March 19, 2011

Screen of Death

In many computer operating systems a special type of error message will display onscreen when the system has experienced a fatal error. Computer users have dubbed these messages screens of death as they typically result in unsaved work being lost and often indicate serious problems with the system’s hardware or software.

Screens of death are usually the result of a ‘kernel panic’ (an action taken by an operating system upon detecting an internal fatal error from which it cannot safely recover), although the terms are frequently used interchangeably. Most screens of death are displayed on an even background color with a message advising the user to restart the computer.

March 19, 2011

Kill Screen

A kill screen is a stage or level in a video game (often an arcade game) that stops the player’s progress due to a programming error or design oversight. Rather than ‘ending’ in a traditional sense, the game will crash, freeze, or behave so erratically that further play is impossible. Pac-Man has a famous kill screen often referred to as the ‘Pac-Man Bomb Screen.’ The game’s level counter was a single 8-bit byte and could therefore store only 256 distinct values. Reaching the 256th level causes the counter that is used while drawing the fruit to overflow to zero, causing 256 fruits and seven blank spaces to be drawn.

Kill screens were much more common during the Golden Age of Arcade Games. Games from this era were often written with the assumption that the player would stop playing long before the numerical limits of the game code were reached; most games from this period were intended to continue until the players lost all of their lives. Additionally, the limited hardware of these early machines often meant that programmers could not spend memory on logical checks of the game state.

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March 19, 2011

Stereographic Projection

The stereographic projection, in geometry, is a particular mapping that projects a sphere onto a plane. The projection is defined on the entire sphere, except at one point — the projection point. Intuitively, then, the stereographic projection is a way of picturing the sphere as the plane, with some inevitable compromises. Because the sphere and the plane appear in many areas of mathematics and its applications, so does the stereographic projection; it finds use in diverse fields including complex analysis, cartography, geology, and photography.

The projection has been used to map spherical panoramas. This results in interesting effects: the area close to the point opposite to the center of projection becomes significantly enlarged, resulting in an effect known as little planet (when the center of projection is the nadir) and tube (when the center of projection is the zenith).

March 19, 2011

Operation Odyssey Dawn

Operation Odyssey Dawn is the codename for the United States participation in a Libyan no-fly zone. The United Kingdom counterpart to this is Operation Ellamy, the French Opération Harmattan. The no-fly zone was proposed during the 2011 Libyan uprising to prevent government forces loyal to Muammar Gaddafi from carrying out air attacks on rebel forces.

Allied operations began with surveillance operations, air attacks and missiles aimed at Libyan military targets. It was reported by the Pentagon that the first strike involved the launch of over 100 Tomahawk cruise missile against shoreline air defenses of the Gaddafi regime.