USB booting :: usb boot pendrive in more that 1 pc

I used a pendrive with boot dsl in 3 pcs with diferents hardwhare and i am interested in have a generic boot ,  with no changes betwen pcs ....i think that the usb pendrive boot make a saved config when you end the session???..(  i am new be).dsl 2.4 rc2


Also when i begin a session with normal hd boot and mount sda1 with dsl boot and when i end the session the sda1 record something of the pc config???.

 Can somebody explain these records..

  Thanks