doubt on taking vertical pitch for dip packages
Pitch between pins in the row is 0.1 inch (2.54 mm);

Distance between the rows E is 0.3 inches (7.62 mm). That's why package is called "300 mil". There're DIP packages being called "600 mil" having 0.6 inches between the rows.

So to place this component onto your board (called footprint) you have 0.3 inches distance between the rows.


  why there is a dimension like eb?what it refers?


I think eB refers to the configuration of the antistatic tube to store chip in.