The file
.I /dev/urandom
has major device number 1 and minor device number 9.
-.LP
+.PP
The random number generator gathers environmental noise
from device drivers and other sources into an entropy pool.
The generator also keeps an estimate of the
number of bits of noise in the entropy pool.
From this entropy pool, random numbers are created.
-.LP
+.PP
Linux 3.17 and later provides the simpler and safer
.BR getrandom (2)
interface which requires no special files;