buffering

hi to all abap gurus

my querry is as follows what is buffer ? and when do we buffer the table ?

how do we decide wether the table has tio be buffered or not ?

we know that all bufeering types 1 full buffering , 2. single record buffering .3.generic buffering .

buffering techniques 1.buffering allowed

2. buffering allowed but switched off

what r the differences between buffering types and buffering techniques

pls give the anser in detail points woll be rewarded definitely