Hexspeak

Hexspeak, like leetspeak, is a novelty form of variant English spelling using the hexadecimal digits. Created by programmers as memorable magic numbers, hexspeak words can serve as a clear and unique identifier with which to mark memory or data.
Hexadecimal notation represents numbers using the 16 digits codice_1. Using only the letters codice_2 it is possible to spell several words. Further words can be made by treating some of the decimal numbers as letters - the digit "codice_3" can represent the letter "O", and "codice_4" can represent the letters "I" or "L". Less commonly, "codice_5" can represent "S", "codice_6" represent "T", "codice_7" represent "R" and "codice_8" or "codice_9" can represent "G" or "g", respectively. Numbers such as codice_10, codice_11 or codice_12 can be used in a manner similar to leet or rebuses; e.g. the word "defecate" can be expressed either as codice_13 or codice_14.
Notable magic numbers.
Many computer processors, operating systems, and debuggers make use of magic numbers, especially as a magic debug value.
Alternative letters.
Many computer languages require that a hexadecimal number be marked with a prefix or suffix (or both) to identify it as a number. Sometimes the prefix or suffix is used as part of the word.
PlayStation 3 RSX.
In reverse engineering aspects of the Sony PlayStation 3, a number of hexspeak codes were found to either trigger, affect or were present in aspects of communicating to and through the PlayStation 3 Hypervisor in communication to its GPU, the RSX Reality Synthesizer.
These projects were largely born out of PS3 homebrew operating on the PS3's OtherOS which allowed Linux to be installed, initially with extremely limited GPU access.