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Encyclopedia > 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 used for entertainment or security purposes. A computer display A computer display or computer monitor is an output device that is part of a computers display system. ...

3D Pipes by Microsoft
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3D Pipes by Microsoft

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Download high resolution version (893x555, 44 KB)3d pipes screen saver by Microsoft. ... Download high resolution version (893x555, 44 KB)3d pipes screen saver by Microsoft. ...

Purpose

Before the proliferation of LCD screens, most computer screens depended on cathode ray tubes (CRTs). Images on a CRT monitor are generated using electron beams which are emitted from electron guns at the back of the tube, and manipulated by electromagnetic fields to form images line-by-line on the phosphorescent screen many times per second. In some situations the images displayed on the screen constantly change, but in other cases some areas of the screen, or the screen as a whole, change very little (the taskbar in Microsoft Windows, for example). When the same image is displayed on a CRT screen for long periods of time, the properties of the exposed areas of phosphor coating on the inside of the screen gradually and permanently change, eventually leading to a darkened shadow or "ghost" image on the screen. Televisions, oscilloscopes and other devices that use CRTs are all susceptible to phosphor burn-in, as are plasma displays to some extent. LCD redirects here. ... It has been suggested that Crookes tube be merged into this article or section. ... Electron gun from a cathode ray tube An electron gun is a component that produces an electron stream that has a precise kinetic energy, being used in all TVs and monitors which use cathode ray tube technology, and in other instruments, eg. ... Electromagnetism is the force observed as static electricity, and causes the flow of electric charge (electric current) in electrical conductors. ... Phosphorescent powder under visible light, ultraviolet light, and total darkness. ... In computing, the taskbar is a term for the application desktop bar which is used to launch and monitor applications in Microsoft Windows 95 and later operating systems. ... Microsoft Windows is a family of operating systems by Microsoft. ... A Tektronix model 475A portable analogue oscilloscope, a very typical instrument of the late 1970s. ... Phosphor burn-in is a permanent disfigurement of areas on a cathode ray tube (e. ... A plasma display panel (PDP) is an emissive flat panel display where visible light is created by phosphors excited by a plasma discharge between two flat panels of glass. ...


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 (thus "saving" the screen). 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. The screensaver then blanks the screen, or more commonly produces animation effects, thus avoiding any "fixed" images. The screensaver remains active until a user presses a key or makes a mouse movement. At that moment, the screensaver closes and the former screen contents are restored, allowing the user to work again.


For CRTs used in public embedded applications such as ATMs and railway ticketing machines, the risk of burn-in is especially high because a stand-by display is shown whenever the machine is not in use. Older machines designed without burn-in problems taken into consideration often display evidence of screen damage, with images or text such as "Please insert your card" (in the case of ATMs) visible even when the display changes while the machine is in use. Blanking the screen is out of the question as it would make the machine look out of service. Thus, in these applications, burn-in is prevented by moving the contents of the display around every few seconds, or by having a number of different images that are changed regularly. An NCR interior, multi-function ATM in the USA Smaller indoor ATMs dispense money inside convenience stores and other busy areas, such as this off-premise Wincor Nixdorf mono-function ATM in Sweden An on-premise NCR interior, multi-function through-the-wall ATM at a CIBC branch in Canada...


Modern CRTs are much less susceptible to burn-in than older models due to improvements in phosphor coatings, and because modern computer images are generally lower contrast than the stark green- or white-on-black text and graphics of earlier machines. LCD computer monitors, including the display panels used in laptop computers, are not susceptible to burn-in because the image is not directly produced by phosphors (although they can suffer from a less extreme and usually non-permanent form of image persistence). For these reasons, screensavers today are primarily decorative or for entertainment, and usually feature moving images or patterns and sometimes sound effects. A laptop computer or simply laptop (also notebook computer or notebook) is a small mobile personal computer, usually weighing from two to six pounds (one to three kilograms), depending on size, materials and other factors. ... Image Persistence is the term used for LCD Screen Burn. Like the burn-in on CRT monitors, image persistence on LCD monitors is caused by the continuous display of static graphics on the screen for extended periods of time. ...

