A
s computers have evolved over the
years, so has the way in which all
the components within them
communicate with one another. From
improvements in the core processors that
drive our systems, such as CPUs and GPUs, to
changes in RAM technology and overhauled
system buses, as one aspect changes, other
components need to follow suit.
In this feature we’ll explore the inner
workings of all these connections, explaining
the difference between a graphics card slot
and a CPU socket, why the latest M.2 SSDs can
run at ridiculous speeds and why USB works
the way it does. Along the way, we’ll explore
just why current PCs came to be this way.
Digital vs analogue
When you consider just why computers are
made the way they are, the starting point is
to consider why computers are even digital.
After all, humans largely interact with an
analogue world. Colours, sound, sensation
and emotion all exist on vast spectrums,
and the way we often get the most joy from
our computers is when they replicate these
nuances as closely as possible – from the rich
colours of games and videos to the sonic bliss
of our favourite music.
Analogue computers certainly exist, and
are still used in some applications. Instead
of abstractly representing an attribute as
a binary number, analogue computers
physically change the characteristics of an
electronic signal – such as its magnitude,
frequency and phase – in order to produce
a result. It’s a bit like how a guitar amplifier
mucks about with the signal from a guitar,
except here the input might be from an
assembly of sensors or an array of switches,
and the output might be a series of dials.
Because analogue computers operate
without the abstraction of digital systems,
they can perform certain functions farquicker,
making them ideal for some applications.
However, there are several reasons why
digital computers have largely taken over.
The first is versatility. While analogue
computers (or hybrid analogue/digital
computers) can perform certain specific
tasks very well, they by and large can’teasily
be turned to a wide variety of other tasksor
made meaningfully programmable. They
tend to be built for a singular purpose(ora
handful of tasks), such as calculating the
projectile trajectories for ships’ cannons.
You can build more general-purpose
circuits for adding, multiplying, differentiating
and more, then adjust the input parameters
and string them together in different ways,
but there are limits on how you can dothis.
After all, because analogue computersare
physically changing the signal, some circuits
might cause these parameters to hit alimit
that the input for another part of the circuit
won’t be able to handle. It’s also inherently
difficult to accurately store an analogue
signal for a reasonable length of time,making
any sort of memory operations difficult.
Conversely, the stark on/off, high/low
voltage state of a digital signal means
it’s much less prone to some types of
interference. By all means, it can still
be affected by interference but
as a starting point, it’s much
more robust.Why binary?
Having established that digital is the way
forward, the next consideration is just how
to represent the digits of our digital device.
While it may seem entirely obvious that
binary is the way to go, it’s an inefficient
numbering in many ways. After all, 99 is
considerably more space-efficient visually,
and much easier for us as humans to read
than 1100011.
What’s more, it’s theoretically possible
to have some sort of decimal electronic
computer system. You could fairly easily have
a system that represents decimal digits by
having ten different voltage levels on a wire,
for instance.
However, in practical terms, such a system
would be highly prone to interference, just as
with analogue devices. What’s more, using a
binary system makes building circuits much
easier, as operations can be broken down into
simple on/off calculations known as Boolean
algebra, which can be represented by simple
and fast-responding electronic switches
such as transistors. Back in the day, it was the
invention of the thermionic valve that reallyOPERATIONS CAN BE
BROKEN DOWN INTO
SIMPLE ON/OFF
CALCULATIONS
KNOWN AS
BOOLEAN ALGEBRA