random: what is the default seed?

Question

For Python 3, I can find many different places on the internet stating that the default seed for the random module is based on system time.

Is this also the case for Python 2.7? I imagine it is, because if I start two different Python processes, and in both I do import random; random.random() then the two different processes return different results.

If it does use system time, what is the actual seed used? (E.g. "number of seconds since midnight" or "number of microseconds since UNIX epoch", or ...) If not, what is used to seed the PRNG?

Answer 1

This is the source code about how to generate default seed for a Random object.

try:
    # Seed with enough bytes to span the 19937 bit
    # state space for the Mersenne Twister
    a = long(_hexlify(_urandom(2500)), 16)
except NotImplementedError:
    import time
    a = long(time.time() * 256) # use fractional seconds

urandom equals to os.urandom. And for more information about urandom, please check this page.