Each library stores 4 types of 
data base information:

LINES, PCB DECALS, LOGIC DECALS,
and PARTTYPES.

Lines are used to represent the Board
Outline,and User Defined shapes 2-D
info.

(PCB/Logic)Decals are used to define a 
parts outline, and its pin locations.
For PCB Decals the pad stack associated
with each pin is defined. 

PartType defines the electrical properties
of a part and the decal associated with
the part.

