because a lot of work has gone into making digital systems as deterministic as possible. there's noise everywhere in the real world, but by thresholding voltage values and operating on clock ticks, digital systems are largely impervious to it.
if you run the same program twice, you get the same result. this is the wonderful result of all that work... but now there's no noise so there's no randomness.
random number generators are actually just mathematical functions that produce a stream of output with a flat distribution given a fixed input. the simplest ones give the exact same output given the same input. (sometimes this is exploited in debugging of algorithms that make use of randomness, like monte carlo methods).
newer hardware has hardware support for generating random numbers using analog phenomena, but older hardware doesn't always have this. there are some clever hacks in the kernel that make use of noise found in the clocks that drive the digital system, as well as sampling from a variety of external sources (interrupts from things like network activity, or keyboard/mouse, or other hardware).
the problem here is that they want good randomness early in the boot process when a lot of those interrupts aren't being generated (because the hardware hasn't started), there's no hardware support for randomness, and the clock noise trick doesn't work.
my guess is that they'll probably add a few more random (hah) hacks to try and generate noise when there's no peripherals although the article states that they're going out and trying to fix userland by adding a program that saves/restores some randomness for each boot.
but. enough with this computer stuff. here's the really interesting question: are living creatures deterministic machines?
there's so much random noise in the environment that it is extremely hard to answer.
moreover, we know that early development of sensorimotor systems is driven by random noise. we learn to control our bodies by being stimulated by environmental noise, attempting to use our effectors (muscles), observing how that works out, correcting errors and then improving on it.
what gives rise to consciousness? i'd argue the randomness from the noise in our environments.
if you run the same program twice, you get the same result. this is the wonderful result of all that work... but now there's no noise so there's no randomness.
random number generators are actually just mathematical functions that produce a stream of output with a flat distribution given a fixed input. the simplest ones give the exact same output given the same input. (sometimes this is exploited in debugging of algorithms that make use of randomness, like monte carlo methods).
newer hardware has hardware support for generating random numbers using analog phenomena, but older hardware doesn't always have this. there are some clever hacks in the kernel that make use of noise found in the clocks that drive the digital system, as well as sampling from a variety of external sources (interrupts from things like network activity, or keyboard/mouse, or other hardware).
the problem here is that they want good randomness early in the boot process when a lot of those interrupts aren't being generated (because the hardware hasn't started), there's no hardware support for randomness, and the clock noise trick doesn't work.
my guess is that they'll probably add a few more random (hah) hacks to try and generate noise when there's no peripherals although the article states that they're going out and trying to fix userland by adding a program that saves/restores some randomness for each boot.