Random Numbers

CLtL2 Reference 

variable *RAND-MAX*
*rand-max* is the largest fixnum that the function random can accept. 

function SEED-RANDOM : (&optional (seed-fixnum (mod (get-internal-real-time) *rand-max*)))
If seed-fixnum is omitted to seed-random, the internal clock is used
in an implementation specific manner. 

function RANDOM : (number)