Redirecting you to https://www.google.com/search?hl=en&rlz=1W1ACEW_enUS375&q=related:en.wikipedia.org/wiki/IBM_System/370+IBM+system+370+psw+program+status++switch&tbo=1&sa=X&ei=zsY_UMvBArG_2QX63IDYDA&ved=0CC4QHzAC