I don´t know exactly if the govenrments are yet
able to build brain interfaces, or "man machine interfaces",but
being a true conspiracy theorist, I would guess they already
got there in the 90´s.
I guess I'll be known as the skeptic of this forums
I agree anything is possible if you are a conspiracy theorist, but for what is known in the academy and computational neuroscience circles even now people struggle to have the sufficient bandwidth and low latency required to read live streams of raw data from brain-computer interfaces. In the 90's it would be VERY unlikely to have anything useful.
I believe that today, it´s possible
for the CIA, NSA etc. to hack into any PC with ease,
without even being physically conected to the web.
I can think of two ways this may happen: personally having someone using the computer, and through some kind of machine-telepathy
You need a physical media to transfer any kind of data signal. Could be the air, yes, but you would need emitting and receiving devices at least, and communication protocols. An isolated PC would be precisely that, isolated.
There´s going
to be 200.000 core cpus in some years available on the free
market, so it´s not hard to imagine that the governments with
their black projects are even much further advancend to this
moment while I´m typing this.
That is extremely impractical. There are limits to miniaturization, and computing efficiency would be greatly affected by the heat produced by having so many components in close proximity. For high-throughout and high-performance computing, it is proven that having multiple units as opposed to single powerful units is better cost and performance wise. That said, there ARE computing systems with more than 1 million cores. It should also be said that cores don't mean much in computing power, what is usually counted is "operations per second", which depends on several things and does not correlate with the number of cores. The Sequoia, current second fastest supercomputer, has 1.57 million cores and peaks at around 20 Peta FLOPS. The number one machine, Titan, has around 560,000 cores and reaches around 27 Peta FLOPS peak performance.
There ARE accessible, high performance computing devices currently available to the mainstream market. They're usually called video cards.