•The VMS FORTRAN Run-Time Library contains a random number generator RANDU, first introduced by IBM IN 1963. This turned out to be a poor random number generator, but nonetheless it has been widely spread.
•INTEGER*4 SEED
•INTEGER*2 W(2)
•EQUIVALENCE( SEED, W(1) )
•R = FOR$IRAN( W(1), W(2) )
•R is the return value between [0,1). W(1) and W(2) together is the seed value for the generator. This goes
back to the PDP-11 days of
16 bit integers. SEED is really a 32 bit
integer, but it was represented as two 16 bit integers.