Einstein@Home automatically scans astronomical data for evidence of pulsars
Einstein@Home automatically scans astronomical data for evidence of pulsars

One increasingly popular application is for screensavers to activate a useful background task, such as a virus scan or a distributed computing application (such as the SETI@home project). This is convenient because these applications only use resources when the computer would be otherwise idle. Image File history File links Download high-resolution version (1280x994, 107 KB) A snapshot from my Einstein@home-BOINC-client. ... Image File history File links Download high-resolution version (1280x994, 107 KB) A snapshot from my Einstein@home-BOINC-client. ... A screenshot of the Einstein@home graphics. ... Anti-virus software consists of computer programs that attempt to identify, thwart and eliminate computer viruses and other malicious software (malware). ... Distributed computing is decentralised and parallel computing, using two or more computers communicating over a network to accomplish a common objective or task. ... SETI@home (SETI at home) is a grid computing (distributed computing in the projects own terminology) project using Internet-connected computers, hosted by the Space Sciences Laboratory, at the University of California, Berkeley, in the United States. ...


Considerations

Monitors running screensavers consume the same amount of power as when running normally, which can be anywhere from a few watts for small LCD monitors to several hundred for large plasma displays. Most modern computers can be set to switch the monitor into a lower power mode, blanking the screen altogether. A power saving mode for monitors is usually part of the power management options supported in most modern operating systems, though it must also be supported by the computer hardware and monitor itself. The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...


Additionally, using a screensaver with a flat panel or LCD screen instead of powering down the screen can actually reduce 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 they can be expensive or difficult to replace. A typical LCD screen loses about 50% of its brightness during a normal product lifetime, if left on continuously. (In most cases, the tube is an integral part of the LCD and the entire assembly needs to be replaced.) A TFT LCD 15 display TFT LCDs is a variant of Liquid Crystal Display (LCD) which use Thin-Film Transistor (TFT) technology to improve their image quality. ...


Thus the term "screen saver" is, in most cases, a misnomer--the best way to save the screen (and also save electricity) would simply be to have the computer turn off the monitor.


Entertainment

XScreenSaver displaying a Matrix-style screensaver
XScreenSaver displaying a Matrix-style screensaver

After Dark was an early screensaver for the Macintosh 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, games, and visual expressions of mathematics equations such as fractals. Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... The Matrix is a science fiction/action film written and directed by Larry and Andy Wachowski and starring Keanu Reeves, Laurence Fishburne, Carrie-Anne Moss and Hugo Weaving. ... After Dark is the name given to a series of successful screensaver software products first released in 1989 by Berkeley Systems for the Macintosh (and later ported to Windows). ... The first Macintosh computer, introduced in 1984, upgraded to a 512K Fat Mac. The Macintosh or Mac, is a line of personal computers designed, developed, manufactured, and marketed by Apple Computer. ... After Dark is a the name given to a series of successful screensaver software products first released in 1989 by Berkeley Systems for the Macintosh (and later ported to Windows). ... This article needs a complete rewrite for the reasons listed on the talk page. ... Euclid, Greek mathematician, 3rd century BC, known today as the father of geometry; shown here in a detail of The School of Athens by Raphael. ... A fractal is a geometric object which can be divided into parts, each of which is similar to the original object. ...


The ability of screensavers to divert and entertain is used for promotional purposes, especially to build buzz for "event-based" products such as feature films. Scale model of a Wheaties cereal box at a pep rally Promotion is one of the four aspects of marketing. ... Buzz may refer to: // General definitions Buzz, a feeling of mild intoxication Buzz, a low, vibrating sound. ... Film is a term that encompasses motion pictures as individual projects, as well as the field in general. ...


The screensaver is also an outlet for the work of creative computer programmers. The UNIX-based screensaver XScreenSaver collects the display effects of other UNIX screensavers, which are termed "display hacks" in the jargon file tradition of US computer science academics. It also collects forms of computer graphics effects called demo effects, originally included in demos created by the demo scene. Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... XScreenSaver-demo and the XMatrix hack XScreenSaver is a screensaver program for Unix-like operating systems running the X Window System. ... A still image from the famous munching squares display hack. ... The Jargon File is a glossary of hacker slang. ... A still screenshot of a typical plasma effect. ... A demo is a non-interactive multimedia presentation made within the computer subculture known as the demoscene. ... The demoscene is a computer sub-culture that came to prominence during the rise of the 16 bit micros (the Atari ST and the Amiga), but demos first appeared during the 8-bit era on computers such as C64 and ZX Spectrum. ...


Security

Gnome-screensaver has an option for password protection
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Gnome-screensaver has an option for password protection

Screensaver software can also be used as a rudimentary security measure. Many screensavers can be configured to ask users for a password before permitting the user to resume work. However, a user might be able to circumvent the password by restarting the computer if the computer's owner has set their account to automatically log in upon startup. Image File history File links Gnome-screensaver-screenshot-Ubuntu_6. ... Image File history File links Gnome-screensaver-screenshot-Ubuntu_6. ... . The initial letter is shown capitalized due to technical restrictions. ... A password is a form of secret authentication data that is used to control access to a resource. ...


