Infrastructure/ Hardware Layer

Nodes are essentially a blockchain’s “source of truth”. They are important because they store the history of the blockchain and use this information to moderate the network. 

‍

If someone wanted to hack the blockchain to give themselves 1 million BTC, nodes would detect the bad actor and stop them. Nodes are there to make sure that everyone follows the rules as they validate transactions and execute decisions for the blockchain. 

‍

Adding more nodes to the blockchain increases security and decentralization since it will be harder for power/control to be concentrated in just one place when there are nodes all over the world. 

Nodes perform 3 main functions - maintenance, validation and accessibility. 

1. Maintenance: Nodes maintain a secure ledger of all transactions, including past and incoming ones. They ensure that data is stored correctly and stays in sync.
2. Validation: Nodes authenticate transactions by accepting or rejecting proposals. Only transactions with majority consensus among nodes are added to the blockchain.
3. Accessibility: Nodes store transaction data in an open ledger that anyone can access for free. People can search for the data they need by interacting with a node.

‍

The cool thing is that there are different types of nodes, each with a specific role based on how much blockchain history they store:

‍

1. Full Nodes: These are like the guardians of the blockchain. They keep a complete record of the entire blockchain history, ensuring data accuracy. They also participate in decision-making for blockchain upgrades.

• Pruned Nodes: A type of full node that trims old data to save space over time.
• Archival Nodes: Another type of full node with unlimited storage, preserving the entire history. They're common and used in mining.

2. Light Nodes (Simplified Payment Verification - SPV): These nodes are like the speedsters of the blockchain. They prioritize fast transactions by downloading only essential data, not the full history. They rely on full nodes to work properly.

‍

These nodes collaborate to create the blockchain's storage layer. Next, we'll explore the data these nodes store as we dive into the data layer.