworld.de/

Fractalmovies.com
A page dedicated to computer generated art.
http://www.fractalmovies.com/

Charakteranimation and Animation-Art, 3D Galleries by CORPORATEARTS.de & 3rdART.de
3D-Art, Charakter-Animation and AnimationArt. Charakter-Animation with real looking Persons and Figures. Photorealistic presentation of Humans and Animals as virtual digital 3D Figures.
http://www.3rdart.de/

Unterwasservideo Galerie, Fische, Tauchplatzbeschreibungen, Film, Fotos, Meerwasseraquarium-Weblog
UnterwasserVideos, Fotos und Screensaver, Faszination Tauchen. Original Videoaufnahmen unter Wasser, Tauchplatzbeschreibungen und wissenwertes zu Fischen und Wirbellosen. Filme und Videoclips für Werbung und privat, für Taucher und Nicht-Taucher, sowie Aquarien-Freunde. Die UW-Video Clips sind Original-Aufnahmen von verschiedenen Tauchplätzen, teils mit UnterwasserFilmMusik und Sound unterlegt. Informationen zu Divespots und Fischen werden mit kurzen Texten und Hinweisen vorgestellt. Desweiteren finden Sie diverse Unterwasser-Screensaver und ein Meerwasseraquarium-Weblog. Alle Movieclips und DV-Filmaufnahmen können für gewerbliche und kommerzielle Zwecke erworben werden
http://www.videounterwasser.com/

MX-5 Austria
mx5-austria.com versteht sich als Anlaufstelle für alle MX-5, Miata und Eunos Roadster Enthusiasten im deutschsprachigen Raum, jedoch mit dem Fokus auf die lebendige österreichische MX-5 Szene. Aktuelle Informationen, Videos, Testberichte, ein Forum, Chat, eine der umfangreichsten Linksammlungen rund um den MX-5, eine große Downloadsektion, ein Marktplatz und eine österreichische MX-5 Halterliste runden das umfassende Angebot ab. mx5-austria.com ist ein privates, unabhängiges Ein-Mann Webprojekt, das von Michael Tieber im Herbst 2000 gegründet wurde, um der keimenden MX-5 Szene in Österreich zur Blüte zu verhelfen, und bereits gesammelte Informationen und Erfahrungen weiterzugeben.
http://www.mx5-austria.com/

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/

Sport Gallery
Features athletes pictures, themes, wallpaper and poster on several sport category.
http://www.sport-gallery.com/

Shareware software resource, search and browse for free downloadable files.
Free software resource - Features a variety of shareware categorized by topic, including games, business, screensavers, and education software. Programs have screenshots, reviews and author info. Free downloads of the latest Windows 95/98/2000/XP shareware.
http://www.softdepia.com/

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

Galt Shareware Zone
Directory of shareware downloads, reviews and a free newsletter.
http://www.galttech.com/

Screensaver.nu
Enjoy the free screen savers collected from all corners of the web in an easy to navigate fashion. The screen savers are all freeware.
http://www.screensaver.nu/

Sophos Anti-Virus
Antivirus software package targeted at business customers
http://www.sophos.com/

Scholastic Corporation
Publishes and distributes children's books, classroom and professional magazines and other educational materials. (Nasdaq: SCHL).
http://www.scholastic.com/