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 CPU and GPU to perform more calculations, and keep the hard disk running for longer than if the computer were idle. Power management is a feature of some electrical appliances, especially copiers and computer peripherials, such as a monitor or printer that turns off the power or switches the system to a low-power state after a period of inactivity. ... CPU redirects here. ... GeForce 6600GT (NV43) GPU Radeon 9800 Pro (R350) GPU A Graphics Processing Unit or GPU (also occasionally called Visual Processing Unit or VPU) is a dedicated graphics rendering device for a personal computer, workstation, or game console. ...


Security risks for Microsoft Windows screensavers

On older versions of Microsoft Windows the native screensaver format had the potential to install a virus when run. When any file with the file suffix ".scr" was opened, for example from an e-mail attachment, Windows would execute the .scr (screensaver) file automatically — this had the potential to allow a virus or malware to install itself. Modern versions of Windows will detect that the file originated from the Internet and warn the user before executing it. Microsoft Windows is a family of operating systems by Microsoft. ... A filename extension or filename suffix is an extra set of (usually) alphanumeric characters that is appended to the end of a filename to allow computer users (as well as various pieces of software on the computer system) to quickly determine the type of data stored in the file. ... An e-mail attachment (or email attachment) is a computer file which is sent along with an e-mail message. ... In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents (for a complete definition: see below). ... Malware is software designed to infiltrate or damage a computer system, without the owners informed consent. ...


In addition, on August 5, 2006, the BBC reported that "screensavers" and "free screensavers" respectively were the most and third most likely search terms to return links to malware.[1] August 5 is the 217th day of the year in the Gregorian Calendar (218th in leap years), with 148 days remaining. ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...


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, 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). IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... John Socha-Leialoha is software developer most recognized for creating Norton Commander, a very popular file managing tool for DOS. John grew up in the woods of Wisconsin, earned a PhD degree in Electrical Engineering from University of Wisconsin, and his PhD in Applied Physics from Cornell University. ... Pre-Symantec version of Norton Commander for DOS Norton Commander v. ... 1983 (MCMLXXXIII) was a common year starting on Saturday of the Gregorian calendar. ... The front cover of the September 1980 issue of Softalk (Vol 1, No. ...


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 or C++ programming languages, along with Graphics Device Interface (GDI), DirectX, or OpenGL, to craft their final products. Several Mac OS X screensavers are created and designed using the Quartz Extreme graphics layer. 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. Wikibooks has a book on the topic of C Programming The C programming language (often, just C) is a general-purpose, procedural, imperative computer programming language developed in the early 1970s by Dennis Ritchie for use on the Unix operating system. ... C++ (generally pronounced /si plÊŒs plÊŒs/) is a general-purpose, high-level programming language with low-level facilities. ... GDI is short for Graphics Device Interface or Graphical Device Interface, and is one of the three core components or subsystems of Microsoft Windows. ... To meet Wikipedias quality standards, this article may require cleanup. ... OpenGL (Open Graphics Library) is a standard specification defining a cross-language cross-platform API for writing applications that produce 3D computer graphics (and 2D computer graphics as well). ... Mac OS X (IPA pronunciation: ) is a line of proprietary, graphical operating systems developed, marketed, and sold by Apple Computer, the latest of which is pre-loaded on all currently shipping Macintosh computers. ... Quartz Compositor is the windowing system that is responsible for the user interface in Mac OS X. On a Mac OS X system, the Quartz Compositor can be seen in a process list as Window Manager or, in more recent versions, WindowServer. ...


References

  1. ^ BBC News: Warning on search engine safety

External links


  Results from FactBites:
 
FileTransit - Software Downloads, News, Reviews and More! (594 words)
Flash ScreenSaver Master is an easy-to-use but powerful screensaver maker, which enables you to make your own screensavers from your favorite images(JPG or BMP files) or Macromedia Flash files, and you can add MP3 or MIDI sound files as background...
ES Screensaver maker allows you to create and distribute your own high-quality slideshow image screensaver, shockwave flash screensaver and movie screensavers easily and quickly.
Flash ScreenSaver Master is an easy-to-use but powerful screensaver maker, which enables you to make your own screensavers from your favorite images(JPG,BMP and GIF files) or Macromedia Flash files, and you can add MP3 or MIDI sound files as...
Screensaver - Wikipedia, the free encyclopedia (1390 words)
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.
Additionally, using a screensaver with a flat panel or LCD screen instead of powering down the screen can actually reduce the lifetime of the display, since the fluorescent backlight remains lit and ages faster than it would if the screen was turned off completely.
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.
  More results at FactBites »

 
 

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