The Role Of GLBDATA.PS2 in a PS2 game disc

The GLBDATA.PS2 File is used when loading the main part of a game. If the file is deleted from the game disc, the game boot will load when you start it. But after going through the menus, when the game is to be loaded, the game wouldnt load. What I mean is that the game first loads into the menus, and then loads into the place you are to play, but it wont. This file tells the ps2 what sector of the game files to read so as to be able to play the game.