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What is a Blockchain and a Blockchain node

In 2008 an individual or a group of individuals going by the name Satoshi Nakamoto issued a draft named Bitcoin: a peer-to-peer electronic cash system. This draft conceptualized a blockchain, which became a core component when the first release of the cryptocurrency Bitcoin was launched a year later.

The Bitcoin blockchain has a wide range of applications for both financial and non-financial systems and is referred to as an alternative chain when used for other purposes than Bitcoin. It should be noted that alt-chains can either use the Bitcoin blockchain (fork) or use it as a reference for their own blockchain. If they chose to do so, they might also use a:

  • Different algorithms for calculating the block hash.
  • Other name conventions for things such as blocks, computer roles and other.
  • Different definition for what transaction is.
  • Other consensus protocols.
  • Different network protocol for their P2P network.

However, the fundamentals of the Bitcoin blockchain architecture still apply. There are various reasons explaining why one may opt to use an alt-chain, but the primary reason is the ability to scale Transactions Per Second (TPS).

 Reddit Solana vs Ethereum vs Binance Smart Chain vs Polkadot vs Cardano vs Tron

Reddit
Solana vs Ethereum vs Binance Smart Chain vs Polkadot vs Cardano vs Tron

Bitcoin blockchain (fundamental) architecture

A blockchain is an immutable chain of validated append-only blocks, where each block is linked to the preceding block by its headers cryptographic hash a blockchain develops from a hard-coded genesis block, and each succeeding block is added chronologically as shown below.

Blocks are data stored on the blockchain. A new block is created by a miner. Before a block is added to the chain it has to be validated. Some steps have been omitted due to being less relevant to explain the blockchain. The main steps are:

  1. A mathematical problem needs to be solved, this process is called Proof of Work (PoW).
  2. The network needs to reach a consensus.

Read also: How Can Blockchain Skill Crypto Wallets for a Better Proficiency

Not only is the PoW process time and resource-consuming, but it also has a certain level of difficulty. It is an algorithm that calculates the new blocks’ header hash value. The difficulty lies in the header hash value must be less than the preceding blocks header hash value and that all miners are competing to be the first with the solution. This is referred to as Bitcoin mining due to it is resource-consuming and done by a miner. Though the reward for coming up with the solution is Bitcoins, those are not what is actually being mined.

Next, the block needs to be validated. This is done by using a consensus protocol where the nodes in the network validate the PoW. When the nodes reach a consensus, based on a majority vote, the block is then added to the chain. A blockchain is only deemed valid if the blocks and data within are valid and originated from the genesis block.

How a blockchain works
How a blockchain works

How is a block processed?

Because of the way each block is processed and connected to the chain altering a block’s contents or deleting a block is nearly impossible. To alter or delete a block will require all succeeding blocks’ header hash to be recalculated, which would be extremely costly.

A blockchain is stored in a database. The innovation and power of the blockchain lie in the database is distributed over a large number of computers on the internet. Bitcoin and most other alt-chains use a public Distributed Ledger (Technology) database. This means that once data is recorded on the ledger it will remain there forever and since it is publicly available there will be a certain level of transparency to it as well. Block Explorer offers a real-time view of all current and past Bitcoin transactions. You can see the original genesis block transaction.

What are Blockchain nodes?

In a conventional enterprise computing network nodes are normally defined as:

  • A server is a dedicated unit running 24/7/365 on purpose-made hardware and normally placed in a data center.
  • A Client can be anything from a PC or laptop to a smartphone basically anything that a user brings to the office and connects on the network.

Though both the server and the client can have multiple roles depending on what their purpose is, they are bound by being classified (read referred to as) either as a server or a client and are hosted in a dedicated infrastructure.

The blockchain was designed to not rely on dedicated hardware and or dedicated infrastructure, but on a Peer-to-Peer (P2P) network infrastructure where anyone can participate, and be both a server and a client at the same time. However exceptions can be found, there are blockchains that are hosted in a dedicated enterprise computing infrastructure. Ripple is an example of this.

Rather than using the common server and client distinction, the blockchain talks about nodes. Nodes are then normally prefixed on a non-standard naming that indicates their role on the blockchain. To avoid causing more confusion, the Bitcoins naming convention will be used to explain the role of each node.

The blockchain explained
The blockchain explained

Full node

Make up the backbone of the network. Their purpose is to collect, store, transmit, validate and enforce; all a part of the services they provide to the miner and lightweight nodes in the network.

You can think of these as servers, but unlike traditional servers, these can in theory run on anything you have at home that has enough space (a couple of hundreds of gigabytes) to store the entire blockchain that could be your home PC, laptop, or NAS; and it is even possible to prune the blockchain database to the extent that it will fit on a USB key and can be run on a Raspberry Pi. Preferable a full node should run 24/7/365, but being online when you are is also fine it will still contribute to the growth and stability of the network.

Miner node

Make up the workforce that crunches the numbers. Their purpose is to create new blocks and compete with other miner nodes for who creates the block first. Only the winners block is added to the chain. The winning miner node is then financially rewarded for the work it contributed.

Unlike a full node, a miner node does not need storage space but needs computing power – and lots of it. The miner nodes today run on purpose build hardware, and use a special type of computer chip called an ASIC (Application Specific Integrated Circuit). Miner nodes in general consume a vast amount of electricity for computing and cooling.

A more comprehensive article about the whole mining process can be found here.

Lightweight node

Think of these as clients that also serve as your digital wallet. They only store the block headers in order to authenticate transactions you make, or someone is making to you. They depend on the full node to validate that the transaction is authentic and has not been double-spent.

Lightweight nodes can literally run on anything the software can be installed on. Most commonly though is your PC, laptop, tablet/iPad, and phone.

Full node vs Light node vs Mining node
Full node vs Light node vs Mining node

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