Saturday, May 22, 2010

The Pac-Man Bug

I had just shut my laptop down and was wondering abt to dos for the rest of the day.. but somehow the Pac Man mania aint goin outta my head ... so here s another post


I don't know how many of u know abt it but there was a famous bug in the original PacMan.. As a side effect to its awesome unendability after the 255th level was done the 256th level's screen looked clogged withunwanted symbols a representation of generation of garbage values instead of the required symbols...


   It was called the "split screen"..evidently..and this meant Pac-Man was no longer infinite.... :(..But what caused this seemingly revolutionary game to fail...the game that u could paly untill u die wasn't so ne more..

This error was a result of a single 8-bit level counter which could store only 256 distinct values rangin from(0-255) and thus a kill screen at level 256.Normally, no more than seven fruits are displayed at any one time, but when the internal level counter (stored in a single byte) reaches 255, the subroutine erroneously causes this value to "roll over" to zero before drawing the fruit. This causes the routine to attempt to draw 256 fruits, which corrupts the bottom of the screen and the whole right half of the maze with seemingly random symbols.

Pac-Man and the ghosts can move freely throughout the right half of the screen, barring some fractured pieces of the maze. Despite claims that someone with enough knowledge of the maze pattern could play through the level, it is technically impossible to complete since the graphical corruption eliminates most of the dots on the right half of the maze. A few edible dots are scattered in the corrupted area, and these dots reset when the player loses a life (unlike in the uncorrupted areas), but these are insufficient to complete the level. As a result, the level has been given a number of names, including "the Final Level", "the Blind-Side", and the ending. It is known more generally as a kill screen.


A perfect Pac-Man game occurs when the player achieves the maximum possible score on the first 255 levels (by eating every possible dot, energizer, fruit, and monster) without losing a single life then scoring as many points as possible in the last level. The first person to achieve the maximum possible score (3,333,360 points) was Billy Mitchell of Hollywood, Florida, who performed the feat in about six hours.


An 8-year-old boy, Jeffrey R. Yee, supposedly received a letter from U.S. President Ronald Reagan congratulating him on a worldwide record of 6,131,940 points, a score only possible if the player has passed the Split-Screen Level. Whether or not this event happened as described has remained in heated debate among video-game circles since its supposed occurrence.No video game player could demonstrate this ability. In 1999, Billy Mitchell offered $100,000 to anyone who could provably pass through the Split-Screen Level before January 1, 2000; the prize went unclaimed.

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