The first type of mining hardware used was a CPU, or central processing unit.
As of late September 2017, mining with a CPU would take you about 7.6 million years to find a block.
This is because there is much more powerful hardware nowadays, which makes it much harder for a CPU to compete with the rest of the network.
The pseudocode above is what was run originally by CPU miners.
They were the original type of computing power available to the general public.
This is because CPUs are meant to do generic computation, but they are not great at specifically calculating hashes.
Some members of the gaming community quickly recognized that they had some more powerful computation devices available at their hands: GPUs.
GPUs, or graphic processing units, are devices typically used for processing media, like video games.
These devices are also generic computational devices in that they can handle many different types of computation, including hashing.
They are an order of magnitude faster than CPUs when it comes to computing, meaning that they can hash 10 times as fast.
If you look in the chart, you’ll see that in order to mine a block, GPUs only take about a mere 762 thousands years! GPU miners were most common about 6 years ago, back in 2012, when still not many people had heard of Bitcoin.
They were repurposed from gaming to mining, providing GPU miners a significant advantage above CPU miners.
Some of the disadvantages of using GPUs, however, stems from their components irrelevant to mining.
For example, mining does not require any floating point numbers, so the excess components are not helpful but are still included in the cost of GPU hardware.
In addition, they are not meant to be run in farms side by side, so it is difficult to operate a large scale GPU mining setup.
This is where FPGAs, or Field Programmable Gate Arrays, come into play.
These were the first forms of specialized mining hardware in Bitcoin.
These devices were optimized for mining Bitcoin, but they did not lose all general computation power.
The reason for this tradeoff was because there was still some uncertainty around Bitcoin’s future success, and Bitcoin-specific hardware would become useless if Bitcoin disappeared.
However, if Bitcoin thrives, then there is a desire to beat out other mining competition.
However, FPGAs were only used briefly, because much more powerful hardware quickly came into the market around 2014.
ASICs, or Application Specific Integrated Circuits, are mentioned throughout the Bitcoin ecosystem.
These are fully specialized devices that can do only one thing.
Bitcoin ASICs are capable of one type of computation alone: mining.
These devices do nothing but solve the Bitcoin hash puzzle, but they do it better than anything else.
There are large amounts of customizability when it comes to ASICs.
These range from choosing a lower base cost in exchange for higher electricity use, or choosing a smaller device and losing out on hashrate.
Depending on your specific needs, there probably exists a relevant ASIC.
One issue with ASICs, however, is their initial cost.
Not only do ASICs take a lot of upfront capital to produce, but they also need to be bought in tremendous batches to make a reasonable profit.
A fun stat: one of the most popular and powerful ASICs, the Antminer S9, can perform 14 trillion hashes per second but would still take about 10.9 years to find a block.