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Smartphones inside out – part 1 of 2

Mobile phones were originally pretty simple, even completely analog electronic devices. They were closer to (and originated partly from) military portable radios. When the Finns sporadically ventured into guerrilla marketing in the 1980s, a delegation of politicians surprised head of Soviet Union, Mikhail Gorbachev by stashing a mobile phone and an open connection to the Kreml.

Nowadays ‘smartphones’ as we tend to know these devices, are an advanced species – even so that we might think of them a bit like Arthur C. Clarke defined magic: “Any sufficiently advanced technology is indistinguishable from magic”.

That is, we start to accept our limited understanding and capability to know what really goes on behind the scenes in a smartphone.

Let’s open the curtains a bit.

A smartphone is a computer in a small form factor, using a mobile network to do things that are fun and useful to us.

I’ll first introduce general electronics, regardless of what size the “computer is”.

You don’t have to know basically anything about either computers or mobile phones (I’ll use the term ‘mobile phone’ and smartphone interchangeably).

“In the old days” the electronics seemed to be less visible and only served a kind of infrastructure (auxiliary) role in mobile phones. The batteries lasted for weeks, since the phone was mostly in a very passive state; waiting for activity, with no large bright colorful displays like today’s (2013) phones. Nowadays people find the battery depleted almost habitually in 12 hours or less. And all this, even though the capacities of the batteries have increased considerable. The culprit? Vastly more complex and power-hungry circuits and displays. Also the network traffic is different; the 1990s mobile phones could achieve data speeds of only

The electronics starts with current; that is, a stream of electrons. An electron is a carrier of negative charge. It can move either via a charge conductor, or in ‘ether’ (air, or vacuum – doesn’t matter) through spaces. When we’re talking about electronics, the charge movement happens usually in copper. Copper is abundant and relatively cheap substance, thus very common in electronics.

When talking about a “45 nm” (or 5, 10, 14, …) production technology, the number 45 nanometers is referring to the width of those copper via’s. A “via” means just that; you can think of it as a road for the charge carriers, electrons. Between two vias there is space (empty), so that current doesn’t flow inappropriately. In reality, the pitch area (space between vias) is made of such material that electrons do not flow. Resistance is high, whereas in conductors the resistance is very low.

Since electronics is a physical realization, there comes the limitations imposed by physics. Electric impulses, although fast, travel at finite speed. Also in parallel data it has to be taken into account that the individual pulses encoding a “bit” might arrive slightly at different times, if the via length differs from each other. This is what EDA tackles in optimizing routes.

A baby computer? 

If you know something about the inner workings of computers, then think of a smartphone as a computer with just a unique layout of components (screen, external buttons, speaker, microphone, camera) and add to that essentially a “long range Wifi” (wireless connection). Why I use the word ‘Wifi’ in referring to actually the family of GSM/GPRS/3G/4G connections is that essentially there’s no magic in the “native” mobile connection – it’s a radio network, and in fact when the mobile phone’s signal has reached the base station, it travels – not via radio – but via fiber optic cables into switching centers, which take it through routing into the closest base station of your discussion partner. There’s your phone!

A smartphone has developed so fast that some phones pack more memory and computing power than laptops. Just now, approaching the year 2014 the year 2016, a major barrier between 32-bit and 64-bit processors is being overcome. 32-bit processors have an innate limit of accessing at most 2^32 (two to the power of thirty two) bytes of memory, which amounts to 4 gigabytes (4096 times one megabyte of memory). This of the equivalent of storing approximately 4000 high quality images. When the processors are done in 64-bit technology, it means that their internal registers (pointers to memory) are added another 32 bits, and thus the new maximum memory is increased to quite a remarkable amount: 4 billion times the old barrier, or 2 to the power of 64.

Stay tuned for part 2…

 

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