"Polca Knowledge Graph"It is our entry-level article for Polkadot from zero to one. We try to start from the most basic part of Polkadot and provide you with a comprehensive understanding of Polkadot. Of course, this is a huge project and full of challenges However, we hope that through such efforts, everyone can correctly understand Polkadot, and also make it easy for people who don’t know Polkadot to quickly grasp Polkadot-related knowledge.It is our entry-level article for Polkadot from zero to one. We try to start from the most basic part of Polkadot and provide you with a comprehensive understanding of Polkadot. Of course, this is a huge project and full of challenges However, we hope that through such efforts, everyone can correctly understand Polkadot, and also make it easy for people who don’t know Polkadot to quickly grasp Polkadot-related knowledge.

Today is the second issue of this column, and I will introduce Polkadot's "look" and its internal structure in detail.

first level titleUnderstanding Polkadot from FragmentationIn the previous popular science article we said:

Sharding to the extreme is Polkadot. So what exactly does this shard look like?The innovation of Ethereum on the blockchain has allowed us to see more application scenarios. With more and more people participating and paying attention,

The problems of capacity expansion and information islands are gradually emerging, and the birth of Polkadot just solved these two problems.

First, sharding solves the problem of expansion, To give a simple example, the current situation of Ethereum is like 10,000 accountants are calculating the ledger, but every time a new page of the ledger is calculated, each accountant needs to calculate, keep the account and pass it on to the next person. The sharding of Ethereum 2.0 is like dividing these 10,000 accountants into 50 groups, each group has only 200 people. The information of the group is exchanged and a unified consensus is obtained.But this is the sharding of Ethereum 2.0,The architecture of each shard of Ethereum is the same, known as homogeneous sharding。

, but Polkadot's sharding is sharding to the extreme, that is, each shard becomes a chain,

For Polkadot's sharding, we can understand that these 50 groups, each group develops further, is no longer just a group, but becomes a large accounting firm, and the work they do is different, Some focus on project cost, and some focus on auditing, but they can still pass information to each other through some mechanisms. And this is the principle of Polkadot.

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Polkadot architecture

secondary title1. Heterogeneous multi-chainThe so-called "heterogeneous" means different architectures. For the shards on Ethereum, each shard belongs to the same architecture, so the shards of Ethereum are isomorphic shards, but

Polkadot maximizes each shard, that is, each shard is a chainThis is the principle of the Polkadot architecture. To implement heterogeneous multi-chains,。

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2. Relay chain + Parallel chain

textPolkadot's architecture is mainly composed of two parts, namely the relay chain and the parachain. (Of course, there are many different contents in the specific details of Polkadot’s architecture. For the convenience of understanding, we first introduce the two main components)The relay chain can be regarded as the main chain of Polkadot, and other chains can be linked to this main chain, and these other chains are parallel chains.The relay chain is mainly responsible for the consensus of parallel chains, providing shared security for all parallel chains。

. Shared security means that all parachains connected to the Polkadot relay chain by renting parachain slots will benefit from the economic security provided by the relay chain validators. And the parallel chain can no longer spend energy on consensus,Parachains can have more energy to independently design their own architecture and run their own business logicParallel chains communicate with each other through the cross-chain information exchange protocol (XCMP).

XCMP can ensure that information can be delivered and processed in an orderly, timely and fair mannerAs I just mentioned, under normal circumstances, parallel chains can be directly connected to the relay chain because they are all based on the Substrate framework. They have the same architecture as Polkadot and belong to isomorphic chains. But there are other public chains that have been running for many years, such as Bitcoin, Ethereum, etc., which belong to heterogeneous chains with different architectures. When these chains want to be connected to Polkadot, they need to pass a special The chain is used for intermediate conversion, and this chain is called a transfer bridge.

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Unlimited scalabilitytext

To become a parachain and enter the Polkadot network, you need to occupy a slot on the relay chain. The situation disclosed so far is that Polkadot’s relay chain only supports 100 slots, but what should we do when the Polkadot network matures and more and more chains want to join in?Polkadot also thought of this problem, soOne of the parachains on the relay chain can act as a transfer bridge to another secondary relay chain。

, and this secondary relay chain can have 100 slots, just like when using electrical appliances at home, when there are not enough sockets on the plug board, we will use a new plug board to plug in the previous one. board so that multiple jacks can be added. Of course, in real life, this is very dangerous, but in Polkadot's world, in this way, it can be deduced by analogy,Achieve unlimited scalability and eventually form a huge blockchain network。

At present, Kusama was originally the leading network of Polkadot, and it was responsible for trying many new functions of Polkadot, but now there is an official team working on the conversion bridge from Kusama to Polkadot, that is to say, Kusama is very likely It is Polkadot's first secondary relay chain. Since many Polkadot ecological projects have deployed their own advanced networks on Kusama, such as Acala's Karura, Moonbeam's Moonriver, and Plasm's Shiden, Kusama itself will also be a huge ecology, andWhen Kusama becomes Polkadot’s secondary relay chain, the two huge ecologies will also connect with each other, bringing huge value to both parties。